Surface Plasmon Resonance (SPR) Instrument
About the Instrument:
The SPR instrument detects extremely low concentrations of biological compounds in solution. It contains a sensor surface onto which specially designed ‘bait’ ligands, are attached to selectively trap target compound molecules as they float past in solution. The SPR device uses a very clever mechanism, involving ‘surface plasmon resonance’ to measure how many target molecules are bound to the surface at any one time. This gives you a measure of the solution’s concentration, and provides information about how fast molecules are binding and dissociating from the surface which allows you to calculate rate constants and equilibrium constants for the reactions. Although vulnerable to larger particles, the instrument is capable of handling turbid solutions containing nano-particulates.
The SPR instrument has brought back to life an old area of research – sensor technologies. Massey chemist Ashton Partridge spent ten years at Callaghan Innovation (CI) and overseas researching sensors. For much of that time he collaborated with Nobel Laureate Alan MacDiarmid. Now with the SPR instrument and Ashton’s wealth of experience his group are developing the chemistry for robust, real world applications. They are focusing on liquid based strip sensors for biological applications such as detecting toxins in water and testing fertility in humans or cattle. For many of these applications, the target compounds are present in tiny concentrations such as a billionth of a gram per litre — so great sensitivity and specificity is required to detect them. The SPR machine is the perfect tool. The new opportunities for commercialisation have enabled Ashton and his collaborator, Dr Yinqiu Wu from Plant and Food Research to found a small start-up company. Having spent three years as a Senior Business Analyst for a web-based marketing company in Wellington, Ashton has the business understanding to take concepts from the lab desk to the market.
The SPR instrument has given rise to a plethora of new collaborations with both research and commercial organisations. “We’re developing a collaboration with Fonterra to measure some of their milk products,” says Ashton. “We’ll measure things like bacteria, spores, mould and fungi within the milk at very low levels. It wouldn’t have been possible before.” They have developed strong collaborations with NZ researchers measuring toxin levels in water and with the Massey Vet School developing fertility sensors for farm animals. “It has also enabled us to help a little local company here in Palmerston North,” says Ashton. “Science Haven develops hormone sensors. We are testing their antibodies using the SPR.” Ashton has travelled to give conference presentations on the group’s SPR work in both Korea and China and this has also given rise to a new collaboration. The group is very happy to share their new facility. The lab works on a cost recovery basis so outside researchers can use the instrument for a base rate fee.