Incorporation Of Chitosan Research Articles

Tumor Microenvironment Activatable Nanoprodrug System for In Situ Fluorescence Imaging and Therapy of Liver Cancer.

The development of new imaging and treatment nanoprodrug systems is highly demanded for diagnosis and therapy of liver cancer, a severe disease characterized by a high recurrence rate. Currently, available small molecule drugs are not possible for cancer diagnosis because of the fast diffusion of imaging agents and low efficacy in treatment due to poor water solubility and significant toxic side effects. In this study, we report the development of a tumor microenvironment activatable nanoprodrug system for the diagnosis and treatment of liver cancer. This nanoprodrug system can accumulate in the tumor site and be selectively activated by an excess of hydrogen peroxide (H2O2) in the tumor microenvironment, releasing near-infrared solid-state organic fluorescent probe (HPQCY-1) and phenylboronic acid-modified camptothecin (CPT) prodrug. Both HPQCY-1 and CPT prodrugs can be further activated in tumor sites for achieving more precise in situ near-infrared (NIR) fluorescence imaging and treatment while reducing the toxic effects of drugs on normal tissues. Additionally, the incorporation of hydrophilic multivalent chitosan as a carrier effectively improved the water solubility of the system. This research thus provides a practical new approach for the diagnosis and treatment of liver cancer.

Nanowire Array Breath Acetone Sensor for Diabetes Monitoring.

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes characterized by the accumulation of ketone bodies in the blood. Breath acetone, a ketone, directly correlates with blood ketones. Therefore, monitoring breath acetone can significantly enhance the safety and efficacy of diabetes care. In this work, the design and fabrication of an InP/Pt/chitosan nanowire array-based chemiresistive acetone sensor is reported. By incorporation of chitosan as a surface-functional layer and a Pt Schottky contact for efficient charge transfer processes and photovoltaic effect, self-powered, highly selective acetone sensing is achieved. The sensor has exhibited an ultra-wide acetone detection range from sub-ppb to >100 000ppm level at room temperature, covering those in the exhaled breath from healthy individuals (300-800ppb) to people at high risk of DKA (>75ppm). The nanowire sensor has also been successfully integrated into a handheld breath testing prototype, the Ketowhistle, which can successfully detect different ranges of acetone concentrations insimulated breath samples. The Ketowhistle demonstrates the immediate potential for non-invasive ketone monitoring for people living with diabetes, in particular for DKA prevention.

Alginate and Chitosan-Based Hydrogel Enhance Antibacterial Agent Activity on Topical Application.

Untreated topical infections can become chronic, posing serious health issues. Optimal skin adherence is crucial in addressing such infections. In this context, chitosan and alginate emerge as promising candidates for use as a foundation in the development of topical hydrogels. The aim of this review is to examine the literature on topical hydrogel formulations that use chitosan and alginate as foundations, specifically in the context of topical antibacterial agents. The research methodology involves a literature review by examining articles published in databases such as PubMed, Scopus, ScienceDirect, and Google Scholar. The keywords employed during the research were "Alginate", "Chitosan", "Hydrogel", and "Antibacterial". Chitosan and alginate serve as bases in topical hydrogels to deliver various active ingredients, particularly antibacterial agents, as indicated by the search results. Both have demonstrated significant antibacterial effectiveness, as evidenced by a reduction in bacterial colony counts and an increase in inhibition zones. This strongly supports the idea that chitosan and alginate could be used together to make topical hydrogels that kill bacteria that work well. In conclusion, chitosan and alginate-based hydrogels show great potential in treating bacterial infections on the skin surface. The incorporation of chitosan and alginate into hydrogel formulations aids in retaining antibacterial agents, allowing for their gradual release over an optimal period. Therefore, hydrogels specifically formulated with chitosan and alginate have the potential to serve as a solution to address challenges in the treatment of topical bacterial infections.

