Single-Cell Isolation Using Light-Activated Electrochemically-Switchable Surfaces

Abstract

The main objective of this thesis was to show a new technology that has the potential to gain a further understanding of diseases. It does this by introducing a strategy that can isolate a predetermined individual diseased cell such that analysis of it can take place.

This was achieved by forming well-defined acetylene-terminated organic monolayers on hydrogen-terminated, p-type (10-20 Ω.cm) Si(100) through a hydrosilylation procedure from 1,8-nonadiyne. From here, a synthesised electrochemically-switchable component containing an azide group was attached to these terminal acetylene groups using ‘click’ chemistry. An antifouling component (oligo(ethylene oxide)) (OEO) was then added to the surface using a succinimidyl coupling chemistry that enabled the surface to be further modified with an antibody (anti-EpCAM) that selectively captured the model diseased cells, MCF-7 breast cancer cells. Once it was confirmed that the subpopulation of diseased cells were selectively captured, an individual cell was observed under a microscope and in doing so, causing accumulation of electrons in the region of silicon directly below that cell. Applying a negative bias (-1.2 V vs Ag/AgCl) to the silicon surface initiated electrochemical switching of the switchable component in the illuminated region only and therefore subsequent release of the individual observed cell.

Gene expression arrays were then performed on these individually released cells to show that this technology was capable of analysing individual diseased cells and therefore show its potential to give further insights into the behaviour of diseases.