Treat the "Untreatable" by a Photothermal Agent: Triggering Heat and Immunological Responses for Rabies Virus Inactivation

Revolutionary Pyrazole-based Aza-BODIPY: Harnessing Photothermal Power Against Cancer Cells and Bacteria

In the realm of cancer therapy and treatment of bacterial infection, photothermal therapy (PTT) stands out as a potential strategy. The challenge, however, is to create photothermal agents that can perform both imaging and PTT, a so-called theranostic agent. Photothermal agents that absorb and emit in the near-infrared region (750-900 nm) have recently received a lot of attention due to the extensive penetration of NIR light in biological tissues. In this study, we combined pyrazole with aza-BODIPY (PY-AZB) to develop a novel photothermal agent. PY-AZB demonstrated great photostability with a photothermal conversion efficiency (PCE) of up to 33 %. Additionally, PY-AZB can permeate cancer cells at a fast accumulation rate in less than 6 hours, according to the confocal images. Furthermore, in vitro photothermal therapy results showed that PY-AZB effectively eliminated cancer cells by up to 70 %. Interestingly, PY-AZB exhibited antibacterial activities against both gram-negative bacteria, Escherichia coli 780, and gram-positive bacteria, Staphylococcus aureus 1466. The results exhibit a satisfactory bactericidal effect against bacteria, with a killing efficiency of up to 100 % upon laser irradiation. As a result, PY-AZB may provide a viable option for photothermal treatment.

Molecular Engineering of AIE Photosensitizers for Inactivation of Rabies Virus

Rabies is a zoonotic neurological disease caused by the rabies virus (RABV) that is fatal to humans and animals. While several post-infection treatment have been suggested, developing more efficient and innovative antiviral methods are necessary due to the limitations of current therapeutic approaches. To address this challenge, a strategy combining photodynamic therapy and immunotherapy, using a photosensitizer (TPA-Py-PhMe) with high type I and type II reactive oxygen species (ROS) generation ability is proposed. This approach can inactivate the RABV by killing the virus directly and activating the immune response. At the cellular level, TPA-Py-PhMe can reduce the virus titer under preinfection prophylaxis and postinfection treatment, with its antiviral effect mainly dependent on ROS and pro-inflammatory factors. Intriguingly, when mice are injected with TPA-Py-PhMe and exposed to white light irradiation at three days post-infection, the onset of disease is delayed, and survival rates improved to some extent. Overall, this study shows that photodynamic therapy and immunotherapy open new avenues for future antiviral research.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

NIR-II-absorbing diimmonium polymer agent achieves excellent photothermal therapy with induction of tumor immunogenic cell death

Photothermal therapy has shown great promise for cancer treatment and second near-infrared (NIR-II) -absorbing particles could further improve its precision and applicability due to its superior penetration depth and new imaging ability. Herein, high NIR-II-absorbing polymer particles were prepared by using soluble isobutyl-substituted diammonium borates (P-IDI). The P-IDI showed stronger absorption at 1000-1100 nm, which exhibited excellent photostability, strong photoacoustic imaging ability and high photothermal conversion efficiency (34.7%). The investigations in vitro and in vivo demonstrated that the excellent photothermal effect facilitated complete tumor ablation and also triggered immunogenic cell death in activation of the immune response. The high solubility and excellent photothermal conversion ability demonstrated that polymer IDI particles were promising theranostic agents for treatment of tumors with minor side effects.