# 3STEP: A swab-seal-read, point-of-care nucleic acid test to address disparity in STI screening and prevention

> **NIH NIH R43** · SALUS DISCOVERY, LLC · 2024 · $275,736

## Abstract

ABSTRACT
The ongoing epidemic of sexually transmitted infections (STIs), particularly in men who have sex with men
(MSM), is worsening as the fear of HIV and the acceptance/use of barrier methods (e.g condoms) decreases.
STI diagnostics are the critical gateway to treatment, yet traditional test methods (i.e., mail-in kits and centralized
labs) are decidedly ineffective for the individuals and groups most impacted by STIs, such as MSM, economically
disadvantaged communities/countries, and those without health insurance. As stated by the WHO, “A major
barrier to STI control and prevention is the unavailability of reliable, low-cost, point-of-care (POC) tests which
allow diagnosis and treatment in a single visit.” Indeed, technology for POC STI tests that can be accessed at
local clinics and performed by “lay health workers” during the patient visit are needed to address ongoing STI
socioeconomic health disparities. Salus has invented 3STEP, a POC nucleic acid test (NAT) platform that
addresses this critical need by enabling laboratory performance at the POC in a format that is as easy to perform
as a rapid antigen test in <35 min using a single swab/sample. Laboratory performance in 3STEP is
accomplished via exclusion-based sample preparation (ESP) for high-purity extraction/concentration (an often
skipped but vitally important step in POC-NAT tests, particularly samples with more complex matrix such as anal
swabs), while its POC simplicity and affordability is enabled by novel stabilized interface technology (SIFT). The
single disposable device performs sample collection, nucleic acid extraction, and amplification/detection in
spatially separated wells that enables rapid development of multiplexed test panels. Unlike many other POC
NATs, there are no microfluidic valves, pumps, or electronics, minimizing costs, e-waste, and manufacturing
complexity. Salus Discovery is now applying 3STEP to meet important POC STI testing needs. Specifically, in
collaboration with Dr. Striker (MD, PhD) at the University of Wisconsin, we target a significant need/opportunity
in the MSM population identified by the groundbreaking ANCHOR study for an anal HPV NAT to detect infections
with high risk of anal cancer (no approved test is currently available for anal swabs). The multiplexing capability
of 3STEP allows us to also target the need for lab-quality POC single-visit testing and treatment for the curable
and highly prevalent STIs Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). We have preliminary
data in the 3STEP platform with HPV 16, HPV 18, CT, and NG detection chemistries. Thus, in Aim 1 we will
focus on optimizing and integrating the STI test chemistries into a panel and in Aim 2 we will use this panel to
(i) efficiently assess the ability to detect each pathogen in actual patient samples, and (ii) compare different
sampling methodologies (anal CT/NG swab vs. anal HPV cytology swab) setting the stage for a Phase II
proposal.

## Key facts

- **NIH application ID:** 10820325
- **Project number:** 1R43AI181122-01
- **Recipient organization:** SALUS DISCOVERY, LLC
- **Principal Investigator:** Brianna Mullins
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $275,736
- **Award type:** 1
- **Project period:** 2024-04-01 → 2026-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10820325

## Citation

> US National Institutes of Health, RePORTER application 10820325, 3STEP: A swab-seal-read, point-of-care nucleic acid test to address disparity in STI screening and prevention (1R43AI181122-01). Retrieved via AI Analytics 2026-05-31 from https://api.ai-analytics.org/grant/nih/10820325. Licensed CC0.

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