Chitosan, an amino polysaccharide that occurs naturally, is the most significant part of the cell walls of “Zygomycetes,” a particular type of fungi. In addition, it is absent from every other kingdom of fungi. Chitosan, a material used commercially, is produced by deacetylating the chitin from the shells of crab and shrimp over an extended period at high temperatures. Synthesizing structurally modified chitosan has gained more attention recently due to its prospective applications and enhanced solubility. The alkyl or carboxymethyl groups may be added to the structure of chitosan as secondary functional groups during the derivatization process. Derivatization has little impact on chitosan’s skeleton, but it does provide it with new and enhanced properties. Many researchers outline the steps for producing and functionalizing chitosan derivatives chemically and enzymatically and evaluate the properties of this modified chitosan. The researchers successfully isolated chitin by demineralizing and deproteinizing techniques from the crushed internal core of Sepioteuthis lessoniana. Then, to produce chitosan, chitin is deacetylated using 40% NaOH and that produced chitosan is derivatized to sulfated and phosphorylated chitosan. Chitosan quaternary ammonium salt derivatives were prepared and reported with the description that hydrogen bonds are broken down, chargeability is increased, and hence water solubility is improved by quaternary ammonium group addition. In order to produce N-secondary amino-type chitosan crown and the N-Schiff base-type chitosan crown ether, the researchers developed extremely reliable procedures and claimed that the metal ion complexing selectivity in chitosan crown ethers is relatively high. According to one of the reports, the amino groups in chitosan interact with aldehydes through Schiff base intermediaries and methyl iodide is used to quaternized N-alkyl chitosans, which show extraordinarily high levels of antibacterial activity. One of the established reports described a synthetic process for derivatizing chitosan using sugars. Chitosan and gluconic acid may form a covalent link before N-acetylation. Enzymatic techniques are alternatives to environment-unfriendly, hazardous, and non-specific chemical processes. Peroxidases (POD) and oxidase enzymes like polyphenoloxidase (PPO) are the major groups of enzymes. Phenols such as cresol, aniline, 4-hydroxystyrene, and arbutin are grafted onto chitosan by enzymatic methods. The chitosan backbone is chemically functionalized by the addition of tiny functional groups. Some studies indicated that the N-methylene phosphonic chitosan produced in a single step, has consistent modifications, and did not appreciably change its properties. The development of sustained drug release and other biopharmaceuticals is greatly facilitated by the grafted-copolymerized chitosan. One of the studies published the process to produce hydroxyl-ethyl-chitosan (HEC) has potential for bacteriostatic, bactericidal effectiveness against Escherichia coli, and hygroscopic moisturizing effects.

Preparation and Functionalization of the Chitosan Derivatives

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发表日期：

2025年

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Khalid Mahmood Zia

摘要

Chitosan, an amino polysaccharide that occurs naturally, is the most significant part of the cell walls of “Zygomycetes,” a particular type of fungi. In addition, it is absent from every other kingdom of fungi. Chitosan, a material used commercially, is produced by deacetylating the chitin from the shells of crab and shrimp over an extended period at high temperatures. Synthesizing structurally modified chitosan has gained more attention recently due to its prospective applications and enhanced solubility. The alkyl or carboxymethyl groups may be added to the structure of chitosan as secondary functional groups during the derivatization process. Derivatization has little impact on chitosan’s skeleton, but it does provide it with new and enhanced properties. Many researchers outline the steps for producing and functionalizing chitosan derivatives chemically and enzymatically and evaluate the properties of this modified chitosan. The researchers successfully isolated chitin by demineralizing and deproteinizing techniques from the crushed internal core of Sepioteuthis lessoniana. Then, to produce chitosan, chitin is deacetylated using 40% NaOH and that produced chitosan is derivatized to sulfated and phosphorylated chitosan. Chitosan quaternary ammonium salt derivatives were prepared and reported with the description that hydrogen bonds are broken down, chargeability is increased, and hence water solubility is improved by quaternary ammonium group addition. In order to produce N-secondary amino-type chitosan crown and the N-Schiff base-type chitosan crown ether, the researchers developed extremely reliable procedures and claimed that the metal ion complexing selectivity in chitosan crown ethers is relatively high. According to one of the reports, the amino groups in chitosan interact with aldehydes through Schiff base intermediaries and methyl iodide is used to quaternized N-alkyl chitosans, which show extraordinarily high levels of antibacterial activity. One of the established reports described a synthetic process for derivatizing chitosan using sugars. Chitosan and gluconic acid may form a covalent link before N-acetylation. Enzymatic techniques are alternatives to environment-unfriendly, hazardous, and non-specific chemical processes. Peroxidases (POD) and oxidase enzymes like polyphenoloxidase (PPO) are the major groups of enzymes. Phenols such as cresol, aniline, 4-hydroxystyrene, and arbutin are grafted onto chitosan by enzymatic methods. The chitosan backbone is chemically functionalized by the addition of tiny functional groups. Some studies indicated that the N-methylene phosphonic chitosan produced in a single step, has consistent modifications, and did not appreciably change its properties. The development of sustained drug release and other biopharmaceuticals is greatly facilitated by the grafted-copolymerized chitosan. One of the studies published the process to produce hydroxyl-ethyl-chitosan (HEC) has potential for bacteriostatic, bactericidal effectiveness against Escherichia coli, and hygroscopic moisturizing effects.