Smartphone Based Loop Mediated Isothermal Amplification for the Detection of Infectious Diseases

Malaria is a completely treatable and preventable disease. Yet there are over 200 million cases and over 400,000 malaria related deaths annually. Malaria is caused by the protozoan parasite Plasmodium which is spread by anopheles mosquitoes. Current gold standard methods of detection of the Plasmodium parasite include microscopy and rapid diagnostic tests (RDTs). Microscopy requires expensive equipment that must be maintained in a clinic or lab. Those in malaria-endemic countries may find these clinics inaccessible or too time-consuming as results may take weeks to process. RDTs are more feasible for point-of-care diagnostics; however they do not have sensitivity low enough for asymptomatic cases and may generate false positives. Early and asymptomatic diagnosis of malaria is key to preventing malaria related deaths and providing proper treatment.

Isothermal amplification assays have emerged as the front runner in point-of-care diagnostics due to their simplistic heating and accurate detection. Here I use one such assay and apply it for use in complex sample matrices on a portable smartphone platform. First, I optimize 2 different loop mediated isothermal amplification (LAMP) primer sets for specific and sensitive detection of Plasmodium falciparum and Plasmodium vivax in blood using particle diffusometry. Next, I explore freeze drying techniques and optimizing this assay for the use of non-invasive samples, urine and saliva. Next, I develop techniques using magnetic separation and RCA to enrich the sample prior to amplification.

Lastly, I applied this platform to COVID-19, a deadly global infectious disease with a need for rapid detection. I was able to further field ready the device by combining lyophilization techniques and on chip heating for the detection of SARS-CoV-2. The development of this portable platform for the rapid detection of Plasmodium parasites from blood, saliva and urine is the first of its kind and can easily be modified for the detection of other infectious diseases.