Research Projects

Impedance spectroscopy for flow cytometry applications

Microfluidic systems for dielectric cell characterization will contribute to the development of new diagnostics and therapies. One of the most exciting applications for this technology will be for stem cells, which are at present characterized using biochemical and immunological techniques. In addition to protein markers and altered gene expression, differentiating cells can also exhibit changes in morphology or nuclear size. Such changes are readily detected as changes in dielectric properties whereas they would not be detected using biochemical or immunological techniques. As a rapid, label-free, and non-invasive technique, dielectric characterization will yield additional information without the use of immunological markers, thus giving a more complete picture of the cells and the underlying intracellular processes. This method will complement the existing immunological and gene expression methods, thus giving another dimension of data toward a more complete understanding of stem cells.

Biocompatible coatings for implantable polymer-based multielectrode arrays

An engineered biomolecular interface between implantable biomedical microdevices and the surrounding tissue is one of the key issues for long-term implant functionality. Chronic deep-brain stimulation for the treatment of Parkinson's disease is one of the most well-known therapies for neural disorders. Chronic recording from the motor cortex in primates has already shown that such signals can be used to control devices such as robot limbs. Implantable electrodes for recording or stimulation have traditionally consisted of microwire arrays. More recently, the advent of microfabrication technology has led to the development of silicon-based arrays, permitting the mass production of neural probes with precise electrode spacing. However, the mechanical mismatch between these rigid probe and the soft tissue is thought to be an aggravating factor in the inflammation at the implantation site, encouraging the formation of a glial scar which encapsulates the probe with time. This fibrous tissue isolates the probe electrically from the surrounding neural tissue, leading to loss of probe function. A flexible polymer-based microelectrode array promises to reduce this inflammation. Coating the implant with a biodegradable polymer or hydrogel, which releases an antibiotic, anti-inflammatory agent, neural growth factor, or other bioactive molecule will mitigate tissue reaction to the implanted device.

Integrated on-chip cell culture system

This project will develop a novel closed system to culture cells inside microfluidic networks, move them through microchannels to an area of the chip equipped for characterization, and then bring them back to the culture area. The cells will be cultured and characterized within the same chip, enabling the analysis of small numbers of precious cells with low cell loss. Such a system will contain its own micro-incubator environment with integrated micro heaters, gas exchange, and microchannels for fluidic exchange. This would allow both sterile cell culture and hands-free monitoring of the growth and differentiation of stem cells. A microfluidic system with multiple inlets will also permit easy exchange of culture medium for cell maintenance, or to induce differentiation or transdifferentiation.