Preparation and characterization of chitosan from crab shell (Portunus trituberculatus) by NaOH/urea solution freeze-thaw pretreatment procedure

A scientometric analysis and recent advances of emerging chitosan-based biomaterials as potential catalyst for biodiesel production: A review

Chitosan is a widely available polymer with a reasonably high abundance, as well as a sustainable, biodegradable, and biocompatible material with different functional groups that are used in a wide range of operations. Chitosan is frequently employed in widespread applications such as environmental remediation, adsorption, catalysts, and drug formulation. The goal of this review is to discuss the potential applications of chitosan and its chemically modified solids as a catalyst in biodiesel production. The existing manuscripts are integrated based on the nature of materials used as chitosan and its modifications. A short overview of chitosan's structural characteristics, properties, and some ideal methods to be considered in catalysis activities are addressed. This article includes an analysis of a chitosan-based scientometric conducted between 1975 and 2023 using VOS viewer 1.6.19. To identify developments and technological advances in chitosan research, the significant scientometric features of yearly publication results, documents country network, co-authorship network, documents funding sponsor, documents institution network, and documents category in domain analysis were examined. This review covers a variety of organic transformations and their effects, including chitosan reactions against acids, bases, metals, metal oxides, organic compounds, lipases, and Knoevenagel condensation. The catalytic capabilities of chitosan and its modified structures for producing biodiesel through transesterification reactions are explored in depth.

Trash to Treasure: An Up-to-Date Understanding of the Valorization of Seafood By-Products, Targeting the Major Bioactive Compounds

Fishery production is exponentially growing, and its by-products negatively impact industries' economic and environmental status. The large amount of bioactive micro- and macromolecules in fishery by-products, including lipids, proteins, peptides, amino acids, vitamins, carotenoids, enzymes, collagen, gelatin, chitin, chitosan, and fucoidan, need to be utilized through effective strategies and proper management. Due to the bioactive and healthy compounds in fishery discards, these components can be used as functional food ingredients. Fishery discards have inorganic or organic value to add to or implement in various sectors (such as the agriculture, medical, and pharmaceutical industries). However, the best use of these postharvest raw materials for human welfare remains unelucidated in the scientific community. This review article describes the most useful techniques and methods, such as obtaining proteins and peptides, fatty acids, enzymes, minerals, and carotenoids, as well as collagen, gelatin, and polysaccharides such as chitin-chitosan and fucoidan, to ensure the best use of fishery discards. Marine-derived bioactive compounds have biological activities, such as antioxidant, anticancer, antidiabetic, anti-inflammatory, and antimicrobial activities. These high-value compounds are used in various industrial sectors, such as the food and cosmetic industries, owing to their unique functional and characteristic structures. This study aimed to determine the gap between misused fishery discards and their effects on the environment and create awareness for the complete valorization of fishery discards, targeting a sustainable world.

King crab gills as a new source of chitin/chitosan and protein hydrolysates

This is the first report on the physicochemical properties of chitin obtained from gills of the king crab Paralithodes camtschaticus. In the present study, we investigated the chemical composition of red king crab gills and considered methods of its complex processing to obtain chitin and enzymatic protein hydrolysates. The gills contained approximately 21 % chitin in terms of dry matter. For the first time, the gills of the king crab were investigated as a source of chitin and chitosan. Chitin was isolated from crab gills using chemical and enzymatic methods. The physicochemical properties of chitin and chitosan from the gills were investigated. By performing infrared spectroscopy and X-ray phase analyses, the chitin present in the gills was established to be α-chitin. The physical and chemical properties (degree of deacetylation, molecular weight and crystal structure) of gill chitin and chitosan were absolutely similar to those of crab shell. Crab gills can be used as an additional source of chitin in the integrated processing of king crabs. The yield of chitin from the gills is up to 45 % of the yield of chitin from the crab carapace.

