Programmable Digital-Microfluidic Biochips for SARS-CoV-2 Detection

Abstract

Biochips, a novel technology in the field of biomolecular analysis, offer a promising alternative to conventional testing equipment. These chips integrate multiple functions within a single system, providing a compact and efficient solution for various testing needs. For biochips, a pattern-control micro-electrode-dot-array (MEDA) is a new, universally viable design that can replace microchannels and other micro-components. In a Micro Electrode Dot Array (MEDA), each electrode can be programmatically controlled or dynamically grouped, allowing a single chip to fulfill the diverse requirements of different tests. This capability not only enhances flexibility, but also contributes to cost reduction by eliminating the need for multiple specialized chips. In this paper, we present a visible biochip testing system for tracking the entire testing process in real time, and describe our application of the system to detect SARS-CoV-2.

Keywords: SARS-CoV-2; digital-microfluidic biochip (DMFB); loop-mediated isothermal amplification (LAMP); micro-electrode-dot-array (MEDA); programmable biochip.

Figure 1

(a) DMFB bio-test platform with real-time observation system. (b) Chip socket detail of red box in Figure 1a with a chip. (c) Microscope imaging of sample loaded area on the chip (the detail image of blue box in Figure 1b). (d) Microscope imaging of a droplet sample on the chip. (e) Sandwich structure of testing environment.

Figure 2

(a) Temperature vs. current curve. (b) Temperature vs. time curve under LAMP test mode. (c) Thermal images of testing area at LAMP test mode.

Figure 3

(a) Starting-point and end-point images of RT-LAMP samples with a standard heating process (65 °C 30 min) on chips. Samples 1–3 are positive samples, and Sample 4 is a negative control. (b) End-point Agarose gel results (stained by Ethidium bromide), lanes: M 1 kb DNA ladder, 1–4 the same samples corresponding to Samples 1–4 in (a). Visible turbidity changes of colorimetric LAMP samples on chips for (c) Phenol red and (d) Hydroxy naphthol blue.