Biomedical investigations reveal that excessive formaldehyde generation is possibly a critical factor for tissue cancerization, cancer progression and metastasis. Responsive molecular probes that can detect lysosomal formaldehyde in live cells and tumors and monitor drug-triggered formaldehyde scavenging contribute potentially to future cancer diagnosis and treatment monitoring. Herein, a novel "dual-key-and-lock" strategy-based ruthenium(II) complex probe, Ru-FA, is reported as an effective tool for formaldehyde detection in vitro and in vivo. Ru-FA shows weak luminescence due to photon-induced electron transfer (PET) process from Ru(II) centre to electron withdrawing group 2,4-dinitrobenzene (DNB). Triggered by the specific reaction with formaldehyde (first "key") in an acidic microenvironment (second "key"), DNB is cleaved from Ru-FA, affording an emissive Ru(II) complex derivative, Ru-NR. Spectrometric analysis including steady-state and time-gated luminescence indicates that Ru-FA is favourable to be used as the probe for quantification of formaldehyde in human sera and mouse organs. Ru-FA is biocompatible and cell membrane permeable. Together with its smart "dualkey-and-lock" response to formaldehyde, luminescence imaging of lysosomal formaldehyde in live cells, visualization of tumor-derived endogenous formaldehyde and monitoring of formaldehyde scavenging in mice were achieved, followed by the successful demonstration on detection of formaldehyde in tumors and other organs. These in vivo and in vitro detection confirm not only the excessive formaldehyde generation in tumors, but also the efficient drug administration to scavenge formaldehyde, demonstrating the potential application of Ru-FA in cancer diagnosis and treatment monitoring through lysosomal formaldehyde detection.
Development of novel bioanalytical methods for monitoring of H S is key toward understanding the physiological and pathological functions of this gasotransmitter in live organisms. A ruthenium(II)-complex-based luminescence probe, Ru-MDB (MDB: 4'-methyl-[2,2'-bipyridine]-4-yl)methyl 2-((2,4-dinitrophenyl)thio)benzoate), was developed by introducing a new H S responsive masking moiety to a red-emitting Ru luminophore. Cleavage of this masking group by a H S-triggered reaction leads to a luminescence "off-on" response. The long-lived emissions of Ru-MDB and its reaction product with H S allowed quantitative detection of H S in autofluorescence-rich human sera and adult zebrafish organs using the time-gated luminescence mode. Ru-MDB exhibits red emission, a large Stokes shift, high specificity and sensitivity for H S detection, and low cytotoxicity, which enables imaging and flow cytometry analysis of lysosomal H S generation in live inflamed cells under drug stimulation. Monitoring of H S in live Daphnia magna, zebrafish embryos, adult zebrafish, and mice, was conducted by in vivo imaging using Ru-MDB as a probe.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.