Chitosan oligosaccharides alleviates the formation of atherosclerotic plaque through up-regulating core-fucosylation of SRBI in mice / 基础医学与临床

Objective To explore the mechanism of chitosan oligosaccharides(COS)in reducing atherosclerotic plaque formation from the perspective of protein glycosylation modification.Methods Totally 40 ApoE-/-mice were randomly divided into control group and COS group.The control group was given a high-fat diet for 12 weeks,and COS group was given a high-fat diet plus COS(gavage per day,500 mg/kg)for 12 weeks.Serum lipid detection,HE staining and Oil red O staining were used to detect plaque formation.Lectin chip,liquid chromatography tan-dem-mass spectrometry and ELISA were used to detect potential changes of glycoprotein in serum.Cholesterol ester outflow and free cholesterol ester determination experiment were used to evaluate the effect of changes in scavenger receptor class B type Ⅰ(SRBI)protein glycosylation modification site on cholesterol effluence in macrophages.Results COS significantly reduced the level of TC and LDL-C(P＜0.05)in mice,but had no effect on the level of TG,HDL-C,ApoA1 and ApoB100.The intima thickness and plaque size of the aorta were significantly thinner and smaller(P＜0.05)in the COS group compared with the control group.The molecular weight of lens culinaris ag-glutinin(LCA)binding protein with the most obvious change is 80-90 ku,and SRBI was one of them.COS promo-ted the cholesterol outflow and inhibited the accumulation of free cholesterol ester in RAW264.7 cell(P＜0.05).Knockdown or glycosylation site mutation with SRBI inhibited cholesterol outflow caused by COS,and increased the accumulation of intracellular free cholesterol(P＜0.05).Conclusions COS promotes lipid efflux by increasing SRBI glycosylation and expression,thereby alleviating atherosclerotic plaque formation.

Imaging of lung cancer with molecular beacons delivered by octreotide-modified chitosan nanoparticles / 天津医药

Objective To investigate the identification of octreotide(OCT)modified chitosan(CS)miR-155 molecular beacon nanoparticles(CS-miR-155-MB-OCT)and imaging of lung cancer cells for the early screening of lung cancer.Methods A nude mouse model of lung transplantation tumor was established by injecting A549 lung cancer cells into tail veins to establish lung xenograft models.Cre adenovirus was injected through nasal cavity,and mice were killed at 4,6,8 and 12 weeks after adenovirus injection to establish lung cancer models of atypical hyperplasia,adenoma,carcinoma in situ and adenocarcinoma of lung in LSL K-ras G12D transgenic mice at different pathological stages.Lung tissue samples were taken and observed by HE staining.Immunohistochemistry were used to detect the expression of somatostatin receptor 2(SSTR2).Real-time fluorescence quantitative PCR was used to detect miR-155 expression levels in lung xenograft models and transgenic mice at different stages of lung cancer.Then CS-miR-155-MB and CS-miR-155-MB-OCT were injected via tail vein in lung xenograft models.CS-miR-155-MB-OCT was injected via tail vein in transgenic mice models.The fluorescence signals of lung in nude mice and transgenic mice at different disease stages were imaged by living imaging system.Frozen slices of lung tissue were made.The source of fluorescence signal was detected by laser confocal scanning microscope(CLSM).Results HE staining showed that lung transplantation tumor models and lung cancer models of atypical hyperplasia,adenoma,carcinoma in situ and lung adenocarcinoma at different pathological stages were successfully constructed.Immunohistochemical analysis showed somatostatin receptor 2(SSTR2)was expressed in transplanted lung tumor and tissue at different pathological stages.In transgenic mouse models,the expression of miR-155 was gradually increased as the disease progressed(P＜0.05).In lung xenograft models,the fluorescence signals were significantly higher in the CS-miR-155-MB-OCT group than those of the CS-miR-155-MB group(P＜0.05).In transgenic mouse models,the fluorescence signals gradually increased with the gradual progression of lesions(P＜0.05).After re-imaging the lung tissue,it was found that the fluorescence signal came from lung,and CLSM showed that the fluorescence signal came from cancer cells and some normal alveolar epithelial cells.Conclusion CS-miR-155-MB-OCT can dynamically reflect the occurrence and development of lung cancer according to changes of different fluorescence intensity,thus providing a new technology for the early diagnosis of lung cancer.

Preparation and in vitro evaluation of a three-dimensional porous cartilage scaffold made of silk fibroin/gelatin/chitosan / 中国组织工程研究

BACKGROUND:Cartilage defects are one of the major clinical challenges faced by orthopedic surgeons.Tissue engineering is an interdisciplinary approach that combines knowledge of engineering and cell biology to provide new ideas and approaches for the repair of cartilage defects. OBJECTIVE:To prepare a multi-component composite scaffold based on silk fibroin,gelatin,and chitosan to screen for a three-dimensional porous scaffold suitable for cartilage regeneration by evaluating its physicochemical properties and biological performance. METHODS:Four groups of porous scaffolds were prepared by vacuum freeze-drying method using silk fibroin,gelatin and chitosan as the base materials,namely chitosan/gelatin scaffold,silk fibroin/chitosan scaffold,silk fibroin/gelatin scaffold and silk fibroin/chitosan/gelatin scaffold.The suitable cartilage scaffolds were screened by scanning electron microscopy,X-ray diffractometer,porosity,water absorption and swelling rate,biodegradation rate and mechanical property detection.Then cartilage scaffolds were co-cultured with chondrocytes isolated and extracted from patients with osteoarthritis.The feasibility of porous scaffolds for cartilage injury repair was evaluated in vitro by cell adhesion rate assay,cell live-dead staining and cell activity proliferation assay. RESULTS AND CONCLUSION:(1)All four groups of scaffolds had porous structures.The comprehensive physical performance test results showed that the silk fibroin/gelatin/chitosan scaffold was more in line with the requirements of cartilage defect repair.This scaffold had a pore size of(176.00±53.68)μm,the porosity of(80.15±2.57)%,and water absorption and swelling rate of(3 712±358)%.After immersion in PBS containing lysozyme for 28 days in vitro,the biodegradation rate was(46.87±3.25)%,and it had good mechanical properties.(2)Chondrocytes could adhere well on the silk fibroin/gelatin/chitosan scaffold,and the cell adhesion rate increased with time.CCK8 and live/dead cell double staining results showed that silk fibroin/gelatin/chitosan scaffold had good biocompatibility and low cytotoxicity.(3)The results showed that silk fibroin/gelatin/chitosan scaffold had a highly hydrated 3D structure,suitable pore size and porosity,good biodegradability and superior mechanical properties,which can provide a good reticular skeleton and microenvironment for nutrient transport and chondrocyte attachment and proliferation.

