As a new type of non-invasive treatment, Photodynamic therapy (PDT) has been widely used in the treatment of tumors and bacterial infections. However, the shallow tissue penetration depth of short-wavelength light and the generation of low reactive oxygen species (ROS) have hindered its development. The realization of long-wavelength near-infrared zone two (NIR-II) light-induced multiple enhanced photodynamic therapy is essential. On the basis of this scientific problem, Professor Zhang Jiatao, the PI team of Biomedical New Materials of the Institute of Medical-Industry Fusion, designed and synthesized a multi-enhanced near-infrared two-region (NIR-II) Au with semiconductor doping and local surface plasmon resonance (LSPR) enhancement. /CdSexS1-x nano-dumbbell hybrid structure, in cooperation with researchers from the National Nanoscience Center Wang Hao and Qiao Zengying, developed a new material for efficient NIR-II light-induced antibacterial photodynamic therapy. Related results were published online in the top international journal ACS Nano.

To achieve high-efficiency ROS generation and higher PDT efficiency, the team prepared near-infrared Au/CdSe nano-dumbbell structures, high-efficiency hot electron injection effects, photoelectric catalytic hydrogen production, and photo-reduction CO2 performance application research progress (Adv. Energy Mater. 2019, 9(15), 1803889; Small2020, 16, e2000426) to control the growth of Ag-doped CdSexS1-x with different Se and S ratios to the hot spots at both ends of the LSPR of the anisotropic Au NRs . Au nanorods absorb long-wavelength NIR-II light, and the precise heterogeneous interface construction enables Plasmon hot electrons to be efficiently injected into the semiconductor structure at both ends. By adjusting the ratio of Se and S to adjust the band structure to obtain the maximum hot electron injection efficiency, the introduction of doped Ag can inhibit the combination of electrons and holes. In addition, the nanodumbbell heterostructure promotes the effective separation of electrons and holes. Multiple enhancements such as high hot electron injection efficiency and effective separation of electrons and holes realize the generation of high-efficiency ROS, and the NIR-II light-induced PDT inhibits the growth of bacteria and biofilms. This hybrid nano-dumbbell structure can generate 40 times more superoxide radicals (·O2 -) and more hydroxyl radicals (·OH). The experimental results in mice further prove that the nano dumbbell has a good PDT curative effect. This nanostructure provides a new strategy for NIR-II light-induced PDT.

The above-mentioned research results have won the funding support of the Institute of Medical-Industry Convergence, and the Beijing Key Laboratory of Advanced Functional Materials and Green Applications with Controllable Structure, and the Key Laboratory of Pharmaceutical Molecular Science and Preparation Engineering of the Ministry of Industry and Information Technology. Doctoral student Wang Dong from the School of Materials Science and Engineering of BIT is the first author of the article. The National Nanoscience Center Qiao Zengying, researcher Wang Hao and Professor Zhang Jiatao of BIT are the co-corresponding authors, and BIT is the first correspondent unit.