Effects of solid lipid nanocarrier containing methyl urolithin A by coating folate-bound chitosan and evaluation of its anti-cancer activity.

BACKGROUND: Nanotechnology-based drug delivery systems have received much attention over the past decade. In the present study, we synthesized Methyl Urolithin A-loaded solid lipid nanoparticles decorated with the folic acid-linked chitosan layer called MuSCF-NPs and investigated their effects on cancer cells. METHODS: MuSCF-NPs were prepared using a high-pressure homogenization method and characterized using FTIR, FESEM, DLS, and zeta potential methods. Drug encapsulation was assessed by spectrophotometry and its cytotoxic effect on various cancer cells (MDA-MB231, MCF-7, PANC, AGS, and HepG2) by the MTT method. Antioxidant activity was assessed by the ABTS and DPPH methods, followed by expression of genes involved in oxidative stress and apoptosis by qPCR and flow cytometry. RESULTS: The results showed the formation of monodisperse and stable round nanoparticles with a size of 84.8 nm. The drug loading efficiency in MuSCF-NPs was reported to be 88.6%. MuSCF-NPs exhibited selective cytotoxicity against MDA-MB231 cells (IC50 = 40 µg/mL). Molecular analysis showed a significant increase in the expression of Caspases 3, 8, and 9, indicating that apoptosis was occurring in the treated cells. Moreover, flow cytometry results showed that the treated cells were arrested in his SubG1 phase, confirming the pro-apoptotic effect of the nanoparticles. The results indicate a high antioxidant effect of the nanoparticles with IC50 values ​​of 45 µg/mL and 1500 µg/mL against ABTS and DPPH, respectively. The reduction of catalase gene expression confirmed the pro-oxidant effect of nanoparticles in cancer cells treated at concentrations of 20 and 40 µg/mL. CONCLUSIONS: Therefore, our findings suggest that the MuSCF-NPs are suitable candidates, especially for breast cancer preclinical studies.

Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice.

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

Encapsulation of propolis extracted with methylal in the chitosan nanoparticles and its antibacterial and cell cytotoxicity studies.

In this study we develop novel type of antibacterial chitosan-propolis NPs to improve theantimicrobial activity against various pathogens. To this aim, we primarily extracted propolis with methylal and ethanol as green solvents and its encapsulation with chitosan NPs. The developed propolis loaded chitosan NPs indicated antimicrobial and anti-biofilm properties against various gram positive and negative. FTIR revealed the successful encapsulation of the propolis extract with Ethanol (PE) and Methylal (PM) into the chitosan nano career matrix. HPLC and GC-MASS also confirmed the presence of flavonoids and phenols compounds of propolis extracted with both solvents. In addition, we confirmed the total phenolic and flavonoid compounds in propolis by calorimetric method of Folin-Ciocalteu and aluminum trichloride complex formation assays, respectively. PE-CH and PM-CH were optimized regarding physicochemical properties such as particle size, zeta potential, and poly dispersity index (PDI) index. DLS and SEM micrographs confirmed a spherical morphology in a range of 360-420 nm with Z potential values of 30-48 mV and PDI of 0.105-0.166 for PE-CH and PM-CH, respectively. The encapsulation efficiency was evaluated using colorimetric analysis, with median values ranging from 90 to 92%. The MIC values within the range of 2 to 230 µg/ml and MBC values between 3 to 346 µg/ml against both gram-positive and negative bacteria. While both PE and PM showed a significant reduction in the number of E. coli, S. aureus, and S. epidermidis, the use of PE-CH and PM-CH led to a statistically significant and greater reduction in number of E. coli, S. aureus, and S. epidermidis strains on the biofilm, pre-formed biofilm and planktonic phases. Besides, the DPPH assay showed significant antioxidant activity for these NPs within the range of 36 to 92%. MTT assay for MHFB-1, HFF, L929, MDF, and MCF-7 cells exhibited statistically significant differences in each other that show the IC50 between 60-160 µg/ml for normal cells and 20 for cancer cells. Finally the present study indicated that both PM and PM-CH greater than PE and PE-CH in which contain high flavonoid and phenolic contents with a high antioxidation potential antioxidant properties, which could be beneficial for cell proliferation and antibiotic and anticancer applications.

