Portable sample processing for molecular assays: application to Zika virus diagnostics

Abstract

A digital microfluidic system was developed for portable Zika virus diagnosis, featuring integrated, automated sample extraction and amplification.

All-in-One digital microfluidics pipeline for proteomic sample preparation and analysis

“…The open-source DropBot 38 control system used here was modified to include two automated heating units – an auxiliary heating unit (introduced here for the first time) was used to denature the sample at 70 °C during disulfide reduction by exposure to TCEP (Fig. 3d), and an integrated unit (reported previously 48,49 ) was used to incubate the sample at 37 °C during enzymatic digestion by exposure to trypsin, after an alkylation reaction by exposure to IAA (Fig. 3e), both programmed by the user and controlled by pulse-width modulation (PWM).…”

“…Devices were controlled by using a custom version of the open-source DropBot system 38 (version 3.0, https://github.com/ sci-bots/dropbot-v3). 48,49 The DropBot and the built-in heater unit were controlled using a custom version of MicroDrop soware (version 2.31.1, https://github.com/sci-bots/ microdrop), while the auxiliary unit was controlled by a separate interface (in-house soware, written in Python). Devices were interfaced to the DropBot system through a pogopin connector, and electrodes were actuated in preprogrammed steps which allowed droplet dispensing, moving, and mixing by applying (typically) 100 V RMS as square waves at 10 kHz (parameters optimized as described below).…”

“…The rmware implemented a proportionalintegral-derivative (PID) algorithm for the ne control of the heating unit using the temperature readings from the thermistors. The PID algorithm was modied from previous versions 48,49 to output both positive and negative values to facilitate heating and cooling respectively. The thermistor closest to the thermoelectric unit was used for feedback while the thermistor further away from the unit served as a monitor of the heat distribution over the heating block.…”

Applications of magnetic and electromagnetic forces in micro-analytical systems

“…88 Further, they demonstrated portable sample-processing DMF molecular assays for the detection of the Zika virus from a 5 μL sample using RNA captured on magnetic beads. 89 Oleschuk's group showed that the combination of lowfriction superhydrophobic surfaces and droplets containing superparamagnetic particles could reliably dispense droplets with high precision (≤6%). Droplets ranging in size from 5 to 20 μL were used for an EDTA-based on-chip complexometric colorimetric titration for water hardness.…”

“…88 Further, they demonstrated portable sample-processing DMF molecular assays for the detection of the Zika virus from a 5 μL sample using RNA captured on magnetic beads. 89…”