Degradation of Chitin and Chitosan by a Recombinant Chitinase Derived from a Virulent <i>Aeromonas hydrophila</i>Isolated from Diseased Channel Catfish

A chitinase was identified in extracellular products of a virulent?Aeromonas hydrophila?isolated from diseased channel catfish (Ictalurus punctatus). Recombinant chitinase (rChi-Ah) was produced in?Escherichia coli. Purified rChi-Ah had optimal activity at temperature of 42℃?and pH 6.5. The affinity (Km) for chitosan was 4.18 mg·ml-1?with?Vmax?of 202.5 mg·min-1·mg-1. With colloidal chitin as substrate, rChi-Ah generated N,N’-diacetyl-glucosamine predominantly. Conversion of chitosan (≥75% deacetylated) by rChi-Ah revealed five major products: 2 to 4 units of glucosamine, all of which had at least one acetyl group. It was determined that N-acetylated glucosamine was the recognition and cleavage site of rChi-Ah;the minimal and maximal cleavages were two and four glucosamine units, respectively. Functional analysis of rChi-Ah suggests that?A. hydrophilachitinase is a bioactive chitinolytic enzyme, which may benefit the pathogen for survival and/or infection.

A Review of Various Sources of Chitin and Chitosan in Nature

Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.

Optimization of the methods for extraction of chitin in crab shell and preparation of chitosan

A combination of both acid and alkali treatments was used to extract chitin from crab shell in this study. Then, a three factors (NaOH solution concentration, reaction time, reaction temperature) and three levels (35, 45, 55; 2, 6, 10; 70, 105, 140) L 9(3 4) orthogonal experiment design is further adopted to conduct a de acetyl treatment to prepare chitosan by considering the viscosity and de acetyl degree of the chitosan as the main performance indexes. Determination of de acetyl degree of chitin complys with the procedures given by the reference and the viscosity meter was used for determination of viscosity of chitosan. The results show that the extraction of chitin shall use pulverized crab shell as the raw material and such raw material shall be immersed in 10% HCl solution for 6 hours and washed with water for one time in every 2 hours, then heated in boiled water for 2 hours by the use of 10% thin NaOH solution. Afterwards, the said material shall be washed with water to become a neutral solution and dried over a stove. When chitin is mixed with 55% NaOH solution in a proportion of 1∶10 (W/V, g/mL) and the reaction takes place at a temperature of 105℃ for 6 hours, chitosan having a de acetyl percentage of 94% and viscosity of >200 cps can be available.

Effects of Chitin Nanocrystal on Solution Behavior and Gelation of Chitosan/β-Glycerophosphate Thermosensitive Hydrogel

The chitosan/β-glycerophosphate( CS/β-GP),a physical hydrogel system with thermosensitive and injectable features combined with biocompatibility and biodegradability, has great potentials as matrices for drug or cell encapsulation and delivery,or as in situ gel-forming materials for tissue repair. Here,the chitin nanocrystal( Chi NC) was introduced into the aforementioned system, and its effects on solution behavior and mechanical properties was investigated. The results showed the incorporation of Chi NC complicated sol-to-gel transition process; a higher loading ratio( 20%) speeded up sol-to-gel transition rate,reduced the solto-gel transition temperature,while still maintained shear-thinning behavior or injectable feature. Moreover,the mechanical properties of gels were significantly enhanced by Chi NC, accompanied by decreased water uptake. The above mentioned behavior favored better applications as injectable tissue-repair implants.

Synthesis and Characterization of a Novel Liquid Crystalline Chitin Quaternary Ammonium Chitosan Salt

N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.

Biodegradation of Crystalline Chitin:A Review of Recent Advancement,Challenges,and Future Study Directions

Chitin is the second most abundant renewable polysaccharide on Earth.The degradation of chitin into soluble and bioactive N-acetyl chitooligosaccharides(NCOSs)and N-acetyl-D-glucosamine(GlcNAc)has emerged as a pivotal step in the efficient and sustainable utilization of chitin resources.However,because of its dense structure,high crystallinity,and poor solubility,chitin typically needs pretreatment via chemical,physical,and other methods before enzymatic conversion to enhance the accessibility between substrates and enzyme molecules.Consequently,there has been considerable interest in exploring the direct biological degradation of crystalline chitin as a cost-effective and environment-friendly technology.This review endeavors to present several biological methods for the direct degradation of chitin.We primarily focused on the importance of chitinase containing chitin-binding domain(CBD).Additionally,various modification strategies for increasing the degradation efficiency of crystalline chitin were introduced.Subsequently,the review systematically elucidated critical components of multi-enzyme catalytic systems,highlighting their potential for chitin degradation.Furthermore,the application of microorganisms in the degradation of crystalline chitin was also discussed.The insights in this review contribute to the explorations and investigations of enzymatic and microbial approaches for the direct degradation of crystalline chitin,thereby fostering advancements in biomass conversion.