Hydroxyapatite-polyvinyl alcohol/collagen-chitosan-gelatin composite hydrogel for repairing rabbit osteochondral defect / 中国组织工程研究

BACKGROUND:Osteochondral defect of the joint is a difficult problem faced by orthopedic surgeons,and traditional repair methods are difficult to obtain satisfactory curative effects.Hydroxyapatite-polyvinyl alcohol-based composite hydrogel material is a direction of current research. OBJECTIVE:To prepare hydroxyapatite-polyvinyl alcohol/collagen-chitosan-gelatin composite hydrogel material and characterize its physical characteristics,to verify its histocompatibility and cell adhesion and proliferation ability after implantation in vivo,and explore its repair effect on rabbit osteochondral defects. METHODS:The cylindrical porous poly(lactic acid)scaffold was prepared by 3D printing technology(the pore sizes were 1.2,1.4,1.6 and 1.8 mm,respectively).The poly(lactic acid)scaffold was injected with polyvinyl alcohol and hydroxyapatite mixed emulsion.After freezing thawing and dichloromethane dissolution,hydroxyapatite-polyvinyl alcohol hydrogel was prepared.Then,the collagen-chitosan-gelatin mixture was injected into the hydroxyapatite-polyvinyl alcohol hydrogel and crosslinked with genipin.Finally,the hydroxyapatite-polyvinyl alcohol/collagen-chitosan-gelatin composite hydrogel was prepared by alcohol cleaning and freeze-drying.The physical characteristics of the four groups of hydrogels were characterized,and the hydrogels with the best performance were screened for follow-up experiments.Hydroxyapatite-polyvinyl alcohol hydrogel and collagen-chitosan-gelatin composite hydrogel were implanted subcutaneously in SD rats.Hematoxylin-eosin staining and Masson staining were used to observe the adhesion growth of cells on the material surface.Osteochondral defect(diameter:5 mm,depth:6 mm)models were made in the femoral trochlea of bilateral knee joints of 15 rabbits.The composite hydrogel was implanted on the left side(experimental group),while no material was implanted on the right side(control group).Micro-CT and histology were used to evaluate the repair effect of osteochondral defects. RESULTS AND CONCLUSION:(1)Based on the results of porosity,water content,mechanical testing and scanning electron microscopy,it was concluded that the hydroxyapatite-polyvinyl alcohol/collagen-chitosan-gelatin composite hydrogel with a pore size of 1.2 mm was more consistent with the general characteristics of natural cartilage,which was used for subsequent experiments.(2)Hematoxylin-eosin staining and Masson staining exhibited that with the extension of subcutaneous implantation time of the materials,the adhesion of cells around the two materials increased significantly,and the proliferation of cells after the implantation of collagen-chitosan-gelatin was better,a large number of cells could be seen growing into the formed network structure,and the network structure was gradually degraded.(3)In the rabbit osteochondral defect experiment,8 weeks after surgery,Micro-CT examination demonstrated that the material implanted in the experimental group had good integration with the surrounding bone-cartilage,with some bone growth on the surface and inside,while the cartilage and subcartilage in the control group still had obvious defects,without effective repair.Hematoxylin-eosin staining and toluidine blue staining displayed that the composite hydrogel in the experimental group integrated with the surrounding articular cartilage 4-8 weeks after implantation.With the extension of time,new cartilage gradually formed on the surface of the material.At 12 weeks,most of the defect was covered by new cartilage,and good bone growth was also observed in the subcartilage.In the control group,the deep bone defects were mostly repaired and the superficial cartilage and subchondral bone defects were also repaired to a certain extent,but they were mainly replaced by fibrous tissue and part of fibrocartilage 12 weeks after surgery.(4)In conclusion,hydroxyapatite-polyvinyl alcohol/collagen-chitosan-gelatin composite hydrogel material can mimic the structure and function of natural cartilage,and can effectively repair osteochondral defects in animal experiments.

Various arginine configurations-modified chitosan hydrogels promote skin wound repair / 中国组织工程研究

BACKGROUND:Clinical skin wound healing continues to be a significant concern,and tissue repair research has moved to the forefront with the development of biomaterials with immunomodulatory properties.Therefore,it is crucial to research wound dressings that have immunomodulatory properties. OBJECTIVE:To prepare chitosan hydrogels that have been modified by arginine with different configurations and assess their capacity to speed up wound healing in a rat animal model. METHODS:(1)In vitro trial:Chitosan modified by pure L-arginine,pure D-arginine,and L-arginine and D-arginine was synthesized by EDC/NHS system,which was then crosslinked with aldehyde-modified four-arm polyethylene glycol.Different chitosan-based hydrogels(CS-L,CS-D,and CS-DL)were finally formed via the Schiff base reaction.Three kinds of hydrogel extracts were co-cultured with fibroblasts respectively.Hydrogel cytocompatibility was assessed using the CCK-8 assay and live/dead staining.The effect of hydrogel on the migration capacity of fibroblasts was assessed by using a scratch test.Three kinds of hydrogels were incubated with rat erythrocyte suspension respectively to evaluate the hemocompatibility of the hydrogels.The hydrogel extract was co-cultured with RAW264.7 macrophages to test the hydrogels'capacity to enhance macrophage NO generation and polarize macrophage phenotype.(2)In vivo experiment:A total of 36 adult SD rats were divided into 4 groups with 9 rats in each group by the random number table method.Two full-layer skin defect wounds of 2 cm×2 cm were made on the back of each rat.Normal saline was added to the wounds of the control group,and corresponding hydrogel was added to the wounds of the CS-L,CS-D,and CS-DL groups,respectively,and then bandaged and fixed.The wound healing was observed regularly after operation.Hematoxylin-eosin staining was performed at 3,10,and 21 days after operation.The samples were collected 10 days after operation and M2 macrophage immunofluorescence staining was performed. RESULTS AND CONCLUSION:(1)In vitro experiments:Under scanning electron microscopy,the three kinds of hydrogels exhibited obvious interpenetrating network structures with pore sizes ranging from 70-200 μm.The three kinds of hydrogels have good swelling performance,degradation performance,self-healing performance,and suitable mechanical strength.The three kinds of hydrogels had good cytocompatibility and hemocompatibility and could promote the migration of fibroblasts.All three kinds of hydrogels had the ability to promote the polarization of macrophages,and CS-D hydrogels had the strongest ability to promote the polarization of macrophages.CS-L hydrogel could significantly promote the production of NO in macrophages.(2)In vivo experiment:3 and 10 days after operation,the wound healing rate in the CS-L and CS-D groups was higher than that in the control group(P<0.05).After 21 days,the wound healing rate of the three hydrogel groups was higher than that of the control group.Hematoxylin-eosin staining displayed that a large number of inflammatory cells were infiltrated in the wound tissue of rats in all groups,accompanied by neovessels and fibroblasts 3 days after operation.10 days after operation,there was still more inflammatory cell infiltration in the wound of the control group,and the inflammation of the other three groups was improved,especially the decrease of inflammatory cells in the CS-D group was more obvious.21 days after operation,the wound epithelium of each group was well repaired,and there was basically no inflammatory cell infiltration in the CS-L and CS-D groups,while there was still a small amount of inflammatory cell infiltration in the control group.Immunofluorescence staining revealed that the number of M2-type macrophages in the CS-D group was higher than that in the other three groups(P<0.05).(3)The results conclude that chitosan hydrogels modified by different configurations of arginine can promote wound healing through different mechanisms.

