Development of a point-of-care device for syphilis infection screening

Abstract

The ability of conduct self-testing of diseases from a single drop of blood in a point-of-care setting has been of great interest by many researchers. While the application of lateral flow technology to screen for pregnancy has been a great success story, many of the blood-based or serum-based lateral flow tests are limited to be used in clinic settings. Poor sensitivity in the inherent lateral flow technology leads to a requirement for large amounts of blood (> 50 l) required during testing, making it difficult for an untrained person to conduct the test. Alternative approach using microfluidic techniques appear promising to miniaturize immunoassays with improved sensitivity. However, the requirements of pumps in microfluidic device to drive fluids and specialized readers for interpretation make microfluidic platform less attractive for commercial use. Hence, advancements in immunoassay technology are necessary to path ways for novel easy-to-use home-based test kits.

This final year project aims to develop a syphilis screening test that requires only a single drop of blood. Hence, the author developed and optimized 2 syphilis-related paper-based enzyme-linked immunosorbent assays (ELISAs) – treponemal and non-treponemal. This allows a patient to differentiate between a newly diagnosed syphilis incident compared to a past syphilis incident where the patient has recovered from the infection. In addition, the author designed, fabricated and tested the hardware that enabled paper-based ELISA to be conducted equipment-free, without loss of quality in assay performance.

This work will path insights to the development of the first battery-less, fully integrated duplex syphilis test that allows processing of whole blood from sample-to-answer within ten minutes. As the readout produces a strong colorimetric signal, the test results can be easily interpreted by the naked eye. Applications for this technology include screening of cancer, infectious diseases and other diseases.

Lastly, a summary finding as well as discussion on some of the experimental data will be presented. This research serve as a platform for future assay development such as integrating with saliva based testing.