β-Chitin/Chitosan Obtained from Loligo and Humboldt Squids Effectiveness as Wound Dressing Material

A number of materials are utilized to develop wound care dressing materials with metallic treatments such as ionic silver and zinc. Metallic ions if used for a prolonged time may lead to toxicity. Alternatively chitin,a natural polysaccharide found in nature, is utilized. It is found in fungi, crabs, mushrooms,squids, octopus, and many other living organisms. Chitin has similar structure to cellulose but its deacetylated derivate chitosan has amine groups that provide potential antibacterial properties along with a number of other advantages. Chitin in its natural form is found in three different structural forms,namely α,β,and γ.The β-chitin and chitosan are mostly found in the exoskeleton of squids. Loligo and Humboldt squids were studied. It is anticipated that Humboldt chitin is more effective in serving as antibacterial material and can be utilized for wound care. Differences in steriochemical structure were observed among β-chitin structures obtained and amine group's presences were found along with ability of materials to swell.

Anomalous Proton Conductivity in Chitin-Chitosan Mixed Compounds

In order to investigate a key factor for the appearance of proton conductivity in chitin-chitosan mixed compounds, the chitin-chitosan mixed compounds (chitin)x(chitosan)1-x were prepared and these proton conductivities have been investigated. DC proton conductivity σ is obtained from Nyquist plot of impedance measurement data, and the relationship between σ and mixing ratio x has been made clear. It was found that the x dependence of σ is non-monotonous. That is, σ shows the anomalous behavior, and has peaks around x = 0.4 and 0.75. This result indicates that there exist optimal conditions for the realization of high-proton conductivity in the chitin-chitosan mixed compound in which the number of acetyl groups is different. From the FT-IR measurement, we have found that the behavior of proton conductivity in (chitin)x(chitosan)1-x is determined by the amount of water content changed by x. Using these results, proton conductivity, which is important for the application of conducting polymers in chitin-chitosan mixed compounds, will be able to be easily controlled by adjusting the mixing ratio x.

Using Electrodeposition of Carboxylated Chitosan for Green Preparation of Copper Nanoclusters and Nanocomposite Films

On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

Smart Colorimetric Corn Starch Films Combined with Anthocyanin-Loaded Glutenin-Carboxymethyl Chitosan Nanocomplexes for Freshness Monitoring of Chilled Pork

In this study,intelligent,pH-responsive colorimetric films were prepared by encapsulating anthocyanins in nanocomplexes prepared from glutenin and carboxymethyl chitosan.These nanocomplexes were added to a corn starch matrix and used in the freshness monitoring of chilled pork.The effects of anthocyanin-loaded nanocomplexes on the physical,structural,and functional characteristics of the films were investigated.The addition of anthocyanin-loaded nanocomplexes increased the tensile strength,elongation at break,hydrophobicity,and light transmittance of the films while decreasing their water vapor permeability.This is because new hydrogen bonds are formed between the film components,resulting in a more homogeneous and dense structure.The colorimetric film has a significant color response to pH changes.These films were used in experiments on the freshness of chilled pork,in which the pH changes with changing freshness states.The results show that the colorimetric film can monitor changes in the freshness of chilled pork in real time,where orange,pink,and green represent the fresh,secondary fresh,and putrefied states of pork,respectively.Therefore,the intelligent colorimetric film developed in this study has good application potential in the food industry.

Isolation and Screening of Strains for Silkworm Puparium Chitin Degradation and the Optimization of Chitinase Production by Response Surface Methodology

[Objective] The aim of this study was to optimize the conditions of chitinase-produce strains.[Method] A kind of screened chitinase-produce strain G-254 was habituated cultured,and then the single factor experiment was carried out to explore the effects of different carbon source,nitrogen source and inorganic salt on the activity of produced chitinase;the response surface test was used to determine the optimal conditions for chitinase production.[Result] The optimal conditions for chitinase production were：8% of glucose,5% of beef extract and 0.07% of MgSO4,and the activity of chitinase reached the maximal value（6.86 U）under these conditions.[Conclusion] The study improved the activity of chitinase produced by strain G-254 and provided good foundation for industrial production.

