# Enhanced Reusability of Immobilized T7 DNA Polymerase in Multi-Cycle Exonuclease Reactions on Gold-Coated SAM Biosensor Platforms

## TL;DR

This study shows how T7 DNA polymerase can be reused multiple times on a biosensor, improving sustainability in biotechnology.

## Contribution

The paper introduces a quantitative evaluation of DNA polymerase reusability using QCM and real-time monitoring.

## Key findings

- Immobilized T7 DNA polymerase retained 50% activity after three cycles and 20% after five.
- Longer reaction times unexpectedly improved enzyme stability.
- A scalable framework for reusing DNA-processing enzymes was established.

## Abstract

The reusability of enzymes is a fundamental aspect of sustainable biotechnology and the development of biosensors. This study presents one of the first quantitative evaluations of DNA polymerase reusability by utilizing integrated quartz crystal microbalance (QCM) kinetics and real-time monitoring of exonuclease activity. The results showed that immobilized T7 DNA polymerase retained approximately 50% of its initial activity after three 90-min cycles and around 20% after five cycles. Significantly lower activities were observed for shorter, 45-min cycles. This indicates an unexpected time-dependent enhancement in stability for longer reaction times. The findings suggest a promising trend in enzyme stability and reusability, establishing a quantitative relationship between reaction duration and enzyme performance. This relationship offers a scalable pathway for the regeneration of biosensors and for sustainable enzymatic catalysis. Additionally, the work provides a transferable framework that can be applied to other DNA-processing enzymes, which supports long-term biosensor performance and industrial biocatalysis. The demonstrated approach offers a transferable and scalable methodology for the development of reusable polymerase-based biosensors and sustainable biocatalytic systems.