Cross-Linked Proteins with Gold Nanoclusters: A Dual-Purpose pH-Responsive Material for Controllable Cell Imaging and Antibiotic Delivery

This report describes the development of a facile method for the synthesis of cross-linked proteins with gold nanoclusters (CP-GNC). The synthesis reaction is completed within 15 min at 97 °C. The synthesized CP-GNC are characterized by using UV–vis absorption, fluorescence, X-ray photoelectron spectroscopy, and transmission electron microscopy. CP-GNC are approximately 100 nm in diameter and 700 nm in length, whereas AuNCs within the nanorods are approximately 6 nm in size. These materials are highly fluorescent with quantum yield of 7.2% and can be absorbed onto and release from bacterial cells in a pH-dependent and reversible manner. The recent data show that CP-GNC can be a useful, new tool with potential applications in fluorescent cell imaging and antibiotic targeting.