The preparation, characterization and antibacterial properties of chitosan/pectin silver nanoparticle films

Sustained antimicrobial polymer film from γ-CD-MOF humidity switch for fruit and vegetable preservation

To address the poor hydrolytic stability of CD-MOF in food applications, CD-MOF loaded with thymol (TCDM) was prepared and filled into a pectin (PEC)/sodium alginate (SA) substrate with the aid of zein to obtain a thymol-CD-MOF/zein-PEC-SA (TCDM/ZPS) polymer film. Characterization revealed that zein-PEC/SA (ZPS) protected TCDM by forming amphiphilic microspheres. TCDM was able to exist stably in the hydrophilic polysaccharide substrate and achieve a long-term slow release over 336 h. Besides, environmental humidity could also be used as a switch for regulating the thymol release rate, which was consistent with the first-order release model (R2 > 0.99). TCDM and TCDM/ZPS showed excellent antimicrobial effects against E. coli, S. aureus, and B. cinerea, the most common fungi in plant-based foods. The preservation experiment maintained the quality of strawberry and Agaricus bisporus mushroom. This strategy holds the potential to broaden the application scope and enhance the utility of CD-MOF in food preservation.

Green synthesis of silver nanoparticles using persimmon polysaccharides for enhanced polysaccharide-based film performance

Herein, the polysaccharide-based film was prepared by using persimmon polysaccharides extraction (PPE) and sodium alginate (SA) with the synthesized silver nanoparticles (AgNPs). Firstly, PPE was used as reducing and stabilizing agents for the green synthesis of PPE-AgNPs for the first time. The synthesized AgNPs had face-centered-cubic crystal structure with an average particle size of 55.88 nm. Also, the synthesized AgNPs solution exhibited superior dispersion with yellow-brown, and showed excellent antimicrobial activity (p < 0.05). Then, with incorporating AgNPs, the SA-PPE-AgNPs film showed excellent performance, the tensile strength (TS) and elongation at break (EAB) reached 18.24 MPa and 21.94 %, the water vapor permeability (WVP) decreased to 4.91 × 10-11 g·m-1·s-1 Pa-1, and significantly improved UV-vis barrier property. Moreover, the SA-PPE-AgNPs film showed excellent antibacterial activities (p < 0.05) against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisiae and Aspergillus niger, with the highest antibacterial activity against Escherichia coli (inhibition zone diameter for 16.92 ± 0.14 mm). Preservation tests on sugar oranges showed that the SA-PPE-AgNPs coating treatment maintained the good appearance and color, slowed down the loss of weight (8.34 %), firmness (8.58 N), titratable acid (decreased by 30.23 %) and total soluble solids content (decreased by 10.46 %), and kept the stability of pH (4.26) and Vitamin C (Vc) (decreased by 17.51 %) during the storage period. In summary, SA-PPE-AgNPs film was an effective method for maintaining fruit freshness instead of the traditional films.

Tea polyphenol-loaded chitosan/pectin nanoparticle as a nucleating agent for slurry ice production and its application in preservation of large yellow croaker (Pseudosciaena crocea)

Slurry ice preparation experiences considerable supercooling, which can be mitigated by nano-nucleating agents. A nano-nucleating agent (CH/PE-TP NPs) was prepared by ultrasonication-assistant self-assembly of chitosan (CH) and pectin (PE), encapsulated with tea polyphenols (TP). Ultrasonication for 10 min downsized self-assembled aggregates from 5.4 μm to approximately 500 nm and improved the dispersion of NPs. Optimal encapsulation efficiency was achieved with a CH/PE ratio of 1:5 (v/v), pH 5.0 and a TP concentration of 0.8 mg/mL. FTIR analysis indicated CH and PE encapsulated TP through electrostatic interaction between amino and carboxyl groups. Furthermore, the spherical shape of NPs was captured by electron microscopy. The addition of CH/PE-TP NPs (simulated seawater/NPs 4:6, v/v) for slurry ice production led to a reduction in supercooling by 8.3 °C and decreased energy consumption by 24.8 %. Notably, the CH/PE-TP NPs could be reused by refreezing the melted water of slurry ice. Total volatile basic nitrogen, pH, thiobarbituric acid reactive substances and total viable bacteria count demonstrated that CH/PE-TP NPs-based slurry ice was more effective than flake ice and conventional slurry ice in preserving large yellow croaker. In summary, CH/PE-TP NPs as nucleating agent effectively reduce energy consumption and extend the shelf life of aquatic products.

