RESUMO
This paper outlines a novel simple protocol for tuning the structure and properties of jute using sodium periodate (NaIO4) oxidation and coating with alginate. When compared to the raw jute, fabrics oxidized with a 0.2 or 0.4 % NaIO4 solution for 30-120 min exhibited an increased aldehyde group content (0.185 vs. 0.239-0.398 mmol/g), a significantly increased negative zeta potential (from -8.57 down to -20.12 mV), a slight disruption of fiber crystallinity, 15.1-37.5 % and 27.9-49.8 % lower fabric maximum force and stiffness, respectively. Owing to the removal of hydrophobic surface barrier, decreased crystallinity index and the presence of micropores on the fabrics' surfaces, oxidized fabrics have a 22.3-29.6 % improved ability for moisture sorption compared to raw fabric. Oxidized fabrics characterized by very long wetting times and excellent antioxidant activities (> 98 %), can find applications as hydrophobic packaging materials. To further extend the utilization of jute in biocarpet engineering such as water-binding geo-prebiotic supports, oxidized fabrics were coated with alginate resulting in 7.9-24.9 % higher moisture sorption and 352-660 times lower wetting times than their oxidized counterparts. This modification protocol has never been applied to lignocellulosic fibers and sheds new light on obtaining jute fabrics with tuned structure and properties intended for various applications.
Assuntos
Alginatos , Alginatos/química , Ácido Periódico , Oxirredução , Interações Hidrofóbicas e HidrofílicasRESUMO
Oxidation of ß-cyclodextrin (ß-CD) using varying molar ratios of sodium periodate (NaIO4) was investigated in detail on synthesis, characterization and antibacterial property. Synthesis and characterization results showed that Oxidized ß-cyclodextrins (OX-ß-CDs) were obtained and aldehyde (CHO) groups were successfully introduced. Our results demonstrated that aldehyde content and yield increased with increasing NaIO4 molar amount. However, the structure of ß-CD was degraded as a result of glycosidic ring opening with increasing stoichiometric ratio of NaIO4/ß-CD to 5/1 and 7/1. Aldehyde functional groups in OX-ß-CDs were characterized by employing FTIR, 1H NMR, XRD, SEM techniques and confirmed by the detection of CHO peak at 1730 cm-1 in the FTIR and detection of the aldehyde H peak between 9 to 10 ppm in the 1H NMR spectrum. In addition, SEM and XRD of OX-ß-CDs showed alterations in the morphological and crystal structure (transforming from crystalline to amorphous) of ß-CD as a result of increasing oxidation. Especially, antibacterial activity of OX-ß-CDs was investigated against both Gram-negative and Gram-positive bacteria by using the minimal inhibitory concentration (MIC) and the Disk diffusion method. The results showed that OX-ß-CDs possessed good antibacterial activity, which can destroy the bacterial cell wall, and may be used as an antibacterial agent.
Assuntos
Ciclodextrinas , beta-Ciclodextrinas , beta-Ciclodextrinas/farmacologia , beta-Ciclodextrinas/química , Antibacterianos/farmacologia , Antibacterianos/química , Oxirredução , Aldeídos , Ciclodextrinas/farmacologia , Ciclodextrinas/química , SolubilidadeRESUMO
Dialdehyde cellulose nanocrystals (DCNC) are defined as C2 and C3 aldehyde nanocellulose, which can be used as raw materials for nanocellulose derivatization, owing to the high activity of aldehyde groups. Herein, a comparative study in NaIO4 pre-oxidation and synchronous oxidation is investigated for DCNC extraction via choline chloride (ChCl)/urea-based deep eutectic solvent (DES). Ring-liked DCNC with an average particle size of 118 ± 11 nm, a yield of 49.25 %, an aldehyde group content of 6.29 mmol/g, a crystallinity of 69 %, and rod-liked DCNC with an average particle size of 109 ± 9 nm, a yield of 39.40 %, an aldehyde group content of 3.14 mmol/g, a crystallinity of 75 % can be extracted via optimized DES treatment combined with pre-oxidation and synchronous oxidation, respectively. In addition, the average particle size, size distribution, and aldehyde group content of DCNC were involved. TEM, FTIR, XRD, and TGA results reveal the variation of microstructure, chemical structure, crystalline structure, and thermostability of two kinds of DCNC during extraction even though the obtained DCNC exhibiting different micromorphology, pre-oxidation, or synchronous oxidation during ChCl/urea-based DES treatment can be considered as an efficient approach for DCNC extraction.
