Microfluidic Devices with Dr Geoff Willmott

At present, there is tremendous commercial interest in microfluidic devices, including so-called “lab on a chip” devices. It is hoped that such technology will trigger a revolution in medical diagnostics and other lab processes, equivalent to what has happened to consumer electronics over the past three decades. Already, consumers are familiar with cheap, reliable, hand-held diagnostics for pregnancy and blood glucose levels in diabetics.

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Microfluidic Devices with Dr Geoff Willmott

IZON Nanopore Device My research, as part of a team at Industrial Research Limited (IRL), is focussed on methods of micro- and nanoscale ‘plumbing’ for a new generation of devices and processes. IRL is committed to transferring commercial benefits to industry in New Zealand, and this kind of technology has many potential applications beyond diagnostics, including interrogation of single nanoparticles and molecules, biosecurity, manufacture of advanced composite materials and a host of other industrial processes.

One of the key tools in this work is the tunable nanopore, a technology being developed by a New Zealand startup, Izon Science (pictured right, www.izon.com). This is a remarkably simple yet effective nanotechnology, consisting of a (very) small hole at the centre of a thin rubber membrane. When the membrane is stretched (and relaxed) by millimetres, the hole opens (and closes) on a scale of nanometres. When the pore is filled with electrolyte, individual particles can be detected electronically as they pass through the pore, from one side of the membrane to the other. In one particular project being supported by the MacDiarmid Institute (pictured below), we are attempting to co-ordinate detection of single particles using the nanopore with surface-enhanced Raman spectroscopy (SERS), which can also have single-molecule resolution. This project shows potential in the field of genomics, because a strand of DNA (for example) can be threaded quickly though the pore, so that the base sequence might be ‘read off’ during this process.

Other tools under development include technologies for manipulating small droplets using capillary tubes, and hydrophobic (water-repelling) surfaces. Droplets are used for emulsions, microreactors and drug delivery among other applications. We are studying the use of tubes for picking up and dispensing droplets in a controlled manner on micro- and nanoscales. The filling process itself is of some interest for manufacturing processes, including growth of carbon nanotubes from liquid catalyst droplets. Hydrophobic surfaces can be incorporated into any of the simple geometries we study – pores, tubes, droplets, flat surfaces etc. – in order to give novel properties for fluid manipulation and flow on the nanoscale.

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Geoff Willmott

IRL Nanofluidics