Synthesis of chitosan oligosaccharide selenium and its antitumor activity

Background:Polysaccharides have various biological activities;the complexation of polysaccharides with trace element ions can produce synergistic effects,improving the original biological activities of sugars and trace elements.Methods:The preparation process of chitosan oligosaccharide selenium(COSSe)was optimized by the response surface method,followed by a detailed analysis of the resultant compound’s characteristics.The anti-cancer activity of COSSe was studied using the human ovarian cancer cell line SKOV3 as a cell model.Results:The prepared COSSe response surface was well predicted,indicating successful chitosan oligosaccharide binding with selenium.Response surface method analyses identified the optimal synthesis conditions for COSSe:the reaction time of 5.08 h,the reaction temperature of 71.8°C,and mass ratio(Na2SeO3:chitosan oligosaccharide)of 1.02.Under the optimal conditions,the final product,the selenium content,reached 1.302%.The results of cell experiments showed that COSSe significantly inhibited SKOV3 proliferation in a concentration-dependent manner.RNA-seq results showed that chitosan oligosaccharide and COSSe significantly modulated the expression of genes’DNA metabolic processes and cell cycle in SKOV3 cells.Gene enrichment analysis showed the inhibition of the cell cycle,and the results of flow cytometry showed that SKOV3 cells increased in the S phase and decreased in the G2/M phase,with a noted suppression in the protein expression of cyclin-dependent kinase 2(CDK2)and cyclin A1(CCNA1).Conclusion:COSSe has a stronger effect than chitosan oligosaccharide,leading to the arrest of the cell cycle in the S phase.Thus,COSSe may be an effective candidate for the treatment of ovarian cancer.

Antoioxidant Activity of Carboxymethyl Chitosan with Different Substituted Degrees

[Objective] In order to study the relations among different positions, degrees of substitution and antioxidant ability. [Method] N, O-carboxymethyl chitosan （NOA, NOB and NOC）with various degrees of substitution （DS）were obtained by etherizing chito-oligosacchaside. Their structure and substituted degree were characterized and their antioxldant activity to·OH was evaluated. [ Result] The IC50 s of NOA ,NOB and NOC were 0.15 ,0. 29 ,0. 23 mg/ml while their DSs of -NH2 position（DSN） were 0.51,0.29 and 0.38 and DSo were 0. 74 ,0. 84 ,0. 97respectively.[ Conclusion] With the increase of DSN ,antioxidant activity of N,O-carboxymethyl chitosan oligosaccharide to·OH was up.

The ceRNA Network Indicates Its Immune Function in Peripheral Blood Leukocytes of Half-Smooth Tongue Sole(Cynoglossus semilaevis)After Stimulation with Chitosan Oligosaccharide

As an efficient immunostimulant,chitosan oligosaccharide(COS)can enhance the immunity of teleosts;however,the underlying molecular mechanisms still require elucidation.Competing endogenous RNAs(ceRNAs)are vital regulators in the immune response,but their roles in half-smooth tongue sole(Cynoglossus semilaevis)remain unclear.In this study,for the first time,we studied whole-transcriptome expression profiles and analyzed ceRNA networks in peripheral blood leukocytes of half-smooth tongue sole treated with COS.A total of 19 circRNAs(DE-circRNAs),18 miRNAs(DE-miRNAs)and 50 previously identified lncRNAs(DElncRNAs)were differentially expressed after COS stimulation.The DE-lncRNAs and DE-miRNAs targeted numerous immunity-related genes,and were enriched in important pathways,including MAPK and Toll-like receptor signaling pathways,suggesting the immunoregulatory roles of COS.Furthermore,we constructed circRNA-miRNA-mRNA and lncRNA-miRNA-mRNA regulatory networks using DE-circRNAs,DE-miRNAs,DE-lncRNAs,and DE-mRNAs.Additionally,a ceRNA network with immunity-related DEmRNAs was constructed,showing that 3 DE-circRNAs,12 DE-lncRNAs,and 29 DEGs exhibited crosstalk through 9 DE-miRNAs.Intriguingly,a DE-miRNA in the ceRNA network,miR-144-3p,was targeted by DE-lncRNA tnrc6a,and negatively regulated the genes of inhibitor of nuclear factor kappa B kinases(IKKs)(ikbkg,ikbkb,and ikbip)and c3ar1.Ikbkg,ikbkb,and c3ar1 were significantly up-regulated in macrophages stimulated by LPS.It could be inferred that ncRNAs participated in the immune and inflammatory response by acting as ceRNAs after COS stimulation in teleosts.These findings indicate that COS could enhance the immunity of teleosts by regulating ncRNAs,and lay the foundation for further practical application of COS in aquaculture.

