A microfluidic platform for dissociating clinical scale tissue samples into single cells.

The advancement of sample preparation techniques is essential for the field of cell-based therapeutics. To obtain cells suited for clinical applications, the entire process starting from acquiring donor tissue biopsy, all through cell transplantation into the recipient, should occur in an integrated, safe, and efficient system. The current laboratory approach for solid tissue-to-cell isolation is invasive and involves multiple incoherent manual procedures running in an open operator-dependent system. Such an approach provides a chain of events for systematic cell loss that would be unfavorable for rare cell populations such as adult and cancer stem cells. A few lab-on-chip platforms were proposed to process biological tissues, however, they were limited to partial tissue dissociation and required additional processing off-chip. Here, we report the first microfluidic platform that can dissociate native biological tissue into ready-to-use single cells. The platform can merge the successive steps of tissue dissociation, debris filtration, cell sieving, washing, and staining in one streamlined process. Performance of the platform was tested with diverse biological tissues and it could yield viable cells that were ready for on or off-chip cell culture without further processing. Microfluidic tissue dissociation using this platform produced a higher number of viable single cells (an average of 2262 cells/ml per milligram of tissue compared to 1233.25 cells/ml/mg with conventional dissociation).

Characterization of Mechanical Signature of Eutopic Endometrial Stromal Cells of Endometriosis Patients.

Endometriosis affects 5-10% of women in reproductive age and causes pelvic pain and subfertility. Exact etiology of the disease is unknown. Here, we present a microfluidic platform for characterizing mechanical properties of eutopic endometrial stromal cells of endometriosis patients based on cellular deformability inside narrow microchannels. Primary human endometrial stromal cells were isolated from eutopic endometrium of endometriosis patients (4407 cells, from 7 endometriosis patients) and from disease-free women (4541 cells, from 6 control women) and were pumped through microchannels (formed of polydimethylsiloxane (PDMS) by standard soft lithography, with dimensions of 8 × 20 × 150 µm, as width × height × length) at a constant flow rate of 2 µL/min. High-speed imaging was used to capture videos of cells as they flow inside microchannels, and a computer vision code was used to track cells, measure their area, and calculate the time each cell takes to pass through the microchannel. Compared with their counterparts from control women, eutopic endometrial stromal cells from endometriosis patients showed significantly increased deformation index (1.65 ± 0.2 versus 1.43 ± 0.19, respectively, P value < 0.001), and higher velocity in travelling through narrow microchannels (96.530 ± 0.710 mm/s versus 57.518 ± 0.585 mm/s, respectively, P value < 0.001). The same difference in velocities between the two cell types was maintained after controlling for cell area. Eutopic endometrial stromal cells of endometriosis patients showed a mechanical phenotype characterized by high deformability and reduced stiffness. This mechanical signature can represent basis of a mechanical biomarker of endometriosis.

On-Channel Integrated Optofluidic Pressure Sensor with Optically Boosted Sensitivity.

A novel optofluidic sensor that measures the local pressure of the fluid inside a microfluidic channel is presented. It can be integrated directly on-channel and requires no additional layers in fabrication. The detection can be accomplished at a single wavelength; and thereby, only a single laser diode and a single photodetector are required. This renders the sensor to be compact, cheap and easy to fabricate. Basically, the sensor consisted of a Fabry⁻Pérot microresonator enclosing the fluidic channel. A novel structure of the Fabry⁻Pérot was employed to achieve high-quality factor, that was essential to facilitate the single wavelength detection. The enhanced performance was attributed to the curved mirrors and cylindrical lenses used to avoid light diffraction loss. The presented sensor was fabricated and tested with deionized water liquid and shown to exhibit a sensitivity up to 12.46 dBm/bar, and a detection limit of 8.2 mbar. Numerical simulations are also presented to evaluate the mechanical⁻fluidic performance of the device.