Green and single-step simultaneous composite starch aerogel formation-high bioavailability curcumin particle formation

The high porosity and specific surface area of aerogels offer an ideal platform for loading bioactive molecules. In the present study, the microstructure of the bio-based starch aerogels was modulated by the incorporation of chitosan. The starch hydrogel precursors were prepared from high amylose corn starch in the presence of 0, 0.50, and 0.75 wt% chitosan. Afterward, a green single-step simultaneous aerogel formation-curcumin deposition method was applied to impregnate curcumin into the aerogels through supercritical carbon dioxide (SC-CO2) drying technology. Composite starch/chitosan aerogels showed a more open porous structure and lighter weight than the neat starch counterpart. Confocal microscopy and fluorescence spectroscopy analysis confirmed curcumin molecules' attachment to the aerogels' hydrophobic cavities. The impregnation capacity was 24–27 mg curcumin per gram of aerogel depending on the composition of the aerogels. The loading of curcumin in the aerogels significantly enhanced the bioaccessibility of curcumin in the simulated gastrointestinal fluid by almost 30-fold when compared to the unloaded curcumin. Furthermore, the bioaccessibility of the curcumin loaded in starch-chitosan composite aerogels was higher than that in neat starch aerogels. While unloaded curcumin showed an undetectable intestinal Caco-2 cell transportation, curcumin-loaded aerogels revealed a cumulative curcumin passing of 0.15–0.23 μg/mL.

Secretion of osteocalcin in chitosan–hydroxyapatite scaffold with seeding of cryopreserved human umbilical cord mesenchymal stem cells

In recent years, regenerative therapy using tissue engineering has rapidly developed. One of the applications is for alveolar bone tissue engineering in prosthodontics. Currently, the most widely developed biomaterial in bone tissue engineering is a scaffold. The incorporation of chitosan and hydroxyapatite (CS-HA) improves osteoconductive ability. Human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) are capable of acting as osteoprogenitors and promoting bone formation. Purpose: To determine the influence of osteocalcin secretion in the CS[1]HA scaffold with seeding of cryopreserved hUCMSCs in vitro. Methods: The thawing process was carried out on frozen hUCMSCs, which were then examined for characterization using immunocytochemistry. The hUCMSCs were seeded on the CS-HA scaffold. Finally, examination of osteocalcin secretion levels was carried out by collecting cell culture supernatant on the 14th and 21st days of observation groups using the human osteocalcin ELISA kit. Results: Immunocytochemistry testing revealed that the hUCMSCs had the characteristics of the MSCs marker, namely positive expression on the CD90 marker and negative expression on the CD45 marker. Scanning electron microscope (SEM) observation revealed that the CS-HA scaffold had a structure with many pores and hUCMSCs could be attached and proliferation among the porosity of the scaffold. Based on the ELISA result, there was a significant difference in the average amount of osteocalcin secretion on days 14 and 21 which indicated osteogenic differentiation. Conclusion: Osteocalcin secretion in the CS-HA scaffold using the seeding of in vitro hUCMSCs demonstrated a bone regeneration process that showed a significant increase on day 21.

Preparation and characterization of peach gum/chitosan polyelectrolyte composite films with dual cross-linking networks for antibacterial packaging

Peach gum (PG) is a valuable polymeric feedstock for developing eco-friendly, bio-safe, and functional materials. However, PG has limited use in food packaging due to its inferior mechanical and antibacterial properties. To overcome these limitations, we created a dual cross-linked network by introducing chitosan (CS) and glycerol to the PG matrix. Our research discovered that incorporating CS into the PG matrix significantly improved its Young's modulus, from 277.62 to 925.89 MPa, and its tensile strength from 5.96 to 39.94 MPa. Furthermore, the inclusion of glycerol greatly increased the elongation. These enhancements were attributed to the ionic and hydrogen-bonding interactions between the two biopolymers. Additionally, the composite films exhibited strong antibacterial effects, reducing the total number of colonies by 99.2 % and 99.9 % against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. The incorporation of CS resulted in more amorphous films, enhancing their stiffness, flexibility, and barrier properties. To assess the practical application of PG/CS composite films, we conducted a comparative analysis between non-packaged strawberries and strawberries packaged with these films. The results demonstrated that the composite polyelectrolyte film extended the shelf life of strawberries better than the non-packaged fruits.

