Moisture Power in Natural Polymeric Silk Fibroin Flexible Membrane Triggers Efficient Antibacterial Activity of Silver Nanoparticles

Abstract The deepening research and development of micro currents/potentials has made the tiny electrical signals very common in many applicable fields, such as radio frequency identification (RFID), smart chip cards, cosmetics, low-power wearable electronics, etc. A typical alternative energy source from water vapor/moisture, which is prevalent in nature, moisture power (MP) has not been heavily developed and it is usually applied only as a power supply side, without being assigned new tasks and missions leading to the sharpness being covered up. Here, we designed a flexible antibacterial MP membrane by electrospinning and in situ synthesis of AgNPs. The electrospun membrane containing Oxi-silk fibroin with AgNPs (AgNPs@Oxi-SF) in an asymmetric humid environment can generate MP by the presence of directionally migrating charged ions, which can trigger the release of more free Ag+ from AgNPs and allow AgNPs@Oxi-SF to exhibit better antibacterial activity. The continuous and moderate MP generated by AgNPs@Oxi-SF electrospun membrane (AOSFEM) in a humid environment (RH = 99%, 2 h) allowed it to exhibit nearly 100% bactericidal rate compared to 36.7% to 56.3% in a non-MP environment.