Project Lead(s): Julianne Gibbs-Davis
The World Health Organization has identified proper diagnosis as a bottleneck to proper control and treatment of the tuberculosis (TB) epidemic in low- and middle-income countries.
The most accurate diagnostic methods amplify and detect tuberculosis DNA directly, but such methods require temperature cycling instrumentation and are costly consumables.
Lesion-induced DNA amplification (LIDA) makes a specific DNA sequence – indicative of disease – self-replicate until many copies of that sequence are present and detectable using very simple read-out methods.
Towards the goal of creating a kit for multi-drug resistant TB detection, the project team developed temperature tunable LIDA that allows for heat-free amplification; developed a mismatch sensitive and RNA triggered variant of LIDA for drug resistance and viral detection, respectively; created a rapid, colour-based read-out method using DNA-modified gold nanoparticles; and studied the behaviour of DNA chips to optimize chip-based read-out.
The team developed the different components needed to build a prototype TB diagnostic device.
They detected single-nucleotide polymorphism (SNP) utilizing LIDA and managed to amplify a small DNA sequence based on the ligase chain reaction (LCR), rather than polymerase chain reaction (PCR).
They were able to demonstrate room-temperature, heat-free amplification, allowing replication of a given sequence at anywhere from 18°C to 30°C, a significant advantage over other point-of-care diagnostics.
The colour-based detection method is rapid (less than five minutes) and works at room temperature, making it ideal for point-of-care detection.
Results of the project have been discussed in several presentations at conferences.
Papers were published in Chemical Communications, Langmuir and Analyst, and Gibbs-Davis received a Research Fellowship of $66,17750,000 USD from the Alfred P. Sloan Award Foundation based on this work.