Enhancing biodegradable smart food packaging: Fungal-synthesized nanoparticles for stabilizing biopolymers

The increasing global concern over environmental plastic waste has propelled the progress of biodegradable supplies for food packaging. Biopolymer-based packaging is undergoing modifications to enhance its mechanical properties, aligning with the requirements of smart food packaging. Polymer nanocomposites, incorporating reinforcements such as fibers, platelets, and nanoparticles, demonstrate significantly improved mechanical, thermal, optical, and physicochemical characteristics. Fungi, in particular, have garnered significant interest for producing metallic nanoparticles, offering advantages such as easy scaling up, streamlined downstream handling, economic feasibility, and a large surface area. This review provides an overview of nano-additives utilized in biopackaging, followed by an exploration of the recent advancements in using microbial-resistant metal nanoparticles for food packaging. The mycofabrication process, involving fungi in the extracellular or intracellular synthesis of metal nanoparticles, is introduced. Fungal functionalized nanostructures represent a promising avenue for application across various stages of food processing, packaging, and safety. The integration of fungal-derived nanostructures into food packaging materials presents a sustainable and effective approach to combatting microbial contamination." By harnessing fungal biomass, this research contributes to the development of economical and environmentally friendly methods for enhancing food packaging functionality. The findings underscore the promising role of fungal-based nanotechnologies in advancing the field of active food packaging, addressing both safety and sustainability concerns. The study concludes with an investigation into potential fungal isolates for nanoparticle biosynthesis, highlighting their relevance and potential in advancing sustainable and efficient packaging solutions.

Cytotoxicity and antibacterial susceptibility assessment of a newly developed pectin-chitosan polyelectrolyte composite for dental implants

Biopolymers such as chitosan and pectin are currently attracting significant attention because of their unique properties, which are valuable in the food industry and pharmaceutical applications. These properties include non-toxicity, compatibility with biological systems, natural decomposition ability, and structural adaptability. The objective of this study was to assess the performance of two different ratios of pectin-chitosan polyelectrolyte composite (PCPC) after applying them as a coating to commercially pure titanium (CpTi) substrates using electrospraying. The PCPC was studied in ratios of 1:2 and 1:3, while the control group consisted of CpTi substrates without any coating. The pull-off adhesion strength, cytotoxicity, and antibacterial susceptibility tests were utilized to evaluate the PCPC coatings. In order to determine whether the composite coating was the result of physical blending or chemical bonding, the topographic surface parameters were studied using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). PCPC (1:3) had the highest average cell viability of 93.42, 89.88, and 86.85% after 24, 48, and 72 h, respectively, as determined by the cytotoxicity assay, when compared to the other groups. According to the Kirby-Bauer disk diffusion method for testing antibacterial susceptibility, PCPC (1:3) showed the highest average diameter of the zone of inhibition, measuring 14.88, 14.43, and 11.03 mm after 24, 48, and 72 h of incubation, respectively. This difference was highly significant compared to Group 3 at all three time periods. PCPC (1:3) exhibited a significantly higher mean pull-off adhesion strength (521.6 psi) compared to PCPC (1:2), which revealed 419.5 psi. PCPC (1:3) coated substrates exhibited better surface roughness parameters compared to other groups based on the findings of the AFM. The FTIR measurement indicated that both PCPC groups exhibited a purely physical blending in the composite coating. Based on the extent of these successful in vitro experiments, PCPC (1:3) demonstrates its potential as an effective coating layer. Therefore, the findings of this study pave the way for using newly developed PCPC after electrospraying coating on CpTi for dental implants.

Curcumin and silver nanoparticles loaded antibacterial multifunctional pectin/gelatin films for food packaging applications

Renewable biomass-based materials have a huge potential to replace petroleum-based products in food packaging. Herein, pectin/gelatin films loaded with curcumin and silver nanoparticles (AgNPs) are prepared by solution-pouring technology to serve as antimicrobial multifunctional food packaging films. AgNPs and curcumin are found to equally distribute in the films. Fourier transform infrared spectroscopy (FT-IR) reveal the hydrogen bonding and electrostatic interaction among curcumin, AgNPs, pectin and gelatin. The composite films show good antioxidant activity, mechanical performance, hydrophobicity and antibacterial ability. The films of P-GCA 0.5 showed 99.57 ± 0.16 % and 100 % inhibition against E. coli and S. aureus, respectively. The films also demonstrate excellent water vapor barrier qualities. In addition, the composite films possess pH-responsive color change behaviors from yellow (pH 3-8) to light red (pH 8-9) to dark red (pH 11-12), which is suitable for monitoring the freshness of shrimp packaging based on pH changes during deterioration process. As sustainable biomass-based materials, the multifunctional composite films are promising in intelligent food packaging applications.

