Influence of silver speciation on the inflammatory regulation of AgNPs anchoring onto titania nanotubes

AgNPs were immobilized on titania nanotubes (TNT) by chelation of polydopamine (PD) to generate a TNT/PD/ AgNPs (TPAS) via a simple dipping method. The inflammatory regulation of the TPAS coating were investigated. To gain a deep insight into the transformation of AgNPs in macrophages, a cation exchange reaction was introduced for speciation analysis of AgNPs and Ag+ by inductively coupled plasma-mass spectrometry. Owing to the magic signal amplification strategy, the trace AgNPs and Ag+ in release media and even in macrophages were easily detected. In simulated inflammatory microenvironment, M1 macrophages promoted the cell-responsive release of Ag+ from TPAS at 3 d, which dampened inflammation. Then, macrophages reduced Ag+ by intracellular metabolites, leading to the formation of new AgNPs in cells. This study give a new sight for discovering the inflammatory regulation mechanism of silver containing biomaterials.