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Kevin Paul Nichols (promotion date: 9 April 2009)

Droplet-based microfluidic systems coupled to mass spectrometry for enzyme kinetics

Promotion date: 9. April 2009

Promotor: Prof. Dr. Han Gardeniers

Three miniaturized systems were developed to analyze enzyme kinetics: a digital microfluidic system, a digital nanofluidic system, and an non-digital droplet-based microfluidic system.

A digital microfluidic system is described that electrically combined substrate and enzyme droplets and quenched an array of such droplets at varying time intervals.

A nanochannel system was constructed in order to overcome internal standard requirements of the digital microfluidic system.

Finally a non-digital droplet-based system was described, that manipulated nanoliter droplets in microchannels as opposed to microliter droplets on a planar electrode surface.

Why did you use mass spectrometry?

It allows the study of enzyme kinetics without the incorporation of a chromophore, such as a fluorescent substrate, which many biologically relevant substrates do not contain.

In my view the general strategy of utilizing droplets allows superior methods of probing enzyme kinetics, due to the lack of dispersion, faster mixing, and discrete nature of the sampling in droplet-based microfluidic systems. Where appropriate, using mass spectrometry coupled to droplet-based microfluidics, allows kinetic interrogation without enzyme modification.

Where did you carry out your research activities?

I worked with the MSC-group: Mesascale Chemical Systems. First I started with a different project. During the project I stumbled upon this subject. It took some time to discover the correct way to produce and work with this kind of devices.

What are your future plans?

Now I moved to the university of Chicago to work on a post-doc project. In the future I prefer to stay in research: academic, to pursue new ideas of which is not quite obvious what their future utility will exactly be, or an interesting position in industry, to further investigate and develop promising ideas or work out feasible technological principles.