Towards ultra-sensitive and rapid near-source wastewater-based epidemiology
Da Huang, Alyssa Thomas DeCruz, Dounia Cherkaoui, Benjamin S. Miller, Diluka Peiris, Samuel Hopgood, Jessica L. Kevill, Kata Farkas, Rachel Williams, Davey L. Jones, Rachel A. McKendry
Abstract
Wastewater-based epidemiology is emerging as a powerful early-warning public health surveillance tool. However, gold-standard PCR necessitates transporting samples to laboratories, with significant reporting delays (24-72 h), prompting growing interest in rapid, near-source tests for resource-limited settings. Research has focused on gold nanoparticle dipsticks, but these typically lack sensitivity in wastewater. Herein, we explore two complementary nanomaterial based approaches, using SARS-CoV-2 as an exemplar: 1) visually-read carbon black dipsticks; 2) spin-enhanced fluorescent nanodiamond dipsticks, exploiting selective separation from background autofluorescence. The assay provides a 2-hour turnaround from sample preparation to result with minimal equipment and achieves a limit of detection down to 7 copies per assay. A pilot study with samples from the Welsh National WBE programme finds 80% sensitivity and 100% specificity for carbon black, and 100% sensitivity, specificity for nanodiamonds. A proof-of-concept lab-in-a-suitcase nanodiamond assay tests raw, unprocessed wastewater samples. These findings lay the foundations for near-source WBE early-warning quantum sensors in the environment.