Towards point-of-care molecular diagnostics for prenatal screening
OA Version
Citation
Abstract
The spread of infectious diseases remains a critical challenge in the Global South and among vulnerable populations. Effective and accessible screening is essential for timely diagnosis and treatment, yet infections such as P. falciparum, T. vaginalis, C. trachomatis, and N. gonorrhoeae often go undetected due to asymptomatic presentations. Molecular diagnostics, particularly nucleic acid amplification tests (NAATs), have transformed disease monitoring with their high sensitivity and specificity. However, many NAATs are not well suited for point-of-care or near-point-of-care use because of extended time to readout, complex equipment requirements, or insufficient sensitivity. In this work, I aim to improve the accessibility and efficiency of disease monitoring.First, I present the development and validation of three novel isothermal assays based on the Identical Multi-Repeat Sequence (IMRS) algorithm. IMRS assays operate on principles similar to other isothermal amplification workflows but require only two primers, simplifying assay design. I demonstrate the utility of IMRS for detecting C. trachomatis, N. gonorrhoeae, and T. vaginalis in both PCR and isothermal formats. Compared to gold-standard 16S and 18S rRNA primers, PCR-IMRS assays show improved performance. Clinically relevant detection using iso-IMRS is achieved in just 30 minutes.
Next, I describe a multiplexed iso-IMRS assay for the simultaneous detection of P. falciparum and T. vaginalis, with amplification completed in 30 minutes. Urine was selected as the sample matrix because it is noninvasive and available in high volumes. An efficient sample preparation workflow using desalting chromatography columns allows completion in under 5 minutes, and results are readable by lateral flow immunoassay within 10 minutes.
Finally, the full diagnostic platform including sample preparation, amplification, and lateral flow readout demonstrates analytical sensitivities of approximately 0.571 and 1.03 genomic copies per microliter for P. falciparum and T. vaginalis respectively, with a complete workflow achievable within 45 minutes. Current work aims to extend the multiplexed platform to include C. trachomatis, further optimize novel reagent additions to circumvent sample preparation, and evaluate performance in a prospective clinical study. These results highlight a modular design that can be adapted to detect multiple pathogens rapidly, accurately, and in point-of-care settings.
Description
2026
License
Attribution-NonCommercial-ShareAlike 4.0 International