Chitin whiskers enhanced methacrylated hydroxybutyl chitosan hydrogels as anti-deformation scaffold for 3D cell culture

Hydrogel, as three-dimensional (3D) cell culture scaffold, is an effective strategy for tissue and organ regeneration due to their good biocompatibility, biodegradability and resemblance to body microenvironments in vivo. However, the inherent weak mechanical properties and strong shrinkage of hydrogels during cell culture hinder its application in clinical. In this study, a two-component thermo/photo dual-sensitive hydrogel (M/C) was prepared from methacrylated hydroxybutyl chitosan (MHBC) and chitin whisker (CHW) via physical and chemical cross-linking methods. M/C hydrogel showed a special internal structure with lamellar arrangement. The rheological properties of the hydrogels could be regulated with the change of M/C ratio. It is worth emphasizing that the mechanical properties, shrinkage resistance and cellular capacitances of the M/C hydrogel were improved with the addition of CHW. Moreover, the M/C hydrogel not only exhibited excellent degradability and antibacterial properties, but also significantly promoted the adhesion and proliferation of MC3T3-E1 cells in vitro. Therefore, the M/C hydrogel showed a wide application potential in tissue regeneration as a 3D cell culture scaffold.

Recent advances in biopolymer-based advanced oxidation processes for dye removal applications: A review

Over the past few years, synthetic dye-contaminated wastewater has attracted considerable global attention due to the low biodegradability and the ability of organic dyes to persist and remain toxic, causing numerous health and environmental concerns. As a result of the recalcitrant nature of those complex organic dyes, the remediation of wastewater using conventional wastewater treatment techniques is becoming increasingly challenging. In recent years, advanced oxidation processes (AOPs) have emerged as a potential alternative to treat organic dyestuffs discharged from industries. The most widely employed AOPs include photocatalysis, ozonation, Fenton oxidation, electrochemical oxidation, catalytic heterogeneous oxidation, and ultrasound irradiation. These processes involve the generation of highly reactive radicals to oxidize organic dyes into innocuous minerals. However, many conventional AOPs suffer from several setbacks, including the high cost, high consumption of reagents and substrates, self-agglomeration of catalysts, limited reusability, and the requirement of light, ultrasound, or electricity. Therefore, there has been significant interest in improving the performance of conventional AOPs using biopolymers and heterogeneous catalysts such as metal oxide nanoparticles (MONPs). Biopolymers have been widely considered in developing green, sustainable, eco-friendly, and low-cost AOP-based dye removal technologies. They inherit intriguing properties like biodegradability, renewability, nontoxicity, relative abundance, and sorption. In addition, the immobilization of catalysts on biopolymer supports has been proven to possess excellent catalytic activity and turnover numbers. The current review provides comprehensive coverage of different AOPs and how efficiently biopolymers, including cellulose, chitin, chitosan, alginate, gelatin, guar gum, keratin, silk fibroin, zein, albumin, lignin, and starch, have been integrated with heterogeneous AOPs in dye removal applications. This review also discusses the general degradation mechanisms of AOPs, applications of biopolymers in AOPs and the roles of biopolymers in AOPs-based dye removal processes. Furthermore, key challenges and future perspectives of biopolymer-based AOPs have also been highlighted.

Chitosan: Sources, Processing and Modification Techniques

Chitosan, a copolymer of glucosamine and N-acetyl glucosamine, is derived from chitin. Chitin is found in cell walls of crustaceans, fungi, insects and in some algae, microorganisms, and some invertebrate animals. Chitosan is emerging as a very important raw material for the synthesis of a wide range of products used for food, medical, pharmaceutical, health care, agriculture, industry, and environmental pollution protection. This review, in line with the focus of this special issue, provides the reader with (1) an overview on different sources of chitin, (2) advances in techniques used to extract chitin and converting it into chitosan, (3) the importance of the inherent characteristics of the chitosan from different sources that makes them suitable for specific applications and, finally, (4) briefly summarizes ways of tailoring chitosan for specific applications. The review also presents the influence of the degree of acetylation (DA) and degree of deacetylation (DDA), molecular weight (M_w) on the physicochemical and biological properties of chitosan, acid-base behavior, biodegradability, solubility, reactivity, among many other properties that determine processability and suitability for specific applications. This is intended to help guide researchers select the right chitosan raw material for their specific applications.

