Chitosan Particles Research Articles

Synthesis of nanochitosan from oyster pearl shell (Pinctada maxima) as renewable energy candidate

The increase in energy needs must be balanced by environmentally friendly technological innovations. Chitosan polymer is one of the technological innovations of energy materials that are being developed by many developed countries. This research aimed to identify the potential of oyster pearl shell waste as a source of electrolyte polymers. The study was conducted experimentally by synthesizing chitosan nanoparticles from chitosan using the ionic gelation method. Chitosan is obtained through the isolation method from Pinctada maxima oyster pearl shell waste. The isolation method is carried out by three processes: deproteination, demineralization, and deacetylation. Several characterizations were carried out to analyze the material from the synthesis, including a proximate test, FTIR analysis, and PSA analysis. Isolated chitosan was identified to have a deacetylation degree that reached 88.63% with the formation of OH and NH2 functional groups. In general, the proximate tets data has shown that the obtained chitosan already meets the Indonesian standard SNI 7949:2013. PSA analysis resulted in differences in size distribution, PDI, and zeta potential between chitosan and chitosan nanoparticles. The results were obtained by the average distribution of chitosan particle size of 52.043 μm and chitosan nanoparticle size of 2.3365 μm—the analysis of the potential zeta of chitosan -3.9 mV and chitosan nanoparticle -21,6 mV. Thus, changes in the size of the chitosan material affect its potential PDI and zeta values. The change of these two values is a good indicator of the initial data and the potential of the material as an energy material. Therefore, chitosan polymer is an electrolyte material that can be used as a candidate for environmentally friendly renewable energy materials

Dual drug delivery systems based on natural and synthetic polymer particles for isoniazid and rifampicin vehiculization

AbstractThe purpose of this work is the design and characterization of novel systems based on micro and nanoparticles prepared from poly(lactic‐co‐glycolic) acid (PLGA), chitosan (CHT) and gelatin (GEL) for compartmentalization and dual release of rifampicin and isoniazid. The emulsion/evaporation method is employed for the preparation of PLGA based microparticles and nanoparticles. CHT and GEL are used for the preparation of microparticles by spray‐drying. Entrapment efficiencies are in the range of 35%–73% and 5%–29% for rifampicin and isoniazid in PLGA microparticles, respectively. For isoniazid GEL:CHT particles the entrapment efficiencies are within 82%–100%. Isoniazid shows a complete release at acid condition from GEL:CHT particles, while rifampicin release is maintained from GEL:CHT particles or displays an slightly increase from PLGA particles during buffer conditions. Antimycobacterial activity experiments show that the formulations present the ability to inhibit the bacterial growth in comparison with a control culture without treatment. Rifampicin PLGA and isoniazid GEL:CHT microparticles could be used for the preparation of a dual drug delivery system with each antibiotic in a single particulate compartment. GEL:CHT microparticles containing free isoniazid and rifampicin PLGA nanoparticles are a novel two compartment delivery system.

The impact of chitosan nanoparticles on seedling and germination attributes and enzymatic activity of guar (Cyamopsis tetragonoloba L.) under osmotic stress

