Chemo-enzymatic synthesis of polydimethylsiloxane curcumin copolymer for detection of nitro-aromatics

Curcumin is well-known for its wide range of physiological actions. It is a fluorescent polyphenol, and its optical properties could be used for sensing chemicals. Major impediment is the aggregation of curcumin in thin film, thereby, reducing the fluorescence quantum yield. Herein, we report the chemo-enzymatic polymerization of curcumin with polydimethylsiloxane (Curcumin-PDMS) to address the aggregation problem. PDMS was applied as the matrix because of its low glass transition temperature, which renders diffusion of analyte molecules in and out of the polymer film. Synthesis of Curcumin-PDMS copolymer is regio-selectively catalyzed by Candida antarctica lipase (Novozym 435) in solvent-less condition under vacuum at 90°C. The optical, thermal and sensing properties of Curcumin-PDMS copolymer are also investigated. Current study presents a generic approach, which could be used to modify other natural products including polyphenols for various applications.