Investigating the Mechanisms and Applications of Liquid Metal-Biomolecule Interactions

Abstract

Gallium (Ga)-based liquid metals have attracted increasing attention due to their metallic conductivity, fluidity, and unique surface chemistry. However, their interactions with biological macromolecules remain insufficiently understood. This thesis investigates the interfacial interactions between liquid Ga droplets and biomolecules, focusing on protein self-assembly and nucleic acid reactivity.

First, a self-standing soy protein isolate (SPI)-Ga composite film is developed to study interactions between Ga droplets and protein fibrils. Protein fibrils reduce Ga surface oxidation, promote droplet coalescence, and facilitate conductive pathway formation without disrupting the β-sheet-rich fibrillar network. The resulting composites exhibit combined electrical conductivity and mechanical robustness, enabling applications in gas sensing and electrically stimulated antibacterial activity.

This thesis then investigates the interaction between Ga droplets and DNA. The results demonstrate that Ga droplets can cleave DNA phosphodiester bonds, with preference for adenine- and thymine-rich sequences. Mechanistic studies show that the activity originates from interfacial electron transfer associated with Ga surface oxidation, generating reactive species that cleave the DNA backbone while largely preserving nucleobase integrity. The nuclease-mimicking activity can also be tuned through droplet characteristics and external stimuli.

Together, this thesis establishes a fundamental understanding of how liquid Ga interfaces interact with protein fibrils and nucleic acids, providing guidance for the design of liquid metal-based biohybrid materials and future biomedical applications.