My work on “Enhancing sensitivity and specificity in rare cell capture microdevices with dielectrophoresis”was recently published in Biomicrofluidics, with co-authors Charlie Huang and Brian Kirby. This paper describes numerical simulations that identify microfluidic obstacle array geometries where dielectrophoersis (DEP) can be combined with immunocapture to increase the capture of target rare cells, such as circulating tumor cells (CTCs), while simultaneously repelling contaminating cells. These simulations build on our previous efforts that have shown that cancer cells exhibit a different DEP response than healthy blood cells, and lay the groundwork for the experimental study of hybrid DEP–immunocapture obstacle array microdevices.
Separately, I have also reported on “A transfer function approach for predicting rare cell capture microdevice performance” in Biomedical Microdevices. This work describes a numerical technique that extends our previously-reported computational fluid dynamics (CFD) simulations of rare cell transport and capture in microfluidic devices into larger, more complex geometries. This transfer function approach matches the full CFD simulation within 1.34% at a 74-fold reduction in computational costs, and the transfer function’s predictions for lateral displacement within complex reversing geometries were validated experimentally using particle tracking and polystyrene microspheres in a GEDI device.
I recently presented work in the Cornell Micro/Nanofluidics Laboratory on “Circulating tumor cell (CTC) cancer biomarkers using geometrically enhanced differential immunocapture (GEDI) microdevices” at the 2014 meeting of the Society for Laboratory Automation & Screening. In this poster presentation, I cover my work in the design and optimization of GEDI, as well as recent unpublished work by my colleagues in the Cornell Micro/Nanofluidics Lab. In addition to enjoying my own presentation and the various technical talks, I found SLAS2014’s career planning and networking resources to be a valuable part of the conference. A copy of the poster is available on my website.
We have recently published two papers on the collision and capture dynamics of circulating tumor cells (CTCs) and other rare cells in geometrically enhanced differential immunocapture (GEDI) microdevices.
The first paper, “Cell capture simulations for the optimization of microfluidic rare cell immunocapture devices” was published in Biomedical Microdevices by James Smith, Timothy Lannin, Yusef Syed, S Santana, and Brian Kirby. We use computational fluid dynamics (CFD), particle advection, and exponential-based cell capture simulations to identify capture-optimized GEDI geometries. We show that it’s possible to select a geometry which maximizes capture efficiency while rejecting small contaminating cells via infrequent collisions and large contaminating cells via high shear stress; the accompanying figure shows this as capture probability vs. particle diameter in an example GEDI geometry.
I recently published a peer-reviewed article on “Cell capture simulations for the optimization of microfluidic rare cell immunocapture devices” in Biomedical Microdevices, along with my colleagues Tim Lannin, Yusef Syed, S Santana, and Brian Kirby. We detail a coupled computational fluid dynamics (CFD), particle advection, and experimentally-informed cell capture simulation to identify capture-optimized geometrically enhanced differential immunocapture (GEDI) designs. I show that it is possible to select a geometry which maximizes capture efficiency while rejecting small contaminating cells via infrequent collisions and large contaminating cells via high shear stress.
I have recently founded a startup company, Captura Diagnostics, Inc., to commercialize microfluidic rare cell capture technologies for applications in research and clinical care. Captura currently consists of myself, handling the initial technical work, and Max Dougherty, who is managing the business; Captura is advised by Brian Kirby. It is our hope that Captura will facilitate the widespread adoption of technologies like GEDI and others by researchers and clinicians using rare cells (such as CTCs) to better understand disease progression, to develop new drugs, and for patient-specific treatments.
I’m excited to announce that Captura has won a $25,000 “Grants For Growth” proof of concept grant. Awarded by the CenterState Corporation for Economic Opportunity and funded by New York State, this award will support the development and fabrication of a prototype for a mass-produced rare cell capture device and significantly increases Captura’s ability to secure additional rounds of funding. Captura is pursuing additional support from the NSF and NIH Small Business Innovation in Research (SBIR) programs and other sources, and is applying for residency in Cornell University’s McGovern Center for Venture Development in the Life Sciences incubator.
The article reviews biorheology, rare cell surface markers and adhesion models, as well as general transport phenomena at the microscale. Several design strategies, including micromixers, porous filtration systems, and obstacle arrays, are presented in a transport context. A key conclusion is that advection (i.e., motion of the fluid itself) dominates diffusion in most rare cell capture devices; a successful device is designed not by maximizing the ratio of surface area to volume, but by inducing cross-streamline motion to bring cells into contact with a capture surface.
This review summarizes the knowledge we have gained developing the GEDI microdevice, and we hope that other researchers will find it useful in the development of their own rare cell capture devices. A copy of our review is available on my website.
I presented my recent work on cell capture simulations at the Fall meeting of the American Physical Society’s Division of Fluid Dynamics (APS DFD) in San Diego. During this podium presentation, I detailed a reduced order model for predicting the adhesion of rare cells, such as circulating tumor cells (CTCs) to antibody-functionalized obstacle surfaces in microdevices. This work builds on my past projects involving particle collision dynamics and will facilitate the design of a new generation of rare cell capture microdevices.
I recently attended the 2011 Gordon Research Conference on the Physics and Chemistry of Microfluidics in Waterville Valley, NH. I presented a poster on “Transport and collision dynamics in GEDI cell capture microdevices” at both the Gordon Research Seminar, organized and run by students and preceding the conference, and at the Gordon Research Conference itself. I’m pleased to announce that my poster was one of four selected during the Conference to receive a Poster Merit Award, along with a small prize sponsored by Cambridge University Press. A copy of the poster is available on my website.