Chemical Modification Of Chitin Research Articles

Advances of Chitin Biomass Derived from Seafood Waste in Biomedical Applications

As the second abundant biomass in nature, chitin widely exists in crustaceans, insects, plankton, fungi and so on. Thus, extracting chitin from crustaceans’ seafood waste and applying it and its derivatives in biomedicine represents the idea of turning waste into treasure. However, the poor solubility severely limits the application range and field of chitin. Thus, the chemical modification of chitin has always been a hot field in the research of such compounds, endowing chitin better solubility, pH-sensitive targeting, and drug delivery functions. In this review, the modification methods of chitin were summarized to improve the water solubility, pH sensitivity and targeting of chitin derivatives. At the same time, the application of chitin derivatives in many fields such as antibacterial, sustained release, targeting and drug delivery are introduced. This review offers a good reference for sustainable development.

Fabrication of chitin monoliths with controllable morphology by thermally induced phase separation of chemically modified chitin

As a natural polymer, chitin has excellent biological properties such as biodegradability and immunological, antibacterial, and wound-healing activities and has numerous applications in cosmetics, drug delivery, and pharmaceuticals. Organic polymer monoliths have also drawn significant attention, owing to their high permeability, large surface area, and high mechanical strength. They are usually applied to separation, ion exchange, catalysis, and chromatography. We have previously prepared cellulose monoliths using biopolymers; however, because chitin possesses amide groups on its side chain, it is superior to cellulose for further chemical modification and applications. However, the utilization of chitin is restricted by its insolubility in water and common organic solvents. In this study, for the first time, a monolith was prepared by chemical modification of chitin using a thermally induced phase separation (TIPS) method. First, we prepared dibutyrylchitin (DBC) as a starting polymer that is soluble in organic solvents. To prepare the monolith, DBC was dissolved completely in dimethyl sulfoxide (DMSO) while heating, and deionized water was added to the solution. It was then cooled at 20 °C to form a monolith via phase separation. The porous morphology of the DBC monolith was altered by regulating the DBC concentration, DMSO/H2O ratio, and aging temperature. The DBC monolith was converted to a chitin monolith by the alkaline hydrolysis of butyryl ester. The successful hydrolysis of butyryl ester was confirmed by the disappearance of the peak at 1735 cm−1 in the FT-IR spectra, which is related to the ester moiety of DBC. The chitin monolith has the potential to be utilized under water flow for catalysis, metal capture from wastewater, dye sorption, and drug delivery systems.

Degradability of Polyurethanes and Their Blends with Polylactide, Chitosan and Starch.

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCLtriol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).

Implications of molecular diversity of chitin and its derivatives.

Chitin is a long unbranched polysaccharide, made up of β-1,4-linked N-acetylglucosamine which forms crystalline fiber-like structure. It is present in the fungal cell walls, insect and crustacean cuticles, nematode eggshells, and protozoa cyst. We provide a critical appraisal on the chemical modifications of chitin and its derivatives in the context of their improved efficacy in medical applications without any side effect. Recent advancement in nanobiotechnology has helped to synthesize several chitin derivatives having significant biological applications. Here, we discuss the molecular diversity of chitin and its applications in enzyme immobilization, wound healing, packaging material, controlled drug release, biomedical imaging, gene therapy, agriculture, biosensor, and cosmetics. Also, we highlighted chitin and its derivatives as an antioxidant, antimicrobial agent, anticoagulant material, food additive, and hypocholesterolemic agent. We envisage that chitin and chitosan-based nanomaterials with their potential applications would augment nanobiotechnology and biomedical industries.

Ionic liquids in the processing and chemical modification of chitin and chitosan for biomedical applications

Ionic liquids (ILs) have huge potential to provide new ways for the sustainable processing of chitin and chitosan to a variety of matrices for biomedical applications

Chemical modification of chitin with polypyrrole for the uptake of Pb(II) and Cd(II) ions

This study described the possibility of using chemically modified chitin with polypyrrole (PPy-g-Ch) as an adsorbent for the removal of Pb(II) and Cd(II) ions from aqueous solution. The PPy-g-Ch was characterized using FTIR, SEM, EDX, XRD, TGA and DSC techniques. The influence of various parameters such as pH, dosage, co-ions, contact time and concentration on the removal of Pb(II) and Cd(II) ions was investigated. Among the various isotherm models studied, the Freundlich isotherm model fitted well to the equilibrium data. The magnitude of ΔG0, ΔH0 and ΔS0 indicated the feasibility, spontaneity and the endothermic nature of the adsorption process, respectively. The kinetic process followed the pseudo-second-order kinetic model. The applicability of the PPy-g-Ch has been tested for the removal of Pb(II) and Cd(II) ions from a real water sample spiked with Pb(II) and Cd(II) ions.

