Ambient Temperature Molecular Detection of Sexually Transmitted Infections from Vaginal Swabs on a Power-free Device

ABSTRACT Despite being easily treatable, STIs such as Chlamydia (infection with Chlamydia trachomatis) and Gonorrhea (infection with Neisseria gonorrhoeae) represent the majority of reportable annual STI cases, indicating that screening and detection efforts for these STIs are inadequate. Untreated infections with C. trachomatis or N. gonorrhoeae can result in increased risk for HIV in both men and women, however, untreated infections in women are more likely to result in long-term adverse health effects, such as pelvic inflammatory disease, infertility, and pregnancy complications. As the majority of infections are asymptomatic in women, access to accurate screening is critical in this population. Several barriers limit the screening habits of sexually-active adults, including lack of privacy in clinical settings, fear of stigmatization by visiting a healthcare professional for testing, and access to clinics, appointments, and results in a timely and equitable manner. Additionally, current gold-standard STI tests are generally only available in-clinic, and require expensive heating or electrical components, making regular screening expensive and inaccessible to the lay consumer. Alternative technologies without these components do not provide PCR-level accuracy. Sherlock’s goal is to develop a PCR-level STI diagnostic device to detect C. trachomatis and N. gonorrhoeae from self-collected vaginal swabs, and which does not require any isothermal or cycled heating elements, battery power, or force in the product design. Specifically, this project will utilize a proprietary amplification chemistry based on high-sensitivity, high-specificity assays, in combination with a prototype microfluidic device design that will control the timed assay amplification and produce an easy-to-read output. 300 vaginal swabs will be qPCR screened for absence of target pathogens, then spiked with in-house cultured C. trachomatis and N. gonorrhoeae. Aim 1 will identify the optimal filter and neutralizing chemical treatment to separate and neutralize human genomic DNA which can obscure pathogen detection from samples, while Aim 2 will establish optimal lyophilized reagent bead size and timing delay, and Aim 3 will assess the device sensitivity, specificity, and failure rate using positive clinical samples. This project will aid in refining the prototype accuracy for validation and extension to other STIs in Phase 2, and will demonstrate the potential of Sherlock’s proprietary amplification chemistry and power-free microfluidics design for at-home PCR-level tests. By creating a heating and power- free molecular test for C. trachomatis and N. gonorrhoeae that is accurate, transportable, easy-to-use and read, and inexpensive, this device can be utilized by the lay consumer in point-of-need settings (at-home) rather than only in point-of-care settings (in-clinic), thereby creating a more accessible and equitable STI screening product.