Bionano

This research is driven by discussions with industry partners on the necessity for a fluidic-based method for rare cell separation and includes:

Fluid handling of cells

We are utilising fluidic properties to concentrate particles in suspension, thus enabling us to isolate biological cells using novel methodology.

Thermal convection occurs in a body of water when the base is maintained at a higher temperature than the rest. In a small cylindrical droplet (10-50μl) a single convection cell of "doughnut" symmetry is usually formed. If particles denser than the liquid are present they will tend to drop to the base of the droplet, where the the convention driven flow will try to move them to the centre. If sticking can be avoided, this combination can be used to concentrate particles at the centre of the base.

In the device developed by IRL this is achieved by levitating the particles by means of the electric field above a planar array of interdigitated electrodes. For 20 micron inter-electrode spacing the levitation height can be up to 30 microns. The power loss in the electric field serves as the source of heat to drive the convection.
                           
This device can be used to isolate biological cells from very dilute suspensions.

Single cell cultivation

We have developed a method which enables us to trap micro particles, eg. a single cell, by using highly structured alternating electric fields.

Using highly structured, alternating electric fields formed between parallel microelectrodes it is possible to trap biological cells (or other micro particles). Given suitable sizes of the electrode structures, the cells can be trapped individually.

Growth and division of yeast cells during long periods of application of an electrical field have been routinely observed. The doublet cell held in a field trap in the upper right of videomicroscope frame A divides several times as shown in frames B (after 1.5h), C (2h) and D (4.5h). The apparently normal growth is significant in view of the considerable electric field strength. (30kV/m)

Our method has the potential to allow isolation, separation and cultivation of targeted biological cells.

Electrical manipulation of bionano particles

This project aims to position cells in order to better carry out the replication and imaging of nanostructures in and on them. The program includes a post doctoral fellow and a PhD student and is funded as a MacDiarmid Institute collaboration between Maan Alkaisi (University of Canterbury), John Evans (Canterbury Health) and Mike Arnold (IRL).