Background/introduction Brunel DoCLab is part of the eSTI2 Consortium which is developing electronic self-testing and portable instruments for sexually transmitted infections using nucleic acid amplification test technologies. We have designed a point of care test platform that integrates a proprietary sample collection device directly with a microfluidic cartridge. A low cost benchtop real-time isothermal amplification platform has been developed capable of running six amplifications simultaneously.
Aim(s)/objectives To evaluate the sample preparation and isothermal amplification within the low cost diagnostic platform.
Methods The microfluidic device incorporates passive mixing of the lysis-binding buffers and sample. Cell lysis, within the cartridge, is conducted using a chemical method and nucleic acid purification is done on an activated cellulose membrane. Isothermal amplification was conducted using recombinase polymerase amplification (RPA).
Results Preliminary results have shown extraction efficiencies for this new membrane of 69% and 57% compared to the commercial Qiagen extraction method of 85% and 59.4% for 0.1 ng/µL and 100 ng/µL salmon sperm DNA respectively spiked in phosphate buffered solution. Extraction experiments in the passive mixer cartridges with lysis and nucleic acid purification showed extraction efficiency around 80% of the commercial Qiagen kit. The platform is capable of detecting Chlamydia trachomatis genomic DNA within 10 min using RPA for 100,000 copies/µL.
Discussion/conclusion The work presented here shows a low cost, rapid nucleic acid extraction, isothermal amplification and detection platform for diagnosing C. trachomatis. Work is on-going to fully integrate the sample-in to result platform for rapid diagnosis of STIs using genital samples.