This research was conducted to examine the effects of nano chitosan particles on seed germination and seedling growth of guar (Cyamopsis tetragonoloba L.) under osmotic stress conditions. This experiment was conducted in a factorial layout based on a completely randomized design with two factors and four replications. The experimental factors included: osmotic stress at five levels (0, −3, −6, −9 and −12 bar) and seed priming with nano chitosan particles at five concentrations (0, 50, 100, 200, and 300 ppm). The evaluated parameters in this study were alometric traits and enzymatic activities including proline, catalase, ascorbate peroxidase, superoxide dismutase, and total soluble sugar, as well as the content of chlorophyll a, b, and carotenoids. The results indicated the significant effect of most of the studied quantitative and qualitative traits. The highest values of seedling, plumule and radicle length (48.20, 17.79 and 30.15 mm, respectively), and the fresh weight of seedlings and plumule (0.9743 and 0.9192 g, respectively) were observed at a concentration of 200 ppm of chitosan nanoparticles. The highest amount of all studied parameters observed under non-stress conditions (control), and the lowest values of them obtained in −12 bar of osmotic stress. Furthermore, by increasing of osmotic stress levels, germination percentage and rate and seed vigor showed a decreasing trend about 56, 83 and 95% compared to the control. Besed on the interaction effects, the maximum values of seedling and plumule length were achieved with the application of 200 ppm chitosan nanoparticles in combination with no osmotic stress. Under non-osmotic conditions, concentrations of 300, 100, and 200 ppm chitosan led to the highest values of germination percentage and rate and seed vigor, respectively. Additionally, the highest percentage of normal seedlings (94%) and the lowest percentage of abnormal seedlings (zero) were obtained under the application of 200 ppm of nano chitosan and no osmotic stress. In relation to qualitative traits, the lowest values of soluble sugar and proline were obtained at the osmotic level of −12 bar. Moreover, the application of 200 ppm of nano chitosan and −6 bar of osmotic stress resulted in the highest levels of catalase, superoxide dismutase, ascorbate peroxidase, chlorophyll a, b, and carotenoids. As a whole, the results of the study demonstrated that seed priming with chitosan nanoparticles can reduce the negative effects of drought stress on guar seedlings. In addition, application of 200 ppm of this substance was the most suitable treatments that improve most quantitative and qualitative indices of guar. Keywords: Enzymatic activity, Nano particles, Priming, Seed structure.

Prevention of secondary caries using fluoride-loaded chitosan nanoparticle-modified glass-ionomer cement.

To study the effect of incorporating chitosan and fluoride-loaded chitosan nanoparticles into a glass-ionomer cement (GIC) to prevent secondary caries. A standard cervical cavity (mesio-distal width 6mm, cervico-occlusal width 2mm, and depth 2mm) was prepared on 30 molars for the following restoration groups: group 1, conventional GIC restoration; group 2, chitosan (10%) modified GIC restoration; group 3, fluoride loaded chitosan nanoparticles (10%) modified GIC restoration. The restored teeth were subjected to 1,500 thermal cycles before undergoing a multi-species cariogenic biofilm challenge. The restored teeth were examined by micro-computed tomography (micro-CT), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). Data were analyzed by the one-way ANOVA, Tukey HDS, Kruskal Wallis, and Dunn's test. Micro-CT determined outer lesion depths for groups 1-3 were: 614 ± 20μm, 589 ± 17μm, and 560 ± 19μm respectively. Both modifications with chitosan and fluoride-loaded chitosan nanoparticles significantly affected outer lesion depth (p < 0.05). The modification with fluoride-loaded chitosan nanoparticles statistically significantly decreased the outer lesion depth compared to all other groups (p < 0.05). SEM/EDX showed an increase of calcium, phosphorus, and fluoride at the root dentine adjacent to the restoration in groups 2 and 3 (modified GIC). This increase was statistically significantly higher in the group modified with fluorine-loaded nano chitosan particles compared to the other groups (p < 0.05). Incorporation of 10% chitosan and 10% fluoride-loaded chitosan nanoparticles into GIC restorative material can prevent secondary root caries development. 10% fluoride-loaded chitosan nanoparticles were more effective. Glass ionomer cement modified with fluoride-loaded chitosan nanoparticles may be a promising restorative material in pediatric and preventive dentistry due to their controlled release properties.

High internal phase Pickering emulsion solely stabilized by low-content chitosan: Insight into relations between network microstructures and rheological properties

Nano-sized and well-dispersed chitosan particles (CSPs) are prepared by adjusting pH towards pKa of chitosan (CS) aqueous solutions. The prepared CSPs are able to stabilize high internal phase Pickering emulsions (HIPPEs) with low CSP contents, at minimum of 0.2 wt% CSP stabilizing a maximum of 85 % oil phase fraction in a near-neutral environment. It is clarified by microscopy, small amplitude oscillatory shear (SAOS) and large amplitude oscillatory shear (LAOS) measurements that CSPs act as Pickering particle emulsifiers to form a network immobilizing oil droplets in HIPPEs. Using power-law analysis on SAOS results, the solid-like but frequency-dependent rheological response is attributed to the physical connection among CSPs, while the overshoot of the loss modulus in LAOS test is assigned to the featured resistance of networks to the applied large deformation. The oil phase fraction, CSP concentration, temperature and ionic strength are found to be key factors for the rheological behavior and emulsion stability. This work is expected to guide the design and processing of HIPPE stabilized solely by polysaccharides.

