Gold nanoparticles incorporated liquid metal for wearable sensors and wound healing

Liquid metals, especially for eutectic gallium-indium (EGaIn) have become popular materials in various bioapplications due to their fluidity, conductivity, biocompatibility and antibacterial properties. However, gallium can rapidly form oxide films at ambient conditions, limiting its performance. Taking advantages of the hydrogen bonding between amine groups and gallium oxide interface on EGaIn, EGaIn nanoparticles are modified with p -phenylenediamine (PPD) to inhibit oxidation and attach gold nanoparticles (AuNPs) to achieve EGaIn-PPD@Au nanoparticles. The addition of PPD in making EGaIn nanoparticles can diminish the oxidation of gallium while forming the ligand shell on EGaIn with amine groups. EGaIn-PPD@Au nanoparticles demonstrate high electrical and thermal conductivity together with outstanding photothermal capability. EGaIn-PPD@Au based wearable skin patch can be modified with aptamers for electrochemical detection of C-reactive protein, achieving detection limit of 0.5 mg L -1 . A pressure sensor patch fabricated by incorporating EGaIn-PPD@Au into polydimethylsiloxane (PDMS) can withstand more than 4 MPa pressure (error of less than 0.003 MPa −1 ). EGaIn-PPD@Au based PDMS photothermal patches also demonstrate anti-inflammation and wound healing properties in S. aureus treated inflammation rat model.