Assuntos
Colina , Solventes Eutéticos Profundos , Solventes/química , Colina/química , Ureia/químicaRESUMO
Establishing a vascular network in biofabricated tissue grafts is essential for ensuring graft survival. Such networks are dependent on the ability of the scaffold material to facilitate endothelial cell adhesion; however, the clinical translation potential of tissue-engineered scaffolds is hindered by the lack of available autologous sources of vascular cells. Here, we present a novel approach to achieving autologous endothelialisation in nanocellulose-based scaffolds by using adipose tissue-derived vascular cells on nanocellulose-based scaffolds. We used sodium periodate-mediated bioconjugation to covalently bind laminin to the scaffold surface and isolated the stromal vascular fraction and endothelial progenitor cells (EPCs; CD31+CD45-) from human lipoaspirate. Additionally, we assessed the adhesive capacity of scaffold bioconjugationin vitrousing both adipose tissue-derived cell populations and human umbilical vein endothelial cells. The results showed that the bioconjugated scaffold exhibited remarkably higher cell viability and scaffold surface coverage by adhesion regardless of cell type, whereas control groups comprising cells on non-bioconjugated scaffolds exhibited minimal cell adhesion across all cell types. Furthermore, on culture day 3, EPCs seeded on laminin-bioconjugated scaffolds showed positive immunofluorescence staining for the endothelial markers CD31 and CD34, suggesting that the scaffolds promoted progenitor differentiation into mature endothelial cells. These findings present a possible strategy for generating autologous vasculature and thereby increase the clinical relevance of 3D-bioprinted nanocellulose-based constructs.
Assuntos
Laminina , Fração Vascular Estromal , Humanos , Alginatos , Alicerces Teciduais , Células Endoteliais da Veia Umbilical Humana , Engenharia Tecidual/métodosRESUMO
Wound-healing of drug-resistant bacterial infections has always been a clinical challenge. The design and development of effective and economically safe wound dressings with antimicrobial activity and healing-promoting properties is highly desirable, especially in the context of wound-infections. Herein, we designed a physical dual-network multifunctional hydrogel adhesive based on polysaccharide material for the treatment of full-thickness skin defects infected with multidrug-resistant bacteria. The hydrogel utilized ureido-pyrimidinone (UPy)-modified Bletilla striata polysaccharide (BSP) as the first physical interpenetrating network for providing some brittleness and rigidity; and then branched macromolecules formed after cross-linking Fe3+ with dopamine-conjugated di-aldehyde-hyaluronic acid as the second physical interpenetrating network for providing some flexibility and elasticity. In this system, BSP and hyaluronic acid (HA) are used as synthetic matrix materials to provide strong biocompatibility and wound-healing ability. In addition, ligand cross-linking of catechol-Fe3+ and quadrupole hydrogen-bonding cross-linking of UPy-dimer can form a highly dynamic physical dual-network structure, which imparts good rapid self-healing, injectability, shape-adaptation, NIR/pH responsiveness, high tissue-adhesion and mechanical properties of this hydrogel. Meanwhile, bioactivity experiments demonstrated that the hydrogel also possesses powerful antioxidant, hemostatic, photothermal-antibacterial and wound-healing effects. In conclusion, this functionalized hydrogel is a promising candidate for clinical treatment of full-thickness bacteria-stained wound dressing materials.
