Graduate Student Seminar Series – Raegan Allan

Graduate Student Seminar Series
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Location: MS2158 – 1 King’s College Circle
Presentation Title: CRISPR-Responsive Material Development for At-Home STI Detection
Abstract: In 2025, the World Health Organization (WHO) established the development of low-cost, rapid point-of-care tests (POCTs) for sexually transmitted infections (STIs) as a worldwide research priority. STIs are often asymptomatic and, if left untreated, can lead to long-term health consequences that disproportionately affect women, including pelvic inflammatory disease and infertility. Regular screening is therefore essential, but current diagnostics are poorly suited for routine use: antigen-based POCTs lack adequate sensitivity while nucleic acid amplification tests require sophisticated laboratory infrastructure. Even where resources are abundant, uptake remains low due to stigma and inconvenience. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas diagnostics offer programmable, low-cost, rapid, isothermal nucleic acid detection. CRISPR diagnostics use controllable DNA cleavage upon detection of the target pathogen to generate signal. Traditional CRISPR diagnostics are fluorescence-based, but recently CRISPR-responsive materials have emerged as an alternative to enable their use at the point-of-care. Here, we design a multiplexed point-of-care CRISPR-Cas diagnostic platform incorporated into a tampon for at-home STI screening in women to detect Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV). The assay combines isothermal recombinase polymerase amplification and CRISPR-Cas12a reactions to detect species-specific nucleic acid sequences. Our platform leverages a DNA hydrogel with an immobilized colourimetric dye that is released by activated Cas12a in the presence of the target pathogen, enabling equipment-free colourimetric readout, eliminating the need for laboratory infrastructure. The CRISPR-Cas assay designs for CT detection in a standard fluorometric assay have a 1 aM limit of detection within 1 hour. Transitioning these designs to a hydrogel-based dye-release assay, we achieve 500 aM sensitivity within 2 hours. The hydrogels will be tested with NG and TV CRISPR-Cas assays for multiplexed detection. The tampon diagnostic platform design combines detection with sample collection and processing which has the potential to lay the groundwork for at-home STI diagnostics.
Supervisor Name: Caitlin Maikawa
Year of Study: 3
Program of Study: PhD
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