作者：Rongrong Qin, Yongchun Liu, Fei Tao, Chen Li, Wenfei Cao, Peng Yang*
关键字：Organic-metal materials, protein-bound composite, free-standing, metal film, stealth information transmission
论文来源：期刊
具体来源：Advanced Materials
发表时间：2019年

The welding and sintering of nanomaterials is relevant, for example, to forming electrical contacts between metallic particles and hybrid metal films. Usually, the welding of nanoparticles is achieved at high temperatures and high pressures. Here, we find that merging of metal nanoparticles occurs under ambient conditions in an aqueous solution via protein bonding. We discovered that the silver nanoparticles from the in situ reduction of silver ammonium ions by glucose underwent confined nucleation and growth and were bound by ultrathin amyloid-like β-sheet stacking of lysozyme. This room-temperature and aqueous merging of silver nanoparticles created a free-standing large-area (e.g., 400 cm2) 2D silver film at the air/water interface with a purity up to 98% and controlled nanoscale thickness. This reaction system is general to other proteins and metals, and shows the great ability for controlled synthesis of highly reflective and highly conductive silver films with elongation nearly 10 times higher than that of pure metal without protein bonding. The ultrathin protein-bonding layer then functioned as a key mediator to dynamically tune the silver conductance in response to external pressures and strains. The sensors exhibited ultrasensitive capability for stealth transmission of Morse code via the detection of minute finger tapping and for silent speech recording via the detection of tiny human throat vibration. This approach will shed light on the development of protein bonding of a given material for bespoke functions.