Article Text

002.6 A low-cost mobile naat platform for chlamydia trachomatis
1. DJ Shin1,
2. P Athamanolap1,
3. L Chen2,
4. J Hardick3,
5. CA Gaydos3,
6. TH Wang1,2,4
1. 1Department of Biomedical Engineering, Johns Hopkins University
2. 2Department of Mechanical Engineering, Johns Hopkins University
3. 3Division of Infectious Diseases, Johns Hopkins University School of Medicine
4. 4Institute for NanoBioTechnology, Johns Hopkins University

## Abstract

We report the development of a low-cost mobile nucleic acid analysis platform (mobiLab) utilising a smartphone-enabled microfluidic device for streamlined analysis of biological samples. Using magnetic particles as a mobile solid phase for nucleic acid capture and transport, fluidic processing is simplified to particle translocation on a robust and scalable cartridge.

Process integration facilitated by Bluetooth-enabled microcontrollers enables full control of the instrument by the user with a smartphone application. Each cartridge costs less than $2 using off-the-shelf reagents and materials, an order of magnitude cheaper than$9.98/test for a GeneXpert cartridge. The instrument utilises a microcontroller which controls the rotary bead manipulator, thermal incubation and Bluetooth-based communication with the smartphone application. Each assay consumes approximately 10% of the battery capacity, allowing up to 10 assays to be performed consecutively without access to a power outlet.

We designed a single-stream loop-mediated isothermal amplification (LAMP) assay to operate in tandem with the mobiLab platform. We tested the single-stream assay using plasmid targets and were able to capture and amplify 103 copies of gene targets. Absence of cross-reactivity with human genomic DNA or other vaginal flora was verified.

The platform was validated by testing Chlamydia trachomatis infection from patient-collected vaginal swab samples. Volunteers enrolled in an internet-based Chlamydia screening program, where two sets of swabs were self-collected and mailed back to our lab. One set of swabs was analysed using the gold standard Gen-Probe AC2 CT assay. The second set of swabs was tested using the mobiLab platform. The two results were in agreement for 20 out of 20 samples at a time threshold of 30 min, demonstrating that the droplet assay performance is comparable to the gold standard for the samples tested. To our knowledge, this abstract presents the first smartphone-based NAAT platform that integrates sample preparation, amplification and data processing.

Disclosure of interest statement None to disclose.

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