Cinnamon essential oil incorporated chitosan submicron emulsion as a sustainable alternative for extension of mango shelf life

In the present study, cinnamon bark essential oil (CEO)-incorporated chitosan-based submicron emulsion coatings (CEO-CSSEs) were successfully prepared by an ionic gelation method using sodium tripolyphosphate (STPP) as a crosslinking agent and Tween 20 as a surfactant. A chitosan:CEO mass ratio ≤1:0.5 was found to have a unimodal and narrow size distribution. The FTIR absorption bands confirmed the successful encapsulation of CEO into the chitosan particles, which exhibited a spherical shape and aggregated regions with cracks. Acute oral toxicity tests revealed that the cinnamon bark essential-loaded chitosan submicron emulsion was nontoxic and could be used for coating mango fruits. Postharvest submicron emulsion coatings on mangos significantly delay physio-chemical changes linked to ripening. However, mangos coated with CEO-CSSEs at 1:0.75 and 1:1 ratios remained unripen, while those coated with CEO-CSSEs at 1:0.5 ratio ripened slowly, implying a negative impact of CEO at higher concentrations on mango quality and shelf quality. Therefore, it is concluded that CEO-CSSEs at 1:0.5 successfully slowed different physio-chemical parameters linked to the deterioration of mango quality; thus, treatments can be suggested to extend the shelf life to 18 days during ambient storage at 25 ± 2 °C and 65% RH.

Macroporous cellulose microspheres with high specific surface area via semi-dissolved chitosan templating for protein separation

The conflict between macroporous structure and high specific surface area strongly limited the dynamic adsorption performance of chromatographic media. Here, macroporous and high-specific-surface-area cellulose microspheres (PCMs) are prepared by using semi-dissolved chitosan as a dual-functional template and subsequently functionalized with diethylaminoethyl (DEAE) as anion exchangers for protein separation. The dual-functional template strategy leverages dissolved chitosan nanofibers as meso/micropore templates and the undissolved chitosan particles as macropore templates. The macropores of DEAE-PCMs (average size: 0.4–1.2 μm) efficiently decrease mass transfer resistance for fast uptake kinetics. The high specific surface area (272.34 m2/g) provides sufficient ligand sites for ensuring exceptional adsorption capacities. Therefore, the chitosan bifunctional templated PCMs, possessing a macro/meso/microporous structure, are promising candidates for high-performance chromatographic media.

Encapsulation of β-carotene in Pickering emulsions stabilized by self-aggregated chitosan nanoparticles: Factors affecting β-carotene stability

For conventional emulsions used to encapsulate easily degradable bioactive compounds, achieving small droplet size and high encapsulation capacity is a challenging. Pickering emulsions stabilized by self-aggregated chitosan particles may offer high encapsulation efficiency due to the robust mechanical barrier formed by solid particles adsorbed at the oil-water interface. Therefore, the effects of pH, chitosan concentration, oil volume fraction, homogenization pressure, and homogenization cycle on the stability of chitosan Pickering emulsions and the degradation of β-carotene were investigated. Effective interfacial adsorption of chitosan nanoparticles and moderate homogenization intensity facilitated the formation of small emulsion droplets. Unlike conventional emulsions, chitosan Pickering emulsions with smaller droplets provided enhanced protection for β-carotene. This enhancement was primarily attributed to the improved interfacial coverage of chitosan nanoparticles with smaller droplet sizes, which was advantageous for β-carotene protection. The optimal conditions for preparing β-carotene-loaded chitosan Pickering emulsions were as follows: pH 6.5, chitosan concentration of 1.0 wt%, oil volume fraction of 20 %, homogenization pressure of 90 MPa, and 6 homogenization cycles. These findings indicate that chitosan Pickering emulsions are well-suited for encapsulating β-carotene with both small droplet size and high encapsulation efficiency.