Encapsulation of Clove Oil Nanoemlusion in Chitosan-Based Nano-Composite: In Vitro and in Vivo Antifungal Activity against Rhizoctonia solani and Sclerotium rolfsii

Rhizoctonia solani Kühn and Sclerotium rolfsii Sacc.are the primary soil-borne plant diseases responsible for sig-nificant reductions in global crop yields.The primary goal of this study was to investigate the antifungal potentials of clove essential oil(CEO),nanoemulsion form(CEONE)and chitosan/nanoemulsion nanocomposite(CS/CEONE)against R.solani and S.rolfsii through in vitro and in vivo trials.Both CEONE and CS/CEONE were prepared and investigated for their physical chemical and morphological characterization.The poisoned medium method was utilized to evaluate the inhibitory effects of CEO,CEONE and CS/CEONE on the mycelial growth and enzymatic activity of R.solani and S.rolfsii.The changes of hyphae of R.solani and S.rolfsii in response to treating with CEONE and CS/CEONE were observed with scanning electron microscope(SEM).The results revealed that CEONE have larger size 86±3 nm and a broader range of PDI 0.121±0.011 on the average.While,CS/CEONE has smaller size of 49±4 nm and narrower PDI of 0.099±0.009.Both nanoemulsions had uniform spherical nanodroplets form and exhibited acidic nature.Fourier Transform Infrared Spectroscopy(FTIR)and UV-Visible Spectroscopy(UV-Vis)verified the successful incorporation of both CS and CEO within the nanoe-mulsion system.The results demonstrated a sustained and prolonged release profile from CS/CEONE for up to 4 days.The inhibitory effect of CEONE and CS/CEONE showed dose-dependent activity against mycelial growth of both fungi.CEONE and CS/CEONE at concentration 500µL/L exhibited the strongest inhibition with a sig-nificant(p<0.05)variation among them with value ranging from 56.11%to 71.94%and 52.2%to 79.2%,respec-tively.Comparing to control,CS/CEONE revealed the highest inhibitory effect against S.rolfsii after 96 h followed by CEONE with value reached 50.6%and 44.1%,respectively.The antifungal activity of the nanoemulsion showed strain–dependent behavior,where S.rolfsii was the most affected.SEM images showed changes in the hyphal structure of S.rolfsii and R.solani resulting from the impact of CEONE and CS/CEONE.Activity of pectinase and cellulase secreted by both fungi was also negatively affected by CEO,CEONE and CS/CEONE at all tested concentrations.Greenhouse trials revealed that increasing the concentrations of CEO,CEONE,and CS/CEONE from 50 to 500μL/L gradually increased their effectiveness in reducing the DI%and DS%of black scurf,stem canker,pre-damping off,and post-damping off diseases on potato.The results suggest that incorporation of CS to CEONE enhanced its activity and can be utilized as a secure and non-toxic nanocomposite.

Adsorption of Cr(VI) by modified chitosan from heavy-metal polluted water of Xiangjiang River, China

Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate reparative adsorption for Cr（VI） from the polluted Xiangjiang River water. A comparative X-ray analysis shows that the degree of crystallization in the imprinted polymer was significantly weakened, the area of the non-crystalline region was larger. There were more adsorption sites in the imprinted polymer, and the adsorption capacity towards Cr（VI） was increased. The adsorption capacity of the imprinted polymer towards Cr（VI） increased with time and reaches saturation after 8 h. The optimal adsorption time was 4-8 h after the adsorption starting and the optimal pH value for the solution was in the range of 4.5-7.5. When the chitosan reaches saturation, the adsorption capacity achieves a state of equilibrium, and the maximum Cr（VI） extraction rate reaches 33.7%. Moreover, the adsorption capacity of the imprinted polymer towards Cr（VI） increases with increasing chitosan concentration. In this situation, the Cr（VI） extraction rate shows little variation, and the maximum removal rate can reach 98.3%. Furthermore, the Cr（VI） extraction rate increases with an increase in the degree of deacetylation in the chatoyant and chitosan, with the best adsorption effect corresponding to 90% deacetylation. Fitting the adsorption data to the quasi first- and second-order kinetic models yields correlation coefficients of 0.9013 and 0.9875, respectively. The corresponding rate constants for the two models are 0.0091 min-1 and 7.129 g/（mg.min）, respectively. Hence, the adsorption using Cr（VI）-imprinted chitosan is more consistent with the second-order kinetics. Comparing the data to Freundlich and Langrnuir adsorption isotherms shows that the latter has a better linear fit and a maximum adsorption capacity of 15.784 mg/g.

