Engineering a Red Fluorescent Protein Chromophore for Visualization of RNA G-Quadruplexes.

Synthetic red fluorescent protein (RFP) chromophores have emerged as valuable tools for biological imaging and therapeutic applications, but their application in the visualization of endogenous RNA G-quadruplexes (G4s) in living cells has been rarely reported so far. Here, by integrating the group of the excellent G4 dye ThT, we modulate RFP chromophores to create a novel fluorescent probe DEBIT with red emission. DEBIT selectively recognizes the G4 structure with the advantage of strong binding affinity, high selectivity, and excellent photostability. Using DEBIT as a fluorescent indicator, the real-time monitoring of RNA G4 in biological systems can be achieved. In summary, our work expands the application of synthetic RFP chromophores and provides an essential dye category to the classical G4 probes.

Nanozyme-based dual-signal sensing system for colorimetric and photothermal detection of AChE activity in the blood of liver-injured mice.

Acetylcholinesterase (AChE), a crucial enzyme related to liver function, is involved in numerous physiological processes such as neurotransmission and muscular contraction. The currently reported techniques for detecting AChE mainly rely on a single signal output, limiting their high-accuracy quantification. The few reported dual-signal assays are challenging to implement in dual-signal point-of-care testing (POCT) because of the need for large instruments, costly modifications, and trained operators. Herein, we report a colorimetric and photothermal dual-signal POCT sensing platform based on CeO2-TMB (3,3',5,5'-tetramethylbenzidine) for the visualization of AChE activity in liver-injured mice. The method compensates for the false positives of a single signal and realizes the rapid, low-cost portable detection of AChE. More importantly, the CeO2-TMB sensing platform enables the diagnosis of liver injury and provides an effective tool for studying liver disease in basic medicine and clinical applications. Rapid colorimetric and photothermal biosensor for sensitive detection of acetylcholinesterase (I) and acetylcholinesterase levels in mouse serum (II).