Preparing high-performance microspheres based on the chitosan-assisted dispersion of reduced graphene oxide in aqueous solution for bilirubin removal.

The removal of excess bilirubin from blood is of great clinical importance. Reduced graphene oxide (rGO) is often used to efficiently remove bilirubin. However, thin rGO pieces tend to aggregate in the aqueous phase because they are hydrophobic. In this context, we propose an effective strategy based on the chitosan-assisted (CS-assisted) dispersion of rGO to produce high-performance bilirubin-adsorbing microspheres. CS possesses a hydrophobic CH structure, which offers strong hydrophobic interactions with rGO that assist its dispersion, and the large number of hydrophilic sites of CS increases the hydrophilicity of rGO. CS serves as a dispersant in a surfactant-like manner to achieve a homogeneous and stable CS/rGO dispersion by simply and gently stirring CS and rGO in a LiOH/KOH/urea/H2O system. Subsequently, CS/rGO hybrid microspheres were prepared by emulsification. CS ensures blood compatibility as a base material, and the entrapped rGO contributes to mechanical strength and a high adsorption capacity. The CS/rGO microspheres exhibited a high bilirubin adsorption capacity (215.56 mg/g), which is significantly higher than those of the rGO and CS microspheres. The determined mass-transfer factors revealed that the rich pores of the CS/rGO microspheres promote mass transfer during bilirubin adsorption (equilibrium is almost achieved within 30 min). The CS/rGO microspheres are promising candidates for bilirubin removal owing to a combination of high strength, blood compatibility, and high adsorption capacity.

Affinity purification/immobilization of poly histidine-tagged proteins by nickel-functionalized porous chitosan membranes.

Although immobilized metal ion affinity chromatography (IMAC) is one of the most effective methods for purifying his-tagged proteins, it has limitations such as expensive commercial resins and non-specific binding of unwanted proteins to the nickel immobilized on the resin. In this study, biocompatible chitosan and porous chitosan membranes as alternative resins were synthesized for protein immobilization and purification, but finally porous chitosan membrane was selected due to its higher porosity and consequently higher nickel adsorption. Once the membrane was functionalized with nickel ions and its metal adsorption confirmed by EDS and ICP methods, it was used to immobilize and purify recombinant ß-NGF as a protein model with his-tag tail in batch-fashion. Protein binding and purification were also approved by FTIR and UV-Vis spectroscopy and SDS-PAGE technique. Our results indicated that the protein of interest could bind to the nickel-functionalized porous chitosan membrane with high efficiency at pH=7. Furthermore, for protein purification, the pH value of 6 and an imidazole concentration of 750 mM were suggested for the final elution buffer. In conclusion, nickel-functionalized porous chitosan membrane could be a suitable alternative to IMAC for low cost and specific protein immobilization and purification.

[Immunoadjuvant Effect of Chitosan Oligosaccharide and Its Feasibility of Being Used as an Adjuvant for Attenuated Live Bacteria Vector Vaccines]. / å£³å¯¡ç³–çš„å ç–«ä½å‰‚æ•ˆæžœåŠä½œä¸ºå‡æ¯’æ´»èŒè½½ä½“ç–«è‹—ä½å‰‚çš„å¯è¡Œæ€§æŽ¢ç´¢.