Adding chitosan nanoparticles of green tea extract in diluent and thawing temperatures ameliorate the post-thawed quality of Boer buck semen

Objective:To improve the quality of post-thawing Boer buck semen for artificial insemination by adding green tea extract chitosan nanoparticles to skimmed egg yolk diluent,and the proper thawing temperature.Methods:The ejaculate of Boer buck was added to skimmed egg yolk diluent without(the control group)and with adding 1μg of chitosan nanoparticles of green tea extract per mL of diluent(the treatment group).Then,the diluted semen was filled in French mini straws containing 60×106 live sperm per straw,frozen in a standard protocol,and stored as frozen semen at−196℃for a week.Six replicates from each group were diluted for 30 s at 37℃or 39℃sterile water to evaluate the semen quality.Results:Post-thawing(at 37℃or 39℃)of live sperm,progressive motility,and plasma membrane integrity were lower compared to those of the pre-freezing stage(P<0.05).Thawing at 37℃resulted in no significant difference in live sperm,progressive motility,and plasma membrane between the control group and the treatment group(P>0.05).The live sperm,progressive motility,and plasma membrane of the treatment group in the pre-freezing stage,and post-thawed at 39℃were higher compared to those of the control group(P<0.05).There was no significant difference in malondialdehyde(MDA)concentration,DNA fragmentation,and catalase concentration of thawing at 37℃compared to those of 39℃in the same group.The MDA concentration and DNA fragmentation in thawing at 37℃and 39℃of the treatment group were significantly lower than those of the control group(P<0.05).However,the catalase concentration in thawing at 37℃and 39℃of the treatment group was not significantly different than the control group(P>0.05).Conclusions:Higher quality post-thawing Boer buck semen is achieved by adding 1μg/mL of chitosan nanoparticles of green tea extract to the skimmed egg yolk diluent and thawing at 39℃.

Extraction, Production and Quality Evaluation of Margarine from Oil Extracted from Waste Biomass Peels of Avocado and Virgin Coconut Oil, Using Chitosan from Reared Shells as Preservative

The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable and palatable with R20 being most palatable and the most accepted being R26 with a mean score of 7.07 ± 0.70. Decrease in color intensity increased acceptability. This study therefore demonstrated that avocado peel waste biomass can be valorized by using it as raw material for oil extraction, which can serve as good material for the production of trans-free margarines with good oxidative stability, functional and antioxidant properties.

Release Model of Water-soluble Chitosan Nanoparticles for Protein Delivery

[Objective] The experiment aimed to explore release rule of water-soluble chitosan (WSC) in vitro. [Method]The bovine serum albumin(BSA) was taken as a model protein drug and some existing release models such as Kinetics model, Gompertz model, Weibull model, Higuchi model and Logistic model were used to fit the BSA release profile from WSC carriers. [Result] Except Higuchi model and Logistic model, other models could fit BSA release profile better. [Conclusion] Gompertz two-order kinetics model could fit the release of WSC nano-particles better and model parameters had practical physical meaning.

ZnO Incorporated Acrylamide Grafted Chitosan Based Composite Film for Advanced Wound Healing Applications

This study was carried out to prepare ZnO nanoparticles incorporated acrylamide grafted chitosan composite film for possible biomedical application especially drug loading in wound healing. ZnO nanoparticles were prepared by co-precipitation method from zinc acetate di-hydrate and incorporated in acrylamide grafted chitosan. FT-IR and TGA of the prepared composite film confirmed the successful incorporation of ZnO nanoparticles in the acrylamide-grafted polymer matrix. SEM images showed that the ZnO nanoparticles were homogeneously distributed on the porous matrix of the composite film. Water uptake and buffer uptake analysis revealed that the composite film could hold water and buffer sufficiently, which facilitated the absorption of exudate from the wound site. Amoxicillin was loaded in the prepared composite film and the maximum loading efficiency was found to be 67.33% with drug concentration of 300 ppm. In vitro studies showed greater antimicrobial activity of drug-loaded composite film compared to both pure film and standard antibiotic disc. Finally, the In vivo mouse model showed maximum healing efficiency compared to conventional gauge bandages because the loading of antibiotic in the film produced a synergistic effect and healing time was reduced.