Effect and mechanisms of soil functional groups in bacterial-enhanced cadmium contaminated soil phytoremediation

Considering the detrimental impact of heavy metals on agricultural soils, in situ remediation technology has gained considerable attention worldwide. Green materials have emerged as a promising option for enhancing plant-mediated remediation of contaminated soils. In this study, bacteria capable of mobilising cadmium (Cd) and promoting plant growth were screened and isolated. A synergistic system was established by combining bone meal and chitosan as soil amendments with the Cd-mobilising bacteria to improve the extraction of available Cd from soils by plants. The highest Cd accumulation was observed in the bone meal + bacteria, which increased by 131.81% when compared to the control group (CK). The highest available Cd content was observed in the chitosan + bacteria, which increased by 52.31% when compared to CK. Fourier-transform infra-red spectroscopy and X-ray photoelectron spectroscopy results revealed that organic compounds, such as hydroxyl and carboxyl groups, and aliphatic compounds in the soil were crucial in mobilising Cd. Cd activation occurred through substitution of protons in the functional groups and chelation, leading to the formation of chelates with Cd2+ and in turn, facilitating Cd mobilisation in the soil. The incorporation of bone meal and chitosan into phytoremediation strategies can enhance the ability of bacteria to mobilise Cd, thereby increasing the effectiveness of phytoremediation.

The Impact of Chitosan Incorporation on the Mechanical Characteristics of Biodegradable Packaging based on PLA/PCL Blend

The development of environmentally sustainable plastics has gained prominence due to their eco-friendliness and renewable nature. In this research, eco-friendly plastic was formulated by blending Polylactic Acid (PLA) and Polycaprolactone (PCL) with the incorporation of chitosan as a filler. The primary objective of this study is to scrutinize and delineate the influence of varying compositions of PLA/PCL/chitosan on the mechanical attributes of eco-friendly plastics. This was achieved through hot pressing methods at a temperature of 200°C for a duration of 1 hour. The composition ratios for PLA/PCL were set at 2/8 g, 3/7 g, 5/5 g, 7/3 g, and 8/2 g, while chitosan compositions ranged from 0.2 g to 0.6 g. Comprehensive assessment of the eco-friendly plastics involved biodegradability tests, tensile strength measurements, elongation evaluations, functional group analyses, and examination of plastic film morphology. Optimal performance, ascertained through characterization, was achieved with a composition of PLA/PCL/Chitosan at 8/2/0.6 g, yielding a 38.8% degradation rate, a tensile strength of 42.53 MPa with a composition of PLA/PCL/Chitosan at 8/2/0.4 g, and an elongation of 6.96% with a composition of PLA/PCL/Chitosan at 8/2/0.2 g. The functional groups identified included N-H, C-H, C=O, and C-O groups, indicating a blending process without the formation of new functional groups. Morphology testing revealed a smooth surface, although some undissolved chitosan particles were evident, likely due to non-uniform blending.

Study adsorbents based on bent-Al13-CS-CTA and its application to the removal of CR from wastewater.

For rapid and efficient removal of Congo red (CR) from aqueous solutions, a composite of bent-Al13-CS-CTA was prepared from bentonite (bent), chitosan (CS), citric acid (CTA) and Al13 compounds. To comprehend the adsorption process, adsorption variables were changed, including initial pH of the solution, contact time, temperature, initial CR concentration, and adsorption dose. Bent intercalated with X-ray diffraction (XRD), specific surface area (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR) were used to analyze the material. Physicochemical and structural analysis proven the incorporation of Al13, CS, and CTA into the bent matrix. The pseudo-second-order model aligns with the adsorption kinetics. The adsorption isotherm conformed to the Langmuir adsorption isotherm, with a maximum adsorption capacity of 476.8 mg g-1 at pH 9, a dosage of 2 g L-1, and a temperature of 25 °C. Upon examining the thermodynamic properties of ΔS, ΔH, and ΔG, it was found that the reaction is a spontaneous endothermic process that could potentially be utilized to eliminate CR.

