Nanodome coins for intracellular surface-enhanced Raman spectroscopy

Abstract

-Surface-enhanced Raman spectroscopy offers a tremendous potential for intracellular sensing, because it combines fingerprint specificity with sensitive signals. However, the colloidal gold nanoparticles used for this purpose lead to strong spatiotemporal variations in intracellular SERS experiments. This unpredictable behaviour, which complicates reproducible measurements, strongly contrasts to the advances made in the last decades on the fabrication of controllable and robust plasmonic substrates with high enhancement factors. Here, we propose an alternative approach to intracellular SERS by developing planar, nanostructured microcoins which enable to use top-down fabricated substrates for intracellular applications. We develop a nanosphere-lithography based technique for the fabrication of gold-nanotriangle and -nanodome structured silicon-nitride micron-sized chips (micro-coins). These microcoins can be lifted off form their substrate and are subsequently incorporated into fibroblast-and HeLa cells. In a model experiment, the SERS sensors are used for the label-free detection of extraneous molecules in live cells. The use of reproducible SERS substrates for intracellular sensing is expected to be an important step towards reproducible and quantitative live-cell, label-free measurements.

Stretching the Horizon of Nanosphere Lithography

“…Hence, nanostructures, rich in various spin-wave modes, are of high importance [66][67][68][69][70]. NSL has also been used to fabricate plasmonic color filters [71,72], waveguides [73,74], and antennas [74][75][76] with high efficiency and tunability [71]. Moreover, smart window application employs a lithographed pattern of thermochromic material by NSL to control the transmittance of the window material [77].…”