Monday, 18 October 4:00pm – 4:45pm

This seminar will be delivered via Zoom – Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Ms Jiarun Lin

Host: Professor Elizabeth New & Professor Emeritus Peter Lay

Title: Novel multimodal approaches to analysing cellular environments

Abstract: Biochemical changes in specific organelles underpin cellular function, and studying these changes is crucial to understanding health and disease. Cellular structure and function can be examined with a variety of imaging techniques, with capabilities dependent on mode of action, sensitivity and spatio-temporal resolution. Multimodal imaging with two or more modalities can overcome the intrinsic limitations of a single modality alone, providing complementary information for improved sensitivity and accuracy.

Fluorescent probes have become important biosensing and imaging tools, as they can be targeted to specific organelles and detect changes in their chemical environment. However, the sensing capacity of fluorescent probes is highly specific and often limited to a single analyte. A novel approach to imaging organelles is to combine fluorescent probes with vibrational spectroscopy techniques that map the spatial distribution of multiple analytes throughout the cell, particularly organic biomolecules including lipids, proteins, carbohydrates and nucleic acids. We have developed NpCN1, a novel bimodal fluorescence-Raman probe targeted to the lipid droplets.¹ NpCN1 was successfully used to image lipid droplets in 3T3-L1 adipocytes in both modalities, reporting on the chemical composition and distribution of the lipid droplets in the cells.

This approach has been extended with NpCNBr1, a probe with an additional tag for synchrotron x-ray fluorescence microscopy (XFM), a technique that maps the spatial distribution of metals and other elements. To our knowledge, this is the first small molecule probe with tags for these multiple modalities. Like NpCN1, NpCNBr1 selectively images lipid droplets during optical fluorescence and Raman studies in 3T3-L1 cells. XFM mapping provided additional correlation of the localisation of our probe and reported on the elemental distribution of the cell and organelles. XANES studies provided further insight on the localisation of NpCNBr1. This new multimodal approach provides complementary, orthogonal information on the chemical environment of the cell and its organelles.

1. Lin, J; Graziotto, ME; Lay, PA; New, EJ. A Bimodal Fluorescence-Raman Probe for Cellular Imaging. Cells 2021, 10(7), 1699.