title: A two-photon fluorescent probe for bio-imaging of formaldehyde in living cells and tissues.
abstract: Formaldehyde (FA) plays an important role in living systems as a reactive carbonyl species (RCS). An abnormal degree of FA is known to induce neurodegeneration, cognitive decrease and memory loss owing to the formation of strong cross-link DNA and protein and other molecules. The development of efficient methods for biological FA detection is of great biomedical importance. Although a few one-photon FA fluorescent probes have been reported for imaging in living cells, probes excited by two photons are more suitable for bio-imaging due to their low background fluorescence, less photobleaching, and deep penetration depth. In this study, a two-photon fluorescent probe for FA detection and bio-imaging in living cells and tissues was reported. The detection is based on the 2-aza-Cope sigmatropic rearrangement followed by elimination to release the fluorophore, resulting in both one- and two-photon excited fluorescence increase. The probe showed a high sensitivity to FA with a detection limit of 0.2 μM. Moreover, enabled the two-photon bio-imaging of FA in live HEK-293 cells and tissues with tissue-imaging depths of 40-170 μm. Furthermore, could be applied for the monitoring of endogenous FA in live MCF-7 cells, presaging its practical applications in biological systems.
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Jun-Bin
authors.initials: JB
authors.lastname: Li
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Wang
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Yong-Xiang
authors.initials: YX
authors.lastname: Wu
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Xiao-Xiao
authors.initials: XX
authors.lastname: Hu
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zhang
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 410082, China. xbzhang@hnu.edu.cn lyuan@hnu.edu.cn.
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
mesh_terms: D000818:Animals; D005456:Fluorescent Dyes; D005557:Formaldehyde / Q000032:analysis*; D057809:HEK293 Cells; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D061986:MCF-7 Cells; D008819:Mice, Nude; D015394:Molecular Structure; D017785:Photons
chemical_list: D005456:Fluorescent Dyes; D005557:Formaldehyde