An emerging sustainable approach for development and characterization of gluten-based nanocomposite films reinforced with starch nanocrystals in conjugation with chitosan

The present study aimed to access the influence of starch nanocrystals (SNCs) with chitosan on functionality of gluten-based bionanocomposite films. Films were reinforced with SNCs (1, 2, and 3 %) along with chitosan (1.5 % and 2.5 %) and characterized for their functional, barrier, morphological, biodegradable, and antimicrobial properties. Results showed that water absorption capacity, solubility, and water vapour transmission rate were significantly (P < 0.05) reduced with the incorporation of SNCs and chitosan, however, highest tensile strength (40.82 MPa) and elongation at break (31.09 %) were observed in 2 % of SNCs and 2.5 % of chitosan. The multifunctional films have high opacity (lightness value >90) confirming with higher thickness (0.17–0.22 mm) of films. X-ray diffraction studies interpret no significant change in A-type crystallinity of the base biopolymer. Field emission scanning electron microscopy showed that bionanocomposite films have fewer surface cracks, less configuration, and crystallinity changes in the composite structure of biopolymer. Fourier transform infrared spectra revealed no differences in the bands, suggesting a positive molecular association confirming the synergistic effect of polyvinyl alcohol (PVOH) and SNCs on gluten in comparison to control film. However, chitosan in films enhanced antioxidant and antimicrobial properties, showing 13.05 mm and 16.66 mm of a zone of inhibition against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, all films showed noticeable degradation >95 % within 55 days under soil conditions. In summary, the addition of SNCs and chitosan produced a stronger/antibacterial film comparable to plastic films for commercialized food packaging industries.

Biodegradation and swelling behaviour of cellulose-based plastic incorporation of pennisetum purpureum, chitosan and gelatine

This paper reports on the biodegradation and swelling behaviour of cellulose-based plastic incorporation of Pennisetum purpureum (PS), chitosan and gelatine. Cellulose-based plastic (CP) was obtained from chitosan and gelatin; and from the cortex (CPS), pith (PPS), and whole (WPS) of Pennisetum purpureum (PS). The films were prepared by solution casting with untreated, 4, 8, 12, 16, and 20% alkali-treated cellulose of CPS, PPS, and WPS. The ASTM D5988-method was used to conduct the CP biodegradation tests. The swelling behaviour test was performed to measure the swelling percentage for each CP samples in aqueous solution with different pH values. The results reveal that the biodegradation of untreated CPS (60.30%), untreated WPS (49.74%), and untreated PPS (CP) showed the biggest relative weight reduction. CP added with the 8, and 16% alkali-treated cellulose of CPS, and PPS continues swelling in the solution of pH 7 throughout 24 hours of analysis. Increasing the cellulose loading accelerated the biodegradation rate of the bioplastic films. The results also suggest that the CP with the incorporated cortex (CPS) of Pennisetum purpureum (PS), is the most water-resistant in neutral followed by acid and alkali.

Directional transport of drug droplets based on structural and wettability gradients on antibacterial Janus wound plaster with hemostatic, antiextravasation, and prehealing properties

The failure of wound healing is majorly attributed to uncontrolled bleeding and bacterial infections. However, developing a wound plaster that can stop bleeding, resist blood extravasation, and realize directional transportation of drugs to promote wound healing remains a significant challenge. Herein, a superhydrophilic/hydrophobic polyvinyl alcohol/chitosan/silver@Thermoplastic polyurethane (PVA/CS/Ag@TPU) Janus membrane with structural and wettability gradients is developed. In this newly developed membrane, water is absorbed from blood via the superhydrophilic layer, which is attached to the wound, and the charge interactions between platelets and the introduced chitosan (CS) promote blood clotting. The capillary pressure resistance (∆p > 0) of the superhydrophilic layer toward the hydrophobic layer prevents blood permeation, thereby reducing blood loss. The favorable ∆p (< 0) of the membrane based on its structural and wettability gradients can realize the directional transportation of drugs that promote wound healing from the hydrophobic to the superhydrophilic layer. The incorporation of CS and silver endows the Janus membrane with intrinsic antibacterial properties (99.9%). The formation of the hydrated layer on the hydrophilic layer imparts a resisting effect, further endowing the membrane with antiadhesion and antibacterial properties. Experiments involving mice with full-thickness skin wounds revealed that the wound-healing rate increased from 87.65% to ~ 100% when the Janus membrane was loaded with the prehealing drug. Moreover, the dressing accelerated wound healing, regenerated epidermal and granulation tissues, promoted collagen formation, and reduced scar size. Thus, this gradient design strategy opens an avenue for the development of next-generation wound dressings.Graphical abstract

