Microfluidics-based extraction of viral RNA from infected mammalian cells for disposable molecular diagnostics

A disposable plastic microfluidic device capable of extracting viral RNA from complex biological mixtures has been developed as a step towards building low-cost, mass produced molecular diagnostic systems for infectious diseases. The device offers a robust, easy-to-use sample preparation platform for rapid processing of clinical samples for nucleic acid-based diagnostics for pathogens. As a platform model, we have successfully isolated viral RNA from mammalian cells infected with influenza A (H1N1) virus. The microfluidic chip was fabricated in cyclic polyolefin by hot-embossing with a nickel–cobalt electroformed master mold. The isolation of total RNA was done on-chip with a solid-phase extraction (SPE) system formed by trapping silica particles in a porous polymer monolith. Separation of RNA is achieved through reversible binding of the nucleic acids to the silica particles in the monolith. The μSPE system allows isolation of intact total RNA from a mixture of infected whole cell lysates and serum supplemented cell culture supernatant. The system requires minimal user-handling, so the isolated RNA sample has low risk of degradation. The μSPE system also significantly reduces the required hands-on time for extraction compared to the conventional bench-top extraction procedures. The sample preparation platform presented here uses a very compact design that can be easily coupled with downstream amplification and detection modules to form a fully integrated lab-on-a-chip for nucleic acid analysis.