Nanocarrier optimization: Encapsulating Hydrastis canadensis in chitosan nanoparticles for enhanced antibacterial and dye degradation performance

This study focuses on the optimization of Hydrastis canadensis-based nanocarriers in environmental and microbial applications like antibacterial and dye degradation. Hydrastis canadensis (H. canadensis) is loaded into the nanocarrier using a gelation method. Characterization involves pH analysis, UV-VIS spectrophotometry, scanning electron microscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, high-performance liquid chromatography, encapsulation efficiency. Further antimicrobial activity against Staphylococcus aureus and Escherichia coli were tested. Dye degradation was evaluated at concentrations of 1 % of high molecular (HM) and 1.5 % of low molecular (LM) chitosan nanoparticles with both 3C and 1000C concentrations of the drug. The obtained results confirm the presence of chitosan nanocarrier alongside the pure drug in 1 % HM and 1.5 % LM chitosan particles with a notable encapsulation efficiency activity in both 3C and 1000C concentrations. Antimicrobial studies were carried out using the agar well diffusion method and revealed a significant zone of inhibition of 20 mm and 25 mm for E. coli and S. aureus, respectively in chitosan nanocarrier-loaded samples compared to pure drug and chitosan nanocarriers samples. The dye degradation studies of four dyes methylene blue, methylene orange, methylene red, and safranin using both pure drugs and chitosan nanocarrier-loaded drugs showed the highest percentage of degradation (76 %) against methylene blue in the chitosan nanocarrier-drug loaded formulation. These findings cumulatively underscore chitosan nanoparticles can be used as an effective carrier for Hydrastis Canadensis, with enhanced antimicrobial and dye degradation capabilities. Varied concentrations and molecular weights highlight the versatility of the ionotropic gelation method in optimizing drug delivery. Enhanced efficacy of the nanocarrier was evident in the observed zone of inhibition in antimicrobial testing. The substantial degradation percentage in methylene blue emphasizes the formulation's applicability in environmental dye removal processes, with potential avenues for improvement explored through interactions between the chitosan nanocarrier and H. canadensis characteristics. Future investigations may focus on scaling up the optimized formulation for large-scale applications and exploring release kinetics and comprehensive toxicity assessments for a holistic understanding of potential environmental and biomedical implications.

The numerical simulation investigates the influence of agitator parameters on particle suspension characteristics

This study investigates the effect of different agitator parameters in a baffleless stirred reactor on solid particle suspension during quaternary ammonium chitosan synthesis. Computational Fluid Dynamics (CFD) simulations investigate different agitator configurations, including blade diameter, rotational speed, and bottom clearance, to optimize chitosan particle distribution. Reducing the bottom clearance reduces particle accumulation, but can create stagnant zones that may disrupt fluid flow. Increasing the rotational speed improves particle distribution until a saturation point is reached. Increasing paddle diameter improves axial fluid circulation. Optimal settings for the vane size of a 180 mm reactor vessel are identified as 0.45 times the diameter, with a speed of 350 rpm, and a bottom clearance of 0.25 times the diameter. These simulations provide critical insight into the suspension of solid particles in baffleless stirred reactors and provide valuable guidance for optimizing stirrer parameters.

Chitosan-Cement Composite Mortars: Exploring Interactions, Structural Evolution, Environmental Footprint and Mechanical Performance.

