Molecule Imaging Techniques Research Articles

Liver Injury Traceability: Spatiotemporally Monitoring Oxidative Stress Processes by Unit-Emitting Carbon Dots.

Exploring the etiology of liver injury is critical to fundamental science and precise treatment, which has not yet been achieved by molecule imaging techniques. Herein, we manage to conquer this challenge by spatiotemporally monitoring oxidative stress processes using the proposed unit-emitting carbon dots (UE-C-dots) as fluorescent probes. We discover and reveal that the UE-C-dots can specifically determine hypochlorous acid (HClO) molecules, one of the important reactive oxygen/nitrogen species (ROS/RNS) in liver injury, by an excited state oxidation mechanism. Other ROS/RNS do not interfere with the assay even if their concentrations are 1000 times higher than that of HClO due to the lowest unoccupied molecular orbital level mismatch. Real-time tomographic imaging demonstrates that different stimuli cause distinctly different HClO bursts in both temporal and spatial dimensionalities. Therefore, the measurement and analysis of temporal information substantially extend our understanding on the relationships of hepatic oxidative stress and corresponding physiological/pathological behaviors.

Single molecule image formation, reconstruction and processing: introduction.

The ability to image at the single molecule scale has revolutionized research in molecular biology. This feature issue presents a collection of articles that provides new insights into the fundamental limits of single molecule imaging and reports novel techniques for image formation and analysis.

Studies on biomolecules using single molecule imaging and manipulation techniques

The best way to obtain unambiguous information about the function of biomolecules is to study their function at the single molecule level. By attaching a small tag such as a single fluorescent dye molecule to biomolecules, or a tag that is huge compared to the size of a biomolecule, we have been able to image the individual behaviours in real time under an optical microscope. Huge tags such as micrometer-sized plastic beads also allow the manipulation of individual molecules with, e.g. optical or magnetic tweezers. Using these techniques, we have observed individual behaviours of RNA polymerase, a molecular machine that copies the genetic information on DNA onto a messenger RNA. We found that some of the RNA polymerase molecules underwent linear diffusion along DNA, helping RNA polymerase to search for the promoter. We also found that a single RNA polymerase molecule rotated around the right-handed screw axis of the double helix of DNA during transcription with a rotary torque of >5 pN nm. The present methods are potentially applicable to the examination of a wide variety of protein–nucleic acid interactions, especially those involved in the process of transcription.