Preparing Fluorescent Conjugated Polymers through One Pot Enzymatic Polymerization for Sensing Applications

Abstract

Abstract Fluorescence based polymeric sensors are simple, extremely sensitive, versatile and adaptable for detection of different types of analysts. However, the multi-step synthesis using toxic chemicals followed by purification is often required for obtaining these fluorophores. Here the possibility of utilizing enzymes as the catalyst, for the one step polymerization of naturally occurring monomers to yield fluorescent conjugated polymers is presented. Four monomers, 4- Hydroxyphenylacetic acid (HPA), Hydroxytyrosol (HDT), Chlorogenic acid (CGA) and Serotonin (Sero) were polymerized using Horseradish peroxidase as the biocatalyst. The broad peaks of IR spectrum were obtained from all polymers comparing with the sharp peaks of monomers. The decrease of UV-Vis intensity at significant wavelength of each monomer was found when the polymer was formed. These polymers exhibit fluorescence with significant stokes shift around 100 nm rendering them useful in fluorescence quenching-based sensors. In the detection of lead ion, DNT and TNT in solution through fluorescence-quenching are studied. Both nitro aromatic compounds were detected from electron interaction between phenol and nitro-aromatic compound structures that poly(HPA) and poly(Sero) detected at 1 ppm level. From having carboxylic group, poly(HPA) detected lead at 50 ppb at neutral pH.