Objective: To study the immunoadjuvant effects of chitosan oligosaccharide (COS), including the immune activation and the triggering of lysosomal escape, and to explore whether COS can be used as an adjuvant for attenuated live bacteria vector vaccines. Methods: 1) Mouse macrophages RAW264.7 cells were cultured with COS at 0 mg/mL (the control group) and 0.1-4 mg/mL for 24 h and the effect on cell viability was measured by CCK8 assay. Mouse macrophages RAW264.7 were treated with COS at 0 (the control group), 1, 2, and 4 mg/mL for 24 h. Then, the mRNA expression levels of the cytokines, including IFN-γ, IL-10, TGF-ß, and TLR4, were determined by RT-qPCR assay. 2) RAW264.7 cells were treated with 1 mL of PBS containing different components, including calcein at 50 µg/mL, COS at 2 mg/mL, and bafilomycin A1, an inhibitor, at 1 µmol/mL, for culturing. The cells were divided into the Calcein group, Calcein+COS group, and Calcein+COS+Bafilomycin A1 group accordingly. Laser scanning confocal microscopy was used to observe the phagocytosis and the intracellular fluorescence distribution of calcein, a fluorescent dye, in RAW264.7 cells in the presence or absence of COS intervention to determine whether COS was able to trigger lysosomal escape. 3) LM∆E6E7 and LI∆E6E7, the attenuated Listeria vector candidate therapeutic vaccines for cervical cancer, were encapsulated with COS at the mass concentrations of 0.5 mg/mL, 1 mg/mL, 2 mg/mL , 4 mg/mL, and 8 mg/mL. Then, the changes in zeta potential were measured to select the concentration of COS that successfully encapsulated the bacteria. Phagocytosis of the vaccine strains by RAW264.7 cells was measured before and after LM∆E6E7 and LI∆E6E7 were coated with COS at 2 mg/mL. Results: 1) CCK8 assays showed that, compared with the findings for the control group, the intervention of RAW264.7 cells with COS at different concentrations for 24 h was not toxic to the cells and promoted cell proliferation, with the difference being statistically significant (P<0.05). According to the RT-qPCR results, compared with those of the control group, the COS intervention up-regulated the mRNA levels of TLR4 and IFN-γ in RAW264.7 cells, while it inhibited the mRNA expression levels of TGF-ß and IL-10, with the most prominent effect being observed in the 4 mg/mL COS group (P<0.05). 2) Laser scanning confocal microscopy revealed that the amount of fluorescent dye released from lysosomes into the cells was greater in the Calcein+COS group than that in the Calcein group. In other words, a greater amount of fluorescent dye was released from lysosomes into the cells under COS intervention. Furthermore, this process could be blocked by bafilomycin A1. 3) The zeta potential results showed that COS could successfully encapsulate the surface of bacteria when its mass concentration reached 2 mg/mL. Before and after the vaccine strain was encapsulated by COS, the phagocytosis of LM∆E6E7 by RAW264.7 cells was 5.70% and 22.00%, respectively, showing statistically significant differences (P<0.05); the phagocytosis of LI∆E6E7 by RAW264.7 cells was 1.55% and 6.12%, respectively, showing statistically significant differences (P<0.05). Conclusion: COS has the effect of activating the immune response of macrophages and triggering lysosomal escape. The candidates strains of coated live attenuated bacterial vector vaccines can promote the phagocytosis of bacteria by macrophages. Further research is warranted to develop COS into an adjuvant for bacterial vector vaccine.

Effects of Shrimp Shell-Derived Chitosan on Growth, Immunity, Intestinal Morphology, and Gene Expression of Nile Tilapia (Oreochromis niloticus) Reared in a Biofloc System.

Chitosan (CH) shows great potential as an immunostimulatory feed additive in aquaculture. This study evaluates the effects of varying dietary CH levels on the growth, immunity, intestinal morphology, and antioxidant status of Nile tilapia (Oreochromis niloticus) reared in a biofloc system. Tilapia fingerlings (mean weight 13.54 ± 0.05 g) were fed diets supplemented with 0 (CH0), 5 (CH5), 10 (CH10), 20 (CH20), and 40 (CH40) mL·kg-1 of CH for 8 weeks. Parameters were assessed after 4 and 8 weeks. Their final weight was not affected by CH supplementation, but CH at 10 mL·kg-1 significantly improved weight gain (WG) and specific growth rate (SGR) compared to the control (p < 0.05) at 8 weeks. Skin mucus lysozyme and peroxidase activities were lower in the chitosan-treated groups at weeks 4 and 8. Intestinal villi length and width were enhanced by 10 and 20 mL·kg-1 CH compared to the control. However, 40 mL·kg-1 CH caused detrimental impacts on the villi and muscular layer. CH supplementation, especially 5-10 mL·kg-1, increased liver and intestinal expressions of interleukin 1 (IL-1), interleukin 8 (IL-8), LPS-binding protein (LBP), glutathione reductase (GSR), glutathione peroxidase (GPX), and glutathione S-transferase (GST-α) compared to the control group. Overall, dietary CH at 10 mL·kg-1 can effectively promote growth, intestinal morphology, innate immunity, and antioxidant capacity in Nile tilapia fingerlings reared in biofloc systems.

