The main research themes are:
i. Alternative activation mechanisms for chemical process control and process intensification
Research on this topic was initiated through the VICI Vernieuwingsimpuls "Exciting" chemistry in microreactors granted by STW in December 2004 and focuses on microfluidic systems with inner dimensions in the range 5 to 500 μm, containing materials fabricated by nanotechnology (e.g. nanofibers) and integrated features by which controlled stimuli (electrical fields, ultrasound) can be applied in order to activate and control chemical reactions. The core of the approach is to exploit the advantages of down-scaling of physical principles to enhance conversion and selectivity of chemical reactions. Applications of this research can be found in miniaturized reaction screening of catalysts and process conditions to create more efficient and more selective, and therewith more sustainable and "greener" process routes for production, and in the development and understanding of new concepts for chemical process intensification and distributed small-scale chemical production.
ii. Microsystems for chemical analysis and process analytical technology
The focus is on new concepts of (bio)chemical analysis in all its aspects, by exploiting the advantages of microsystem integration and nanotechnology. Within this field, strategic collaborations exist with prof. Desmet at the Vrije Universiteit van Brussel (integrated chromatography-based separation methods) and with prof. Kentgens at Radboud Universiteit Nijmegen (microscale NMR). Liquid chromatography on a chip has clear advantages over conventional LC, because the extreme ordering and symmetry that can be obtained in artificial column packing leads to unprecedented plate heights, and with that to very fast and efficient separations. Even higher performance is obtained when structures of sub-micron dimensions are used, e.g. by nanoimprint technology, which also opens the way for novel, size-exclusion based separation methods. Excellent results can however only be achieved if also injection and detection parts are integrated with the column, or if very low-dead-volume interfacing to spectroscopic equipment can be achieved, e.g. to mass spectrometry. Applications of the research in this area can be found in miniaturized screening tools for chemical and biological research, fundamental studies of chemical and biological processes, and stand-alone miniaturized analysis systems for point-of-care, forensic crime scene, or industrial process analytical applications.
iii. Biomolecular behaviour in a nanostructured environment
The aim of this research topic is to study protein folding, misfolding, agglomeration and complexation dynamics and kinetics, with the aid of micro and nanofluidic systems. Protein folding is a very relevant and general process in nature, where proteins have evolved to a native state in which they provide important biomolecular functions in organisms. In industry enzymes, either in an isolated form or present in a micro organism, are the workhorses that manufacture important food ingredients or pharmaceuticals. Of medical relevance is that proteins under specific circumstances will misfold or agglomerate, which is the basis for many different disease patterns.
Micro and nanofluidic systems have some unique advantageous properties which aid the study of protein dynamics and enzyme activity:
i. modern lithographic methods allow the fabrication of artificial nanostructures which can act as perfect models for macomolecular crowding or biological nanopore confinement, or as a biomimetic surface for the study of biomolecular, cell and tissue behaviour (like in our collaboration with Prof. Jansen of the Radboud UMC, in which the beviour of bone tissue on nanostructured sbiomaterials is investigated);
ii. modern integration technology allows to integrate "actuators" to direct a specific stimulus (electronic, chemical, etc.) to a biological or biomolecular system, and to monitor its response in-situ or in-line in real time;
iii. fast mixing in combination with fast quenching, due to the small geometry and the limited amounts of material that has to be brought together, in combination with optics (fast by nature), integrated spectroscopy, or low-dead-volume and therefore fast interfaces to analytical equipment, allows the study of biomolecular dynamics at the required fast timescale.
The objective of this research is mainly to apply the micro and nanofluidic tools to obtain a fundamental insight into biomolecular mechanisms and determine their kinetics, on the long term these tools may be further developed for high-throughput screening in a clinical or pharma-research setting.