Hollow Plasmonic nanostructures for multifunctional microfluidics biodevices

Michele DIPALO, IIT

In recent years the applications of novel nanostructures in biology and in electrophysiology have multiplied significantly; among the main achievement have been the improved interface and coupling between cells and biosensing elements. In this direction, recently we have developed a novel technique to produce hollow three-dimensional nanocylinders that present several interesting features[1]; they have high plasmonic electromagnetic field enhancement, behave like nanoelectrodes, work as fluidic nano-channels between two isolated compartments, and can be fabricated with high aspect-ratio on large scale. When applied to biotechnologies, these features give rise to new analysis approaches that combine so far incompatible techniques. In particular, the nanofluidics and the plasmonic characteristics of these nanostructures allow to perform noninvasive cell poration for targeted in-vitro intracellular delivery of drugs and in general any molecule[2]. The delivery is achieved by the gold nanocylinders that are tightly adhering with cells on one side, and directly connected to a micro-fluidic channel on the other; the plasmonic enhancement leads to a localized nanometre-size cell membrane poration by mean of excitation with a low power ultra-fast-pulsed infrared laser. On the other hand, the plasmonic enhancement and the electrical characteristics of the nanocylinders can be exploited simultaneously for combining enhanced Raman spectroscopy with electrical recording of neurons and other electrogenic cells[3,4]; such integration allows to perform chemical analysis of living neurons at the nanometre scale while measuring the spontaneous electrical activity of the complete neuronal network. These efforts go in the direction of merging various investigation techniques that work on different time-space scales in order to design novel multifunctional biodevices, with the aim of deepening our understanding of the human brain and of its working processes.

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