Microfluidic device for single step measurement of protein C in plasma samples for sepsis prognosis

Isoelectric trapping and discrimination of histones from plasma in a microfluidic device using dehydrated isoelectric gate

Histones are basic proteins with an isoelectric point around 11. It has been shown that the level of plasma circulating histones increases significantly during sepsis, and circulating free histones are associated with sepsis severity and mortality. It was found that the median plasma total free histone concentration of sepsis ICU non-survivors is higher compared to survivors. Therefore, histone concentration can serve as a prognostic indicator and there is a need for a simple, low-cost, and rapid method for measuring histone levels. In this work, we have developed a microfluidic device containing an isoelectric membrane made of dehydrated agarose gel of a specific pH embedded in a porous membrane for isoelectric trapping of histones rapidly. Although isoelectric gates have been used for trapping proteins before, they have to be introduced at the time of the experiment. Here, we show that isoelectric gates formed by gels loaded in a scaffold can be integrated directly into the fabrication process flow, dehydrated for storage, and rehydrated during the experiment and still function effectively to achieve isoelectric trapping. A low-cost and rapid microfabrication technique, xurography, was used for agarose integration and device fabrication. The integrated device was tested with samples containing buffered histone, histone in the presence of high-concentration bovine serum albumin (BSA), and histone spiked in blood plasma. The results show that the device can be used to distinguish between survivors and non-survivors of sepsis in less than 10 min, making it suitable as a point-of-care device for sepsis prognosis.

Open Hardware for Microfluidics: Exploiting Raspberry Pi Singleboard Computer and Camera Systems for Customisable Laboratory Instrumentation

The integration of Raspberry Pi miniature computer systems with microfluidics has revolutionised the development of low-cost and customizable analytical systems in life science laboratories. This review explores the applications of Raspberry Pi in microfluidics, with a focus on imaging, including microscopy and automated image capture. By leveraging the low cost, flexibility and accessibility of Raspberry Pi components, high-resolution imaging and analysis have been achieved in direct mammalian and bacterial cellular imaging and a plethora of image-based biochemical and molecular assays, from immunoassays, through microbial growth, to nucleic acid methods such as real-time-qPCR. The control of image capture permitted by Raspberry Pi hardware can also be combined with onboard image analysis. Open-source hardware offers an opportunity to develop complex laboratory instrumentation systems at a fraction of the cost of commercial equipment and, importantly, offers an opportunity for complete customisation to meet the users' needs. However, these benefits come with a trade-off: challenges remain for those wishing to incorporate open-source hardware equipment in their own work, including requirements for construction and operator skill, the need for good documentation and the availability of rapid prototyping such as 3D printing plus other components. These advances in open-source hardware have the potential to improve the efficiency, accessibility, and cost-effectiveness of microfluidic-based experiments and applications.