Search

Microfluidic paper-based analytical devices (μPADs) are a relatively new group of analytical tools that represent an innovative low-cost platform technology for fluid handling and analysis. Nonetheless, μPADs lack in the effective handling and controlling of fluids, which leads to a main drawback for their reproducibility in large volumes during manufacturing, their transition from the laboratory into the market and thus accessibility by end-users. Herein we investigate the applicability of ionogel materials based on a poly( N -isopropylacrylamide) gel with the 1-ethyl-3-methylimidazolium ethyl sulfate ionic liquid as fluid flow manipulator in μPADs using the ionogel as a negative passive pump to control the flow direction in the device. A big challenge undertook by this contribution is the integration of the ionogel materials into the μPADs. Finally, the characterisation and the performance of the ionogel as a negative passive pump is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a very simple, industrially scalable method for transferring a high-resolution, biologically active protein pattern from one substrate to another. We demonstrate the transfer of a protein pattern formed initially by microcontact printing from a silicon surface (to which this form of printing is applicable) onto a glass or polymer substrate, almost independently of the surface/bulk properties of the second substrate. A very thin, spin-coated layer of a sugar is used to preserve the structure and organization of proteins during the subsequent plasma deposition of a siloxane polymer, after which the protein pattern could simply be peeled off the silicon substrate and glued onto any other desired substrate. [Copyright &y& Elsevier]

Graphical abstract Abstract 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 (<200 mg/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. [ABSTRACT FROM AUTHOR]

This paper reports an innovative technique for reagents storage in microfluidic devices by means of a one-step UV-photoprintable ionogel-based microarray on non-modified polymeric substrates. Although the ionogel and the ink-jet printing technology are well published, this is the first study where both are used for longterm reagent storage in lab-on-a-chip devices. This technology for reagent storage is perfectly compatible with mass production fabrication processes since pre-treatment of the device substrate is not necessary and inkjet printing allows for an efficient reagent deposition process. The functionality of this microarray is demonstrated by testing the release of biotin-647 after being stored for 1 month at room temperature. Analysis of the fluorescence of the ionogel-based microarray that contains biotin-647 demonstrated that 90% of the biotin-647 present was released from the ionogelbased microarray after pumping PBS 0.1% Tween at 37 C. Moreover, the activity of biotin-647 after being released from the ionogel-based microarray was investigated trough the binding capability of this biotin to a microcontact printed chip surface with avidin. These findings pave the way for a novel, one-step, cheap and mass production on-chip reagents storage method applicable to other reagents such as antibodies and proteins and enzymes. [ABSTRACT FROM AUTHOR]

The fabrication of new self-powered micropumps by 3D-printing techniques (3Dp-μPumps) and its integration on portable microfluidic devices. [Display omitted] • Modular polymeric micropumps were fabricated by 3D printing. • 3D printed micropumps could be assembled with any type of microfluidic device. • Different flow rates were obtained depending on the pump material and surface area. • Direct assembly pump-cartridge was achieved thanks to 3D printing manufacturing. • Autonomous colorimetric test for starch detection was performed with the micropumps. In order to facilitate the implementation of microfluidic technology for rapid point-of-care analysis, there is a demand for self-powered microfluidics. The modular architecture of degas driven plug-and-play polymeric micropumps and microfluidic cartridges arose during last decade as a powerful strategy for autonomous flow control. So far, reported polymeric micropumps were made of poly-dimethyl siloxane and were fabricated by casting. In this work, we showed that the advantages of three-dimensional printing can greatly benefit the development of modular micropumps. In addition, micropumps were created with a geometry that cannot be manufactured with conventional techniques, making it easily assemblable to microfluidic devices. Four types of polymeric resins and three printing methods were used to create a set of functional micropumps. It was shown that the material and the design of the printed micropumps were related to their power, making them tuneable and programmable. Finally, as proof of concept, a self-powered colorimetric test for the detection of starch was demonstrated. Three-dimensional printed micropumps emerge as an innovative element in the field of self-powered microfluidics, which may be the key to develop integrated microsystems for several applications such as in rapid point-of-care analysis. [ABSTRACT FROM AUTHOR]