Recent advances in chitosan-based materials; The synthesis, modifications and biomedical applications

The attention to polymer-based biomaterials, for instance, chitosan and its derivatives, as well as the techniques for using them in numerous scientific domains, is continuously rising. Chitosan is a decomposable naturally occurring polymeric material that is mostly obtained from seafood waste. Because of its special ecofriendly, biocompatible, non- toxic nature as well as antimicrobial properties, chitosan-based materials have received a lot of interest in the field of biomedical applications. The reactivity of chitosan is mainly because of the amino and hydroxyl groups in its composition, which makes it further fascinating for various uses, including biosensing, textile finishing, antimicrobial wound dressing, tissue engineering, bioimaging, gene, DNA and drug delivery and as a coating material for medical implants. This study is an overview of the different types of chitosan-based materials which now a days have been fabricated by applying different techniques and modifications that include etherification, esterification, crosslinking, graft copolymerization and o-acetylation etc. for hydroxyl groups' processes and acetylation, quaternization, Schiff's base reaction, and grafting for amino groups' reactions. Furthermore, this overview summarizes the literature from recent years related to the important applications of chitosan-based materials (i.e., thin films, nanocomposites or nanoparticles, sponges and hydrogels) in different biomedical applications.

Potential use of propolis-loaded quaternized chitosan/pectin hydrogel films as wound dressings: Preparation, characterization, antibacterial evaluation, and in vitro healing assay

Quaternized chitosan (QCS) was blended with pectin (Pec) to improve water solubility and antibacterial activity of the hydrogel films. Propolis was also loaded into hydrogel films to improve wound healing ability. Therefore, the aim of this study was to fabricate and characterize the propolis-loaded QCS/Pec hydrogel films for use as wound dressing materials. The morphology, mechanical properties, adhesiveness, water swelling, weight loss, release profiles, and biological activities of the hydrogel films were investigated. Scanning Electron Microscope (SEM) investigation indicated a homogenous smooth surface of the hydrogel films. The blending of QCS and Pec increased tensile strength and Young's modulus values of the hydrogel films. Moreover, the blending of QCS and Pec improved the stability of the hydrogel films in the medium and controlled the release characteristics of propolis from the hydrogel films. The antioxidant activity of the released propolis from the propolis-loaded hydrogel films was ~21-36 %. The propolis-loaded QCS/Pec hydrogel films showed the bacterial growth inhibition, especially against S. aureus and S. pyogenes. The propolis-loaded hydrogel films were non-toxicity to mouse fibroblast cell line (NCTC clone 929) and supported the wound closure. Therefore, the propolis-loaded QCS/Pec hydrogel films might be good candidates for use as wound dressing materials.

Phosphorus biorecovery from wastewater contaminated with multiple nitrogen species by a bacterial consortium

Recovering finite and non-substitutable phosphorus from liquid waste streams through bio-mediated techniques has attracted increasing interest, but current approaches are incredibly dependent on ammonium. Herein, a process to recover phosphorus from wastewater under multiple nitrogen species conditions was developed. This study compared the effects of nitrogen species on the recovery of phosphorus resources by a bacterial consortium. It found that the consortium could not only efficiently utilize ammonium to enable phosphorus recovery but also utilize nitrate via dissimilatory nitrate reduction to ammonium (DNRA) to recover phosphorus. The characteristics of the generated phosphorus-bearing minerals, including magnesium phosphate and struvite, were evaluated. Furthermore, nitrogen loading positively influenced the stability of the bacterial community structure. The genus Acinetobacter was dominant under nitrate and ammonium conditions, with a relatively stable abundance of 89.01% and 88.54%, respectively. The finding may provide new insights into nutrient biorecovery from phosphorus-containing wastewater contaminated with multiple nitrogen species.

Assessment of antimicrobial activity of chitosan/silver nanoparticles hydrogel and cryogel microspheres

This research investigates the synthesis and characterization of hydrogel and cryogel microspheres that are doped with green synthesised silver nanoparticles (CS-AgNPs). Also, the study assesses the antibacterial activity of hydrogel and cryogel microspheres by comparing them with commercial antibiotics. The porous structure of CS and the adequate dispersion of AgNPs were confirmed by SEM and EDX techniques, respectively. The disk diffusion method and the optical density measurement (OD600) confirm the outstanding antimicrobial activity of CS-AgNPs hydrogel and cryogel microspheres in comparison to antibiotics for both Gram-positive and Gram-negative bacteria. The CS-AgNPs microspheres demonstrate promising antimicrobial and biocompatible agents for medical field applications.

