Handheld battery-operated sample preparation device for qPCR nucleic acid detections using simple contactless pouring

Abstract

Sample preparation is an essential process that precedes nucleic acid detections which use quantitative polymerase chain reaction (qPCR). However, sample preparation is a labor-intensive process and requires skilled labor, thus limiting the public's access in low-resource settings to many high-quality nucleic acid-based detection mechanisms. In this paper, we present a simple, handheld, battery-operated sample preparation device to minimize user's involvement. The device uses a simple pouring method to process the DNA sample without pipetting or using disposable pipette tips. The developed device has a size of 12 × 8 × 8 cm³ and mass of only 364 g. The device is compared to gold standard methods, including magnetic bead-based and silica filter-based DNA extractions. For a short segment DNA target of 68 bp, the presented device captured 8.67× more DNA compared to that of the manual magnetic bead-based method. Because of automation, the measured capture efficiency is more consistent and has a smaller deviation between multiple repetitions than the manual method. To present a comprehensive, portable, battery-operated diagnostic system, the sample preparation device is tested in conjunction with a 3D-manufactured qPCR device. The test using three diluted target DNA samples, each spiked in whole blood (1×, 0.1×, and 0.01×), revealed a quantitative detection with ideal cycle threshold separations between the measurements. The combination of two devices will aid in resource-limited settings to promptly and accurately diagnose infections of patients.