Search Results (3)

The objective of this review is to investigate the potential of functionalized magnetic polymer composites for use in electromagnetic micro-electro-mechanical systems (MEMS) for biomedical applications. The properties that make magnetic polymer composites particularly interesting for application in the biomedical field are their biocompatibility, their adjustable mechanical, chemical, and magnetic properties, as well as their manufacturing versatility, e.g., by 3D printing or by integration in cleanroom microfabrication processes, which makes them accessible for large-scale production to reach the general public. The review first examines recent advancements in magnetic polymer composites that possess unique features such as self-healing capabilities, shape-memory, and biodegradability. This analysis includes an exploration of the materials and fabrication processes involved in the production of these composites, as well as their potential applications. Subsequently, the review focuses on electromagnetic MEMS for biomedical applications (bioMEMS), including microactuators, micropumps, miniaturized drug delivery systems, microvalves, micromixers, and sensors. The analysis encompasses an examination of the materials and manufacturing processes involved and the specific fields of application for each of these biomedical MEMS devices. Finally, the review discusses missed opportunities and possible synergies in the development of next-generation composite materials and bioMEMS sensors and actuators based on magnetic polymer composites. Full article

A compact, rapid, and portable off-chip pneumatic control valve is significant for the miniaturization and integration of external pneumatic systems for microfluidic chips. In this work, an off-chip microvalve with a high-speed electromagnetic switch actuator and a polydimethylsiloxane (PDMS) material valve body has been designed to be easily encapsulated, simulated using MATLAB/Simulink software, and tested in a micromixer. Multi-physical coupling mathematical models are developed based on the elastic deformation force of the valve membrane, the driving force of the valve core, and the fluid force in the microchannel. Two single microvalves are used to form a three-way microvalve, which can control the air pressure in a pneumatic microchannel on the microfluidic chip. The relationship between the flow–duty cycle, the flow–pressure difference of the single electromagnetic microvalve, and the load pressure of the three-way microvalve is simulated and analyzed. Sample mixing performance controlled by the proposed off-chip three-way microvalve was tested to evaluate the pneumatic control capability, and the results show that the undertaking can fully satisfy the needs of a pneumatic microfluidic chip for most applications. Full article

Micromixers are critical components in the lab-on-a-chip or micro total analysis systems technology found in micro-electro-mechanical systems. In general, the mixing performance of the micromixers is determined by characterising the mixing time of a system, for example the time or number of circulations and vibrations guided by tracers (i.e., fluorescent dyes). Our previous study showed that the mixing performance could be detected solely from the electrical measurement. In this paper, we employ electromagnetic micromixers to investigate the correlation between electrical and mechanical behaviours in the mixer system. This work contemplates the “anti-reciprocity” concept by providing a theoretical insight into the measurement of the mixer system; the work explains the data interdependence between the electrical point impedance (voltage per unit current) and the mechanical velocity. This study puts the electromagnetic micromixer theory on a firm theoretical and empirical basis. Full article