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High-Throughput Cell Mechanical Property Testing for Label-Free Assaying

Charles Eggleton, Department of Mechanical Engineering
Hiren Balsara, Department of Mechanical Engineering
Anthony Crenshaw, Department of Mechanical Engineering
Islem Long, Department of Mechanical Engineering
Vijay Gupta, Department of Mechanical Engineering
Alex Szatmary, Department of Mechanical Engineering
Rohan Banton, U.S. Army Research Lab

 

We introduce a unique microfluidic-based approach for the high-throughput non-destructive assaying of cells without the need for specific labels or reagents. Based on measurement of both static and dynamic cell mechanical properties using applied optical forces, we will apply this technique (known as “optical stretching”) in a high-speed high-throughput manner. To date, optical stretching has been used only on small cell numbers; however, highintensity, microscale laser sources and the integration of these within dynamic microfluidic systems has enabled our proposed approach. In this, fully integrated optical-based sensors and mechanical stretchers will be used to identify and, upon demand, isolate single cells. Once identified, such targeted cells can then be transported on-chip to culture chambers within the device or for dispensing into standard bio-laboratory instrumentation for off-chip analysis. Though there is broad need, our proposed technology will be tested and developed using malaria parasite infected red blood cells as the target cell. This work will be done in collaboration with the Laboratory of Malaria and Vector Research at the NIAID. Our aims include: Aim 1: Mechanical Property Detection and Interpretation. We will employ optical manipulation methods integrated within microfluidic systems for label-free, non-destructive cell mechanical property measurement. Modeling approaches will be developed for both interpretation of applied force/deformation experimental data and for device design. Here, malaria-infected red blood cells will provide a good model target since cell stiffness changes dramatically during parasite development. Demonstrating greatly simplified device designs and associated ease-of-use, we will install an instrument in an active NIH laboratory. Aim 2: Optical Manipulation for Cell Identification and Isolation. We will integrate optical methods within microfluidic systems for single cell detection and manipulation. Here, methods for both on-chip cell isolation and off-chip isolation will be developed and used to improve our installed NIH protototype. Aim 3: High Throughput Mechanical Testing. To achieve high-throughputs, modified microfluidic and faster detection techniques will be required. In this phase, the coupling of hydrodynamic and optical forces will be explored to improve device performance. In addition, time-varying optical forces will be employed to identify optimal signal response and dynamic physical properties.