Recent progress in pectin extraction, characterization, and pectin-based films for active food packaging applications: A review

Pectin is an abundant complex polysaccharide obtained from various plants. Safe, biodegradable, and edible pectin has been extensively utilized in the food industry as a gelling agent, thickener, and colloid stabilizer. Pectin can be extracted in a variety of ways, thus affecting its structure and properties. Pectin's excellent physicochemical properties make it suitable for many applications, including food packaging. Recently, pectin has been spotlighted as a promising biomaterial for manufacturing bio-based sustainable packaging films and coatings. Functional pectin-based composite films and coatings are useful for active food packaging applications. This review discusses pectin and its use in active food packaging applications. First, basic information and characteristics of pectin, such as the source, extraction method, and structural characteristics, were described. Then, various methods of pectin modification were discussed, and the following section briefly described pectin's physicochemical properties and applications in the food sector. Finally, the recent development of pectin-based food packaging films and coatings and their use in food packaging were comprehensively discussed.

Chitosan with Natural Additives as a Potential Food Packaging

Recently, the development of materials based on natural polymers have been observed. This is the result of increasing environmental degradation, as well as increased awareness and consumer expectations. Many industries, especially the packaging industry, face challenges resulting from legal regulations. Chitin is the most common biopolymer right after cellulose and is used to produce chitosan. Due to the properties of chitosan, such as non-toxicity, biocompatibility, as well as antimicrobial properties, chitosan-based materials are used in many industries. Many studies have been conducted to determine the suitability of chitosan materials as food packaging, and their advantages and limitations have been identified. Thanks to the possibility of modifying the chitosan matrix by using natural additives, it is possible to strengthen the antioxidant and antimicrobial activity of chitosan films, which means that, in the near future, chitosan-based materials will be a more environmentally friendly alternative to the plastic packaging used so far. The article presents literature data on the most commonly used natural additives, such as essential oils, plant extracts, or polysaccharides, and their effects on antimicrobial, antioxidant, mechanical, barrier, and optical properties. The application of chitosan as a natural biopolymer in food packaging extends the shelf-life of various food products while simultaneously reducing the use of synthetic plastics, which in turn will have a positive impact on the natural environment. However, further research on chitosan and its combinations with various materials is still needed to extent the application of chitosan in food packaging and bring its application to industrial levels.

Magnetically responsive chitosan-pectin films incorporating Fe3O4 nanoparticles with enhanced antimicrobial activity

Chitosan-pectin films with iron oxide (Fe₃O₄) magnetic nanoparticles were prepared by solution casting in order to produce biopolymer based magnetically active materials. Infrared (FTIR) spectra indicated physical interactions between the matrix and nanoparticles, corroborated by differential scanning calorimetry (DSC) results. In addition, thermal characterization suggested that the interactions between chitosan, pectin and the nanoparticles resulted in a less compact structure, influencing the film mechanical properties. Regarding vibrating-sample magnetometry (VSM) and electrical analysis, chitosan-pectin films with Fe₃O₄ nanoparticles showed ferrimagnetic behavior, with an increase of the dielectric constant as the nanoparticle concentration increased. Furthermore, films displayed enhanced antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus epidermidis (Gram-positive) bacteria. Therefore, chitosan-pectin films with Fe₃O₄ magnetic nanoparticles provide promising results for active and intelligent food packaging applications.

Active Biohybrid Nanocomposite Films Made from Chitosan, ZnO Nanoparticles, and Stearic Acid: Optimization Study to Develop Antibacterial Films for Food Packaging Application

Chitosan is a biopolymer with great potential as food packaging due to its ability to create a film without additives and its better mechanical and antibacterial qualities compared to other biopolymers. However, chitosan film still has limitations due to its high moisture sensitivity and limited flexibility. Incorporating ZnO nanoparticles (ZnO-NPs) and stearic acid (SA) into chitosan films was expected to improve tensile strength, water vapor barrier, and antibacterial capabilities. This study aims to find the optimal formula for biohybrid nanocomposite films composed of chitosan, ZnO-NPs, and SA. The full factorial design approach-4 × 2 with 3 replicates, i.e., two independent variables, namely %ZnO-NPs at 4 levels (0%, 0.5%, 1%, and 3%, w/w) and %SA at 2 levels (0% and 5%, w/w)-was utilized to optimize chitosan-based biohybrid nanocomposite films, with the primary interests being antibacterial activities, water vapor barrier, and tensile strength. The incorporation of ZnO-NPs into chitosan films could increase antibacterial activity, while SA decreased it. The addition of SA had a good effect only in decreasing water vapor transmission rate (WVTR) values but a detrimental effect on other film properties mentioned above. The incorporation of ZnO-NPs enhanced all functional packaging properties of interest. The suggested solution of the optimization study has been validated. As a result, the formula with the inclusion of 1% ZnO-NPs without SA is optimal for the fabrication of active antibacterial films with excellent multifunctional packaging capabilities.