Improvement of Selectivity and Antifouling Properties of Chitosan-modified Polyvinylidene Fluoride (PVDF) Membrane for Protein Filtration

&lt;p&gt;Protein with high purity is currently a valuable commercial commodity, prized for its high value and application in specialized functions. PVDF-based membrane technology has found widespread use in protein purification processes. However, the issue of fouling on the membrane surface frequently hampers the performance of PVDF membranes. The present study aims to enhance PVDF membranes' selectivity and antifouling properties through chitosan modification, thereby optimizing protein filtration. PVDF and PVDF/Chitosan membranes were fabricated using the phase inversion technique, followed by a comprehensive characterization of their surface properties, thermal attributes, and performance in bovine serum albumin (BSA) protein filtration. The collected data revealed notable increases in membrane hydrophilicity, porosity, and pure water flux due to the incorporation of chitosan. The membrane protein rejection capabilities were significantly enhanced to levels exceeding 90% with the introduction of 0.5% chitosan. Moreover, as the chitosan concentration increased, the membrane exhibited superior antifouling characteristics, with the 0.5% chitosan concentration yielding the highest Flux Recovery Ratio (FRR) value of 85.35%. Considering the significant improvement selectivity and antifouling properties in the combined system, the chitosan-modified PVDF membrane holds substantial promise in protein purification applications.&lt;/p&gt;

Improvement of Selectivity and Antifouling Properties of Chitosan-modified Polyvinylidene Fluoride (PVDF) Membrane for Protein Filtration

&lt;p&gt;Protein with high purity is currently a valuable commercial commodity, prized for its high value and application in specialized functions. PVDF-based membrane technology has found widespread use in protein purification processes. However, the issue of fouling on the membrane surface frequently hampers the performance of PVDF membranes. The present study aims to enhance PVDF membranes' selectivity and antifouling properties through chitosan modification, thereby optimizing protein filtration. PVDF and PVDF/Chitosan membranes were fabricated using the phase inversion technique, followed by a comprehensive characterization of their surface properties, thermal attributes, and performance in bovine serum albumin (BSA) protein filtration. The collected data revealed notable increases in membrane hydrophilicity, porosity, and pure water flux due to the incorporation of chitosan. The membrane protein rejection capabilities were significantly enhanced to levels exceeding 90% with the introduction of 0.5% chitosan. Moreover, as the chitosan concentration increased, the membrane exhibited superior antifouling characteristics, with the 0.5% chitosan concentration yielding the highest Flux Recovery Ratio (FRR) value of 85.35%. Considering the significant improvement selectivity and antifouling properties in the combined system, the chitosan-modified PVDF membrane holds substantial promise in protein purification applications.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;img src="/public/site/images/fitria/rsz_72110.png" alt="" /&gt;&lt;/p&gt;

Incorporation of Chitosan in Polyurethanes Based on Modified Castor Oil for Cardiovascular Applications.