Inhibitory effect of bovine serum albumin-chitosan nanoparticles loaded with EPZ6438 on osteosarcoma / 中国组织工程研究

BACKGROUND:The most prominent transcription factor activated by tumor stem cells in osteosarcoma is EZH2,and silencing of EZH2 has been reported to inhibit osteosarcoma cell growth.Studies have confirmed that bovine serum albumin-chitosan nanoparticles are a drug delivery vector with excellent biocompatibility and biodegradability,and the albumin carrier can provide tumor-targeted drug delivery function. OBJECTIVE:To investigate the effect and mechanism of bovine serum albumin-chitosan nanoparticles loaded with EPZ6438(EZH2 inhibitor)for the treatment of osteosarcoma. METHODS:(1)Bovine serum albumin-chitosan nanoparticles loaded with and without EPZ6438 were prepared.The drug encapsulation rate and drug release rate of serum albumin-chitosan nanoparticles loaded with EPZ6438 were detected.(2)MG-63 cells were divided into four groups and added with PBS(control group),serum albumin-chitosan nanoparticle extract solution(blank nanoparticle group),EPZ6438 solution(free drug group),and serum albumin-chitosan nanoparticle extract loaded with EPZ6438(drug-loaded nanoparticle group),respectively.After 3 days of culture,cell apoptosis was detected by flow cytometry and the expression of caspase-3 mRNA was detected by RT-PCR.(3)Twelve nude mice were selected and the subcutaneous tumor-bearing mouse model was established by injecting MG-63 cell suspension under the armpit.After successful modeling,the mice were randomly divided into four groups for intervention.Normal saline(control group),serum albumin-chitosan nanoparticle solution(blank nanoparticle group),EPZ6438 solution(free drug group)and serum albumin-chitosan nanoparticle solution loaded with EPZ6438(drug-loaded nanoparticle group)were injected into tumor tissues,with three animals in each group.After 7 days of injection,the tumor volume and frozen sections of tumor tissue were observed by TUNEL staining. RESULTS AND CONCLUSION:(1)The drug encapsulation rate of the nanoparticles was about 8.8%,and the nanoparticles had a good drug release effect in pure water.The drug release amount was(34.72±1.93)μg at 24 hours,(48.58±1.10)μg at 72 hours,(49.18±1.24)μg at 120 hours,and(50.25±1.13)μg at 168 hours.The drug release reached the plateau at 120 hours,and the release rate was about 97.9%.(2)After 3 days of cell culture with MG-63,the apoptotic rate in the control group and blank nanoparticle group was lower than that in the free drug group and drug-loaded nanoparticle group(P<0.001),and the expression of caspase 3 mRNA was lower than that in the free drug group and drug-loaded nanoparticle group(P<0.000 1).(3)After 7 days of injection,the tumor volume of nude mice in the drug-loaded nanoparticle group was smaller than that in the other three groups(P<0.05),and the percentage of TUNEL-positive cells in tumor tissue was higher than that in the other three groups(P<0.000 1).(4)The results verify that serum albumin-chitosan nanoparticles loaded with EPZ6438 can inhibit the growth of osteosarcoma by inducing apoptosis of tumor cells.

Preparation and characterization of chitosan biguanide hydrochloride hydrogels loading mouse umbilical cord mesenchymal stem cells / 中国组织工程研究

BACKGROUND:With the in-depth research of hydrogel materials,the applicable fields of hydrogel have been gradually broadened,and carrying stem cells for disease treatment has become a new direction of research,but how to construct a hydrogel suitable for stem cell growth is the key problem that needs to be solved at present. OBJECTIVE:To investigate the physicochemical properties of chitosan-chitosan biguanide hydrochloride-collagen composite hydrogels and to evaluate their ability to load mouse umbilical cord mesenchymal stem cells. METHODS:The hydrogels were prepared by physically cross-linking chitosan,chitosan biguanide hydrochloride and collagen with the cross-linking agents β-glycerophosphate sodium and sodium bicarbonate,and the suitable hydrogels were screened according to the gel formation time and gel formation effect(noted as Gel-1,Gel-2 and Gel-3 in this way).Morphology,porosity,swelling properties,and degradability of the three groups of hydrogels were observed by scanning electron microscopy.Hemolysis experiments were performed to examine the hemolysis of the three groups of hydrogels.The mouse umbilical cord mesenchymal stem cells were co-cultured with the hydrogel with the best comprehensive performance of characterization.The cytotoxicity,cell survival and adhesion effect of the composite hydrogel were determined to evaluate the performance of this hydrogel loaded with umbilical cord mesenchymal stem cells. RESULTS AND CONCLUSION:(1)Scanning electron microscopy characterization results showed that all three groups had porous mesh structures inside,and the internal structure of Gel-2 and Gel-3 with the addition of chitosan biguanide hydrochloride was more porous and three-dimensional.(2)The hydrogel porosity of the Gel-3 group was higher than the remaining two groups,with high porosity and uniform pore size distribution.(3)The swelling performance of all three groups of hydrogels was above 100%,and the swelling performance of hydrogels with chitosan biguanide hydrochloride component was better.(4)The degradation rate of the three groups of hydrogels could be degraded by more than 90%in a time scale of 15 days,with good degradation performance.(5)The results of the hemolytic properties showed that the absorbance values measured by each group of hydrogels carrying chicken erythrocytes were basically the same as those of saline carrying chicken erythrocytes,and no hemolysis occurred.(6)The toxicity experiment and living and dead cell staining showed that the survival rate of umbilical cord mesenchymal stem cells in each group of hydrogels was above 100%,indicating that there was no obvious cytotoxicity.Umbilical cord mesenchymal stem cells could survive under the hydrogel package and the hydrogels had a positive effect on the survival rate of umbilical cord mesenchymal stem cells.(7)The cells in the umbilical cord mesenchymal stem cell adhesion assay can survive under the hydrogel package and can adhere to the surface of the hydrogel with normal morphology.

Polypyrrole-chitosan conductive composite hydrogel promotes recovery of cardiac function after ischemia-reperfusion injury / 中国组织工程研究

