Confining Eutectic Gallium Indium (eGaIn) in Expired Artificial Kidneys to Unveil Nanoporous Conductive Wires

TL;DR

This paper presents a novel method to create nanoporous conductive wires by injecting liquid metal into microtubes from expired artificial kidneys, enabling environmentally friendly, cost-effective sensors for biomedical and nanoelectronic applications.

Contribution

It introduces a new upcycling approach using expired medical waste to fabricate nanoporous conductive fibers with sensing capabilities, avoiding traditional complex manufacturing processes.

Findings

Successfully fabricated nanoporous conductive wires from expired kidney microtubes.

Demonstrated sensing and differentiation of water, acid, and ethanol using electrical signatures.

Revealed a new class of environmentally friendly, cost-effective nanomaterials for biomedical and electronic devices.

Abstract

Nanoporous membranes have gained considerable interest in drug delivery1, ion transportation2, micro/nanofluidics3, molecular sensing4, and separation science5. Artificial kidneys, also known as dialyzers, reject pathogens and other unwanted substances from the blood, utilize hundreds of soft and nanoporous polymeric microtubes, and slowly become a burden to the environment with the growing number of dialysis patients worldwide. We demonstrate the fabrication of nanoporous conductive wires utilizing empty polysulfone microtubes collected from expired and unused artificial kidneys, also known as medical wastes. Injecting a fluidic, highly conductive, and room temperature liquid alloy (eutectic gallium indium-eGaIn$_6$, 75% Ga, 25% In) into microtubes of a twenty years old dialyzer, here, we have revealed a new class of nanoporous and conductive functional materials. These conductive fibers upcycle a medical waste, do not require expensive and conventional fabrication processes, and still provide the quintessential metal-oxide/metal framework due to the presence of the native surface oxide (i.e., Gallium Oxide, Ga2O3) of eGaIn at the nanoconfinement (i.e., nanopores) for nano/biosensing. We harnessed these new materials to sense and differentiate microliter volumes of deionized (DI) water, 1M hydrochloric acid (HCl), and 95% ethanol (EtOH), leveraging their electrical signatures. This new class of soft nanomaterials has the potential to become the paradigm-shift platforms for the next-generation of biomedical, bioelectronics, nanoelectronics, and sensor devices.