Assuntos
Infecções Bacterianas , Hidrogéis , Humanos , Hidrogéis/farmacologia , Hidrogéis/química , Adesivos/farmacologia , Ácido Hialurônico/farmacologia , Ácido Hialurônico/química , Cicatrização , Polissacarídeos/farmacologia , Polissacarídeos/química , Antibacterianos/farmacologia , Antibacterianos/químicaRESUMO
The abuse of chrome tanning agent in leather processing has caused great harm to human health and the natural environment. We use tremella polysaccharides (TP), lentinan (LNT) and konjac gum (KG) as raw materials, and sodium periodate as oxidant to prepare the corresponding polysaccharide tanning agent. Tremella polysaccharide was selected as the best tanning agent according to the shrinkage temperature, and the subsequent experiments were carried out. Tremella polysaccharide (TP) as raw material and sodium periodate as an oxidant, dialdehyde tremella polysaccharide (DTP) was prepared and applied in leather tanning. The effects of different oxidation conditions (sodium periodate dosage, temperature, pH, and reaction time) on the shrinkage temperature of DTP tanned leather were studied. The change of shrinkage temperature showed that the dosage of sodium periodate had the greatest influence on the shrinkage temperature. Therefore, the effects of different dosage of sodium periodate on the aldehyde content and molecular weight of DTP were investigated, including the analysis of physical properties and microstructure of tanned leather. In general, the increase of sodium periodate dosage was found to increase the aldehyde content and reduce the molecular weight, which was more conducive to leather tanning.
Assuntos
Polissacarídeos , Curtume , Humanos , Aldeídos , Oxidantes , Cromo/análiseRESUMO
The biodegradable hydrogels with a 3D network structure have potential applications in bone tissue engineering. Here, inspired by natural bone, the novel organic-inorganic composites (GelMPC-x) with high compressive strength are designed via adding magnesium oxide/calcium dihydrogen phosphate (MPC) powders into the oxidized dextran/gelatin (OD/Gel) hydrogel. GelMPC-x composites can trigger the gelation of OD/Gel hydrogel through an acid-alkaline reaction between magnesium oxide and calcium dihydrogen phosphate, thus forming an organic-inorganic double network. The cross-linked network between oxidized dextran and gelatin, and the multiple weak interactions between OD/Gel hydrogel and MPC enable the composites to have remarkable compressive strength (77-652 kPa) at the strain of 44 %. More importantly, the composites with appropriate MPC content possess superior injectability, high porosity, and excellent cytocompatibility. This work provides guidelines for the preparation of oxidized dextran-based composite hydrogels with enhanced mechanical performance.
Assuntos
Gelatina , Hidrogéis , Cálcio , Dextranos , Gelatina/química , Hidrogéis/química , Óxido de MagnésioRESUMO
The osteoarthritis (OA) symptoms cannot be fully remedied by using only a single functional component because of its complex pathogenesis. Herein, a MnO2 nanozyme-encapsulated hydrogel was fabricated via dispersing bovine serum albumin (BSA)-MnO2 (BM) nanoparticles (NPs) into a hyaluronic acid (HA)/platelet-rich plasma (PRP) gel network crosslinked by Schiff base reaction. Due to the self-healing and pH-responsive properties of Schiff base bonds, the hydrogel not only functioned as viscosupplementation but also exhibited pH-responsive release of BM NPs and growth factors in PRP. The BM NPs could attenuate the severe oxidative stress, and the PRP could promote chondrocyte proliferation. In a rat OA model, the HA/PRP/BM hydrogel markedly suppressed cartilage matrix degradation. Both the in vitro and in vivo studies showed that this novel hydrogel platform could inhibit the development of osteoarthritis through a synergetic effect of mechanical dissipation, depressing inflammation, facilitating cartilage repair, and thus has essential application prospects in OA treatment.
Assuntos
Osteoartrite , Plasma Rico em Plaquetas , Animais , Ácido Hialurônico/farmacologia , Hidrogéis/química , Injeções Intra-Articulares , Compostos de Manganês , Osteoartrite/metabolismo , Óxidos , Plasma Rico em Plaquetas/química , Plasma Rico em Plaquetas/metabolismo , Ratos , Bases de Schiff , Resultado do TratamentoRESUMO
In this study, a new type of biodegradable, injectable, self-healing, and low-toxic CMCSH, formed by N, O-carboxymethyl chitosan-heparin (CMCS-Hep) and carboxymethyl cellulose-aldehyde (CMC-A), was designed to deliver drug for promoting the progress of the diabetic wound healing. CMCS was modified with Hep for the first time to synthesize CMCS-Hep, and CMC-A was synthesized by the periodate oxidation method. First, SOD encapsulated in the CMCSH was applied to the diabetic wound bed to moderate the microenvironment, then rhEGF retained in the CMCSH was sustainedly released to the wound area. These results indicated that the dual-drug delivery system had the ability to improve drug availability, promote cell migration and proliferation, reduce DNA damage, shorten the inflammatory period, and accelerate the deposition of collagen fibers and the formation of blood vessels in the model with diabetic skin injury, suggesting that CMCSH as drug carriers had positive effects on diabetic wound healing.
