Microfluidics

Their small size allows portability, small volume of sample, reagent and waste, fast analyses with increased resolution of separations and the possibility of parallel analyses from one sample on a "chip".

Small size and unit cost permit ease of fabrication, rapid development and the creation of practical disposable devices. In turn, this will enable low detection limit analysis, high sample throughput analysis and rapid point-of-care diagnostics.

Areas of research include:

Device fabrication by soft lithography

IRL is designing and fabricating devices using soft lithography and micro-embossing techniques in combination with sol-gel deposition and finite element modelling to develop and optimise a range of polymer-based microfluidic chips.

The sol-gel approach offers increased control of the electro-osmotic flow and the possibility of including enzymes to form a nanolayer for the formation/derivatisation of easily detected analytes. Modifications to the sol-gel surface and improved chip lay-out is expected to give better control of flow and sample injection, while having a high separation efficiency. This will allow detection of a targeted substance by optical and/or electrochemical methods intergrated into the microfluidic device.

These chips are expected to have considerable advantages in terms of compactness and speed compared to standard laboratory methods, with the additional benefits of low sample size and waste, as well as portability. These unique advantages will allow analyses to be rapidly carried out in almost any location.

Analytical chemistry on a chip

Following the protection of new IP, fabrication and operating characteristics of a series of analytical microfluidic chips will be published. The chips will be offered to New Zeland and international organisations for evaluation.

The fabrication of the best "fit for purpose" chips will be obtained by:

• modelling, fabricating and testing a fluidic analytical chip with optimised geometry with respect to sample injection and fluorecence detection
• having defined the on-chip detection limits for 3 amino acids
• depositing layers of either or both SiO₂ and TiO₂ on a polymer surface. The layer will be characterised by SEM and FTIR^[?] and the change in electrokinetic properties measured
• using the sol/gel deposited surface to immobilise two enzymes, such as glucose oxidase and horse radish peroxidase, to form catalytic surfaces on-chip
• designing and fabricating a microfluidic mixer for the effective mixing of two fluid steams
• designing, fabricating and testing a microfluidic chip containing at least two analytical pathways operating simaltaneously on one sample.