BACKGROUND:Conductive biomaterials are considered potential candidates for transmitting electrical signals for myocardial repair.Combining cell-based or cell-free strategies with conductive biomaterials to replenish cardiomyocytes and/or restore electrical signaling pathways is a promising approach for cardiac repair. OBJECTIVE:To evaluate the effect of polypyrrole-chitosan conductive composite hydrogel on cardiac function in rats with myocardial ischemia-reperfusion injury. METHODS:The polypyrrole-chitosan conductive composite hydrogel was prepared by chemical oxidative polymerization.The micromorphology,biocompatibility and conductivity of the hydrogels were characterized.Thirty adult SD rats were selected to establish a myocardial ischemia-reperfusion injury model by clamping the left anterior descending branch of the heart and then releasing it.After 21 days of modeling,the rats were divided into three groups by the random number table method:Normal saline was injected into the left ventricular infarction area and infarction margin area in the blank group.Chitosan hydrogel was injected into the left ventricular infarction area and infarction margin area in the ordinary hydrogel group.The polypyrrole-chitosan conductive composite hydrogel was injected into the left ventricular infarction area and infarction margin area,with 10 rats in each group.The corresponding time points after modeling were set,and cardiac mechanical function(echocardiogram,pressure-volume analysis),cardiac electrophysiology(electrocardiogram,programmed electrical stimulation,optical mapping technology,microelectrode array technology,eight-lead electrocardiogram,and electrical resistivity of the scar area)and cardiac histology were detected. RESULTS AND CONCLUSION:(1)There were a lot of pores on the surface of the conductive composite hydrogel,and the conductivity was(3.19±0.03)×10-3 mS/cm,which had good biocompatibility co-cultured with smooth muscle cells.(2)After 105 days of modeling,echocardiogram and pressure-volume analysis showed that compared with the blank group and the ordinary hydrogel group,the conductive composite hydrogel could significantly improve the contractile function of the heart of rats with myocardial ischemia-reperfusion injury.The results of electrocardiogram,programmed electrical stimulation,optical mapping technology,microelectrode array technology,eight-lead electrocardiogram,and electrical resistivity of the scar area examination at 105 days after modeling displayed that,compared with the blank group and the ordinary hydrogel group,the conductive composite hydrogel could significantly improve the electrical conduction function of the heart of rats with myocardial ischemia-reperfusion injury and reduce the occurrence of arrhythmia.Masson staining of heart tissue at 105 days after modeling exhibited that there were different degrees of fibrosis in the myocardial infarction area of the three groups.Compared with the normal saline group and the ordinary hydrogel group,the conductive hydrogel group had more normal myocardial tissue and less fibrosis in the myocardial infarction area.(3)The results verify that polypyrrole-chitosan conductive composite hydrogel may promote the repair of infarcted heart after ischemia-reperfusion injury by increasing the electrical conduction velocity of infarct scar area tissue,increasing scar thickness,enhancing synchronous cardiac contraction,and reducing damaged tissue.

Repair of infected osteochondral defect with sustained release vancomycin three-dimensional scaffold in rabbits / 中国组织工程研究

BACKGROUND:A large number of studies have confirmed that tissue engineering scaffolds can almost completely repair osteochondral defects.However,when osteochondral defects are complicated with infection,even after thorough debridement in the early stage,the repair effect of simple osteochondral tissue engineering scaffolds is often unsatisfactory. OBJECTIVE:To prepare fibroin/chitosan/nano-hydroxyapatite scaffold loaded with vancomycin hydrochloride sustained release microspheres,and to investigate the repair effect on infected osteochondral defect in distal femur of rabbit. METHODS:(1)Vancomycin hydrochloride sustained release microspheres were prepared by emulsified solvent evaporation method.The sustained-release microspheres of different weights(7.5,10,and 12.5 mg)were mixed with fibroin protein-chitosan nanohydroxyapatite solution,and the scaffolds of fibroin protein/chitosan/nano-hydroxyapatite were prepared by chemical crosslinking method.The porosity,water absorption and expansion rate,hot water loss rate of the scaffolds,and drug sustained-release in vitro were characterized.(2)Forty-five New Zealand white rabbits were randomly divided into blank group,control group,and experimental group,with 15 rabbits in each group.The osteochondral defect and infection model of the distal femur of the right hind limb was established in both groups.The blank group was not treated,and the control group was implanted with fibroin protein-chitosan-nano-hydroxyapatite scaffold.Vancomycin hydrochloride sustained-release microspheres(10 mg)of fibroin/chitosan/nano-hydroxyapatite scaffold were implanted in the defect of the experimental group.The levels of C-reactive protein and leukocytes in blood samples were detected 1 week after operation.At 4,8 and 12 weeks after operation,the tissue of the operative area was taken for gross observation and pathological observation. RESULTS AND CONCLUSION:(1)With the increase of sustained-release microspheres content,the porosity of scaffolds decreased,and there was significant difference among groups(P＜0.05).There were no significant differences in the pore size,water absorption expansion rate and hot water loss rate among the three groups(P＞0.05).Vancomycin hydrochloride was released sustainably in vitro for more than 30 days in all three groups of scaffolds.(2)The levels of C-reactive protein and leukocytes in blood samples of the experimental group were lower than those of the blank group and control group(P＜0.05).The repair of gross cartilage in the experimental group was significantly better than that in the blank group and the control group.Hematoxylin-eosin,Masson,Alcian blue and type Ⅱ collagen immunohistochemical stainings showed that the osteochondral repair effect of the experimental group was significantly better than that of the blank group and the control group at each time point.(3)The results showed that fibroin/chitosan/nano-hydroxyapatite scaffolds loaded with vancomycin hydrochloride sustained-release microspheres could effectively promote the repair of open osteochondral defects.

Performance of 3D-printed polylactic acid-nano-hydroxyapatite/chitosan/doxycycline antibacterial scaffold / 中国组织工程研究

BACKGROUND:Polylactic acid has good biocompatibility and biodegradability,and has become a new orthopedic fixation material.However,the lack of cell recognition signal of this material is not conducive to cell adhesion and osteogenic differentiation,which limits its application in biomaterials. OBJECTIVE:3D-printed polylactic acid-nano-hydroxyapatite(nHA)/chitosan(CS)scaffold to evaluate its drug sustained-release and biological properties. METHODS:The porous polylactic acid scaffold(recorded as PLA scaffold)with interporous pores was printed by fused deposition modeling technique,and the scaffold was soaked in dopamine solution to prepare polylactic acid-dopamine scaffold(recorded as PLA-DA scaffold).Nano-hydroxyapatite was immersed in chitosan solution,and then the PLA-DA scaffold was immersed in it to prepare polylactic acid-nano-hydroxyapatite/chitosan scaffold(recorded as PLA-nHA/CS scaffold).The micro-morphology,porosity,water contact angle,and compressive strength of the three scaffolds were characterized.PLA-nHA/CS scaffold loaded with doxycycline(recorded as PLA-nHA/CS-DOX scaffold)was prepared by freeze-drying method,and its drug release was characterized.PLA,PLA-DA,PLA-nHA/CS,and PLA-nHA/CS-DOX scaffolds were co-cultured with MC3T3-E1 cells,separately,to detect cell proliferation and osteogenic differentiation.Staphylococcus aureus suspensions of different concentrations were co-cultured with four groups of scaffolds.The antibacterial performance of scaffolds was detected by inhibition zone test. RESULTS AND CONCLUSION:(1)Under scanning electron microscopy,the surfaces of PLA and PLA-DA scaffolders were dense and smooth,and nHA particles were observed on PLA-nHA/CS scaffolders.The porosity of PLA,PLA-DA and PLA-nHA/CS scaffolds decreased gradually,and the compressive strength increased gradually.The elastic modulus of PLA-nHA/CS scaffolds met the requirements of cancelous bone.The water contact angle of PLA-DA and PLA-nHA/CS brackets was smaller than that of PLA scaffolds.The PLA-nHA/CS scaffold sustainably released drugs in vitro for 8 days.(2)CCK-8 assay showed that the proliferation of MC3T3-E1 cells was not significantly affected by the four groups of scaffolds.The activity of alkaline phosphatase in PLA-DA group,PLA-nHA/CS group,and PLA-nHA/CS-DOX group was higher than that in PLA group.Alizarin red staining showed that compared with PLA group,the cells in PLA-nHA/CS group and PLA-nHA/CS-DOX group showed higher mineralized water level.(3)Inhibition zone test exhibited that PLA and PLA-DA scaffolds had no antibacterial properties.PLA-nHA/CS scaffolds had certain antibacterial properties.PLA-nHA/CS-DOX scaffolds had super antibacterial properties.(4)The results showed that the PLA-nHA/CS-DOX scaffold had good drug release performance,cell compatibility,osteogenic properties,and antibacterial properties.

