Correlative AFM-FLIM Measurements in Living Cells, Tissues and in Solar Cell Materials

Abstract

We demonstrate the correlation of structural and mechanical information from atomic force microscopy (AFM) with functional information from fluorescence lifetime imaging (FLIM), in the same field-of-view and applied to living cells, tissues and even to solar cell materials. Some AFM systems can be directly aligned with FLIM systems on inverted microscope frames to perform AFM from above and FLIM from below the coverslip. This technique is applied on living cells to probe for stiffness changes (measured by AFM) introduced by the aggregation of certain proteins (measured by FLIM). Similarly, viscoelastic properties of biological tissues can be quantitatively resolved into their viscous component (by FLIM) and elastic component (by AFM) using this technique. In the field of perovskite solar cell research, this correlative information can reveal how structural defects on a perovskite grain relates to the photoluminescence lifetime properties. We demonstrate how correlative AFM-FLIM can inform materials scientists both the structural and functional impact of different sample preparations (changing grain size, chemical composition, atmosphere, sample illumination). We thus establish the versatile potential of correlative AFM-FLIM in biological and materials science research and discuss its limitations and caveats.