Ms.

POLYMER-SPECIFIC AND HIGH-AFFINITY BINDING PEPTIDES FOR THE IDENTIFICATION OF MICROPLASTICS IN MIXED SAMPLES Degradation of plastics in the environment and processing of plastics in industry are main examples for processes responsible for the release of tonnes of microplastics (MP) every year. Current research suggests that MPs are distributed throughout the environment with risks and consequences not yet fully understood. To decrease the release the of MPs the European Union (EU) started to ban intentional microplastics and decreases landfilling space, finally generating awareness to waste streams as a resource. However, the fine nature as well as the heterogeneity of MP samples pose difficulties for recycling processes. This work aims to provide a low-cost and sustainable detection system for MPs allowing fast identification of polymers in environmental and industrial samples. The method utilizes polymer-specific peptides covalently linked to fluorescent probes that ultimately label particles of different polymer types in solution. Polymer specific phages were determined using the phage surface technology. In additional biopanning rounds binding properties of promising phages were characterized. Synthetic peptides of best binding phages were ordered and evaluation of binding constants will be performed using suitable ligand binding assays. Using Fourier Transform Infrared and Raman Spectroscopy the amino acids involved in binding will be determined and experimentally proven by alanine scanning mutagenesis. Optimized peptides will be expressed heterologous in varying lengths and combinations to optimize their binding properties. Finally, peptides will be fused to fluorescent probes and analysis of peptide bound plastic particles will occur using fluorescence microscopy and flow cytometry. Here we present the selection of polyethylene terephthalate and nylon 6 binding phages identified by phage surface display. By application of adapted biopanning procedures, phage-particle interaction was visualized and higher binding affinities compared to the control phage were detected. These results form the basis for further developments. Also see: https://micro2024.sciencesconf.org/564476/document