Porous Nano-Fiber Structure of Modified Electrospun Chitosan GBR Membranes Improve Osteoblast Calcium Phosphate Deposition in Osteoblast-Fibroblast Co-Cultures.

Desirable characteristics of electrospun chitosan membranes (ESCM) for guided bone regeneration are their nanofiber structure that mimics the extracellular fiber matrix and porosity for the exchange of signals between bone and soft tissue compartments. However, ESCM are susceptible to swelling and loss of nanofiber and porous structure in physiological environments. A novel post-electrospinning method using di-tert-butyl dicarbonate (tBOC) prevents swelling and loss of nanofibrous structure better than sodium carbonate treatments. This study aimed to evaluate the hypothesis that retention of nanofiber morphology and high porosity of tBOC-modified ESCM (tBOC-ESCM) would support more bone mineralization in osteoblast-fibroblast co-cultures compared to Na2CO3 treated membranes (Na2CO3-ESCM) and solution-cast chitosan solid films (CM-film). The results showed that only the tBOC-ESCM retained the nanofibrous structure and had approximately 14 times more pore volume than Na2CO3-ESCM and thousands of times more pore volume than CM-films, respectively. In co-cultures, the tBOC-ESCM resulted in a significantly greater calcium-phosphate deposition by osteoblasts than either the Na2CO3-ESCM or CM-film (p < 0.05). This work supports the study hypothesis that tBOC-ESCM with nanofiber structure and high porosity promotes the exchange of signals between osteoblasts and fibroblasts, leading to improved mineralization in vitro and thus potentially improved bone healing and regeneration in guided bone regeneration applications.

Characterization of Three Polysaccharide-Based Hydrogels Derived from Laminaria japonica and Their Hemostatic Properties.

Three Laminaria japonica polysaccharides (LJPs) extracted via water extraction (LJP-W), acid extraction (LJP-A), and enzymatic extraction (LJP-E) were used as raw materials to be cross-linked with chitosan and polyvinyl alcohol to prepare hydrogels. Compared with conventional hydrogel systems, all three types of LJP-based polysaccharide hydrogels exhibited better swelling properties (14 times their original weight) and the absorption ability of simulated body fluid (first 2 h: 6-10%). They also demonstrated better rigidity and mechanical strength. Young's modulus of LJP-E was 4 times that of the blank. In terms of hemostatic properties, all three polysaccharide hydrogels did not show significant cytotoxic and hemolytic properties. The enzyme- and acid-extracted hydrogels (LJP-Gel-A and LJP-Gel-E) demonstrated better whole-blood coagulant ability compared with the water-extracted hydrogel (LJP-Gel-W), as evidenced by the whole blood coagulation index being half that of LJP-Gel-W. Additionally, the lactate dehydrogenase viabilities of LJP-Gel-A and LJP-Gel-E were significantly higher, at about four and three times those of water extraction, respectively. The above results suggested that LJP-Gel-A and LJP-Gel-E exhibited better blood coagulation capabilities than LJP-Gel-W, due to their enhanced platelet enrichment and adhesion properties. Consequently, these hydrogels are more conducive to promoting coagulation and have good potential for wound hemostasis.

The Potential of Chitosan-Based Composites for Adsorption of Diarrheic Shellfish Toxins.

