Репозиторий Университета

© 2020 Elsevier B.V. Large-scale cell culture processes are required to produce biopharmaceuticals, cells for tissue engineering, and vaccine production while being effective in toxicity testing, gene therapy vector production for cancer research, and drug development. A growing trend in these industries, particularly for suspension cells, involves implementation of continuous cell perfusion processes, which require an aseptic, efficient, cost-effective, and reliable cell separation and retention scheme. Many cell separation techniques (membrane-based systems, lateral displacement devices, and acoustophoresis) have proven to be highly efficient, but suffer from issue of clogging and high cost, limiting their reliability, and thus, their overall feasibility. Some cell retention devices—those based on inertial microfluidics—offer high reliability (i.e., clog-free), but their efficiency reduces at higher cell concentrations. To overcome this apparent trade-off, we report the development of an integrated system consisting of two different membrane-less microfiltration techniques for cell separation from spent cell media. Although it could be adapted to numerous cell culture applications, this system was optimized and tested for suspension-adapted Chinese Hamster Ovary (CHO) cells. As the first step of the cell retention system, a miniaturised hydrocyclone was developed that could separate the cells with macroscopic volume processing rates (~200 mL/min). At this stage, up to 75% of the cells were isolated with minimal (<5%) change in the viability. The remaining cells passed through the overflow of the device and entered to a multiplexed spiral microchannel system, where more than 90% of the remaining cells were recovered, yielding an overall efficiency of up to 95%. The proposed integrated system is thus ideal for continuous and high throughput cell retention even at high cell concentrations (~80 million cells/mL), which is in range of current need in the bioprocessing industry.

© 2020 Elsevier B.V. Large-scale cell culture processes are required to produce biopharmaceuticals, cells for tissue engineering, and vaccine production while being effective in toxicity testing, gene therapy vector production for cancer research, and drug development. A growing trend in these industries, particularly for suspension cells, involves implementation of continuous cell perfusion processes, which require an aseptic, efficient, cost-effective, and reliable cell separation and retention scheme. Many cell separation techniques (membrane-based systems, lateral displacement devices, and acoustophoresis) have proven to be highly efficient, but suffer from issue of clogging and high cost, limiting their reliability, and thus, their overall feasibility. Some cell retention devices—those based on inertial microfluidics—offer high reliability (i.e., clog-free), but their efficiency reduces at higher cell concentrations. To overcome this apparent trade-off, we report the development of an integrated system consisting of two different membrane-less microfiltration techniques for cell separation from spent cell media. Although it could be adapted to numerous cell culture applications, this system was optimized and tested for suspension-adapted Chinese Hamster Ovary (CHO) cells. As the first step of the cell retention system, a miniaturised hydrocyclone was developed that could separate the cells with macroscopic volume processing rates (~200 mL/min). At this stage, up to 75% of the cells were isolated with minimal (<5%) change in the viability. The remaining cells passed through the overflow of the device and entered to a multiplexed spiral microchannel system, where more than 90% of the remaining cells were recovered, yielding an overall efficiency of up to 95%. The proposed integrated system is thus ideal for continuous and high throughput cell retention even at high cell concentrations (~80 million cells/mL), which is in range of current need in the bioprocessing industry.

© 2018 WILEY-VCH Verlag GmbH  &  Co. KGaA, Weinheim While noninvasive prenatal testing based on cell-free fetal DNA has recently revolutionized the field of aneuploidy screening in pregnancy, it remains limited to aneuploidy and microdeletion screening, and is unable to reliably detect single gene disorders. A number of recent studies have demonstrated the potential of circulating trophoblastic cells in providing cell-based noninvasive diagnosis with sequencing or array-based assays. However, considering the extreme rarity of these cells in blood, efficient, high-throughput, and clinically applicable enrichment technologies are yet to be developed. This study demonstrates for the first time the utility of inertial microfluidics for efficient isolation of trophoblastic cells from maternal peripheral blood. Under optimal operating conditions, high-recovery yields (79%) are obtained using a trophoblastic cell-line, which is subsequently confirmed with analysis of maternal blood. Feasibility of obtaining a diagnosis from cells isolated from a maternal sample is demonstrated in a case of confirmed fetal trisomy 21 in which six fetal cells are found in a 7 mL blood sample using fluorescence in situ hybridization. Finally, it is demonstrated that trophoblastic cells isolated using inertial microfluidics could be picked and subjected to a clinically validated sequencing assay, paving the way for further validation of this technology and larger clinical studies.

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Inertial microfluidics has emerged recently as a promising tool for high-throughput manipulation of particles and cells for a wide range of flow cytometric tasks including cell separation/filtration, cell counting, and mechanical phenotyping. Inertial focusing is profoundly reliant on the cross-sectional shape of channel and its impacts on not only the shear field but also the wall-effect lift force near the wall region. In this study, particle focusing dynamics inside trapezoidal straight microchannels was first studied systematically for a broad range of channel Re number (20 OpenSPiltSPi Re OpenSPiltSPi 800). The altered axial velocity profile and consequently new shear force arrangement led to a cross-lateral movement of equilibration toward the longer side wall when the rectangular straight channel was changed to a trapezoid; however, the lateral focusing started to move backward toward the middle and the shorter side wall, depending on particle clogging ratio, channel aspect ratio, and slope of slanted wall, as the channel Reynolds number further increased (Re CloseSPigtSPi 50). Remarkably, an almost complete transition of major focusing from the longer side wall to the shorter side wall was found for large-sized particles of clogging ratio K ~ 0.9 (K = a/Hmin) when Re increased noticeably to ~ 650. Finally, based on our findings, a trapezoidal straight channel along with a bifurcation was designed and applied for continuous filtration of a broad range of particle size (0.3 OpenSPiltSPi K OpenSPiltSPi 1) exiting through the longer wall outlet with ~ 99% efficiency (Re OpenSPiltSPi 100).