Chlamydia and gonorrhoea are the two most commonly reported STIs in Australia, with incidences rising over the last few years (The Kirby Institute, 2013). UTIs are highly common in the community and in hospitals, particularly amongst young, sexually active women. All three of these infections share common symptoms - itching, burning, discomfort. What if you could test for all three at once?
What it does
LAMP Diagnostics (formerly The Pussy Protector) is a prototype microfluidic qPCR device for rapid, at-home detection of infectious diseases. The current prototype focuses on detection of E. coli (the cause of 80% of UTIs in otherwise healthy women aged 18-29 [Schmiemann, 2010]), chlamydia, and gonorrhoea. Raw sample (in this case a small quantity of urine) is inserted into the cartridge, where capillary action pulls it through into a series microfluidic tubes that contains all the necessary reagents. Loop-mediated isothermal amplification (LAMP) assays are carried out in quadruplicate for each sample to amplify DNA based on the primer sets used. Amplified DNA from the target organism(s) will fluoresce when excited - the more of that organism is present, the greater the fluorescence. This is captured by an array of phototransistors, the fluorescence level is compared to that of a standard curve, and the amount of infectious bacteria calculated from this.
A crowd-funding campaign for LAMP Diagnostics has been launched, and funds will go to further product development, expansion, and certification with the relevant government bodies.
We believe that greater access to STI screening can help prevent these diseases. As so many chlamydia and gonorrhoea infections are asymptomatic and can go undetected, frequent screening can lead to early detection, preventing the spread of these STIs.
How we built it
Our prototype uses a 3D-printed, resin-moulded microfluidic cartridge that takes in up to four samples. Reagents are entered via syringe at two entry points, and flow through the capillary tubes to combine with the samples in equal volumes in each reaction well. The array of 16 wells in total is heated from underneath by a sheet of ITO glass, activating the amplification reaction for target DNA. LEDs are used to excite a fluorescent dye in the reaction, and this fluorescence is detected by an array of phototransistors. After comparison to a standard curve, a microprocessor evaluates whether this is beyond the detection threshold, which would then indicate a positive or negative result to the user.
Data is also anonymously transmitted to the Biofoundry server for collection of public health records using an ESP8266 chip. This data is visualised online as a representative array of the reaction wells.
Inspiration for the device came from an open-source qPCR device published by Myers et al in 2013.
Challenges we ran into
Making STI testing a sexy, marketable product. We also made the decision to change the focus of our device a few hours in, meaning a whole lot of new research had to be done regarding the public health needs and microbiology.
Accomplishments that we're proud of
Building a qPCR machine completely from scratch in a weekend. These devices are typically around 100x bigger, made with printed circuit boards, and cost in the range of $35,000. Our device is handheld, all circuit boards were hand-crafted, and it only cost around $100. Plus, our system uses LAMP rather than tradition PCR to amplify the DNA - a protocol that has been demonstrated to be more accurate and more robust! (Francois et al 2011, Myers et al 2013)
What's next for LAMP Diagnostics
This device is readily scaleable, to contain as many or as few sample lanes as required. This means we can easily provide single STI tests with just three lanes (sample, and positive/negative controls), or cartridges with more sample lanes for testing for multiple infections simultaneously.
Even better than this, the LAMP technology used in our device means we can theoretically test for any organism, provided we design the right primers to screen for it. This means there are uses for this device in further healthcare models, in the home, and in the environment.
Francois, P., Tangomo, M., Hibbs, J., Bonetti, E. J., Boehme, C. C., Notomi, T., Perkins, M. D., and Schrenzel, J. (2011) Robustness of a loop-mediated isothermal amplification reaction for diagnostic applications. FEMS Immunol. Med. Microbiol. 62, 41–48
The Kirby Institute. HIV, viral hepatitis and sexually transmissible infections in Australia – Annual Surveillance Report 2013. The Kirby Institute, The University of New South Wales, Sydney NSW 2052 (2013).
Myers, F. B., Henrikson, R. H., Bone, J., and Lee, L. P. (2013) A Handheld Point-of-Care Genomic Diagnostic System. PLoS One 8
Schmiemann, G., Kniehl, E., Gebhardt, K., Matejczyk, M. M. & Hummers-Pradier, E. The diagnosis of urinary tract infection: a systematic review. Dtsch Arztebl. Int. 107, 361–367 (2010).