Fluorescence lifetime imaging microscopy and its biological applications
Fangrui Lin1,2, Xin Zhen1, Min Yi1 and Junle Qu1,
1Shenzhen Key Laboratory of Photonics and Biophotonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
2Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hong Kong, 999077, China.
Abstract
Fluorescence lifetime imaging microscopy (FLIM) provides a powerful contrast mechanism that is independent of fluorophore concentration, excitation power, and photobleaching, making it an invaluable tool for quantitative biological and biomedical research. This presentation will provide an overview of our recent efforts in advancing FLIM technology and its biological applications across multiple scales, from cellular dynamics to tissue pathology. We first demonstrate the use of a small squaraine dye as a fluorescence lifetime‑based sensor for serum albumin, enabling real‑time monitoring of serum albumin endocytosis in living ovarian cancer cells. This approach was further translated to tissue analysis, where we employed a multimodal nonlinear optical microscope combining two‑photon excitation fluorescence, second harmonic generation, and FLIM to map the concentration gradient of serum albumin in serous ovarian cancer cryosections, revealing distinct distribution patterns in high‑ and low‑grade tumors. To address the limitation of a small field‑of‑view, we developed FLIStitcher, an automated high‑fidelity method for reconstructing large‑field FLIM mosaics by integrating shading correction, brightness correction, and seam‑guided fusion. This algorithm effectively suppresses stitching artifacts and preserves lifetime‑based contrast across extended tissue areas. Finally, we will showcase a deep learning‑assisted FLIM strategy for rapid, stain‑free histopathological diagnosis of brain tumors. By leveraging autofluorescence signals from flavin adenine dinucleotide and hemoglobin, this approach achieves high‑contrast segmentation of tumor boundaries and microvasculature, providing insights into tumor angiogenesis and metabolic dynamics. Collectively, our work highlights the versatility of FLIM as a powerful platform for fundamental biological research and its translational potential in clinical diagnostics.
Speaker
FANGRUI LIN
Department of Biomedical Engineering, the Hong Kong Polytechnic University
CHINA
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