Assuntos
Quitosana , Diabetes Mellitus , Carboximetilcelulose Sódica/farmacologia , Quitosana/farmacologia , Humanos , Hidrogéis/farmacologia , CicatrizaçãoRESUMO
For cereal-based foods rich in dietary fibers, iron bioavailability is known to be poor. For native cereal ß-glucan extracts, literature has demonstrated that the main factor impacting the bioavailability is phytic acid, which is often found in association with dietary fibers. During food processing, ß-glucan can undergo modifications which could potentially affect the equilibrium between phytic acid, fiber, and iron. In this study, an in vitro digestion was used to elucidate the iron dialysability, and hence estimate iron availability, in the presence of native, chelating resin (Chelex)-treated, oxidised, or partially hydrolysed oat and barley ß-glucan extracts (at 1% actual ß-glucan concentration), with or without phytase treatment. It was confirmed that pure, phytic acid-free ß-glucan polysaccharide does not impede iron availability in cereal foods, while phytic acid, and to a smaller extent, also proteins, associated to ß-glucan can do so. Neither Chelex-treatment nor partial hydrolysis, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or NaIO4 oxidation significantly influenced the phytic acid content of the ß-glucan extracts (ranging 2.0-3.9%; p > 0.05). Consequently, as long as intrinsic phytic acid was still present, the ß-glucan extracts blocked the iron availability regardless of source (oat, barley) or Chelex-treatment, partial hydrolysis or NaIO4-oxidation down to 0-8% (relative to the reference without ß-glucan extract). Remarkably, TEMPO-oxidation released around 50% of the sequestered iron despite unchanged phytic acid levels in the modified extract. We propose an iron-mobilising effect of the TEMPO product ß-polyglucuronan from insoluble Fe(II)/phytate/protein aggregates to soluble Fe(II)/bile salt units that can cross the dialysis membrane. In addition, Chelex-treatment was identified as prerequisite for phytase to dramatically diminish iron retention of the extract for virtually full availability, with implications for optimal iron bioavailability in cereal foods.
RESUMO
Development of versatile medical dressing with good immediate and long-lasting antibacterial, hygroscopic and moisturizing abilities is of great significance for management of chronic wounds. Cotton gauze (CG) can protect wounds and promote scabbing, but can cause wound dehydration and loss of biologically active substances, thereby greatly delays wound healing. Herein, a bi-functional CG dressing (CPCG) was developed by chemically grafting polyhexamethylene guanidine (PHMG) and physically adsorbing chitosan (CS) onto the CG surface. Due to the powerful microbicidal activity of PHMG, CPCG exhibited excellent immediate and long-lasting antibacterial activity against gram-positive and gram-negative bacteria. Moreover, the abundant hydroxyl and amino groups in CS endowed CPCG with good biocompatibility, moisture absorption, moisturizing and cell scratch healing performances. Importantly, CPCG can be easily fabricated into a bandage to conveniently manage infected full-skin wounds. Together, this study suggests that CPCG is a versatile wound dressing, having enormous application potential for management chronic wounds.
