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Date:  Wed, May 30, 2018
Time:  10:00am
Location:  Holmes Hall 389
Speaker:  M Arifur Rahman, EE PhD Candidate

Abstract:

Microfluidics and bio-MEMS technology provide essential tools for next-generation healthcare, in areas of research such as tissue engineering, disease diagnostics, and embryology. Tissue engineering requires precise in vitro patterning and multilayer assembly of cells and biomaterial scaffolds. Tissue engineering often requires mesoscale structures to be assembled with microscale resolution. A potential method of micromanipulation for in vitro tissue constructs is microassembly by a system employing untethered microrobots. Many microrobots should operate in parallel to increase the throughput of such a bio-micromanipulation system. However, current microrobot systems lack the independent actuation of many entities in parallel. In this dissertation, opto-thermocapillary flow-addressed bubble (OFB) microrobots are studied, and the independent actuation of fifty OFB microrobots in parallel is demonstrated. In addition, individual microrobots and groups of microrobots were moved along linear, circular, and arbitrary 2D trajectories. The independent addressing of many microrobots enables higher-throughput microassembly of micro-objects, and cooperative manipulation using multiple microrobots.

Microfluidics provides precise positioning and manipulation of fluids contained in microscale structures. microfluidic techniques were used to precisely position room-temperature liquid metal in microtubes, enabling tunable capacitors for the receive coil of a magnetic resonance imaging (MRI) scanner. This liquid-metal-based flexible tunable capacitor functions as the tuning element of the MRI receive coil. In this dissertation, four types of liquid-metal-based tunable capacitors with a high tuning range are demonstrated. Four different structures are demonstrated: parallel-tube, folded-tube, coil, and spiral capacitors. The highest measured tuning ratio is 42:1, and the highest change in capacitance per unit length of the pumped liquid metal is 0.07 pF/mm.

Fabrication using minaturization techniques known as bnio-MEMS are popular for fabricating microfluidic devices. In this dissertation, a microfluidic device was designed and made to study embryo viability, which is critical for successful In vitro fertilization (IVF) treatment. However, conventional methods of embryo evaluation rely mostly on subjective visuals analysis of embryo morphological features. Here, two non-invasive embryo grading system is studied analyzing their morphology and electrical parameter changes at the different stages of growth. This work shows the potential of impedance spectroscopy for developing a non-invasive test to quantitatively determine the health of embryos.