ABSTRACT
We report new photoluminescent switching systems achieved through pH-induced intramolecular oxa-Michael conjugate addition reactions. Ratiometric absorbance and fluorescence emission were observed across conjugate acceptors triggered by pH, resulting in specific pseudo pKa values. The effect of substituents on the pseudo pKa's was investigated, showing increased values from electron-withdrawing to electron-donating groups. Inspired by the physiologically related pKa, a fluorescent probe was designed, successfully distinguishing cancer cells from normal cells through live cellular imaging.
ABSTRACT
Two-photon autofluorescence (TPAF) imaging is able to offer precise cellular metabolic information with high spatiotemporal resolution, making it a promising biopsy tool. The technique is greatly hampered by the complexity of either the optical system or data processing. Here, the excitation wavelength was optimized to simultaneously excite both flavin adenine dinucleotide and nicotinamide adenine dinucleotide and eliminate the unexpected TPAF. The optical redox ratio (ORR) images were robustly achieved without additional calibration under the optimized single-wavelength excitation. The in vitro, ex vivo, and in vivo biopsy by the TPAF method were systematically studied and compared using hepato-cellular carcinoma and metastasis as examples. It was demonstrated that the proposed TPAF method simplified the optical system, improved the robustness of ORR, and enabled early-stage cancer diagnosis, showing distinguished advantages as compared with previous methods.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Optical Imaging , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/pathology , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/pathology , Optical Imaging/methods , Humans , Animals , Neoplasm Metastasis , Biopsy , Mice , NAD/metabolism , Photons , Flavin-Adenine Dinucleotide/metabolism , Cell Line, TumorABSTRACT
Porous inorganic materials play an important role in adsorbing targeted analytes and supporting efficient reactions in analytical science. The detection performance relies on the structural properties of porous materials, considering the tunable pore size, shape, connectivity, etc. Herein, we first clarify the enhancement mechanisms of porous materials for bioanalysis, concerning the detection sensitivity and selectivity. The diagnostic applications of porous material-assisted platforms by coupling with various analytical techniques, including electrochemical sensing, optical spectrometry, and mass spectrometry, etc., are then reviewed. We foresee that advanced porous materials will bring far-reaching implications in bioanalysis toward real-case applications, especially as diagnostic assays in clinical settings.