Assuntos
Antibacterianos , Bandagens , Quitosana , Fibra de Algodão , Guanidinas , Animais , Movimento Celular , Células Cultivadas , Eritrócitos , Escherichia coli/crescimento & desenvolvimento , Feminino , Hemólise , Humanos , Camundongos Endogâmicos BALB C , Staphylococcus aureus/crescimento & desenvolvimento , Cicatrização , Infecção dos Ferimentos/prevenção & controleRESUMO
Herein, the dopamine (DA) was grafted with oxidized sodium alginate (OSA) via Schiff base reduction reaction, aiming to fabricate novel DA-grafted OSA (OSA-DA) hydrogels with enhanced biocompatibility and suitable adhesion for clinical applications. The chemical structures of OSA-DA were characterized via UV-Vis, FTIR and 1H NMR spectroscopy analysis. The hydrogel characteristics, biocompatibility, as well as the chronic diabetic wound healing efficacy were investigated. Our results demonstrated that DA was grafted with OSA successfully with highest grafting rate of 7.50%. Besides, OSA-DA hydrogels possessed suitable swelling ratio and appropriate adhesion characteristics. Additionally, OSA-DA exhibited satisfactory cytocompatibility and cell affinity in L-929 cells, and superior biocompatibility in SD rats. Moreover, OSA-DA exerted remarkable promoting effects on migration and tube formation of human umbilical vein endothelial cells (HUVECs). Studies on full-thickness excision chronic diabetic wounds further revealed that OSA-DA hydrogels could accelerate healing via promoting angiogenesis, reducing inflammation response, and stimulating collagen deposition. Overall, our studies would provide basis for SA-based hydrogels as clinical wound dressings.
Assuntos
Diabetes Mellitus , Hidrogéis , Alginatos/química , Animais , Dopamina/farmacologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Hidrogéis/química , Hidrogéis/farmacologia , Ratos , Ratos Sprague-Dawley , CicatrizaçãoRESUMO
Serial hemostatic sponges consisting of polysaccharides-modified chitosan foam sponges were prepared by Schiff base crosslinking reaction between the deacetylated chitosan and oxidized dialdehyde cellulose. Such composite foam sponges were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy to confirm their morphology and compositions. Then the coagulation process was evaluated in vitro by thrombus elasticity meters. Furthermore, the hemostasis experiments on mouse tail vein and rabbit femoral artery were also performed in vivo. The results strongly indicated that such synergistic cellulose-modified chitosan foam sponges showed comprehensively excellent water-absorbing quality, improved mechanical performance, low hemolysis rates, benign cytotoxicity, good resilience ability after repeated compression, and superior hemostasis capability both in vitro and in vivo. Furthermore, the hemostatic mechanism is via adhering/activating the red blood cell/platelet to form robust blood clots through the endogenous coagulation pathway, which serves as a good candidate for emergency trauma treatment in daily civilian and military hemostasis.
Assuntos
Bandagens , Quitosana/química , Hemostasia/efeitos dos fármacos , Hemostáticos/química , Polissacarídeos/química , Animais , Coagulação Sanguínea/efeitos dos fármacos , Linhagem Celular , Celulose/análogos & derivados , Celulose/química , Quitosana/farmacologia , Eritrócitos/metabolismo , Artéria Femoral/lesões , Artéria Femoral/metabolismo , Hemólise/efeitos dos fármacos , Hemostáticos/farmacologia , Masculino , Camundongos , Microscopia Eletrônica de Varredura/métodos , Polissacarídeos/farmacologia , Coelhos , Bases de Schiff/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Trombose/metabolismoRESUMO
The present work reports a versatile approach to the manufacture of chitosan beads with tunable pore size and targeted properties. To achieve this, the as prepared chitosan beads were allowed to interact with aqueous solutions of two types of oxidized pullulan derivatives. Depending on the functional groups present on the pullulan structure after oxidation, i.e., carboxyl or aldehyde, covalent or physical hybrid hydrogels could be prepared. The attachment of oxidized pullulan onto chitosan structure was checked by FTIR, RMN, XPS and thermal analysis. The morphology of the hybrid structures was evaluated by using Scanning Electron Microscopy (SEM). After structural evaluations, all the prepared hydrogels were characterized by means of dynamic vapor sorption and swelling degree studies, exhibiting a Case-II swelling mechanism. Drug model compounds, such as ibuprofen, bacitracin and neomycin were used for drug loading and release assays, proving high drug loading capacity and tunable release behavior. Drug loaded beads exhibited antibacterial activity and hemocompatibility experiments indicated no coagulation phenomena.
