Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

143

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

Div. Solid State Physics, Lund University, Lund, Sweden,

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).