Okadaic acid (OA) is one of the most potent marine biotoxins, causing diarrheal shellfish poisoning (DSP). The proliferation of microalgae that produce OA and its analogues is frequent, threatening human health and socioeconomic development. Several methods have been tested to remove this biotoxin from aquatic systems, yet none has proven enough efficacy to solve the problem. In this work, we synthesized and characterized low-cost composites and tested their efficacy for OA adsorption in saltwater. For the synthesis of the composites, the following starting materials were considered: chitosan of low and medium molecular weight (CH-LW and CH-MW, respectively), activated carbon (AC), and montmorillonite (MMT). Characterization by vibrational spectroscopy (FTIR), X-ray diffraction (XRD), and microscopy revealed differences in the mode of interaction of CH-LW and CH-MW with AC and MMT, suggesting that the interaction of CH-MW with MMT has mainly occurred on the surface of the clay particles and no sufficient intercalation of CH-MW into the MMT interlayers took place. Among the composites tested (CH-LW/AC, CH-MW/AC, CH-MW/AC/MMT, and CH-MW/MMT), CH-MW/MMT was the one that revealed lower OA adsorption efficiency, given the findings evidenced by the structural characterization. On the contrary, the CH-MW/AC composite revealed the highest average percentage of OA adsorption (53 ± 11%). Although preliminary, the results obtained in this work open up good perspectives for the use of this type of composite material as an adsorbent in the removal of OA from marine environments.

A receptor required for chitin perception facilitates arbuscular mycorrhizal associations and distinguishes root symbiosis from immunity.

Plants establish symbiotic associations with arbuscular mycorrhizal fungi (AMF) to facilitate nutrient uptake, particularly in nutrient-limited conditions. This partnership is rooted in the plant's ability to recognize fungal signaling molecules, such as chitooligosaccharides (chitin) and lipo-chitooligosaccharides. In the legume Medicago truncatula, chitooligosaccharides trigger both symbiotic and immune responses via the same lysin-motif-receptor-like kinases (LysM-RLKs), notably CERK1 and LYR4. The nature of plant-fungal engagement is opposite according to the outcomes of immunity or symbiosis signaling, and as such, discrimination is necessary, which is challenged by the dual roles of CERK1/LYR4 in both processes. Here, we describe a LysM-RLK, LYK8, that is functionally redundant with CERK1 for mycorrhizal colonization but is not involved in chitooligosaccharides-induced immunity. Genetic mutation of both LYK8 and CERK1 blocks chitooligosaccharides-triggered symbiosis signaling, as well as mycorrhizal colonization, but shows no further impact on immunity signaling triggered by chitooligosaccharides, compared with the mutation of CERK1 alone. LYK8 interacts with CERK1 and forms a receptor complex that appears essential for chitooligosaccharides activation of symbiosis signaling, with the lyk8/cerk1 double mutant recapitulating the impact of mutations in the symbiosis signaling pathway. We conclude that this novel receptor complex allows chitooligosaccharides activation specifically of symbiosis signaling and helps the plant to differentiate between activation of these opposing signaling processes.

Response surface optimization of sludge dewatering process: synergistic enhancement by ultrasonic, chitosan and sludge-based biochar.

Due to the colloidal stability, the high compressibility and the high hydration of extracellular polymeric substances (EPS), it is difficult to efficiently dehydrate sludge. In order to enhance sludge dewatering, the process of ultrasonic (US) cracking, chitosan (CTS) re-flocculation and sludge-based biochar (SBB) skeleton adsorption of water-holding substances to regulate sludge dewaterability was proposed. Based on the response surface method, the prediction model of the specific resistance to filtration (SRF) and sludge cake moisture content (MC) was established. The US cracking time and the dosage of CTS and SBB were optimized. The results showed that the optimal parameters of the three were 5.08 s, 10.1 mg/g dry solids (DS) and 0.477 g/g DS, respectively. Meantime, the SRF and MC were 5.4125 × 1011 m/kg and 76.8123%, which significantly improved the sludge dewaterability. According to the variance analysis, it is found that the fitting degree of SRF and MC model is good, which also confirms that there is significant interaction and synergy between US, CTS and SBB, and the contribution of CTS and SBB is greater. Moreover, the process significantly improves the sludge's calorific value and makes its combustion more durable.

