Light-Driven Mitochondrion-to-Nucleus DNA Cascade Fluorescence Imaging and Enhanced Cancer Cell Photoablation.

Nucleic acids are mainly found in the mitochondria and nuclei of cells. Detecting nucleic acids in the mitochondrion and nucleus in cascade mode is crucial for understanding diverse biological processes. This study introduces a novel nucleic acid-based fluorescent styrene dye (SPP) that exhibits light-driven cascade migration from the mitochondrion to the nucleus. By introducing N-arylpyridine on one side of the styrene dye skeleton and a bis(2-ethylsulfanyl-ethy)-amino unit on the other side, we found that SPP exhibits excellent DNA specificity (16-fold, FDNA/Ffree) and a stronger binding force to nuclear DNA (-5.09 kcal/mol) than to mitochondrial DNA (-2.59 kcal/mol). SPP initially accumulates in the mitochondrion and then migrates to the nucleus within 10 s under light irradiation. By tracking the damage to nucleic acids in apoptotic cells, SPP allows the successful visualization of the differences between apoptosis and ferroptosis. Finally, a triphenylamine segment with photodynamic effects was incorporated into SPP to form a photosensitizer (MTPA-SPP), which targets the mitochondria for photosensitization and then migrates to the nucleus under light irradiation for enhanced photodynamic cancer cell treatment. This innovative nucleic acid-based fluorescent molecule with light-triggered mitochondrion-to-nucleus migration ability provides a feasible approach for the in situ identification of nucleic acids, monitoring of subcellular physiological events, and efficient photodynamic therapy.

Electrostatic Attractive Self-Delivery of siRNA and Light-Induced Self-Escape for Synergistic Gene Therapy.

Small interfering RNA (siRNA) holds immense promise for suppressing gene expression and treating various life-threatening diseases, including cancer. However, efficient delivery and lysosomal escape remain critical challenges that hinder the therapeutic effectiveness of siRNA. Herein, cationic photosensitizer (NB-Br) is grafted onto polo-like kinase 1 (PLK1) siRNA to form an amphiphilic siRNA-photosensitizer conjugate (siPLK1-NB), which can self-assemble into nanoparticles (siPLK1-NB NPs) via electrostatic attraction. Notably, siPLK1-NB NPs exhibit rapid and efficient cell endocytosis, as well as outstanding tumor-targeting property in multiple tumor-bearing mice models. When siPLK1-NB NPs are located inside tumor cell lysosomes, the generated reactive oxygen species (ROS) after photoactivation can disrupt the lysosome membrane structure and facilitate siRNA escape from lysosomes. Under light irradiation, siPLK1-NB NPs can downregulate PLK1 expression and induce photodynamic killing, effectively inhibiting tumor cell growth both in vitro and in vivo. Consequently, this study provides a novel design strategy for carrier-free siRNA delivery systems. As far as it is known, this is the first report of a carrier-free siRNA delivery system based on electrostatic attraction.

Nucleic Acid Probe-Based Difunctional Hematology Analysis Kit for Peripheral Blood Cell Analysis.

Traditional "one for one channel" long-wavelength probes in hematology analyzers limit their resolution and detection efficiency. In this study, we developed a "one for two channels" probe named NATO, which shows a short wavelength (λabs = 460 nm), good nucleus and nucleolus location, and a high signal-to-noise ratio to nucleic acids. When NATO was made into a hematology analysis kit and applied in an automated hematology analyzer, short-wavelength absorbance endows NATO with higher resolution, which in turn leads to better separation of red blood cells and platelets in the blood shadow of the differentiating (DIFF) channel. In addition, this kit showed terrific performance in both DIFF and reticulocytes channels. Our study sheds light on the development of hematology analysis in an automated hematology analyzer by proposing a nucleic acid probe with difunction and higher resolution.