Effect of a new liquid dressing of quaternary ammonium chitosan on facial laceration healing and scar inhibition / 中华医学美学美容杂志

Objective:To investigate the effect of a novel liquid dressing of quaternary chitosan on facial laceration healing and inhibition of scar formation.Methods:This study was a prospective study, including 113 cases of facial skin soft tissue laceration 52 males, 61 females, age range of 18-30 years, with mean (25.8±5.2) years in the Department of Plastic and Reconstructive Surgery, Sichuan Provincial People′s Hospital from May 2022 to February 2023. Patients were divided into two groups: the experimental group (62 cases) used quaternary ammonium chitosan rinsing wounds in the suture, and trauma spray quaternary ammonium chitosan liquid dressing in the dressing change; saline instead of an equal amount of chitosan was used to rinse wounds during the suture process and routine dressing change in the control group (51 cases). Follow-up visits were carried out in 30 d, 60 d, and 90 d postoperatively, and standardized photographs were taken preoperatively in the immediate postoperative period, before and after dressing change. The healing of the patients′ facial lacerations and patient satisfaction were recorded and assessed at the follow-up visits.Results:A total of 113 patients were included in this study, with no lost visits. During postoperative dressing change, 1 d NRS (1.03±0.18), 3 d NRS (2.69±0.53), and 5 d NRS (0.53±0.50) were lower in the experimental group than those in the control group [1 d NRS (2.35±0.59), 3 d NRS (3.27±0.75), and 5 d NRS (0.80±0.40) (all P<0.05)]. Grade A healing rate was 93.5% (58 patients) in the test group were higher than 78.4% (40 patients) in the control group (χ 2= 5.56, P<0.05); the total scores of the Vancouver Scar Rating Scale in the experimental group were lower than those of the control group at 30 d (1.65±0.48), 60 d (3.97±1.11), and 90 d (2.90±0.76) vs. 30 d (2.43 ±0.50), 60 d (5.16±1.21), and 90 d (3.55±0.78) ( t=8.48, 5.44, t=4.43; P<0.05); the overall satisfaction rate in the experimental group (93.6%) was higher than that of the control group (82.3%) (χ 2=8.16, P<0.05). Conclusions:Quaternary chitosan liquid dressing has obvious advantages in reducing wound pain, promoting wound healing, and reducing scar formation. It can improve patients′ satisfaction and worthwhile to be applied clinically.

Preparation and biocompatibility of a bilayer chitosan barrier membrane loaded with tannic acid / 安徽医科大学学报

Objective @#To explore the feasibility of the bilayer chitosan barrier membrane loaded with tannic acid (CS@ TA) for guided bone regeneration by exploring the reactive oxygen species (ROS) scavenging ability , bio- compatibility , and antibacterial properties . @*Methods @#The single-layer chitosan (CS) film was prepared by self-evaporation , and the double-layer CS film was prepared by directional freezing and freeze-drying , and its microstruc- ture was ob served by scanning electron microscope . The prepared CS bilayer membrane was grafted with tannic acid (TA) in different proportions , and the interaction between TA and CS bilayer membrane was analyzed by Fourier infrared spectrometer (FITR) . The ROS scavenging ability was tested by 1 , 1 -diphenyl-2 -picrylhydrazyl (DPPH) , and the double-layer membrane of loading TA scavenging efficiency of more than 90% was selected to continue the follow-up experiment. CCK-8 assay and lived dead staining were used to evaluate the survival rate of cell in each groups . MC3T3 -E1 cells was adhesion the CS@ TA barrier film for studying by SEM . Colony counting was performed to test its antibacterial performance against Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus ) .@*Results @#One side was the smooth , dense while other side was rough , loose and porous , with a longitudinal ordered porous structure in cross-section of the double-layer membrane of CS@ TA . With the addition of TA , the ROS scavenging ability of the double-layer membrane first increased rapidly and then stabilized slowly. The results of CCK-8 and lived and dead cells staining showed that excessive TA addition significantly affected the biocompati- bility of the double-layer membrane . The counting results of bacterial dilution coating showed that compared with the double-layer membrane without TA loading , the double-layer membrane had certain antibacterial ability against E. coli and S. aureus when the appropriate amount of TA was added . @*Conclusion @#Thus the double-layer with ap- propriate TA loading has strong ROS scavenging ability , good biological performance , and certain antibacterial abil- ity for E. coli and S. aureus .

Research progress of chitosan and quaternized chitosan as vaccine adjuvant / 中国生物制品学杂志

@#Adjuvant is the key factor for many new vaccines to play a protective role. The addition of adjuvant can not only reduce the amount of antigen,but also increase the immunogenicity of its antigen,and stimulate the strong immune response of body. Chitosan,as the product of natural polysaccharide chitin removing part of acetyl group,has the characteristics of adhesion,permeability,biocompatibility and so on,and has been widely studied and applied as a vaccine adjuvant. As a novel adjuvant,it can not only help to induce cellular and humoral immunity,but also activate mucosal immunity. This review discussed the recent progress of chitosan and quaternized chitosan as vaccine adjuvants and the related mechanism.

Study on injectable chitosan hydrogel with tendon-derived stem cells for enhancing rotator cuff tendon-to-bone healing / 中国修复重建外科杂志

