Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 14: Poster Session II
BP 14.29: Poster
Dienstag, 10. März 2026, 18:00–21:00, P2
Photothermal imaging of autofluorescent retinal pigment epithelium (RPE) granules — •Sicheng Tian1,2, Maryam Ali1,2, Hanan Alderzy1,3, Christoph Krafft1,2, Martin Hammer1,3, and Daniela Täuber1,2 — 1Friedrich Schiller University Jena — 2Leibniz Institute of Photonic Technology, Jena — 3Jena University Hospital, Jena, Germany
The retinal pigment epithelium (RPE) plays an important role in the photocycle. RPE cells contain varied amounts of micrometer-sized autofluorescent granules, including melanosomes (M), lipofuscin (L) and melanolipofuscin (ML), whose distribution varies throughout the RPE layer and with increasing age. Non-invasive fundus autofluorescence is used for clinically monitoring the distribution of L and ML. Specific alterations in the distribution of L, ML and M are linked to age-related macular degeneration (AMD)[Bermond et al., IOVS, 2020, 61, 35]. In spite of their importance, their chemical composition is not fully understood. Mid-IR Photo-induced Force Microscopy (PiF-IR) can provide a chemical evaluation of cell and organelle surfaces with less than 5 nm spatial resolution [Ali et al., Anal. Chem., 2025, 97, 23914] by combining powerful infrared illumination with mechanical detection using atomic force microscopy (AFM-IR). We utilized PiF-IR for the investigation of isolated M in a dried droplet. We complemented our study by sub-micron photothermal images using Optical Photothermal Infrared spectroscopy (O-PTIR) under illumination at visible wavelengths. We compare the results to PiF-IR spectra and conventional Fourier-transform IR spectra obtained on membrane phospholipids.
Keywords: photothermal imaging; cell organelles; retina; mid-IR photo-induced force microscopy; AFM-IR