Spectroscopic study of self-assembly of anti-hepatitis C virus sofosbuvir drug with bio-polymeric nanoparticles for improving the drug release effect

Self-assembly of Sofosbuvir drug (SOF) anti-hepatitis C virus (HCV) with bio-polymeric nanoparticles such as chitosan nanoparticles (Cs NPs) and polyvinyl alcohol nanoparticles (PVA NPs), the novel composites have been characterized successfully by different analysis such as Energy-dispersive X-ray spectroscopy (EDX), Scanning electron microscopy (SEM), UV-Visible spectrophotometer (UV-Vis) and Fourier Transmittance Infrared (FT-IR). The improvement of the Sofosbuvir effect as a result of loading drug on the bio-polymer NPs surface has been detected by the UV-Vis, and fluorescence spectroscopy techniques. The improvement of SOF efficiency was revealed via studying the drug release of SOF from biopolymers NPs surface at pH 7.4, UV-Vis spectra used for the releasing process. The binding constant (K_b) value was reported at 0.000055 and 0.3613 min^-1 for Cs and PVA NPs respectively. Also, the value of K_SV was documented at 0.0014 and 7.16 min^-1 for Cs@SOF and PVA@SOF hybrid nanocomposite. The incorporation rate (k) of SOF on the surface of biopolymer nano molecules was calculated to be 0.00812 and 0.0165 min^-1 for Cs and PVA NPs, respectively. Besides the observed value of (n) was close to the unit 0.74 and 0.86 for Cs and PVA NPs, respectively. The SOF released from Cs NPs surface was documented at 0.09 mg after 24 h, while PVA NPs reported at 0.7 mg at the same time and the release efficiency is 56.5 and 73% for Cs@SOF and PVP@SOF, respectively. From the results, we suggest Cs/SOF and PVA/SOF hybrid nanocomposites have spectroscopic results that make them promising candidate drugs, but need to the clinical trials.

Sandwich nanohybrid of chitosan-polyvinyl alcohol for water treatment and Sofosbuvir drug delivery for anti-hepatitis C virus (HCV)

The incorporation between nano-polyvinyl alcohol (PVA) and nano-chitosan (Cs) to produce sandwich nanohybrid (SNH) for water treatment and improvement the adsorption of sofosbuvir drug (SOF). The photocatalytic activity and formation of reactive oxygen species (ROS) were detected with oxidation of organic dyes such as Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO). The effect of SNH on the release of SOF in blood and inside the cells at pH 7.4 and pH 6.8, respectively were observed by UV-Visible spectroscopy (UV-Vis). The binding constant (K_b) was reported at 0.0035 min^-1 and the loading constant at 0.0024 min^-1, while the release efficiency was 42.6% at pH 7.4 and 74.7% at pH 6.8. The efficiency of photocatalytic activity against organic dyes MO, MB, and RhB are detected at 2.4% and 1%, and 42%, respectively. The cytotoxicity of SNH has been observed with MDA-MB-231 and HepG2 cell line with three concentrations of SNH, where the little concentration has low effect on the HepG2 and high viability, this result was reversed with the high concentration, also the yellow color due to the lysis of the cells. The antioxidant of the SNH was detected by FRAP technique.

Microwave Technology Using Low Energy Concentrated Beam for Processing of Solid Waste Materials from Rapana thomasiana Seashells

The solid waste of Rapana thomasiana seashells both from domestic activities and natural waste on seashore can be used to obtain viable products for medical applications. However, conventional technologies applied for sintering the materials require massive energy consumption due to the resistance heating. Microwave heating represents an advanced technology for sintering, but the stability of the process, in terms of thermal runaway and microwave plasma arc discharge, jeopardizes the quality of the sintered products. This paper aims to present the results of research focused on viable heating technology and the mechanical properties of the final products. A comparative analysis, in terms of energy efficiency vs. mechanical properties, has been performed for three different heating technologies: direct microwave heating, hybrid microwave heating and resistance heating. The results obtained concluded that the hybrid microwave heating led to final products from Rapana thomasiana solid waste with similar mechanical properties compared with resistance heating. In terms of energy efficiency, the hybrid microwave heating was 20 times better than resistance heating.

