Rational Design of Self-Reporting Photosensitizers for Cell Membrane-Targeted Photodynamic Therapy

A DNA conformational nanoswitch for amplification of both low-abundance protein imaging in living cells and photodynamic therapy

A method was developed for inducing a DNA conformational nanoswitch triggered by proteins, intended for fluorescence signal amplification imaging and photodynamic therapy targeting tumor cells.

Modulating Aggregation and Deaggregation Based on Assembling Strategy to Switch on NIR-II Light-Excited Fluorescence for Self-Reporting Viability of Eliminating Cancer Cell

The fabrication of self-reporting photosensitizers (PSs), enabling real-time evaluation of the extent of elimination of cancer cells, holds significant scientific importance in the photodynamic therapy (PDT) process. To address the intrinsic challenge of the short-wavelength light source, this work proposed an innovative approach of rational design second near-infrared (NIR-II, 1000-1700 nm) light-excited fluorescent PS systems (named HOEt-PI, Me-PI, and Et-PI, respectively) through modulating aggregation and deaggregation based on assembling strategy. Therein, the suitable interplanar distance of adjacent Et-PI linked with C-H···π interactions was an idea for relieving compact π···π packing for fluorescent imaging as well as elevating the spin-orbit coupling for reactive oxygen species (ROS) generation. With ROS continuously increasing, Et-PI underwent cell membrane-to-mitochondria migration, ultimately accumulated in nucleoli, symbolizing programmed cell death, thus distinguishing dead/live cells via three-photon fluorescence imaging (excited on 1250 nm) under photogeneration ROS. Meaningfully, the three-photon fluorescence of Et-PI was triggered by RNA of nucleoli, for which the higher signal-to-noise ratio and in-depth fluorescence imaging observed cancer cellular viability. Collectively, the proposed findings presented a constructing strategy for NIR-II light-mediated self-reporting PS for guiding the PDT of deep cancerous tissue in the future.

Photoimmunotherapy for cancer treatment based on organic small molecules: Recent strategies and future directions

Photodynamic therapy (PDT) is considered as a promising anticancer approach, owning to its high efficiency and spatiotemporal selectivity. Ample evidence indicated that PDT can trigger immunogenic cell death by releasing antigens that activate immune cells to promote anti-tumor immunity. Nevertheless, the inherent nature of tumors and their complex heterogeneity often limits the efficiency of PDT, which can be overcome with a novel strategy of photo-immunotherapy (PIT) strategy. By exploring the principles of PDT induction and ICD enhancement, combined with other therapies such as chemotherapy or immune checkpoint blockade, the tailored solutions can be designed to address specific challenges of drug resistance, hypoxic conditions, and tumor immunosuppressive microenvironments (TIMEs), which enables targeted enhancement of systemic immunity to address most distant and recurrent cancers. The present article summarizes the specific strategies of PIT and discusses recent existing limitations. More importantly, we anticipate that the perspectives presented herein will help address the clinical translation challenges associated with PIT.

Cancer-cell-specific Self-Reporting Photosensitizer for Precise Identification and Ablation of Cancer Cells

Cancer-cell-specific fluorescent photosensitizers (PSs) are highly desired molecular tools for cancer ablation with minimal damage to normal cells. However, such PSs that can achieve cancer specification and ablation and a self-reporting manner concurrently are rarely reported and still an extremely challenging task. Herein, we have proposed a feasible strategy and conceived a series of fluorescent PSs based on simple chemical structures for identifying and killing cancer cells as well as monitoring the photodynamic therapy (PDT) process by visualizing the change of subcellular localization. All of the constructed cationic molecules could stain mitochondria in cancer cells, identify cancer cells specifically, and monitor cancer cell viability. Among these, IVP-Br has the strongest ability to produce ROS, which serves as a potent PS for specific recognition and killing of cancer cells. IVP-Br could translocate from mitochondria to the nucleolus during PDT, self-reporting the entire therapeutic process. Mechanism study confirms that IVP-Br with light irradiation causes cancer cell ablation via inducing cell cycle arrest, cell apoptosis, and autophagy. The efficient ablation of tumor through PDT induced by IVP-Br has been confirmed in the 3D tumor spheroid chip. Particularly, IVP-Br could discriminate cancer cells from white blood cells (WBCs), exhibiting great potential to identify circulating tumor cells (CTCs).