The increasing environmental concerns about synthetic polymers as reinforcement in the construction industry have highlighted the need for eco-friendly, biodegradable fibers as potential alternative materials for cementitious composites. This study examines the influence of chitosan particle concentrations on the midterm compressive strength of mortars. Chitosan particles, derived from shrimp shells, were mixed with high early strength hydraulic cement at various percentages (0, 0.05, 0.25, 0.5, 1, and 2 wt %) and silica sand to prepare the mortar samples. The findings indicate that chitosan affects the hydration process through the distribution of chitosan particles within the mortar matrix and slightly improved midterm mechanical properties. A life cycle assessment (LCA) revealed a slight increase in greenhouse gas emissions and embodied energy for chitosan-modified mortars, likely due to the use of chemicals in the chitosan synthesis and purification process. In fact, the addition of 0.25 wt % of chitosan into the mortar only added 1.3% of the global warming potential of the sample when compared to the control sample. Incorporating chitosan into a mortar matrix does not significantly affect the resistance-mechanical properties of the composite. The hydration of the cement mortar appears to be slowed by the inclusion of chitosan particles in the cementitious matrix. This research lays the groundwork as one of the first studies for the development of high-performance, early strength cement using chitosan, contributing to a more sustainable construction industry.

Innovative multifunctional fire retardance of poly(butylene adipate-co-butylene terephthalate)-based bio-composite formulation

Poly(butylene adipate-co-butylene terephthalate) (PBAT), a biodegradable aromatic-aliphatic copolyester, has been widely applied in various fields, but it shows the flammability, resulting in serious fire risk. The flame retardancy of some PBAT/polymer blend systems have been studied, but that of neat PBAT was seldom reported. In particular, the research and development of the bio-based green flame retardant agent is highly desired. In this work, fully bio-derived modified chitosan particles (C-CS), were synthesized and used to prepare a novel PBAT-based multifunctional flame-retardant composite. The PBAT/3%C-CS composite (PC3) exhibited an excellent anti-dripping and self-extinguishing performance and achieved the highest fire safety rating (V-0). Peak of heat release rate and total heat release reduced by 39.8 % and 14.9 %, respectively. The char residue yield of the PC3 increased by 211.6 % in the PC3, compared with that of neat PBAT. Both condensed- and gas-phase played dual roles on increasing the flame-retardant performance of the PC3. The PC3 showed a relatively compact and continuous char layer which acted as a physical barrier to suppress the heat exchange and O2 entry (into the matrix) in the combustion process. Meanwhile, the concentration of O2 and H·/HO· free radicals were diluted by a small portion of non-flammable gas products in the pyrolysis process. Also, the PC3 presented elevated crystallizability and anti-bacterial effect, and reduced UV-transmittance characteristic.

Innovative Vancomycin-Loaded Hydrogel-Based Systems - New Opportunities for the Antibiotic Therapy.

Surgical site infections pose a significant challenge for medical services. Systemic antibiotics may be insufficient in preventing bacterial biofilm development. With the local administration of antibiotics, it is easier to minimize possible complications, achieve drugs' higher concentration at the injured site, as well as provide their more sustained release. Therefore, the main objective of the proposed herein studies was the fabrication and characterization of innovative hydrogel-based composites for local vancomycin (VAN) therapy. Presented systems are composed of ionically gelled chitosan particles loaded with vancomycin, embedded into biomimetic collagen/chitosan/hyaluronic acid-based hydrogels crosslinked with genipin and freeze-dried to serve in a flake/disc-like form. VAN-loaded carriers were characterized for their size, stability, and encapsulation efficiency (EE) using dynamic light scattering technique, zeta potential measurements, and UV-Vis spectroscopy, respectively. The synthesized composites were tested in terms of their physicochemical and biological features. Spherical structures with sizes of about 200 nm and encapsulation efficiencies reaching values of approximately 60% were obtained. It was found that the resulting particles exhibit stability over time. The antibacterial activity of the developed materials against Staphylococcus aureus was established. Moreover, in vitro cell culture study revealed that the surfaces of all prepared systems are biocompatible as they supported the proliferation and adhesion of the model MG-63 cells. In addition, we have demonstrated significantly prolonged VAN release while minimizing the initial burst effect for the composites compared to bare nanoparticles and verified their desired physicochemical features during swellability, and degradation experiments. It is expected that the developed herein system will enable direct delivery of the antibiotic at an exposed to infections surgical site, providing drugs sustained release and thus will reduce the risk of systemic toxicity. This strategy would both inhibit biofilm formation and accelerate the healing process.