Assuntos
Sistemas de Liberação de Medicamentos , Glucanos/farmacologia , Hidrogéis/química , Polissacarídeos/química , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Quitosana/farmacologia , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Composição de Medicamentos , Glucanos/química , Humanos , Hidrogéis/farmacologia , Microesferas , Oxirredução , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The efficiency of sludge dewatering is affected by the structure and composition of hydrated extracellular polymeric substances (EPS). Degrading EPS can improve the sludge dewatering performance. As an oxidizing agent, sodium periodate (NaIO4 ) has ability to oxidize organics, which is expected to decompose the protein and polysaccharide in EPS and improve the efficiency of sludge dewaterability. This study adopted NaIO4 , for the first time, as an advanced oxidation agent to regulate EPS of waste activated sludge and was combined with anionic polyacrylamide (APAM) as a flocculant to subsequently enhance sludge dewatering. Response surface methodology (RSM) was used to determine the optimal conditions of pH, NaIO4 , and APAM. The results showed that the composite conditioner's specific resistance of filtration (SRF) and the water content of the vacuum-filtered cake (Wc) were highly enhanced compared with those of the raw sludge (RS) under pH 6.5, a NaIO4 concentration of 50 mg/g dry solids (DS), and an APAM concentration of 5 mg/g DS. Owing to the pre-oxidation achieved by NaIO4 under a mildly acid environment, sludge flocs were broken. Subsequently, chemical coagulation (APAM) agglomerated the smaller particles into larger flocs of sludge by adsorption and bridging, thus improving sludge dewaterability. PRACTITIONER POINTS: A novel conditioner, pH/NaIO4 /APAM, was explored for sludge dewatering. IO3 ⢠and HO⢠oxidized extracellular polymeric substances (EPS). Degradation of the protein content of EPS released bound water. Highly enhanced sludge dewaterability was achieved under optimal conditions.
Assuntos
Matriz Extracelular de Substâncias Poliméricas , Esgotos , Ácido Periódico , Eliminação de Resíduos Líquidos , ÁguaRESUMO
The antibacterial and biocompatible films have attracted much attention due to their wide range of applications. Although a lot of work has been done in this area, research in this field is still very active and associated with the continuous development of new materials. In the present study full polysaccharide chitosan-agarose (CS-AG) films were produced by reaction of chitosan with periodate activated agarose, followed by reductive amination. Activated agarose was prepared by periodate oxidation of agarose, and then applied as a crosslinking agent to form a new polymeric network. The structure of periodate activated agarose was studied by nuclear magnetic resonances spectroscopy (1H NMR) and Fourier-transform infrared spectroscopy (FT-IR). Rheological experiments showed that the viscosity of agarose solution changes rapidly by addition of periodate to the solution. Swelling, deswelling, and gel content of the films were determined at different pH. Chitosan-agarose silver nanocomposite (CS-AG/n-Ag) films were prepared by loading silver ions and subsequent reduction. The CS-AG/n-Ag films were characterized by FT-IR, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM).Transmission electron microscopy (TEM) image showed that the size of silver nanoparticles was about 2-7 nm. The bactericidal capacities (MBC/MIC) of the CS-AG/Ag films for Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) were obtained 2.0, 1.0 and 2.0, respectively. The results demonstrate that the CS-AG/n-Ag films have good antibacterial activity against both the gram-negative and the gram-positive bacteria which make them suitable for food packaging and wound healing applications.
Assuntos
Antibacterianos , Antioxidantes , Bactérias/efeitos dos fármacos , Quitosana , Nanogéis/química , Sefarose , Prata/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Quitosana/química , Sefarose/química , Prata/químicaRESUMO
Vitreous, an essential dioptric medium for the human eyes, must be filled with artificial materials once damaged. Carboxymethyl chitosan (CMCTS) is one of the most important water-soluble chitosan derivatives with improved biocompatibility and biodegradability. In this study, oxidized hyaluronic acid (OHA) was prepared as crosslinking reagent. CMCTS and OHA were used to develop a biocompatible, self-repairing and in-situ injectable hydrogel for vitreous substitutes. Results showed the hydrogel with controllable swelling properties, high transparency, acceptable cytocompatibility on mouse fibroblast L929 and histocompatibility in vivo. Furthermore, hydrogel was injected in-situ into the vitreous cavity after vitrectomy on New Zealand Rabbits, no significant and persistent adverse effects were observed during the 90-day follow-up period. In addition, the hydrogel maintained intraocular pressure of the operated eyes and the inherent position of the retina. Collectively, this injectable, biodegradable, nontoxic hydrogel possessed enormous potential to become a vitreous substitute material.
