Proof of concept for a portable platform for molecular diagnosis of tropical diseases: On-chip ready-to-use qPCR for detection of Trypanosoma cruzi or Plasmodium spp

Abstract Although molecular diagnostics is well established in clinical laboratories, its full potential has not been extended to field settings. Typically, diagnostic qPCR reagents require temperature-controlled transportation and storage. Furthermore, thermocyclers are bulky and fragile, requiring good infrastructure for optimal operation. These major hurdles strongly limit the use of molecular-based tests in low-resource scenarios. Here, qPCR was used for detection of Trypanosoma cruzi or Plasmodium spp. DNA, using a commercial equipment (ABI7500) and a prototype platform comprised of a portable device and a silicon chip, named Q3-Plus. Additionally, a ready-to-use reaction format, where all qPCR reagents are stored on-plate or on-chip, was compared with the traditional freezer-stored format. No significant differences were observed in the detection of T. cruzi or Plasmodium spp. DNA between thermocyclers, as well as between reagents' formats for storage periods of up to 28 days (at 2 to 8 or 21 to 23 °C). When challenged with patients' samples, the Q3-Plus system performed as efficiently as the standard equipment for Plasmodium spp. DNA detection, proposing itself as a valuable solution to malaria point-of-care diagnostics. Detection of T. cruzi DNA in chronic patients' samples using the Q3-Plus system yielded about 50% efficiency relative to the ABI7500. The results presented herein are essential to support future endeavors to bring molecular diagnostics to the point-of-care, where it is most needed.