The increased demand for vascular grafts for the treatment of cardiovascular diseases has led to the search for novel biomaterials that can achieve the properties of the tissue. According to this, the investigation of polyurethanes has been a promising approach to overcome the present limitations. However, some biological properties remain to be overcome, such as thrombogenicity and hemocompatibility, among others. This paper aims to synthesize polyurethanes based on castor oil and castor oil transesterified with triethanolamine (TEA) and pentaerythritol (PE) and with the incorporation of 1% chitosan. Analysis of the wettability, enzymatic degradation, mechanical properties (tensile strength and elongation at break), and thermal stability was performed. Along with the evaluation of the cytotoxicity against mouse fibroblast (L929) and human dermal fibroblast (HDFa) cells, the hemolysis rate and platelet adhesion were determined. The castor-oil-based polyurethanes with and without 1% chitosan posed hydrophobic surfaces and water absorptions of less than 2% and enzymatic degradation below 0.5%. Also, they were thermally stable until 300 °C, with tensile strength like cardiovascular tissues. The synthesized castor oil/chitosan polyurethanes are non-cytotoxic (cell viabilities above 80%) to L929 and HDFa cells and non-thrombogenic and non-hemolytic (less than 2%); therefore, they are suitable for cardiovascular applications.

Effect of chitosan coating concentration with glutaraldehyde on the characteristics of bioplastic for environmentally friendly personal protective equipment

ABSTRACT The use of plastic-based personal protective equipment (PPE) has become a worldwide issue of concern today as the need for and supply of PPE for healthcare workers has gradually increased.A possible solution to tackle this problem of plastic PPE waste is through the use of biodegradable plastic.This study aimed to investigate the potential of biodegradable bioplastics production through the combination of Polylactic acid, ZnO, and palm wax.The resulting bioplastic was coated with chitosan to improve its antibacterial properties.The study focused on the difference between various concentrations of chitosan crosslinked with 1% (v/v) glutaraldehyde, which was coated on the surface of 5% (w/v) PLA, 10% ZnO (w/w of PLA), and 2.5% palm wax (w/w of PLA). The resulting bioplastics were evaluated for mechanical properties, characterization, antibacterial properties, biodegradability and water vapor permeability.The incorporation of chitosan enhanced the tensile strength but reduced the elongation of the bioplastic. FTIR and SEM test showed that the overall chemical structure of the bioplastic was modified due to the coating treatment.The antibacterial test indicated that the bioplastics had greater antibacterial properties toward E. coli than S. aureus. Moreover, the biodegradability test demonstrated that the coating treatment increase the biodegradability rate and it effectively inhibited water vapor permeability.

Fabrication of antifungal AgNPs capped with chitosan using endophytic fungus Curvulariakusanoi

This research aimed to myco-fabricate silver nanoparticles (AgNPs) from the endophytic fungus Curvularia kusanoi. The AgNPs were encapsulated with chitosan (Ch-AgNPs) under microwave heating at 650 W for 90s. Characterization of nanoparticles was performed using different UV–vis spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), Zeta potential, and dynamic light scattering (DLS). Antifungal activity of Ch-AgNPs at (50, 25, 12.5, and 6.25 mg/L) was tested against Aspergillus fumigatus, Curvularia lunata, and Cladosporium sp. using the mycelial growth inhibition method (MGI). After capping, UV–vis analysis showed one peak for AgNPs at 400 nm and another for chitosan at 230 nm. FTIR analysis confirmed the incorporation of chitosan as capping agent by interacting with the AgNPs through amide functionalities. The Z-potential revealed the change of nanoparticles charge from −15.7 mV to +59 mV. FES-SEM showed spherical Ch-AgNPs with a size of 33.82 nm. Ch-AgNPs showed a highly significant antifungal activity against all tested fungi. The highest mycelial growth reduction was 97% for C. lunata, followed by 89% for Cladosporium sp. and 83% for A. fumigates at (50 mg/L). The lower concentration (6.25 mg/L) inhibited mycelial growth by 62% of Cladosporium sp., 60% of C. lunata, and 42% of A. fumigates. Biosynthesized AgNPs using C. kusanoi cell-free extract were successfully capped with chitosan for enhanced stability while maintaining their antifungal activity against fungal pathogens.

Characterization and qualitative evaluation of cassava starch-chitosan edible food wrap enriched with culinary leaf powders for eco-friendly food packaging applications.