OBJECTIVE@#To explore the effect of chitosan (CS) hydrogel loaded with tendon-derived stem cells (TDSCs; hereinafter referred to as TDSCs/CS hydrogel) on tendon-to-bone healing after rotator cuff repair in rabbits.@*METHODS@#TDSCs were isolated from the rotator cuff tissue of 3 adult New Zealand white rabbits by Henderson step-by-step enzymatic digestion method and identified by multidirectional differentiation and flow cytometry. The 3rd generation TDSCs were encapsulated in CS to construct TDSCs/CS hydrogel. The cell counting kit 8 (CCK-8) assay was used to detect the proliferation of TDSCs in the hydrogel after 1-5 days of culture in vitro, and cell compatibility of TDSCs/CS hydrogel was evaluated by using TDSCs alone as control. Another 36 adult New Zealand white rabbits were randomly divided into 3 groups ( n=12): rotator cuff repair group (control group), rotator cuff repair+CS hydrogel injection group (CS group), and rotator cuff repair+TDSCs/CS hydrogel injection group (TDSCs/CS group). After establishing the rotator cuff repair models, the corresponding hydrogel was injected into the tendon-to-bone interface in the CS group and TDSCs/CS group, and no other treatment was performed in the control group. The general condition of the animals was observed after operation. At 4 and 8 weeks, real-time quantitative PCR (qPCR) was used to detect the relative expressions of tendon forming related genes (tenomodulin, scleraxis), chondrogenesis related genes (aggrecan, sex determining region Y-related high mobility group-box gene 9), and osteogenesis related genes (alkaline phosphatase, Runt-related transcription factor 2) at the tendon-to-bone interface. At 8 weeks, HE and Masson staining were used to observe the histological changes, and the biomechanical test was used to evaluate the ultimate load and the failure site of the repaired rotator cuff to evaluate the tendon-to-bone healing and biomechanical properties.@*RESULTS@#CCK-8 assay showed that the CS hydrogel could promote the proliferation of TDSCs ( P<0.05). qPCR results showed that the expressions of tendon-to-bone interface related genes were significantly higher in the TDSCs/CS group than in the CS group and control group at 4 and 8 weeks after operation ( P<0.05). Moreover, the expressions of tendon-to-bone interface related genes at 8 weeks after operation were significantly higher than those at 4 weeks after operation in the TDSCs/CS group ( P<0.05). Histological staining showed the clear cartilage tissue and dense and orderly collagen formation at the tendon-to-bone interface in the TDSCs/CS group. The results of semi-quantitative analysis showed that compared with the control group, the number of cells, the proportion of collagen fiber orientation, and the histological score in the TDSCs/CS group increased, the vascularity decreased, showing significant differences ( P<0.05); compared with the CS group, the proportion of collagen fiber orientation and the histological score in the TDSCs/CS group significantly increased ( P<0.05), while there was no significant difference in the number of cells and vascularity ( P>0.05). All samples in biomechanical testing failed at the repair site during the testing process. The ultimate load of the TDSCs/CS group was significantly higher than that of the control group ( P<0.05), but there was no significant difference compared to the CS group ( P>0.05).@*CONCLUSION@#TDSCs/CS hydrogel can induce cartilage regeneration to promote rotator cuff tendon-to-bone healing.

Development of chitosan based microencapsulated spray dried powder of tuna fish oil: oil load impact and oxidative stability / Desenvolvimento de pó microencapsulado por pulverização de óleo de atum à base de quitosana: impacto da carga de óleo e estabilidade oxidativa

Abstract The impact of fish oil concentration on the oxidative stability of microcapsules through the spray drying process using chitosan and maltodextrin as wall material was studied. Emulsions were prepared with different Tuna fish oil (TFO) content (TFO-10%, TFO20%, TF030% TF0-40%) while wall material concentration was kept constant. Microencapsulated powder resulting from emulsion prepared with high fish oil load have high moisture content, wettability, total oil and low encapsulation efficiency, hygroscopicity and bulk tapped density. Oxidative stability was evaluated periodically by placing microcapsules at room temperature. Microcapsules prepared with TFO-10% presented high oxidative stability in terms of peroxide value (2.94±0.04) and anisidine value (1.54±0.02) after 30 days of storage. It was concluded that optimal amounts of fish oil for microencapsulation are 10% and 20% using chitosan and maltodextrin that extended its shelf life during study period.

Resumo Foi estudado o impacto da concentração de óleo de peixe na estabilidade oxidativa de microcápsulas por meio do processo de secagem por atomização, utilizando quitosana e maltodextrina como material de parede. As emulsões foram preparadas com diferentes teores de óleo de atum (TFO) (TFO-10%, TFO20%, TF030% TF0-40%), enquanto a concentração de material de parede foi mantida constante. O pó microencapsulado resultante da emulsão preparada com alta carga de óleo de peixe tem alto teor de umidade, molhabilidade e óleo total e baixa eficiência de encapsulação, higroscopicidade e densidade extraída a granel. A estabilidade oxidativa foi avaliada periodicamente colocando microcápsulas à temperatura ambiente. As microcápsulas preparadas com TFO-10% apresentaram alta estabilidade oxidativa em termos de valor de peróxido (2,94 ± 0,04) e valor de anisidina (1,54 ± 0,02) após 30 dias de armazenamento. Concluiu-se que as quantidades ideais de óleo de peixe para microencapsulação são de 10% e 20% usando quitosana e maltodextrina que prolongaram sua vida útil durante o período de estudo.

Complexos polieletrólitos de quitosana e xantana carregados com ativos naturais e sintéticos: estudo físico/químico e microbiológico para aplicação de drug delivery / Polyelectrolyte complexes of chitosan and xanthan loaded with natural and synthetic actives: physicochemical and microbiological study for drug delivery application

A eficácia dos implantes osseointegrados é amplamente reconhecida na literatura científica. Contudo, infiltrações bacterianas na junção implante-pilar podem desencadear inflamação nos tecidos circundantes, contribuindo para a evolução de condições mais sérias, como a peri-implantite. O objetivo desse estudo foi produzir complexos polieletrólitos (PECs) de quitosana (Q) e xantana (X) em forma de membranas, carregá-las com ativos naturais e sintéticos antimicrobianos, caracterizálas estruturalmente e avaliá-las frente a degradação enzimática, cinética de liberação e ações antimicrobianas com finalidade de aplicação para drug delivery. Membranas de QX a 1% (m/v) foram produzidas em três proporções, totalizando doze grupos experimentais: QX (1:1); QX (1:2), QX (2:1), QX-P (com própolis) (1:1); QX-P (1:2); QX-P (2:1); QX-C (com canela) (1:1); QX-C (1:2); QX-C (2:1) e CLX (com clorexidina 0,2%) (1:1); CLX (1:2); CLX (2:1). Para os estudos de caracterização foram feitas análises da espessura em estado seco; análises morfológicas superficial e transversal em Microscopia Eletrônica de Varredura (MEV); análise estrutural de espectroscopia de infravermelho por transformada de Fourier (FTIR); análise de degradação por perda de massa sob ação da enzima lisozima; e análise da cinética de liberação dos ativos em saliva artificial. Para os testes microbiológicos, análises de verificação de halo de inibição e ação antibiofilme foram feitas contra cepas de Staphylococcus aureus (S. aureus) e Escherichia coli (E. coli). Os resultados demonstraram que a espessura das membranas variou conforme a proporção, sendo que o grupo QX (1:2) apresentou a maior média de 1,022 mm ± 0,2, seguida respectivamente do QX (1:1) com 0,641 mm ± 0,1 e QX (2:1) com 0,249 mm ± 0,1. Nas imagens de MEV é possível observar uma maior presença de fibras, rugosidade e porosidade nos grupos QX (1:2) e QX (1:1) respectivamente, e, no QX (2:1) uma superfície mais lisa, uniforme e fina. No FTIR foram confirmados os picos característicos dos materiais isoladamente, além de observar as ligações iônicas que ocorreram para formação dos PECs. Na análise de degradação, os grupos com ativos naturais adicionados tiveram melhores taxas de sobrevida do que os grupos QX. No teste de liberação, os grupos QX-P tiveram uma cinética mais lenta que os QX-C, cuja liberação acumulada de 100% foi feita em 24 h. Já nos testes do halo inibitório, somente os grupos CLX tiveram ação sobre as duas cepas, e os QX-P tiveram sobre S. aureus. Nas análises antibiofilme, os grupos CLX apresentaram as maiores taxas de redução metabólica nas duas cepas (± 79%); os grupos QX-P apresentaram taxas de redução similares em ambas as cepas, porém com percentual um pouco maior para E. coli (60- 80%) e os grupos QX-C tiveram grande discrepância entre as duas cepas: de 35 a 70% para S. aureus e 14 a 19% para E. coli. Pode-se concluir que, frente as análises feitas, o comportamento do material foi afetado diretamente pelos ativos adicionados a matriz polimérica. As proporções de Q ou X afetaram somente a espessura final. Quanto a aplicação proposta de drug delivery, os dispositivos apresentaram grande potencial, principalmente os grupos CLX e QX-P. (AU)

