Effect of gold nanoparticles and γ-cyclodextrin polymer on physicochemical, antimicrobial, and antibiofilm properties of a novel schiff base derived from dialdehyde cellulose and camphor thiazole-imine.

The present study developed a novel antimicrobial composite based on 2,3-dialdehyde cellulose (DAC), with biocompatible properties and long-term stability. Initially, DAC was synthesized through the periodate oxidation of microcrystalline cellulose, achieving a 61% degree of oxidation. Subsequently, the DAC was successfully modified through the formation of a Schiff base with CTI in the basic medium. The antimicrobial efficacy of the synthesized DAC-CTI was strengthened by the synthesis of Au NPs via a green chemical approach using lemon extract and their subsequent grafting into the DAC-CTI matrix, followed by encapsulation of the produced DAC-CTI/Au nanocomposite into the γ-cyclodextrin ring. The TEM results of DAC-CTI/Au nanocomposite indicated an average Au particle size of 37.4 nm within the nanocomposite. The evaluated samples reveal a positive efficacy against a variety of bacteria, including P. aeruginosa, C. albicans, and S. aureus. Particularly, DAC-CTI/Au NPs/γ-CD exhibited the highest effect on S. aureus (19.0 mm zone of inhibition (ZOI) and 2.5 µg/mL MIC), E. coli (20.0 mm ZOI and 1.25 µg/mL MIC), and C. albicans (18.2 mm ZOI and 2.5 µg/mL MIC). The outcomes achieved open the door to the practical implementation of intriguing compounds in biological fields.