Microencapsulation of pancreatic islets for the treatment of Type I Diabetes Mellitus (T1DM) generates a high quantity of empty microcapsules, resulting in high therapeutic graft volumes that can enhance the host's immune response. We report a 3D printed microfluidic magnetic sorting device for microcapsules purification with the objective to reduce the number of empty microcapsules prior transplantation. In this study, INS1E pseudoislets were microencapsulated within alginate (A) and alginate-poly-L-lysine-alginate (APA) microcapsules and purified through the microfluidic device. APA microcapsules demonstrated higher mechanical integrity and stability than A microcapsules, showing better pseudoislets viability and biological function. Importantly, we obtained a reduction of the graft volume of 77.5% for A microcapsules and 78.6% for APA microcapsules. After subcutaneous implantation of induced diabetic Wistar rats with magnetically purified APA microencapsulated pseudoislets, blood glucose levels were restored into normoglycemia (<200mg/dL) for almost 17 weeks. In conclusion, our described microfluidic magnetic sorting device represents a great alternative approach for the graft volume reduction of microencapsulated pseudoislets and its application in T1DM disease.

A great breadth of questions remains in cellular biology. Some questions cannot be answered using traditional analytical techniques and so demand the development of new tools for research. In the near future, the development of highly integrated microfluidic analytical platforms will enable the acquisition of unknown biological data. These microfluidic systems must allow cell culture under controlled microenvironment and high throughput analysis. For this purpose, the integration of a variable number of newly developed micro- and nano-technologies, which enable control of topography and surface chemistry, soluble factors, mechanical forces and cell–cell contacts, as well as technology for monitoring cell phenotype and genotype with high spatial and temporal resolution will be necessary. These multifunctional devices must be accompanied by appropriate data analysis and management of the expected large datasets generated. The knowledge gained with these platforms has the potential to improve predictive models of the behavior of cells, impacting directly in better therapies for disease treatment. In this review, we give an overview of the microtechnology toolbox available for the design of high throughput microfluidic platforms for cell analysis. We discuss current microtechnologies for cell microenvironment control, different methodologies to create large arrays of cellular systems and finally techniques for monitoring cells in microfluidic devices.

Low cost easy to use cell viability tests are needed in the pharmaceutical, biomaterial and environmental industry to measure adverse cellular effects. Herein we present a new methodology to track cell death with high resolution. We achieved dynamic digital quantification of cell viability by simple optical imaging using "Single Cell Adhesion Dot Arrays" (SCADA). Fibronectin (FN) dot arrays were fabricated on cell culture multiwell plates. The dot array was designed to accomodate a single cell on each fibronectin dot. For cytotoxicity measurements, cell-filled SCADA substrates were exposed to K2CrO4, HgSO4 salts and dimethyl sulfoxide (DMSO). Adherent cells commonly detach from the surface when they die. Dynamic monitoring of the toxic effect of DMSO and K2CrO4 was done measuring cell detachment rate during more than 30 hours by quantifying the number of occupied dots in the SCADA array. HgSO4 inhibited cellular detachment from the surface, and cytotoxicity was monitored using Trypan Blue life/death assay directly on the surface.In all cases, the cytotoxicity effects were easily monitored with single cell resolution and the results were comparable to previous reports. Cytotoxicity SCADA tests require only a transparent substrate, with a patterned area of less than 1 mm 2 and a reduced number of cells. SCADA enabled dynamic measurements at the highest resolution due to the digital measuring of this methodology. Integrated into microfluidic platforms, SCADA will provide a practical tool that will extent to fundamental research and commercial applications.

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Microfluidic microsystems are often designed to analyze samples of small volumes of fluids; however, some applications require the analysis of larger volumes. The ideal miniaturized microfluidic analytical device should be autonomous and capable of integrating all the required functions within a single fluidic network. While a number of self-powered microfluidic network designs are available, the autonomous manipulation of large sample volumes in microsystems is still a challenge. We have developed a universal self-powered microfluidic architecture by combining polymeric micropumps and plastic microfluidic cartridges, which may be adapted to a large range of volumes of fluids. Our polymeric micropumps were able to trigger flow rates from 0.25 to 20 μL·min–1 during more than 90 min, moving over 800 μL of the fluid. A number of fluidic operations were demonstrated, including mixing, aliquoting, waste storage, and autodraining of the microfluidic channels. Finally, a self-powered cartridge for the separation of plasma from whole blood was successfully validated, demonstrating that this constitutes a universal scheme to process a wide range of fluid volumes, which is an unprecedented fact in self-powered microfluidics.