Master assignments

NeuroChip - Nano-electrodes for electrical recordings in human brain cells

Student assignment: NeuroChip - Nano-electrodes for electrical recordings in human brain cells

Techniques to record electrical activity from brain cells are essential for brain research and the screening of potential new drugs against bran disease. However, conventional techniques lack the required resolution or speed to utilize it at its fullest potential. We want to explore a new approach to electrically record many single neurons in parallel, with high-resolution, using nano-electrodes on a chip (Fig.1A). At this moment we are testing different designs for nano-electrodes that can be produced wafer-scale on a chip. The main challenge is to integrate the electrodes into the cellular membrane to create a GigaOhm "seal" to prevent leakage of electrical current from the cell (Fig.1B). We will test different strategies to functionalize the electrode tip (Fig.1A) with hydrophobic/hydrophilic molecules to create a robust seal with the membrane. 

Nanoneedle and corresponding electrical circuit when attached to a cellFigure 1.

 Chip designs are tested in a setup that compares sealing of the cell with a nano-electrode or a conventional patch-clamp pipette (Fig. 2).

 Measurement setupFigure 2. 

Assignment

The main goal of this assignment is to investigate whether, and how, a nanoelectrode should be covered with a hydrophobic or a hydrophilic coating (or a combination of both). The approach will be a surface modification of the silicon nano electrode outer wall, with a molecular monolayer. The tasks to be carried out in this project are:

i) from a literature study, find suitable molecules that can form a stable monolayer on the material of the nano electrode, and define the protocols for monolayer deposition; also study the options to only locally deposit the monolayer (monolayer patterns);

ii) carry out different suitable monolayer depositions, and measure the surface properties before and after deposition;

iii) perform experiments with cells, to study their interaction with the surfaces of the nano electrodes;

iv) perform electrical measurements to establish the electrical seal between nano-needle and cells, and compare with conventional methods (see Fig.2).

The project is a collaboration with researchers at the VUMC in Amsterdam, and the cell experiments will be performed in their laboratories. 


Contact information: Niels Tas; Email: mailto:n.r.tas@utwente.nl