Nora J. Gilliam

Nora, a third-year student at Indiana University – Purdue University majoring in chemistry and epidemiology, amplified genetic material from tick-borne pathogens for detection by the CRISPR-based diagnostic tool SHERLOCK.

CRISPR-based diagnostic tools have the potential to surpass the limits of current diagnostic tools with efficient, field-deployable technology; transforming tick-borne infection clinical care and clinical diagnosis more broadly.

BSRP is a rigorous yet skill-amplifying program in all its facets. I have never felt so confident in myself as well as my career plans as I do now at the end of the program. As for the Broad Institute itself, the environment is extremely encouraging and supportive of everyone who works here. The Broad is a place where the love of science is -- well, infectious. Previous diagnostic tools have either been limited in sensitivity or required consistent and reliable electricity and transportation, which are not always guaranteed in a resource-limited or field setting. SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing) is a CRISPR-based diagnostic tool that couples isothermal recombinase polymerase amplification (RPA) of target genetic material and detection of the amplified material by CRISPR-Cas13a that can then be visualized on lateral-flow paper to achieve sensitivity and deployability. A remaining challenge is multiplexing to test for multiple possible infections; despite RPA’s capability to isothermally amplify target genetic material, this method has been shown to amplify nonspecifically which generates undesired products and introduces design and efficiency challenges for multiplexed amplifications. We found that the isothermal amplification method helicase dependent amplification (HDA) is multiplexable, compatible with CRISPR-Cas13a detection, amplifies more specifically than RPA, and can amplify target genetic material from clinical samples. Further experiments will elucidate the limits of sensitivity and detection for HDA. The outcome of these experiments will lead to further optimization and validation for SHERLOCK technology as a novel approach to clinical detection of tick-borne pathogens.

Project: Optimization of isothermal amplification in SHERLOCK for the detection of tick-borne pathogens

Mentor: Jacob Lemieux, Sabeti Lab