Development of a highly integrated bistable thermal actuator array to construct modular microfluidic systems

• Applicant: Dr.-Ing. Christiane Richter
• Subject Area: Microsystems
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 253801162

Microfluidics is becoming increasingly relevant for biology, chemistry and biotechnology. Often complex fluidic systems for chemical reactions and analysis with precise microfluidic flow control are required. For this purpose microvalves have to be used which must be built in increasing numbers and density. Besides the ability for dense integration these valves should be individually addressable and bistable. This is a decisive disadvantage of most actuators currently known from literature: They either are complex in fabrication and thus cost-intensive or they are not bistable (see, e.g., monolithic membrane valves) which complicates individual addressing. The aim of this project is the design and characterization of a platform with several hundred individually addressable bistable actuators. For this a thermally actuated actuator will be used which was developed within the PhD project of the applicant. The actuator is based on a phase change material which shuts a pressurized microfluidic channel therefore selectively blocking a deflected membrane. The advantage of this actuator is the fact that the only component to be actively modulated is a heating resistor. In preparation of this project proposal an electronic platform including control software for individually addressing a total of 588 resistors has been setup. Within this project the actuator will first be optimized with respect to reaction times. The next step will be the integration of a large number of such actuators on the electronic platform. The platform will then be integrated into a modular system, which allows transferring the displacement caused by the individual actuators to a microfluidic system via a parallel microfluidic bus connector. The translated shift will then be used to deflect an elastic membrane within the microfluidic system thus providing a valve. This approach allows setting up a generic microfluidic actuator platform which may be readily combined with an application specific microfluidic system. For validation two microfluidic application systems will be setup. The first systems allows the flexible generation of microfluidic channel structures from a microfluidic row-and-column array by selectively blocking sections of the channel network by means of integrated microfluidic valves. The second system will provide a microfluidic structure for trapping and recovering individual particles from a fluid stream by combining a static single-particle capturing structure with a microfluidic channel structure for individual recovery of each captured particle. This approach will be demonstrated using polymer particles.

• DFG Programme: Research Grants