Multi-Channel Optical Device for Solar-Driven Bacterial Inactivation under Real-Time Temperature Feedback.

Solar-driven photothermal antibacterial devices have attracted a lot of interest due to the fact that solar energy is one of the cleanest sources of energy in the world. However, conventional materials have a narrow absorbance band, resulting in deficient solar harvesting. In addition, lack of knowledge on temperature change in these devices during the photothermal process has also led to a waste of energy. Here, we presented an elegant multi-channel optical device with a multilayer structure to simultaneously address the above-mentioned issues in solar-driven antibacterial devices. In the photothermal channel, semiconductor IrO2 -nanoaggregates exhibited higher solar absorbance and photothermal conversion efficiency compared with nanoparticles. In the luminescence channel, thermal-sensitive Er-doped upconversion nanoparticles were utilized to reflect the microscale temperature in real-time. The bacteria were successfully inactivated during the photothermal effect under solar irradiation with temperature monitoring. This study could provide valuable insight for the development of smart photothermal devices for solar-driven photothermal bacterial inactivation in the future.

Orthogonal Near-Infrared-II Imaging Enables Spatially Distinguishing Tissues Based on Lanthanide-Doped Nanoprobes.

Multichannel near-infrared (NIR)-II imaging provides more precise and detailed information for studying complex biological processes. When studying specific biological processes, a separated single signal and multisignals are essential but difficult to obtain by traditional multichannel NIR-II imaging methods. Taking advantage of the unique optical properties of lanthanide ions, especially in atom-like absorbance and emission spectroscopy in the NIR region, in this study, we synthesized two lanthanide-doped nanoprobes, NaYF4:Gd@NaYF4:Nd@NaYF4 (cssNd) and NaYF4:Gd@NaYF4:Er@NaYF4 (cssEr). These two nanoprobes show orthogonal NIR-II emissions (1064 and 1330 nm for cssNd and 1550 nm for cssEr) under 730 and 980 nm excitation, respectively. The feasibility of cssNd and cssEr for multichannel NIR-II imaging was proven in vitro. Under different methods of administering the nanoprobes, in vivo multichannel NIR-II imaging with both the separated single signal and multisignals was successfully performed and could spatially distinguish tissues under two different excitation sources. Our results provide a new method for multichannel NIR-II imaging with separable signals, which is promising for precisely studying complex biological processes precisely.

Endogenous H2S-Activable Liposomal Nanoplatform for Synergistic Colorectal Tumor Ablation at Mild Apparent Temperature.

Photoinduced hyperthermia possesses great potential in photothermal therapy and thermal-responsive chemotherapy of tumors. However, traditional thermal-triggered drug release requires high temperature, which results in unpleasant activation of thermal-induced cellular self-protection. In this work, a Cu-complex modified and drug-loaded liposomal nanoplatform was constructed for endogenous H2S-activated synergistic ablation of colorectal tumors. In response to H2S, the incorporated Cu-complex contributed to the formation of semiconductor CuS on the surface of the as-designed liposomal nanoplatform, which led to local heating under near-infrared (NIR) laser irradiation to achieve simultaneous photothermal therapy and drug release. It is noteworthy that although the drug release occurred at a mild apparent temperature, it was actually triggered by the high eigen temperature on the surface of the liposomal nanoplatform. Therefore, efficient and synergistic photothermal and chemotherapy was achieved under mild apparent temperatures. This work provides insights into achieving selective and bioactivated photothermal therapy and therefore thermal-controlled drug release without using excessive hyperthermia.