The focus of this theme is on the development of microfluidic systems for (bio)-medical applications, thereby increasing the knowledge of biological systems and improving the diagnostics and treatment of diseases. Microfluidics are a perfect tool for this, since dimensions comparable to single cells are used, low sample volumes are needed and multiple functionalities can be integrated in one platform. As an example electrodes can be integrated in in these devices, making electrical measurements on single cells such as sperm cells, or a tissue layer like the blood-brain barrier possible. By carefully analyzing these electrical signals, information about the morphology of the sperm cell or tightness of the tissue layer can be retrieved, which can be used to gain information about the semen quality or the functioning of the blood-brain barrier. Additional useful information can be retrieved form (automated) optical analysis using for instance fluorescence or bright field microscopy. So using these and other (new) techniques in combination with microfluidics, biomedical microdevices are developed that can finally be of use in the clinic. There are collaborations with other research groups at this and other universities, but also with doctors at the hospital, making it an applied multidisciplinary research area
This research area covers the development of knowledge and expertise of the electrode-liquid interface and its application in electrochemical micro-and nanodevices. The three basic detection principles are studied: potentiometry, amperometry and conductometry. Besides developing electrochemical sensors, the integration into lab-on-a-chip systems is implemented using cleanroom microfabrication. This opens up new operational principles such as redox cycling and the use of ultra-micro electrodes. In addition, integration of electrochemical cells in a Lab-on-a-chip enables the conversion of electro-active species.
Application of these electrochemical sensors and systems are in the field of health care, life sciences as well as in the field of environment and sustainability.
The theme of Microdevices for Chemical Analysis aims at engineering novel devices to measure chemical quantities, pushing boundaries in applications to explore unknown territory. Often, this relates to faster, or better spatially resolved measurements at lower concentrations in small volumes. Micro- and nanofabrication techniques are used to enhance electrochemical, optical or mass spectrometric readout. The ultimate goal is to create new, yet robust tools for routine use in the lab or point-of-care applications. Collaborations include various research groups specialized in analytical chemistry, microfabrication companies, as well as various research groups oriented towards applications in neurology and (photo)catalysis.
Nanofluidics is a relatively new field with still much to discover. Our research therefore has a strong explorative dimension where we are actively searching for new phenomena. In our explorative research we try to understand on a fundamental level the flow of water, ions and biomolecules such as DNA through various nanometer-scale structures. Especially the fact that surfaces in contact with solution become charged thereby plays a crucial role, and we try to modify and actively control this charge chemically or electrically. Present explorative projects are for example the application of graphene in nanofluidic devices and the investigation of catalysis on metal nanoparticles in nanopores.
The knowledge that we gain in the explorative research is applied in a number of different areas. One important area is that of clinical diagnostics. In the MESA+ cleanroom we can make smart nanostructured designs that open up new ways to separate molecules such as DNA in continuous flow or simultaneously concentrate and separate small proteins in blood for diagnostics of cardiac diseases or refine existing chips for ion separation by electrophoresis. We develop large arrays of gold nanodots for plasmonic detection of tuberculosis. Finally, we are developing 3D printing methods to construct fluidic networks that mimic our blood vessel system, and seed them with human stem cells to create organs on a chip.