The effectiveness of osseointegrated implants is widely recognized in scientific literature. However, bacterial infiltrations at the implant-abutment interface may trigger inflammation in surrounding tissues, contributing to the development of more serious conditions, such as peri-implantitis. The aim of this study was to produce chitosan (Q) and xanthan (X) polyelectrolyte complexes (PECs) in the form of membranes, load and evaluate them for enzymatic degradation, release kinetics, and antimicrobial actions for drug delivery applications. QX membranes at 1% (w/v) were produced in three proportions, totaling twelve experimental groups: QX (1:1), QX (1:2), QX (2:1), QX-P (with propolis) (1:1), QX-P (1:2), QX-P (2:1), QX-C (with cinnamon) (1:1), QX-C (1:2), QX-C (2:1), and CLX (with 0.2% chlorhexidine) (1:1), CLX (1:2), CLX (2:1). Characterization studies included analyses of dry state thickness, surface and crosssectional morphology using Scanning Electron Microscopy (SEM), structural analysis by Fourier Transform Infrared (FTIR) spectroscopy, mass loss degradation analysis under lysozyme action, and active release kinetics analysis in artificial saliva. Microbiological tests included verification analyses of inhibition halos and antibiofilm action against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Results showed that membrane thickness varied according to proportion, with group QX (1:2) presenting the highest average of 1.022 mm ± 0.2, followed by QX (1:1) with 0.641 mm ± 0.1, and QX (2:1) with 0.249 mm ± 0.1. SEM images showed greater presence of fibers, roughness, and porosity in groups QX (1:2) and QX (1:1) respectively, while QX (2:1) exhibited a smoother, more uniform, and thinner surface. FTIR confirmed characteristic peaks of the materials individually, besides showing ionic bonds formed for PECs. Degradation analysis revealed that groups with added natural actives had better survival rates than QX groups. In release tests, QX-P groups exhibited slower kinetics than QX-C, with 100% cumulative release achieved in 24 h. inhibitory halo tests, only CLX groups exhibited action against both strains, while QX-P acted against S. aureus. Antibiofilm analyses showed CLX groups with the highest metabolic reduction rates in both strains (± 79%); QX-P groups showed similar reduction rates in both strains, slightly higher for E. coli (60-80%), and QX-C groups had a significant discrepancy between strains: 35-70% for S. aureus and 14-19% for E. coli. In conclusion, material behavior was directly affected by added actives to the polymeric matrix. Proportions of Q or X only affected final thickness. Regarding proposed drug delivery applications, the devices showed great potential, especially CLX and QX-P groups.(AU)

Development of chitosan based microencapsulated spray dried powder of tuna fish oil: oil load impact and oxidative stability

Abstract The impact of fish oil concentration on the oxidative stability of microcapsules through the spray drying process using chitosan and maltodextrin as wall material was studied. Emulsions were prepared with different Tuna fish oil (TFO) content (TFO-10%, TFO20%, TF030% TF0-40%) while wall material concentration was kept constant. Microencapsulated powder resulting from emulsion prepared with high fish oil load have high moisture content, wettability, total oil and low encapsulation efficiency, hygroscopicity and bulk tapped density. Oxidative stability was evaluated periodically by placing microcapsules at room temperature. Microcapsules prepared with TFO-10% presented high oxidative stability in terms of peroxide value (2.94±0.04) and anisidine value (1.54±0.02) after 30 days of storage. It was concluded that optimal amounts of fish oil for microencapsulation are 10% and 20% using chitosan and maltodextrin that extended its shelf life during study period.

Resumo Foi estudado o impacto da concentração de óleo de peixe na estabilidade oxidativa de microcápsulas por meio do processo de secagem por atomização, utilizando quitosana e maltodextrina como material de parede. As emulsões foram preparadas com diferentes teores de óleo de atum (TFO) (TFO-10%, TFO20%, TF030% TF0-40%), enquanto a concentração de material de parede foi mantida constante. O pó microencapsulado resultante da emulsão preparada com alta carga de óleo de peixe tem alto teor de umidade, molhabilidade e óleo total e baixa eficiência de encapsulação, higroscopicidade e densidade extraída a granel. A estabilidade oxidativa foi avaliada periodicamente colocando microcápsulas à temperatura ambiente. As microcápsulas preparadas com TFO-10% apresentaram alta estabilidade oxidativa em termos de valor de peróxido (2,94 ± 0,04) e valor de anisidina (1,54 ± 0,02) após 30 dias de armazenamento. Concluiu-se que as quantidades ideais de óleo de peixe para microencapsulação são de 10% e 20% usando quitosana e maltodextrina que prolongaram sua vida útil durante o período de estudo.

Síntesis de glicoconjugados de albúmina sérica bovina y oligosacáridos de quitosano para el análisis de adhesión bacteriana / Synthesis of glycoconjugates of bovine albumin and chitosan oligosaccharides for the analysis of bacterial adhesion / Síntese de glicoconjugados de albumina serica bovina e oligossacarídeos de quitosana para análise de adesão bacteriana

Resumen El aumento de la resistencia a los antibióticos por parte de bacterias patógenas ha motivado la búsqueda de alternativas para disminuir su utilización. Dentro de las opciones propuestas se encuentra la terapia de antiadherencia, en la cual se utilizan moléculas análogas a los glicoepítopes que son reconocidos por las bacterias para impedir la unión de éstas al tejido celular. En este estudio se llevó a cabo la obtención de glicoconjugados por medio de la reacción de Maillard partiendo de albúmina sérica bovina (BSA) y oligosacáridos de quitosano (oligosacáridos sin ultrafiltrar, ultrafiltrados y ultrafiltrados acetilados), en proporción 1:1 (p/p) a tres temperaturas de incubación (50, 60 y 70 °C) por 30 min. La caracterización de los conjugados sintetizados se realizó utilizando electroforesis (SDS-PAGE), espectroscopía de infrarrojo y espectroscopía de fluorescencia. Se realizaron ensayos de reconocimiento usando aglutinina de germen de trigo (WGA) y bacterias [Escherichia coli (K88ac y K88+)]. La caracterización por medio de electroforesis y espectroscopía de infrarrojo evidenció la unión de los oligosacáridos de quitosano a la estructura de la BSA. Además, los ensayos evidenciaron el reconocimiento de las moléculas sintetizadas tanto por la lectina WGA como por las bacterias. Los glicoconjugados sintetizados sin ultrafiltrar ni acetilar mostraron resultados muy favorables en el reconocimiento por ambas bacterias, lo que constituye una ventaja práctica, ya que su implementación a mayor escala reduciría costos de producción