Assuntos
Materiais Biocompatíveis/química , Quitosana/análogos & derivados , Ácido Hialurônico/química , Hidrogéis/química , Corpo Vítreo/cirurgia , Animais , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Quitosana/farmacologia , Feminino , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Ácido Hialurônico/farmacologia , Hidrogéis/farmacologia , Injeções Intraoculares , Pressão Intraocular/efeitos dos fármacos , Pressão Intraocular/fisiologia , Masculino , Camundongos , Coelhos , Ratos , Ratos Sprague-Dawley , Solubilidade , Resultado do Tratamento , Vitrectomia/métodos , Água/químicaRESUMO
Hydroxyapatite-associated bacterial cellulose (BC/HA) is a promising composite for biomedical applications. However, this hybrid composite has some limitations due to its low in vivo degradability. The objective of this work was to oxidize BC and BC/HA composites for different time periods to produce 2,3 dialdehyde cellulose (DAC). The BC and oxidized BC (OxBC) membranes were mineralized to obtain the hybrid materials (BC/HA and OxBC/HA) and their physico-chemical, degradability, and bioactivity properties were studied. The results showed that OxBC/HA was more bioactive and degradable than BC/HA, which isa function of the degree of BC oxidation. High glucose levels in the BC degradation were observed as a function of oxidation degree, and other products, such as butyric acid and acetic acid resulted from DAC degradation. Therefore, this chemical modification reaction favors BC degradation, making it a good biodegradable and bioactive material with a potential for bone regeneration applications.
Assuntos
Celulose/química , Durapatita/química , Ácido Acético/química , Acetobacteraceae , Líquidos Corporais/química , Regeneração Óssea , Ácido Butírico/química , Glucose/química , Oxirredução , Engenharia TecidualRESUMO
A simple method was proposed for preparing the dialdehyde-ß-cyclodextrin (DA-ß-CD) cross-linked carboxymethyl chitosan (CMCS) hydrogels for drug delivery. DA-ß-CD was yielded from the sodium periodate oxidation of ß-CD. Phenolphthalein (PhP) was adopted as a model drug to study the drug loading and releasing properties of the obtained hydrogels. The results show that the ability of the hydrogel to load drug is affected by the aldehyde content of DA-ß-CD. The inclusion constant of DA-ß-CD toward PhP is lower than that of the original ß-CD and decreased with the rising of the aldehyde content. An increased cross-linking degree between DA-ß-CD and CMCS slows the PhP release to some extent. In comparison with glyoxal/CMCS, DA-ß-CD/CMCS presents better PhP release properties. Only 19.2 % of PhP loaded in glyoxal/CMCS was released within 24â¯h. Half of PhP loaded in DA-ß-CD/CMCS was released in 2â¯h and about 90 % was released within 12â¯h.
Assuntos
Quitosana/análogos & derivados , Quitosana/química , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Quitosana/farmacologia , Reagentes de Ligações Cruzadas/química , Liberação Controlada de Fármacos , Glioxal/química , Humanos , Hidrogéis/farmacologia , beta-Ciclodextrinas/químicaRESUMO
Dialdehyde carboxymethylcellulose (DCMC) solution generally has quite low solid content, which inevitably limits its industrial application. In this work, carboxymethylcellulose sodium (Na-CMC) was pre-degraded using H2O2 followed by periodate oxidation for preparing DCMC with high solid content as practical tanning agent. Pre-degradation conditions optimization showed that H2O2 dosage most impacted the tanning effect of DCMC, and the Mw and viscosity of Na-CMC underwent remarkable reduction. FT-IR and 1H NMR illustrated that aldehyde group was successfully introduced into DCMC after periodate oxidation. Under the optimized conditions, the solid content of DCMC could be improved to around 30%. This DCMC could endow tanned leather with high shrinkage temperature and satisfactory fiber dispersion. Besides, DCMC tanned leather had comparable physical and organoleptic properties to those of leathers tanned by chrome tanning agent and commercial polyaldehyde tanning agent TWT. This suggests the prospect of DCMC with high solid content as useful tanning agent.