Chemically modified nylons as supports for enzyme immobilization. Polyisonitrile-nylon.

Area of Science:

• Polymer Chemistry
• Bioconjugation
• Materials Science

Background:

• Four-component condensation reactions (Ugi, 1962) form N-substituted amides.
• Nylon, a common polyamide, lacks inherent reactive groups for facile functionalization.
• Introducing reactive handles onto polymer backbones is crucial for advanced material applications.

Purpose of the Study:

• To functionalize the polyamide backbone of nylon with chemically reactive groups.
• To synthesize polyisonitrile-nylon and polyaminoaryl-nylon using four-component condensations.
• To demonstrate the utility of these modified nylons for protein immobilization.

Main Methods:

• Partial hydrolysis of nylon-6 powder followed by resealing via four-component condensation with acetaldehyde and 1,6-di-isocyanohexane to yield polyisonitrile-nylon.
• Conversion of polyisonitrile-nylon to polyaminoaryl-nylon using a four-component condensation with pp'-diaminodiphenylmethane, an aldehyde, and a carboxylate.
• Coupling of proteins (trypsin, papain, pepsin) to modified nylon in aqueous media at neutral pH via amino or carboxyl groups.

Main Results:

• Successful synthesis of polyisonitrile-nylon and its diazotizable derivative, polyaminoaryl-nylon.
• Demonstrated efficient coupling of proteins (trypsin, papain, pepsin) to the modified nylon backbone.
• Proteins were immobilized through their amino or carboxyl groups, and papain was immobilized via tyrosine residues using diazotized polyaminoaryl-nylon.

Conclusions:

• Four-component condensation reactions are effective for introducing isocyanide and arylamino functionalities onto nylon.
• Polyisonitrile-nylon and polyaminoaryl-nylon serve as versatile platforms for bioconjugation and protein immobilization.
• The developed materials show promise for applications in biocatalysis and other biotechnological fields.