(715b) Reversible Molecular Capture and Release with Liquid Metals

Liquid metals, particularly EGaIn (Eutectic Gallium-Indium), have attracted significant interest in microfluidics and sensing due to their remarkable properties, such as low melting point, deformability, and cost-effectiveness compared to noble metals like gold and silver. Traditional biochemical sensing platforms rely on solid surfaces or electrodes modified with specific capture agents (e.g., antibodies, aptamers) to achieve selectivity for certain biomolecules. This conventional methodology, however, tends to restrict sensor reusability due to the capture agents' instability and the complexity of regenerating the active site without diminishing its performance. Addressing these challenges, here we demonstrate a reversible molecular capturing strategy by controlled removal of the thin oxide layer of the LMs to enable active trapping or releasing of specific target molecules. The resultant EGaIn oxide surface not only introduces a 3D structured coating for augmented surface area but also supports versatile chemical interaction such as charge interaction and silane coupling to promote capturing. On other side, the thin oxide layer can be easily removed using strong acid/base solutions or through rapid electrochemical stimulation. We demonstrated the use of LMs to controlled capture and release of a model targeted molecule (FITC), with a capture rate of 79% and recovery rate of 86% over multiple cycles. This new strategy heralds a new era in the design of reusable, real-time sensing technologies for precise biomolecule detection, offering significant advancements over existing biosensing methodologies.