World-to-Digital-Microfluidic Interface Enabling Extraction and Purification of RNA from Human Whole Blood

Abstract

Digital microfluidics (DMF) is a powerful technique for simple and precise manipulation of microscale droplets of fluid. This technique enables processing and analysis of a wide variety of samples and reagents and has proven useful in a broad range of chemical, biological, and medical applications. Handling of "real-world" samples has been a challenge, however, because typically their volumes are greater than those easily accommodated by DMF devices and contain analytes of interest at low concentration. To address this challenge, we have developed a novel "world-to-DMF" interface in which an integrated companion module drives the large-volume sample through a 10 μL droplet region on the DMF device, enabling magnet-mediated recovery of bead-bound analytes onto the device as they pass through the region. To demonstrate its utility, we use this system for extraction of RNA from human whole blood lysates (110-380 μL) and further purification in microscale volumes (5-15 μL) on the DMF device itself. Processing by the system was >2-fold faster and consumed 12-fold less reagents, yet produced RNA yields and quality fully comparable to conventional preparations and supporting qRT-PCR and RNA-Seq analyses. The world-to-DMF system is designed for flexibility in accommodating different sample types and volumes, as well as for facile integration of additional modules to enable execution of more complex protocols for sample processing and analysis. As the first technology of its kind, this innovation represents an important step forward for DMF, further enhancing its utility for a wide range of applications.

Pre-concentration by liquid intake by paper (P-CLIP): a new technique for large volumes and digital microfluidics

“…21 "Open"-format microfluidic systems such as those powered by digital microfluidics (DMF) eliminate the problem of clogging and have proven particularly useful for handling magnetic micro-particles 22 for the analysis of small molecules, 23,24 proteins, [25][26][27][28][29][30][31] and nucleic acids. 32,33 In the most common DMF device format, discrete droplets of liquid are sandwiched between two plates: the bottom plate comprises an array of electrodes that is covered by an insulating dielectric layer and a hydrophobic layer, and the top plate comprises a ground electrode that is covered with a hydrophobic layer. Droplets are moved by sequential application of voltages to electrodes adjacent to the droplet.…”

Rapid and sensitive detection of antibiotic resistance on a programmable digital microfluidic platform

“…[24][25][26][27] More recently, centrifugal forces have been used to control reagent flow in a 'lab-on-a-disc' device capable of extracting and amplifying DNA. 15,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] Based on the phenomenon of electrowettingon-dielectric (EWOD), droplets with a wide range of volumes (microliter to sub-nL) can be individually manipulated using forces generated by an array of microelectrodes. 31,32 Digital microfluidic micro-devices provide an alternative platform for miniaturised, fully automated assays, providing the basis of simple, programmable and portable test systems.…”

Microfluidic Sample Preparation for Medical Diagnostics

“…The extraction of small components from WB, such as nucleic acids (71,72) and specific hormones (73), using DMF also has been reported. More importantly, many recently developed DMF systems are integrated platforms on a single device that can prepare real physiological samples, including tissue and blood, and then detect or analyze the sample (73)(74)(75)(76).…”