(210g) Microneedle-Assisted Detection of Plant Pathogens on a Smartphone

Early detection of plant diseases and timely determination of treatment strategies require a paradigm shift of molecular diagnosis from the laboratory to directly in the field (Nanoscale Adv. 2020, 2, 3083-3094). The current molecular diagnostic methods are inefficient to monitor the disease outbreak and spread over time, as the diagnostic tests are either performed in a laboratory setting (e.g., nucleic acid amplification) or lack sensitivity and specificity (e.g., lateral flow test strips). This work describes a rapid solution for in-field diagnosis of plant diseases by combining MN extraction technology with a smartphone-enabled nucleic acid diagnostic platform for quick amplification, quantification, and result reporting all in one device (Biosensors and Bioelectronics, under revision). The MN patch extracts both DNA and RNA from plant leaf tissues by simple compression and retraction, which reduces nucleic acid extraction time from hours of a conventional extraction method to less than a minute. The MN-extracted DNA/RNA is purification-free and directly applicable to the nucleic acid amplification assays such as PCR and LAMP (ACS Nano 2019, 13, 6540–6549). On the other side, the smartphone device comprises a sample cartridge to run the LAMP assay using MN-extracted sample and a light-emitting diode (LED) based fluorescent imaging system to quantify the LAMP assay signal. This integrated MN-smartphone nucleic acid amplification platform detects Phytophthora infestans DNA and tomato spotted wilt virus (TSWV) RNA from laboratory-inoculated and field-collected tomato leaves within 30 mintures. Moreover, this platform can simultaneously detect multi-infections through a single extraction and amplification on the smartphone without benchtop equipment.