Abstract

Microfluidic Mass Production and Bio-Applications of Liquid Metal Nanoparticles

Shiyang Tang, Vice-Chancellor's Postdoctoral Research Fellow, School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong

Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields of flexible electronics, sensors, catalysts, and drug delivery systems. Methods used currently for producing liquid metal (LM) nanoparticles (NPs) have significant disadvantages as they rely on both bulky and expensive high-power sonication probe systems, and also generally require the use of small molecules bearing thiol groups to stabilize the nanoparticles. In addition, LM NPs in aqueous solutions tend to oxidize and precipitate over time, which hinders their utility in systems that require long-term stability. In this presentation, innovative microfluidics-enabled acoustic platforms are described as inexpensive, easily accessible methods for the on-chip mass production of bio-functional EGaIn nanoparticles with tunable size distributions in an aqueous medium. Several novel nanoparticle-stabilization approaches are demonstrated using polymer macromolecules such as brushed polyethylene glycol and  poly(1-octadecene-alt-maleic anhydride), negating the requirements for thiol additives while imparting a “stealth” surface layer. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies, and the application of such bio-functionalized LM NPs in positron-emission tomography imaging is demonstrated. It is envisioned that the developed microfluidic techniques and the produced liquid metal-based nanoparticles can enable a wide range of biomedical applications.