The MicroActive project: automatic detection of disease-related molecular cell activity

Abstract

The aim of the MicroActive project is to develop an instrument for molecular diagnostics. The instrument will first be tested for patient screening for a group of viruses causing cervical cancer. Two disposable polymer chips with reagents stored on-chip will be inserted into the instrument for each patient sample. The first chip performs sample preparation of the epithelial cervical cells while mRNA amplification and fluorescent detection takes place in the second chip. More than 10 different virus markers will be analysed in one chip. We report results on sub-functions of the amplification chip. The sample is split into smaller droplets, and the droplets move in parallel channels containing different dried reagents for the different analyses. We report experimental results on parallel droplet movement control using one external pump only, combined with hydrophobic valves. Valve burst pressures are controlled by geometry. We show droplet control using valves with burst pressures between 800 and 4500 Pa. We also monitored the re-hydration times for two necessary dried reagents. After sample insertion, uniform concentration of the reagents in the droplet was reached after respectively 60 s and 10 min. These times are acceptable for successful amplification. Finally we have shown positive amplification of HPV type 16 using dried enzymes stored in micro chambers.

A World-to-Chip Interface for Digital Microfluidics

“…As described, the skin depot strategy is similar to the concept of preloaded reagents stored in microchannels. − ,, This is a powerful approach for technology translation, as it spares the end user from having to procure the reagents and interface them with the experimental setup. Unlike these previous methods, in which devices are typically disposed after use, in the skin depot strategy the fundamental device architecture can be reused for any number of assays.…”

“…In a second, reagents are stored in the solid phase in channels and are then reconstituted in solution when the assay is performed. [27][28][29] Preloaded reagents in microfluidic devices is a strategy that will be useful for a wide range of applications. 2 Until now, however, there has been no analogous technique for digital microfluidics.…”

“…Two strategies have emerged for microchannel systems; in the first, reagents are stored as solutions in droplets isolated from each other by plugs of air or an immiscible fluid , until use. In a second, reagents are stored in the solid phase in channels and are then reconstituted in solution when the assay is performed. − Preloaded reagents in microfluidic devices is a strategy that will be useful for a wide range of applications . Until now, however, there has been no analogous technique for digital microfluidics.…”