Photothermal nanoagent for anti-inflammation through macrophage repolarization following antibacterial therapy

Owing to the ignorable bacterial resistance, photothermal therapy (PTT) has been widely studied for bacterial infection. However, few research efforts have focused primarily on the simultaneous utilization of photothermal agents (PTAs) for anti-inflammatory therapy following PTT. Here, we developed a nano-sized PTA ([email protected]) through the self-assembly of Fe3+ and epigallocatechin-3-gallate (EGCG) by using BSA as the nanoreactor and colloidal stabilizer. Next, we assessed its photothermal and reactive oxygen species (ROS) scavenging properties. In addition, we evaluated its antibacterial and anti-inflammatory abilities through in vitro antibacterial and cellular assays, respectively. Finally, we tested its in vivo sterilization and anti-inflammatory effects. Firstly, [email protected] displayed good photothermal capacity due to the inherent photothermal ability of metal-phenolic networks (MPNs). Consequently, [email protected] showed excellent both in vitro and in vivo antibacterial capacities. Moreover, [email protected] exhibited outstanding anti-oxidative property owing to ROS scavenging effect of EGCG. As a result, it presented extraordinary both in vitro and in vivo anti-inflammatory efficiencies through promoting the repolarization of pro-inflammatory (M1) macrophages to anti-inflammatory (M2) macrophages with the released EGCG. The research findings indicated that the prepared nanoagent has great potential to be used for combined antibacterial and anti-inflammatory treatments in future clinical applications.