Cassava starch-based edible food wraps were prepared by incorporating leaf powder from Indian curry leaf and Malabar bay leaf, reinforced with different (0.2, 0.4, 0.6, 0.8) wt.% of chitosan. Eleven combinations of films were prepared and their sensory acceptability, physical properties, Fourier-transform infrared spectroscopic (FTIR) spectrum, and scanning electron microscopy (SEM) image, were evaluated. The thickness of the films ranged from 0.198 ± 0.12 to 0.372 ± 0.27 mm. Tensile strength was reported to be the highest (40.71 ± 1.21 MPa) in the curry leaf powder incorporated sample. Maximum elongation at break was reported by bay leaf powder incorporated (5.8 ± 1.59%) sample. The Young's modulus values were observed to be increasing along with the concentration of chitosan. Maximum seal strength values were reported by curry leaf powder incorporated film with 0.8% chitosan (2.93 ± 0.22 N/mm). The leaf powder incorporated samples reported a higher flavonoid content compared to the control. The color analysis (L*, a*, b*) of the films was identical to the natural leaf color. The SEM images indicated a rough texture for the leaf powder incorporated films. The FTIR evaluation confirmed the presence of the respective functional groups. The statistical evaluation done by statistical package for social sciences software showed that all the data were significantly different (P ≤ 0.05.). The study demonstrated the potential of incorporation of leaf powder and chitosan to enhance the properties of starch-based edible packaging.

Effect of Composition and Freeze-Thaw on the Network Structure, Porosity and Mechanical Properties of Polyvinyl-Alcohol/Chitosan Hydrogels.

We report the synthesis and characterization of poly (vinyl alcohol) (PVA)/Chitosan (CT) cryogels for applications involving the uptake and entrapment of particulate and bacterial colonies. In particular, we systematically investigated the network and pore structures of the gels as a function of CT content and for different freeze-thaw times, combining Small Angle X-Ray Scattering (SAXS), Scanning Electron Microscopy (SEM), and confocal microscopy. The nanoscale analysis obtained from SAXS shows that while the characteristic correlation length of the network is poorly affected by composition and freeze-thaw time, the characteristic size of heterogeneities associated with PVA crystallites decreases with CT content. SEM investigation evidences a transition to a more homogeneous network structure induced by the incorporation of CT that progressively builds a secondary network around the one formed by PVA. A detailed analysis of confocal microscopy image stacks allows to characterize the 3D porosity of the samples, revealing a significantly asymmetric shape of the pores. While the average volume of single pores increases with increasing CT content, the overall porosity remains almost unchanged as a result of the suppression of smaller pores in the PVA network with the progressive incorporation of the more homogeneous CT network. Increasing the freezing time in the FT cycles also results in a decrease of porosity, which can be associated with a growth in the crosslinking of the network due to PVA crystallization. The linear viscoelastic moduli measured by oscillatory rheology show a qualitatively comparable frequency-dependent response in all cases, with a moderate reduction with increasing CT content. This is attributed to changes in the structure of the strands of the PVA network.

Karakteristik Antibakteri Nanoceria-Kitosan yang disintesis menggunakan Metode Presipitasi

&lt;p class="AbstractText"&gt;CeO&lt;sub&gt;2&lt;/sub&gt; nanoparticles (nanoceria) is a material that posseses antibacterial activity. In this study, nanoceria was combined with chitosan to increase its antibacterial property. The formation of nanoceria-chitosan was analyzed using X-ray diffractometer, Fourier Transform Infrared (FTIR) and UV-Vis Spectrophotometer. The antibacterial activity of nanoceria-chitosan was tested using the disc diffusion method on Escherichia coli bacteria. X-ray diffraction pattern analysis showed that nanoceria-chitosan has a cubic structure. The incorporation of chitosan in nanoceria was identified at a wave number of 2919 cm&lt;sup&gt;-1&lt;/sup&gt; from the FTIR spectrum. Nanoceria-chitosan showed a smaller crystallite size, a larger energy band gap and better antibacterial activity than nanoceria.&lt;/p&gt;