Functionalised Antimicrobial Polymers

Kiran Meghwal, Narendra Pal Singh Chauhan, Neda Eghtesadi, Zahra Rezvani, Pinki Bala Punjabi and Masoud Mozafari 

Tew and co-workers studied the biological activities of antimicrobial polymers and found that they were influenced by the amphiphilicity of the polymer or oligomer as an entity rather than the activity of one antimicrobial portion, either embedded or covalently attached, and mostly contained antimicrobial macromolecules that can mimic the biological action of antimicrobial natural host-defence peptides (e.g., synthetic polyphenylene ethynylenes, polynorbornenes and polymethacrylates) [4]. 

The essential characteristics that an ideal antimicrobial polymer should have include 1) simply and economically synthesised, 2) stable in long-term applications and storage at the temperature of its anticipated application, 3) not soluble in water for water disinfectant applications, 4) does not decompose to release toxic products, 5) should not be toxic or harmful to people who handle it, 6) can be regenerated upon loss of activity and 7) biocidal against a broad spectrum of pathogenic microorganisms after brief contact periods. 

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Functionalised Antimicrobial Polymers Based on Poly(hydroxystyrene-co-methyl methacrylate) Derivatives... 

Functionalised antimicrobial polymers can be developed by chain transfer (reversible addition-fragmentation transfer) polymerisation involving amino derivatives of methacrylate containing polydimethylsiloxane, which are further quarternised to yield new cationic polymers and are useful as antimicrobial coatings. 

The chemical modification of CS biopolymers via reductive amination, to yield alkylated CS derivatives, and further quaternisation result in very efficient antibacterial materials the degree of activity is correlated to the length of the alkyl chain and bacterial strain. The most active CS derivatives are more selective at killing bacteria than the quaternary ammonium disinfectants, cetylpyridinium chloride and benzalkonium chloride, and AMP. Vanillin can be used as a crosslinker of CS nsing this approach, functionalised antimicrobial polymers based on CS, vanillin. Tween 60 and so on may be easily prepared. Imino-CS biopolymer films, prepared by the acid condensation of the amino groups of CS with various aldehydes, can be used as functional biodynamic materials. 

Air-ozonolysis has already been revealed to be an accessible and effective approach for surface activation and the further functionalisation of hydrocarbon polymers. Antimicrobial contact-active polyethylene and PS can be designed by the surface generation of OH-functional groups and the covalent grafting of a dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride quaternary ammonium salt. This strategy might establish a new general and safe platform for the future development and applications of contact-active antimicrobial polymers. 

Cationic polymer-functionalised gold NP have large concentrations of positive charge, which promote their adsorption onto negatively charged bacterial membranes via electrostatic interactions. This kind of antimicrobial material, with effective antibacterial activity and better biocompatibility, can promote the healing of microbially infected wounds and could have promising applications in the biomedical field. 

CS, which is natural polymer containing active groups, such as -NH2, can be functionalised to introduce new positively charged N-atoms. The CS-iodine complexes exhibit better antimicrobial properties. 

Biocidal polymers are considered to be the next generation of antibiotics which can be effectively used against microbial infections. The antimicrobial activities of silver-bearing functionalised polymers and L-lactide polymeric NP are an important aspect in the prevention of bacterial skin and urinary tract infections. Biologically derived compounds, such as bacteriocins, phytochemicals and enzymes, can be used in antimicrobial food packaging. 

Abstract Enzymatic polymer functionalisation has entered its most fascinating period with development in this field largely at the basic research level and pilot scale applications. Development of enzymatic processes for the development of lignocellulose-based functional polymers has not been spared, ranging from textile fibres with novel properties (antimicrobials properties, hydrophobic properties, attractive shed colours, etc.) to fibreboards. Enzymatic processes are also being actively pursued aimed at developing functional polymers from lignin (a major by product of the pulp and process). 

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