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Stomach cancer is a global health issue because of its incidence and mortality rates worldwide. We developed a near-infrared (NIR) emissive ratiometric two-photon (TP) probe () for the quantitative analysis of pH in live cells and human stomach tissues. The probe design is based on a restrained hemicyanine core that controls the intramolecular charge transfer from 2-naphthol, with a suitable p value (7.50) under physiological conditions. The probe exhibited improved quantum yield, stability, and TP activity under physiological conditions. In addition, intracellular pH titration (pH 4.0 to 10.0) of revealed an ideal intracellular p of approximately 7.2, negligible cytotoxicity, and TP excited fluorescence in situ, thereby allowing direct imaging of the cellular pH in live cells and tissues. Ratiometric two-photon microscope imaging with of human stomach tissue revealed a clear intratissue pH variation among normal, adenoma, and cancer tissues. Our results demonstrate that is useful as an NIR imaging probe for in situ pH-related studies and in cancer research.
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http://dx.doi.org/10.1021/acsabm.0c01546 | DOI Listing |
bioRxiv
August 2025
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, 14853, USA.
Altered metabolism enables adaptive advantages for cancer, driving the need for improved methods for non-invasive long-term monitoring of cellular metabolism from organelle to population level. Here we present two-photon steady-state fluorescence polarization ratiometric microscopy (FPRM), a label-free imaging method that uses nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) autofluorescence as a functional readout of cellular metabolism. The method is simple to implement and operates an order of magnitude faster than the NAD(P)H-fluorescence lifetime imaging microscopy (FLIM) imaging modality, reducing cytotoxic stress while providing long-term monitoring capacity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2025
Chemistry of Photoresponsive Systems, Laboratoire de Chémo-Biologie Synthétique et Thérapeutique (CBST) UMR 7199, CNRS, Université de Strasbourg, F-67400 Illkirch, France.
Monitoring transient pH variations in vivo remains challenging, particularly in blood, a highly absorbing and dynamic tissue where sustained probe circulation is required. To address this, we developed a dual-emission ratiometric pH probe approach based on dextran conjugates to ensure stability in the circulation comprising (1) AF488, a pH-insensitive fluorophore, and (2) H-Ruby (HR), a red-emitting, fluorogenic, pH-sensitive dye. While H-Rubies are efficient pH indicators, their conjugation to dextran induces strong aggregation-caused quenching (ACQ), which limits both their loading capacity and brightness.
View Article and Find Full Text PDFBiosens Bioelectron
November 2025
Department of Nuclear Medicine First Affiliated Hospital of Anhui Medical University Hefei, Anhui, CN 230022, China. Electronic address:
Pathological alterations in intracellular viscosity, acidity, and lipid droplet (LD) dynamics are critical biomarkers for diseases such as cancer, atherosclerosis, and diabetes. Two-photon fluorescence imaging, renowned for its deep penetration and minimal background fluorescence, is an ideal tool for probing these parameters. However, existing two-photon probes lack the ability to simultaneously detect changes in intracellular viscosity, pH, and LD dynamics within a single platform.
View Article and Find Full Text PDFNat Commun
July 2025
Department of Physics, New York University, New York, NY, USA.
Direct measurement of neural activity in freely moving animals is essential for understanding how the brain controls and represents behaviors. Genetically encoded calcium indicators report neural activity as changes in fluorescence intensity, but brain motion confounds quantitative measurement of fluorescence. Translation, rotation, and deformation of the brain and the movements of intervening scattering or autofluorescent tissue all alter the amount of fluorescent light captured by a microscope.
View Article and Find Full Text PDFSensors (Basel)
May 2025
Key Laboratory for Advanced Materials and Joint International Research, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Rd., Shanghai 200237, China.
Peroxynitrite (ONOO) is a reactive nitrogen species (RNS) that plays pivotal roles in various physiological and pathological processes. The recent literature has seen significant progress in the development of highly sensitive and selective fluorescent probes applicable for monitoring ONOO dynamics in live cells and a variety of animal models of human diseases. However, the clinical applications of those probes remain much less explored.
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