Dissolution and Chemical Modification of Chitin and Chitosan in Ionic Liquids

Chitin and chitosan, as the biological macromolecular materials, are hardly soluble in many traditional solvents. This behavior limits their wide application and chemical modification. Therefore, it will be of great importance to research and develop the better solvent system. In this paper, the dissolution performance and dissolving mechanism of chitin or chitosan in ionic liquids are reviewed in the first place. Secondly, the chemical modifications of chitin or chitosan in ionic liquids (such as hydrolysis, acylation, graft copolymerization and so on) are summarized. Ionic liquid, as a kind of the recycled fine solvent, will provide a better media for the effective application and chemical modification of chitin or chitosan. Based on the ionic liquid solvent, the research and application of chitin or chitosan will be broaden.

Chemistry and Applications of Phosphorylated Chitin and Chitosan

AbstractChitin and chitosan are natural based non-toxic, biodegradable and biocompatible polymers and have been used in biomedical areas in the form of sutures, wound healing materials and artificial skin, and for the sustained release of drugs as well as in various industrial applications. However, practical use of these polymers has been mainly confined to the unmodified forms. Recently, there has been a growing interest in chemical modification of chitin and chitosan to improve their solubility and widen their applications. Among them, phosphorylated chitin and chitosan have attracted considerable interest because of their various advantages: anti-inflammatory property, ability to form metal complexes, blood compatibility and formation of anionic polyelectrolyte hydrogels. The purpose of this review is to take a closer look of different synthetic methods of phosphorylated chitin and chitosan and their potential applications in environmental, food, fuel cell, and biomedical fields. Based on current research and existing products, some new and futuristic approaches in this context area are discussed.

Chemical modification of chitin and chitosan 1: preparation of partially deacetylated chitin derivatives via a ring-opening reaction with cyclic acid anhydrides in lithium chloride/ N, N-dimethylacetamide

Derivatives of partially N-deacetylated chitin (DAC) were prepared via ring-opening reactions with various cyclic acid anhydrides in lithium chloride/ N, N-dimethylacetamide (LiCl/DMAc) system. Some cyclic acid anhydrides such as succinic, maleic, glutaric, and phthalic anhydrides gave successfully water-soluble DAC derivatives. From the enzymatic studies, the glycosyl bond of succinyl and maleoyl DAC-20 (20% DAC) was rapidly degraded by lysozyme or chitinase, though that of phthaloyl DAC-20 was not. The ester linkage of succinyl DAC-20 was stable against lipase for five days at room temperature.

Chemical modification of chitin and chitosan 2: preparation and water soluble property of N-acylated or N-alkylated partially deacetylated chitins

N-Acylated partially deacetylated chitin (DAC-88) derivatives were prepared via ring-opening reactions with various cyclic acid anhydrides in aqueous MeOH system. N-Alkylation of DAC-88 were also performed in aqueous MeOH with various aldehydes, monosaccharides, and disaccharides. The water solubility of N-acylated and N-alkylated chitosan derivatives at various pHs were studied.

Structure-Bioactivity Relationship of Chitin Derivatives—Part I: The Effect of Solid Chitin Derivatives on Blood Coagulation

Chemical modification of chitin led to a series of derivatives: chi tosan, N-acetylchitosan, monoacetylchitin, dibutyrylchitin, chitosan acetate, chitosan butyrate, chitosan citrate and chitosan-poly(acrylic acid) complex. These were used to coat glass surfaces and studied with respect to their wetting properties and thrombogenic characteristics. All materials had much better wetting properties than siliconized glass surface The surface tension of these chitin derivatives was calculated and found to correlate with substrate throm bogenicity. The clotting time of whole blood depended on the chemical modification of the polyaminosaccharide structure and was significantly higher than the silicone surface. Gamma radiation treatment of chitosan led to a decrease in intrinsic viscosity but a small influence on the clotting time of blood in contact with the polymer samples. Solid coatings of acetate, butyrate and citrate salts of chitosan exhibited the greatest thromboresistance of all the investigated derivatives. The kaolin clotting time of plasma shaken in tubes coated with the salts did not show any leachable substances that affected blood coagulation factors except for chitosan-poly(acrylic acid) complex.

Communications from research groups: Advances in the chemical modification of chitin and perspectives of applications

Communications from research groups: Advances in the chemical modification of chitin and perspectives of applications