Monitoring Enzymatic Polymer Degradation Inside a Microplate Format via Integrated Thermal Sensors

Abstract

Plastics are receiving growing scientific attention due to pollution concerns, driving interest in the development of alternative materials that are more readily biodegradable. This work presents a novel sensor system and sensing method for monitoring polymer film degradation in real-time and at high throughput. The platform uses a transient thermal measurement principle to track changes in polymer film thickness, offering a label-free, scalable, and quantitative approach. Using a newly presented design, thin-film sensors were integrated into a conventional 48-well microplate format. The system was validated using commercial-grade Mylar films and in-house fabricated polycaprolactone (PCL) films of varying thicknesses, demonstrating accurate thickness assessment with mean absolute error (MAE) values below 7.5 and $19.5 similar to\mu $ m in the linear regime for Mylar and PCL films, respectively. The ability to monitor polymer degradation was demonstrated through enzymatic degradation of PCL films using Candida antarctica lipase B. Degradation was quantified using the $\boldsymbol {t_{\mathrm {90}}}$ value, defined as the time at which 90 % of sample thickness loss due to degradation was reached. The results show a clear correlation between enzyme concentration and $\boldsymbol {t_{\mathrm {90}}}$ , highlighting the platform's capability for screening degradation conditions. This assay enables convenient and scalable biodegradability testing for research and industry.