Oral delivery of nanomedicine for genetic kidney disease.

Chronic and genetic kidney diseases such as autosomal dominant polycystic kidney disease (ADPKD) have few therapeutic options, and clinical trials testing small molecule drugs have been unfavorable due to low kidney bioavailability and adverse side effects. Although nanoparticles can be designed to deliver drugs directly to the diseased site, there are no kidney-targeted nanomedicines clinically available, and most FDA-approved nanoparticles are administered intravenously which is not ideal for chronic diseases. To meet these challenges of chronic diseases, we developed a biomaterials-based strategy using chitosan particles (CP) for oral delivery of therapeutic, kidney-targeting peptide amphiphile micelles (KMs). We hypothesized that encapsuling KMs into CP would enhance the bioavailability of KMs upon oral administration given the high stability of chitosan in acidic conditions and mucoadhesive properties enabling absorption within the intestines. To test this, we evaluated the mechanism of KM access to the kidneys via intravital imaging and investigated the KM biodistribution in a porcine model. Next, we loaded KMs carrying the ADPKD drug metformin into CP (KM-CP-met) and measured in vitro therapeutic effect. Upon oral administration in vivo, KM-CP-met showed significantly greater bioavailability and accumulation in the kidneys as compared to KM only or free drug. As such, KM-CP-met treatment in ADPKD mice (Pkd1fl/fl;Pax8-rtTA;Tet-O-Cre which develops the disease over 120 days and mimics the slow development of ADPKD) showed enhanced therapeutic efficacy without affecting safety despite repeated treatment. Herein, we demonstrate the potential of KM-CP as a nanomedicine strategy for oral delivery for the long-term treatment of chronic kidney diseases.

New magnetic nanocomposites based on hexafrite and keggin-type -type heteropolyanions: Synthesized and characterized for removal of environmental pollutants

This research paper details the creation of innovative nanocomposites using the sol-gel technique, incorporating polyoxometalates SiW9Ba3 to stabilize ceramic particles of strontium ferrite (SrFe12O19) polymer and Chitosan (CS). The identification and confirmation of the nanocomposites obtained at each stage were carried out through the use of FT-IR, EDX, XRD, and FESEM analyses. To evaluate their ability to remove organic dyes, we analyzed the catalytic activity of these nanocomposites during photocatalytic detoxification procedures. With its exceptional photocatalytic properties, the nanocomposite (SiW9Ba3@SrFe12O19@Cs) was able to remove estamipride poison at an impressive rate of 85 % and xylene dye solution at an even higher rate of 98 %. In addition, an extensive examination was undertaken to explore the primary variables that influence process efficiency. The study suggests that ceramic nanocomposites incorporating heteropolyoxometalate may offer a viable approach to effectively eradicate pollutants from the environment.

Mechanical Properties of Individual Porous Chitosan Particles: Full Scale and Numerical Experiments

Mechanical Properties of Individual Porous Chitosan Particles: Full Scale and Numerical Experiments

Aspirin/amoxicillin loaded chitosan microparticles and polydopamine modified titanium implants to combat infections and promote osteogenesis

It is known that titanium (Ti) implant surfaces exhibit poor antibacterial properties and osteogenesis. In this study, chitosan particles loaded with aspirin, amoxicillin or aspirin + amoxicillin were synthesized and coated onto implant surfaces. In addition to analysing the surface characteristics of the modified Ti surfaces, the effects of the modified Ti surfaces on the adhesion and viability of rat bone marrow-derived stem cells (rBMSCs) were evaluated. The metabolic activities of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) biofilms on the modified Ti surfaces were also measured in vitro. Moreover, S. aureus was tested for its antibacterial effect by coating it in vivo. Using water as the droplet medium, the contact angles of the modified Ti surfaces increased from 44.12 ± 1.75° to 58.37 ± 4.15°. In comparison to those of the other groups tested, significant increases in rBMSC adhesion and proliferation were observed in the presence of aspirin + amoxicillin-loaded microspheres, whereas a significant reduction in the metabolic level of biofilms was observed in the presence of aspirin + amoxicillin-loaded microspheres both in vitro and in vivo. Aspirin and amoxicillin could be used in combination to coat implant surfaces to mitigate bacterial activities and promote osteogenesis.