Abstract The increase in antibiotic resistance by pathogenic bacteria has motivated the search for alternatives to reduce the use of antibiotics. Among these alternatives is anti-adhesion therapy, in which molecules that mimic the glycoepitopes that recognise bacteria are used to prevent their binding to cellular tissue. In this study, glycoconjugates were obtained by means of the Maillard reaction starting from bovine serum albumin (BSA) and chitosan oligosaccharides (unfiltered oligosaccharides, ultrafiltered and acetylated ultrafiltered), in a ratio of 1:1 (w/w) at three incubation temperatures (50, 60 and 70 °C) per 30 min. The characterisation was performed using the techniques of electrophoresis (SDS-PAGE), infrared spectroscopy and fluorescence spectroscopy. Recognition assays were performed using wheat germ agglutinin (WGA) and Escherichia coli bacteria (K88ac and K88+). Characterisation by electrophoresis and infrared spectroscopy demonstrated the binding of chitosan oligosaccharides to the structure of BSA. In addition, the tests showed the recognition of the molecules synthesised by both the WGA lectin and the E. coli bacteria. The glycoconjugates synthesised without ultrafiltration or acetylation showed very favourable results in recognition with both bacteria, which is an advantage, since its implementation on a larger scale would reduce production costs.

Resumo O aumento da resistência aos antibióticos por bactérias patogênicas tem motivado a busca de alterna­tivas para reduzir seu uso. Entre essas alternativas está a terapia anti-adesão, na qual são utilizadas moléculas análogas aos glicoepítopos que são reconhecidas pelas bactérias para impedir sua união ao tecido celular. Neste estudo, os glicoconjugados foram obtidos por meio da reação de Maillard a partir de albumina sérica bovina (BSA) e oligossacarídeos de quitosana (oligossacarídeos não ultra­filtrados, ultrafiltrados e acetilados ultrafiltrados), na proporção de 1:1 (p/p) em três temperaturas de incubação (50, 60 e 70 °C) durante 30 min. A caracterização dos conjugados sintetizados foi realizada utilizando a eletroforese (SDS-PAGE), espectroscopia de infravermelho e espectroscopia de fluorescência. Os ensaios de reconhecimento foram realizados utilizando aglutinina de germe de trigo (WGA) e bactérias [Escherichia coli (K88ac e K88+)]. A caracterização por meio de eletroforese e espectroscopia de infravermelho demonstrou a união dos oligossacarídeos de quitosana à estrutura da BSA. Além disso, os testes evidenciaram o reconhecimento das moléculas sintetizadas tanto pela lectina WGA quanto pelas bactérias. Os glicoconjugados sintetizados sem ultrafiltração ou acetilação apresentaram resultados muito favoráveis no reconhecimento por ambas as bactérias, o que é uma vantagem, visto que sua implementação em maior escala reduziria custos de produção.

Development, characterization and anti - Mycobacterium tuberculosis activity of solid lipid nanoparticles for oral Piper corcovadensis roots extract delivery / Desarrollo, caracterización y actividad anti - Mycobacterium tuberculosis de nanopartículas lipídicas sólidas para la administración oral de extracto de raíces de Piper corcovadensis

The present study thus aimed at the development and physicochemical characterization of solid lipid nanoparticles loaded with crude extract of Piper corcovadensis roots (SLN - CEPc) and chitosan - coated solid lipid nanoparticles loaded with crude extract of P. corcovadensis roots (C - SLN - CEPc), as well as the determination of its antimycobacterial activity against Mycobacterium tuberculosis H37Rv, its cytotoxicity against the Vero cell line and evaluation in the hemolysis assay. Both formulat ions containing the encapsulated extract showed high encapsulation efficiency, formed by a monodispersed system with small and spherical particles, and there was no aggregation of particles. In the biological assays, SLN - CEPc and C - SLN - CEPc showed promisin g anti - M. tuberculosis activity with a minimum inhibitory concentration (MIC) of 12.5 µg/mL, whereas the cytotoxic concentrations obtained at 50% (CC 50 ) in Vero cells were 60.0 and 70.0 µg/mL, respectively. Therefore, nanoencapsulation showed satisfactory results, justifying its usage in the development of new products.

El presente estudio apuntó al desarrollo y caracterización fisicoquímica de na nopartículas lípidas en estado sólido, cargadas con extracto crudo de raíz de Piper c orcovadensis (SLN - CEPc) y nanopartículas lípidas en estado sólido cubiertas con quitosano cargadas co n extracto crudo de raíz de P. corcovadensis (C - SLN - CEPc), así como la determinación de su actividad antimico bacterial contra Mycobacterium tuberculosis H37Rv, su citotoxicidad contra la línea celular Vero y su evaluación en ensayo de hemólisis. Ambas formulaciones que contenían el extracto encapsulado mostraron alta eficien cia de encapsulación, formado por un sistema monodispersado con pequeñas partículas esféricas, y no hubo agregación de partículas. En los ensayos biológicos, SLN - CEPc y C - SLN - CEPc mostraron un a prometedora actividad anti - M. tuberculosis con una mínima conc entración inhibitoria (MIC) de 12,5 µg/mL, mientras que las concentraciones citotóxicas obtenidas al 50% (CC 50 ) en células Vero estuvo en 60,0 y 70,0 µg/mL, respectivamente. Por lo tanto, la nanoencapsulación mostró resultados satisfactorios, justificando su uso en el desarrollo de nuevos productos.

Vestibuloplastia con láser de Er Cr:YSGG y nanotransportador biomolécula EPX: un nuevo cicatrizante periodontal / Vestibuloplasty with Er Cr:YSGG laser and EPX biomolecule nanocarrier: a new periodontal healing agent

La resorción ósea alveolar suele dar lugar a que las inserciones de la mucosa interfieran para la construcción, estabilidad y retención de una prótesis removible, una opción que permite modificar este tejido se obtiene por medio de una vestibuloplastia. Actualmente se puede favorecer la cicatrización de heridas utilizando láser de alta potencia aplicado a procedimientos quirúrgicos orales. Se realiza reporte de caso en paciente femenino a la que se realizó procedimiento de vestibuloplastia con láser de Er,Cr:YSGG, utilizando de forma postoperatoria gel de quitosano en nanotransportador biomolécula EPX. Se observa una cicatrización rápida y favorable al combinar ambas terapéuticas, además al utilizar productos con quitosano se disminuye el riesgo de la necrosis de fibroblastos gingivales humanos como recientemente se reportó en el uso de colutorios de clorhexidina (AU)

Alveolar bone resorption often results in mucosal insertions interfering with the construction, stability and retention of a removable prosthesis, an option to modify this tissue is obtained by means of vestibuloplasty. Currently, wound healing can be promoted by using high power laser applied to oral surgical procedures. A case report of a female patient who underwent a vestibuloplasty procedure with laser Er,Cr:YSGG, using chitosan gel with EPX biomolecule nanocarriers postoperatively. A fast and favorable healing is observed when combining both therapeutics, besides, when using products with chitosan, the risk of necrosis of human gingival fibroblasts is reduced, as recently reported in the use of chlorhexidine mouthwashes (AU)