(191ch) Arduino-Based POC System for the Diagnosis of Viral Diseases through on-Line Conductivity Measurement

The development of cost-efficient Diagnostic Point of Care (POC) systems is a research niche of high relevance; the recent pandemic/epidemic episodes associated with viral diseases (Influenza epi-centered in México 2009; Ebola in West Africa 2013-2015; and Zika in Latin America 2016) are tangible and cruel reminders of the need for portable, low-cost, and easy-to-use diagnostic systems that can effectively address epidemic episodes in remote or underprivileged areas. Here, we describe the development of a simple Arduino-based POC device for quantitative detection of viral pathogens. As a proof-of concept model, we demonstrate the detection, amplification, and quantification of Ebola virus (EBOV) genetic material.

We used Recombinase Polymerase Amplification (RPA), an isothermal amplification technique, for the specific amplification of a sequence of nucleotides that encodes a region of the Ebola GP protein (expressed in Escherichia coli). The use of an isothermal amplification technique, instead of PCR, greatly simplifies the complexity of the system. We show that simple temperature control at 37C in a small chamber allows the amplification of a DNA sequence (at a minimum concentration of 0.0322 ng/mL) in a short time (i.e., 10–20 minutes). An increase in resistivity of the amplification mix (from 10,000 to 600,000 ohms) within the chamber, associated with a decrease in the ionic strength related to the occurrence of the DNA/RNA amplification, is detected online by two electrodes connected to the Arduino.

Our platform exhibits the essential attributes of a POC system: (a) the use of small volumes, (b) low capital cost, (c) portability, (d) and a fast, accurate, and selective response.