Bringing Diagnostics to Worldwide Clinics
A key focus in the Ellington lab is the development of diagnostics for resource-limited settings. DNA molecules can be used as computers, and these “smart” diagnostics can be embedded into otherwise low-tech dipstick devices. These assays are designed to diagnose many different diseases and disease states, such as to identify the particular drug-resistant tuberculosis bacterium present in a sample. By using a dipstick, the results can be read out at the point-of-care, rather than days later, when a patient may no longer be near a clinic.
Gace Eckhart, an undergraduate who worked in Afghanistan collecting drug-resistant tuberculosis samples.
These DNA computers recognize nucleic acid sequences that mark a disease or disease state, which are amplified and read out via the production of a simple, colored signal. This signal can then either be used immediately by clinicians, or uploaded to databases or to other experts via cell phone camera technology. The goal of this work is to increase both the speed and accuracy of diagnoses, which will impact our own health care efforts by ensuring that new disease variants are eradicated at their source. This work is currently funded by the Gates Foundation and the National Institutes of Health.
Catalyzed hairpin assembly to amplify a signal detected from a sample. The ssDNA C1 catalyzes the hybridization of hairpins H1 and H2 through a series of toehold-mediated strand displacement reactions.
Reference: Li B, Ellington AD, Chen X (2011) Rational, modular adaptation of enzyme-free DNA circuits to multiple detection methods. Nucleic Acids Res 39(16):e110. PubMed