Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

90-POS Board 45 Chemically Functionalized Vertical Nanowire Arrays as Molecular Probes for Single-Cell Analysis Inga Von Ahnen 1,2 , Karl Adolfsson 1,2 , Damiano Verardo 1,2 , Laura Abariute 1,2 , Mercy Lard 1,2 , Christelle N. Prinz 1,2 . 1 Div. Solid State Physics, Lund University, Lund, Sweden, 2 NanoLund, Lund, Sweden. Chemically functionalized vertical nanowire (NW) arrays have the potential to provide versatile tools for the investigation of living cells in real time on a single cell level. For this aim it is essential to further investigate and understand the behavior of the cell membrane and its proteins around NWs, such as whether the membrane is pierced or not by the NWs. We are using fluorescence microscopy and stimulated emission and depletion (STED) microscopy to investigate the interactions between the cell membrane and vertical gallium phosphide (GaP) NW arrays. STED microscopy offers sufficient resolution to resolve fluorescently labeled membrane proteins and their distribution around the NWs. To probe the NW intracellular access, we functionalized the nanowires with fluorescein diacetate (FDA). FDA is a non-fluorescent molecule, that becomes fluorescent once inside the cytosol due to acetate group cleavage by intracellular esterase. The NWs were successfully chemically functionalized using a silane linker with a terminal alkyne group, to which different azide-terminated fluorophores or molecular probes can be clicked via the highly specific alkyne azide cycloaddition. [1] The activation of FDA immobilized on NWs was investigated using isolated esterase in solution and the results suggest that a possible steric hindrance of the NWs influences the catalysis of the hydrolysis. Overall vertical NW arrays functionalized with FDA have the potential to provide a simple and straight-forward assay to confirm access of NWs to the cytosol on a single cell level. The chemical functionalization method can be adapted to several different fluorophores and molecular probes to further investigate various properties of living cells on a single cell level. References [1] Y. Maidenberg et al. Langmuir, 29 (38), (2013) 11959. [2] Financed by NanoLund, the Swedish Research Council (VR), and the ERC consolidator grant NanoPokers (682206).

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