Pectin Microspheres: Synthesis Methods, Properties, and Their Multidisciplinary Applications

There is great contemporary interest in using cleaner technologies through green chemistry and utilizing biopolymers as raw material. Pectin is found on plant cell walls, and it is commonly extracted from fruit shells, mostly apples or citrus fruits. Pectin has applications in many areas of commercial relevance; for this reason, it is possible to find available information about novel methods to transform pectin and pursuing enhanced features, with the structuring of biopolymer microspheres being highly cited to enhance its activity. The structuring of polymers is a technique that has been growing in recent decades, due to its potential for diverse applications in various fields of science and technology. Several techniques are used for the synthesis of microspheres, such as ionotropic gelation, extrusion, aerosol drying, or emulsions, with the latter being the most commonly used method based on its reproducibility and simplicity. The most cited applications are in drug delivery, especially for the treatment of colon diseases and digestive-tract-related issues. In the industrial field, it is used for protecting encapsulated compounds; moreover, the environmental applications mainly include the bioremediation of toxic substances. However, there are still many possibilities for expanding the use of this biopolymer in the environmental field.

An Overview on the Novel Core-Shell Electrodes for Solid Oxide Fuel Cell (SOFC) Using Polymeric Methodology

Lowering the interface charge transfer, ohmic and diffusion impedances are the main considerations to achieve an intermediate temperature solid oxide fuel cell (ITSOFC). Those are determined by the electrode materials selection and manipulating the microstructures of electrodes. The composite electrodes are utilized by a variety of mixed and impregnation or infiltration methods to develop an efficient electrocatalytic anode and cathode. The progress of our proposed core-shell structure pre-formed during the preparation of electrode particles compared with functional layer and repeated impregnation by capillary action. The core-shell process possibly prevented the electrocatalysis decrease, hindering and even blocking the fuel gas path through the porous electrode structure due to the serious agglomeration of impregnated particles. A small amount of shell nanoparticles can form a continuous charge transport pathway and increase the electronic and ionic conductivity of the electrode. The triple-phase boundaries (TPBs) area and electrode electrocatalytic activity are then improved. The core-shell anode SLTN-LSBC and cathode BSF-LC configuration of the present report effectively improve the thermal stability by avoiding further sintering and thermomechanical stress due to the thermal expansion coefficient matching with the electrolyte. Only the half-cell consisting of 2.75 μm thickness thin electrolyte iLSBC with pseudo-core-shell anode LST could provide a peak power of 325 mW/cm² at 700 °C, which is comparable to other reference full cells’ performance at 650 °C. Then, the core-shell electrodes preparation by simple chelating solution and cost-effective one process has a potential enhancement of full cell electrochemical performance. Additionally, it is expected to apply for double ions (H⁺ and O²⁻) conducting cells at low temperature.

Antimicrobial textile: recent developments and functional perspective

Antimicrobial textiles are functionally active textiles, which may kill the microorganisms or inhibit their growth. The present article explores the applications of different synthetic and natural antimicrobial compounds used to prepare antimicrobial textiles. Different types of antimicrobial textiles including: antibacterial, antifungal and antiviral have also been discussed. Different strategies and methods used for the detection of a textile's antimicrobial properties against bacterial and fungal pathogens as well as viral particles have also been highlighted. These antimicrobial textiles are used in a variety of applications ranging from households to commercial including air filters, food packaging, health care, hygiene, medical, sportswear, storage, ventilation and water purification systems. Public awareness on antimicrobial textiles and growth in commercial opportunities has been observed during past few years. Not only antimicrobial properties, but its durability along with the color, prints and designing are also important for fashionable clothing; thus, many commercial brands are now focusing on such type of materials. Overall, this article summarizes the scientific aspect dealing with different fabrics including natural or synthetic antimicrobial agents along with their current functional perspective and future opportunities.

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