Chitosan/PVA Films and Silver Nanoparticle Impregnated Nanofibrous Dressings for Evaluation of their Wound Healing Efficacy in Wistar Albino Rat Model

The exoskeleton of marine shrimp contains a natural, biocompatible polymer chitin, which is dumped as a waste. The study proposes the sustainable single-pot-extraction of chitosan from the waste and its use in the fabrication of wound-dressings, and thus leverage its piezoelectric, antioxidant, hypoglycaemic and medicinal properties in wound-healing. The Fourier transform infrared spectrum revealed that marine chitosan contains functional groups with N-O, O-H, and CO stretching. Scanning electron micrographs demonstrated the spherical and mesoporous structures of the extracted chitosan. X-ray diffraction analysis showed a semi-crystalline phase of chitosan particles with a mean size of 28.9 nm. The film prepared with marine shrimp chitosanpolyvinyl alcohol (PVA) composite, and used as a wound dressing exhibited significant wound healing properties with a regeneration efficiency of 78% in 8 days in Wistar albino rats. The wound healing efficiency was enhanced by the addition of cost effective, non-toxic/environmentally friendly silver nanoparticles (AgNPs) synthesized from Rumex acetosa (sorrel) plant extracts and electrospinning of the nanofibrous composites of chitosan/PVA/AgNPs with high antibacterial, antioxidant and wound healing capacity of 96% in 8 days. Thus, the current study supports the use of a natural piezoelectric chitosan polymer as a wound dressing material, either in film or nanofiber, for normal as well as diabetic wounds.

Tailoring the adhesion of electrophoretic chitosan/bioactive glass coatings by the combined surface pre-treatments of Ti substrates

Composite chitosan/bioactive glass coatings developed by electrophoretic deposition (EPD) attract researchers' attention owing to their advantageous effect on the biological and corrosion responses of commonly used biomedical materials. However, fabricating a uniform coating with satisfactory adhesion to the biomaterials substrate is challenging, because chitosan and bioglass particles having different mobilities during the EPD process. Typically, attempts are made to improve adhesion by manipulating the EPD parameters. This work presents an alternative approach that involves combined mechanical and chemical pre-treatments of the Ti substrate. The surface pre-treatment procedure included shot peening and the following variants of acid etching: (i) HF etching, (ii) NaOH etching, and (iii) HF and NaOH etching. Shot peening followed by etching in HF and NaOH significantly improved the adhesion of the EPD coating. It was found that this effect was due to the development of a highly hydrophilic surface with micro- and nano-scale roughness.

Edible chitosan-based Pickering emulsion coatings: Preparation, characteristics, and application in strawberry preservation

The long-term application of plant essential oils in food preservation coatings is limited by their poor water solubility and high volatility, despite their recognized synergistic antimicrobial effects in postharvest fruit preservation. To overcome these limitations, a Pickering emulsion loaded with thyme essential oil (TEO) was developed by utilizing hydrogen bonding and electrostatic interactions to induce cross-linking of chitosan particles. This novel emulsion was subsequently applied in the postharvest storage of strawberries. The shear-thinning behavior (flow index <1) and elastic gel-like characteristics of the emulsion made it highly suitable for spray application. Regarding TEO release, the headspace concentration of TEO increased from 0.21 g/L for pure TEO to 1.86 g/L after two instances of gas release due to the stabilizing effect of the chitosan particles at the oil-water interface. Notably, no phase separation was observed during the 10-day storage of the emulsion. Consequently, the emulsion was successfully employed for the postharvest storage of strawberries, effectively preventing undesirable phenomena such as weight loss, a decrease in firmness, an increase in pH, and microbial growth. In conclusion, the developed Pickering emulsion coating exhibits significant potential for fruit preservation applications, particularly for extending the shelf life of strawberries.