Hydrogen-Bonded Chitosan-Allantoin Assemblies: A Computational and Experimental Approach to Antimicrobials

The present research discusses synthesis and investigation of N-halamines based on supramolecular assembles of chitosan (Cs) and allantoin (Aln). Theoretical insights into the possible pathways of interaction between the pristine molecules have been done with the help of DFT calculations. The change in Gibbs free energy of the potential products of the reaction between Aln and Cs, associated with the formation of supramolecular assemblies, Shiff bases, and hemiketals, was calculated, revealing the formation of noncovalent bonds thermodynamically favorable. FTIR results indicating the formation of multiple hydrogen bonds between allantoin and chitosan have been found consistent with the computational results. Molecular docking findings demonstrated remarkable affinity of halogenated and nonhalogenated Cs-Aln assemblies to AmpC β-lactamase, the target protein of E. coli. Cs-Aln-Cl supramolecular assembly was also characterized using FT-IR spectroscopy and SEM. The content of active chlorine was quantitively analyzed with iodometric titration and EDX. The results of the antimicrobial test demonstrated the formation of prominent inhibition zones around Cs-Aln-Cl samples, emphasizing the prospectives of these N-halamines as antimicrobial agents.