Chitosan Natural Polymer Material for Improving Antibacterial Properties of Textiles

In recent years, the textile industry has been seeking to develop innovative products. It is a good choice to organically combine materials with superior functional characteristics and commercial textiles to form products with excellent performance. In particular, textiles made of biological functional materials are often beneficial to human health, which is an interesting research direction. As a biopolymer material, chitosan has the advantages of strong availability, low cost, excellent safety, outstanding performance, etc., particularly the antibacterial property, and has broad application prospects in the textile field. This review provides an overview of the latest literature and summarizes recent innovations and state-of-the-art technologies that can add value to textiles. To this end, preparation of chitosan fiber, synthesis of chitosan nanofiber, antibacterial activity of chitosan fiber, antibacterial activity of chitosan nanofiber, etc., will be discussed. Furthermore, the challenges and prospects of chitosan-based materials used in textiles are evaluated. Importantly, this review can not only help researchers understand the development status of antibacterial textiles, but also help researchers discover and solve problems in this field through comparative reading.

Crustacean Waste-Derived Chitosan: Antioxidant Properties and Future Perspective

Chitosan is obtained from chitin that in turn is recovered from marine crustacean wastes. The recovery methods and their varying types and the advantages of the recovery methods are briefly discussed. The bioactive properties of chitosan, which emphasize the unequivocal deliverables contained by this biopolymer, have been concisely presented. The variations of chitosan and its derivatives and their unique properties are discussed. The antioxidant properties of chitosan have been presented and the need for more work targeted towards harnessing the antioxidant property of chitosan has been emphasized. Some portions of the crustacean waste are being converted to chitosan; the possibility that all of the waste can be used for harnessing this versatile multifaceted product chitosan is projected in this review. The future of chitosan recovery from marine crustacean wastes and the need to improve in this area of research, through the inclusion of nanotechnological inputs have been listed under future perspective.

Chitosan based-nanoparticles and nanocapsules: Overview, physicochemical features, applications of a nanofibrous scaffold, and bioprinting

Recent advancements in the synthesis, properties, and applications of chitosan as the second after cellulose available biopolymer in nature were discussed in this review. A general overview of processing and production procedures from A to Z was highlighted. Chitosan exists in three polymorphic forms which differ in degree of crystallinity (α, β, and γ). Thus, the degree of deacetylation, crystallinity, surface area, and molecular mass significantly affect most applications. Otherwise, the synthesis of chitosan nanofibers is suffering from many drawbacks that were recently treated by co-electrospun with other polymers such as polyvinyl alcohol (PVA), polyethylene oxide (PEO), and polycaprolactone (PCL). Ultimately, this review focuses on the area of new trend utilization of chitosan nanoparticles as nanospheres and nanocapsules, in cartilage and bone regenerative medicine. Owing to its biocompatibility, bioavailability, biodegradability, and costless synthesis, chitosan is a promising biopolymeric structure for water remediation, drug delivery, antimicrobials, and tissue engineering.

Obtaining chitin, chitosan and their melanin complexes from insects

Interest in insects as a source of valuable biologically active substances has significantly increased over the past few years. Insects serve as an alternative source of chitin, which forms up to 40% of their exoskeleton. Chitosan, a deacetylated derivative of chitin, attracts the attention of scientists due to its unique properties (sorption, antimicrobial, film-forming, wound healing). Furthermore, some insect species are unique and can be used to obtain chitin- and chitosan-melanin complexes in the later stages of ontogenesis. Due to the synergistic effect, chitosan and melanin can enhance each other's biological activity, providing a wide range of potential applications.