Experimental evaluation of PDMS microchamber dimensions for heat-induced biological reaction experiments

In this work, we present an innovative polydimethylsiloxane (PDMS) microfluidic chip designed to enhance sample retention during thermal processes. The chip features an array of microchambers engineered for efficient sample entrapment, addressing challenges in diagnostic and screening applications. Although PDMS typically exhibits inherent sample loss, our design optimizes the microchamber configuration to balance sample consumption and retention after heating. Experimental validation—including fluorescence intensity analysis and Loop-mediated Isothermal Amplification (LAMP)—confirms the chip's ability to retain nucleic acid samples post-heating. Notably, we achieve these results without modifying the microchamber walls, ensuring simplicity and reproducibility. Furthermore, our analysis of the microchamber evacuation process reveals that sample expulsion follows a linear relationship. Leveraging this insight, we determine an optimal microchamber height based on the intrinsic properties of PDMS, thereby further enhancing sample retention. Fabricated using 3D-printed molds, our PDMS chip offers a reliable and accessible solution for point-of-care diagnostics, delivering improved performance in high-temperature applications. • The innovative PDMS microfluidic chip minimizes sample loss during heating, ensuring reliable performance for high-temperature applications. • Optimized for nucleic acid detection, the chip supports Loop-mediated Isothermal Amplification (LAMP) with enhanced sample retention and minimal reagent use. • Its pump-free design and ease of fabrication make the chip ideal for accessible and cost-effective point-of-care diagnostics.