Advancing Photodynamic Antimicrobial Strategy: Sustainable Fabrication of Novel Lauryl Gallate-Chitosan Hydrophobic Films with Rapid Bacterial Capture and Biofilms Elimination Capabilities for Promoting Wound Healing.

Bioinspired photoactive composites, in terms of photodynamic inactivation, cost-effectiveness, and biosafety, are promising alternatives to antibiotics for combating bacterial infections while avoiding antibacterial resistance. However, the weak bacterial membrane affinity of the photoactive substrate and the lack of synergistic antibacterial effect remain crucial shortcomings for their antibacterial applications. Herein, we developed a hydrophobic film from food antioxidant lauryl gallate covalently functionalized chitosan (LG-g-CS conjugates) through a green radical-induced grafting reaction that utilizes synergistic bacteria capture, contact-killing, and photodynamic inactivation activities to achieve enhanced bactericidal and biofilm elimination capabilities. Besides, the grafting reaction mechanism between LG and CS in the ascorbic acid (AA)/H2O2 redox system was further proposed. The LG-g-CS films feature hydrophobic side chains and photoactive phenolic hydroxyl groups, facilitating dual bactericidal activities through bacteria capture and contact-killing via strong hydrophobic and electrostatic interactions with bacterial membranes as well as blue light (BL)-driven photodynamic bacterial eradication through the enhanced generation of reactive oxygen species. As a result, the LG-g-CS films efficiently capture and immobilize bacteria and exhibit excellent photodynamic antibacterial activity against model bacteria (Escherichia coli and Staphylococcus aureus) and their biofilms under BL irradiation. Moreover, LG-g-CS films could significantly promote the healing process of S. aureus-infected wounds. This research demonstrates a new strategy for designing and fabricating sustainable bactericidal and biofilm-removing materials with a high bacterial membrane affinity and photodynamic activity.

Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis.

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

Use of marine occurrent extracts to enhance the stability of dentin extracellular matrix.

Chitosan (CS) and phloroglucinol (PhG), two extracts abundantly found in marine life, were investigated for their ability to biomodify demineralized dentin by enhancing collagen crosslinks and improving dentin extracellular matrix (ECM) mechanical and biochemical stability. Dentin obtained from non-carious extracted human molars were demineralized with phosphoric acid. Baseline Fourier-transform infrared (FTIR) spectra, apparent flexural elastic modulus (AE) and dry mass (DM) of each specimen were independently acquired. Specimens were randomly incubated for 5 min into either ultrapure water (no-treatment), 1% glutaraldehyde (GA), 1% CS or 1% PhG. Water and GA were used, respectively, as a negative and positive control for collagen crosslinks. Specimens' post-treatment FTIR spectra, AE, and DM were obtained and compared with correspondent baseline measurements. Additionally, the host-derived proteolytic activity of dentin ECM was assessed using hydroxyproline assay (HYP) and spectrofluorometric analysis of a fluorescent-quenched substrate specific for matrix metalloproteinases (MMPs). Finally, the bond strength of an etch-and-rinse adhesive was evaluated after application of marine compounds as non-rinsing dentin primers. Dentin specimens FTIR spectral profile changed remarkably, and their AE increased significantly after treatment with marine compounds. DM variation, HYP assay and fluorogenic substrate analysis concurrently indicated the biodegradation of CS- and PhG-treated specimens was significantly lesser in comparison with untreated specimens. CS and PhG treatments enhanced biomechanical/biochemical stability of demineralized dentin. These novel results show that PhG is a primer with the capacity to biomodify demineralized dentin, hence rendering it less susceptible to biodegradation by host-proteases.

Preparation and characterization of chitosan/polyvinyl alcohol antibacterial sponge materials.

