Concentration of Circulating Anodic Antigen for Low-Resource Diagnosis of Schistosomiasis
Schistosomiasis is a water-borne parasite disease found in tropical regions, especially those with diminished access to clean water. Symptoms, including abdominal pain and chronic diarrhea, affect the ability of infected people to work or learn. Traditionally, schistosomiasis is diagnosed by a fecal smear, but this method requires trained personnel and an advanced infection. To overcome these challenges, a lateral flow assay has been developed which tests for Circulating Anodic Antigen (CAA), a negatively-charged glycoprotein produced by the parasites. This assay is easy to use and has high sensitivity, but concentrating CAA in the urine samples used, would further improve it. Our objective was to use positively-charged dendrimers to concentrate CAA onto magnetic beads, which could then be deposited onto the assay. Using an ELISA, an antibody-based quantification method, we determined the most effective conditions for capture and elution of CAA from the beads. We found that larger (generation 4-6) dendrimers provided the best capture of CAA, at >80%. We have also determined that CAA capture stays constant across changes in volume when using 10 μL of functionalized beads, allowing us to use larger urine samples for CAA concentration. Following this optimization, we will incorporate our magnetic beads into a rapid assay, significantly increasing sensitivity for diagnosing schistosomiasis.