Biosensors and Biointerfaces Group - Research Projects

Bioelectronics on silicon electrodes

Silicon, the material of the electronics industry, has seldom been used in bioelectronic devices because of native silicon crystals oxidise in the aqueous solutions used in biological media. We have developed a method for modifying non-oxidised silicon that protects the silicon from oxidation even when used as an electrode and scanning to oxidising potentials. Such a method has applications for both molecular and bioelectronics. Here we are using the method to make 1) electrochemical arrays for DNA sensing and 2) switchable surfaces. The switchable surfaces are being developed with an electrochemically cleavable unit, such that specific portions of the surface chemistry can be electrochemically removed. We will use this method to develop surfaces that can capture rare cells and release them when desired. The candidate type of rare cell we are targeting is circulating tumour cells which are important in the spread of cancer.

surface chemistry used to make switchable surfaces on silicon

Above - Schematic of the surface chemistry used to make switchable surfaces on silicon electrodes. Here surface properties are switched electrochemically with the release of moieties that give surfaces resistance to cell adsorption (as shown by the few round red cells). Upon cleavage of this unit the surface becomes adhesive to cells (as shown by the well spread blue cells). The cleavage is shown by the change in x-ray reflectometry plots.