This study utilized the freeze-drying method to create a chitosan (CS) and polyvinyl alcohol (PVA) sponge. To enhance its antibacterial properties, curcumin and nano silver (Cur@Ag) were added for synergistic antibacterial. After adding curcumin and nano silver, the mechanical properties of the composite sponge dressing (CS-PVA-Cur@Ag) were improved. The porosity of the composite sponge dressing was closed to 80%, which was helpful for drug release, and it had good water absorption and water retention rate. The nano silver diameter was 50-80 nm, which was optimal for killing bacteria. Antibacterial tests usedEscherichia coliandStaphylococcus aureusdemonstrated that little nano silver was required to eliminate bacteria. Finally, in the rat full-thickness skin wound model, the composite sponge dressing can promote wound healing in a short time. In summary, CS-PVA-Cur@Ag wound dressing could protect from bacterial infection and accelerate wound healing. Thus, it had high potential application value for wound dressing.

Chitosan-LeoA-DNA Nanoparticles Promoted the Efficacy of Novel LeoA-DNA Vaccination on Mice Against Helicobacter pylori.

More than half of the world's population is infected with Helicobacter pylori (H. pylori), which may lead to chronic gastritis, peptic ulcers, and stomach cancer. LeoA, a conserved antigen of H. pylori, aids in preventing this infection by triggering specific CD3+ T-cell responses. In this study, recombinant plasmids containing the LeoA gene of H. pylori are created and conjugated with chitosan nanoparticle (CSNP) to immunize BALB/c mice against the H. pylori infection. We used the online Vaxign tool to analyze the genomes of five distinct strains of H. pylori, and we chose the outer membrane as a prospective vaccine candidate. Afterward, the proteins' immunogenicity was evaluated. The DNA vaccine was constructed and then encapsulated in CSNPs. The effectiveness of the vaccine's immunoprotective effects was evaluated in BALB/c mice. Purified activated splenic CD3+ T cells are used to test the anticancer effects in vitro. Nanovaccines had apparent spherical forms, were small (mean size, 150-250 nm), and positively charged (41.3 ± 3.11 mV). A consistently delayed release pattern and an entrapment efficiency (73.35 ± 3.48%) could be established. Compared to the non-encapsulated DNA vaccine, vaccinated BALB/c mice produced higher amounts of LeoA-specific IgG in plasma and TNF-α in splenocyte lysate. Moreover, BALB/c mice inoculated with nanovaccine demonstrated considerable immunity (87.5%) against the H. pylori challenge and reduced stomach injury and bacterial burdens in the stomach. The immunological state in individuals with GC with chronic infection with H. pylori is mimicked by the H. pylori DNA nanovaccines by inducing a shift from Th1 to Th2 in the response. In vitro human GC cell development is inhibited by activated CD3+ T lymphocytes. According to our findings, the H. pylori vaccine-activated CD3+ has potential immunotherapeutic benefits.

Exploring rumen fermentation and microbial populations in Dhofari goats fed a chitosan-added diet.

The use of chitosan (CHI) in ruminant diets is a promising natural modifier for rumen fermentation, capable of modulating both the rumen pattern and microbial activities. The objective of this study was to explore the rumen fermentation and microbial populations in Dhofari goats fed a diet supplemented with CHI. A total of 24 Dhofari lactating goats (body weight, 27.32 ± 1.80 kg) were assigned randomly into three experimental groups (n = 8 ewes/group). Goats were fed a basal diet with either 0 (control), 180 (low), or 360 (high) mg CHI/kg of dietary dry matter (DM) for 45 days. Feeding high CHI linearly increased (p < 0.05) the propionate level and reduced the acetate, butyrate, and total protozoa count (p < 0.05). Ruminal ammonia nitrogen (NH3-N) concentrations and the acetate:propionate ratio decreased linearly when goats were fed CHI (p < 0.05). The abundances of both Spirochetes and Fibrobacteres phyla were reduced (p < 0.05) with both CHI doses relative to the control. Both low and high CHI reduced (p < 0.05) the relative abundances of Butyrivibrio hungatei, Fibrobacter succinogenes, Ruminococcus albus, Ruminococcus flavefaciens, Selenomonas ruminantium and Neocallimastix californiae populations. Adding CHI significantly decreased (p < 0.05) the abundances of Ascomycota, Basidiomycota, and Bacillariophyta phyla compared to the control. Adding CHI to the diet reduces the abundance of fibrolytic-degrading bacteria, however, it increases the amylolytic-degrading bacteria. Application of 360 mg of CHI/kg DM modified the relative populations of ruminal microbes, which could enhance the rumen fermentation patterns in Dhofari goats.

