# Rapid and Ultrasensitive aptamer-based detection technologies for T. pallidum

> **NIH NIH R21** · UNIVERSITY OF WASHINGTON · 2024 · $233,250

## Abstract

ABSTRACT
 Infections with Treponema pallidum, the causative agent of syphilis, have been rapidly rising in the United
States over the past decade and present an increasing threat to public health. However, currently available
diagnostic methods for T. pallidum infection remain suboptimal: they are time consuming, costly, are variably
sensitive and specific for disease, are subject to false positive and false negative results, and are especially
complicated to apply for the diagnosis of congenital syphilis. Moreover, most available testing algorithms
require involvement of clinical reference laboratories able to support high complexity testing, increasing the
overhead surrounding testing and the time necessary to achieve a positive or negative diagnostic result. As a
result of both the practical challenges of testing and the inherent diagnostic limitations of available tests, some
diagnoses are missed, and others are not made in a timely fashion, such that patients may be lost to follow-up
before treatment. There is an increasingly urgent need for robust, rapid, low cost, and widely accessible testing
to enable the diagnosis of T. pallidum in adult and congenital contexts. In response to these needs, we propose a
new diagnostic paradigm based on the detection of T. pallidum antigens using aptamers, short ssDNA molecules
that bind to target molecules with equal or greater affinity than antibodies. This innovative approach will enable
ultrasensitive, point-of-care (POC) testing for T. pallidum infections from a variety of specimen types, such that
syphilis can be rapidly diagnosed in adults and babies and appropriate therapy administered in real time. In
our first Aim, we will develop aptamers that strongly and specifically bind T. pallidum proteins having high
value as diagnostic targets. We will then evaluate the performance characteristics of those aptamers by
measuring their sensitivity of binding to cultured T. pallidum strains, and their specificity of binding by
confirming a lack of binding to related treponemal organisms, other genitourinary pathogens, and organisms
from the normal human microbiota. In our second Aim, we will use these aptamers to develop methods and
protocols for the rapid and ultrasensitive detection of T. pallidum antigens from clinical specimens. Our strategy
will utilize polymerase-assisted cyclic signal amplification of organism-specific aptamers to generate and
amplify fluorescent signal that can be detected at POC using inexpensive instrumentation. After protocol
optimization, we will perform initial clinical validation of the assay using residual human specimens spiked
with cultured T. pallidum. Our overall goal is to generate an inexpensive, ultrasensitive, and rapid detection
method for syphilis that can be implemented at POC, so that accurate diagnosis of syphilis and administration
of effective therapy can be implemented in the same healthcare encounter.

## Key facts

- **NIH application ID:** 10942579
- **Project number:** 1R21AI184484-01
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Stephen J Salipante
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $233,250
- **Award type:** 1
- **Project period:** 2024-08-01 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10942579

## Citation

> US National Institutes of Health, RePORTER application 10942579, Rapid and Ultrasensitive aptamer-based detection technologies for T. pallidum (1R21AI184484-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10942579. Licensed CC0.

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