Kolloide als Grundbausteine für aktive Komponenten in mikrofluidischen Systemen
Final Report Abstract
Complex systems require a large number of distinct components to function in a dynamic, integrated and cooperative fashion. To accomplish this, in current microfluidic networks, individual valves and pumps are often powered and switched separately by using e.g. an external applied pressure or electric fields. This however, requires a large number of additional supplementary channels or electrodes which allows to apply pressure or electric fields at specific positions and thus limits the development of massively parallel architectures that would take best advantage of microscale systems. Within this project we investigated a different approach where individual components are not addressed by local but rather global fields. We demonstrate that by a simple rotating magnetic field we can not only reversibly drive component assembly but also power distinct devices in a parallel, locally uncoupled, and integrated fashion. By employing this single approach we could assemble and demonstrate the operation of check valves, mixers, and pistons within specially-designed microfluidic environments. In addition we show that by linking these individual components together, more complex devices such as pumps can both be fabricated and powered in-situ. In addition, we also accomplished within this project a first step towards the sorting of objects with different chiralities. For this purpose we have prepared micronsized chiral particles with a lithographic process and subjected them to a helical flow. First results suggest that the propagation behavior of particles in such flow fields depend on their chirality and thus can be used for particle sorting purposes. After having demonstrated the basic principle of self-organization of superparamagnetic particles into small rotating objects to drive liquid flow, in a further step, one could use the fluid flow itself to control the position and motion of valves and pumps. This might lead to a microfluidic logic with different types of logical gates. Also, our first results on separation of chiral particles in helical microfluidic flows are promising because the motion of such particles indeed couples to the liquid flow in agreement with theoretical predictions. After the fabrication of three-dimensional colloidal particles with different chiralities has now accomplished within this proposal, as a next step we aim to study how particles with opposite chiralities can be separated in microfluidic devices.
Publications
- Colloidal Particles operating Microfluidic Devices, DPG-Spring meeting (2008)
T. Sawetzki
- In-situ assembly of linked geometrically-coupled microdevices, PNAS 105, 20141 (2008)
T. Sawetzki, S. Rahmouni, C. Bechinger, and D. W. M. Marr
- Dissertation, Mikropartikel als aktive Komponenten mikrofluidischer Operationen (2009)
T. Sawetzki
- Ship-in-a-Bottle" assembly of linked geometrically coupled microdevices, DPG-Spring meeting (2009)
T. Sawetzki
- Ship-in-a-Bottle" assembly of linked geometrically coupled microdevices, Lab-on-a-Chip European Congress, Stockholm, 2009
T. Sawetzki