Characterization and Antioxidant and Antibacterial Activities of Carboxymethylated Tamarind Seed Polysaccharide Composite Films Incorporated with ε-Polylysine and Their Application in Fresh-Cut Green Bell Pepper Preservation.

Traditional petroleum-based food-packaging materials have poor permeability, limited active packaging properties, and difficulty in biodegradation, limiting their application. We developed a carboxymethylated tamarind seed polysaccharide composite film incorporated with ε-polylysine (CTPε) for better application in fresh-cut agricultural products. The CTPε films exhibit excellent water vapor barrier properties, but the mechanical properties are slightly reduced. Fourier transform infrared spectroscopy and X-ray diffraction spectra indicate the formation of hydrogen bonds between ε-PL and CTP, leading to their internal reorganization and dense network structure. With the increase of ε-PL concentration, composite films showed notable inhibition of postharvest pathogenic fungi and bacteria, a significant enhancement of 2,2'- azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity, and gradual improvement of wettability performance. Cytotoxicity experiments confirmed the favorable biocompatibility when ε-PL was added at 0.3% (CTPε2). In fresh-cut bell pepper preservation experiments, the CTPε2 coating effectively delayed weight loss and malondialdehyde increase preserved the hardness, color, and nutrients of fresh-cut peppers and prolonged the shelf life of the fresh-cut peppers, as compared with the control group. Therefore, CTPε composite films are expected to be a valuable packaging material for extending the shelf life of freshly cut agricultural products.

Green Synthesis of Zinc Oxide Nanoparticles from Althaea officinalis Flower Extract Coated with Chitosan for Potential Healing Effects on Diabetic Wounds by Inhibiting TNF-α and IL-6/IL-1ß Signaling Pathways.

Background: Diabetes Mellitus is a multisystem chronic pandemic, wound inflammation, and healing are still major issues for diabetic patients who may suffer from ulcers, gangrene, and other wounds from uncontrolled chronic hyperglycemia. Marshmallows or Althaea officinalis (A.O.) contain bioactive compounds such as flavonoids and phenolics that support wound healing via antioxidant, anti-inflammatory, and antibacterial properties. Our study aimed to develop a combination of eco-friendly formulations of green synthesis of ZnO-NPs by Althaea officinalis extract and further incorporate them into 2% chitosan (CS) gel. Method and Results: First, develop eco-friendly green Zinc Oxide Nanoparticles (ZnO-NPs) and incorporate them into a 2% chitosan (CS) gel. In-vitro study performed by UV-visible spectrum analysis showed a sharp peak at 390 nm, and Energy-dispersive X-ray (EDX) spectrometry showed a peak of zinc and oxygen. Besides, Fourier transforms infrared (FTIR) was used to qualitatively validate biosynthesized ZnO-NPs, and transmission electron microscope (TEM) showed spherical nanoparticles with mean sizes of 76 nm and Zeta potential +30mV. The antibacterial potential of A.O.-ZnO-NPs-Cs was examined by the diffusion agar method against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Based on the zone of inhibition and minimal inhibitory indices (MIC). In addition, an in-silico study investigated the binding affinity of A.O. major components to the expected biological targets that may aid wound healing. Althaea Officinalis, A.O-ZnO-NPs group showed reduced downregulation of IL-6, IL-1ß, and TNF-α and increased IL-10 levels compared to the control group signaling pathway expression levels confirming the improved anti-inflammatory effect of the self-assembly method. In-vivo study and histopathological analysis revealed the superiority of the nanoparticles in reducing signs of inflammation and wound incision in rat models. Conclusion: These biocompatible green zinc oxide nanoparticles, by using Althaea Officinalis chitosan gel ensure an excellent new therapeutic approach for quickening diabetic wound healing.