Modular CRISPR-diagnostics for Infectious Diseases

Infectious diseases continue to represent a significant fraction of worldwide disease burden. A critical part of lowering this burden entails effective testing strategies, as underscored by the ongoing COVID-19 pandemic. The goals of diagnostics, screening, and surveillance have demanded distinct yet innovative approaches to testing. In this work, I present two novel approaches for multiplexed nucleic acid detection (CARMEN and WATSON) that build on the existing CRISPR-diagnostic method SHERLOCK. SHERLOCK combines traditional amplification (PCR or isothermal) with target-specific CRISPR-Cas13 detection and enables new, modular assay designs. With CARMEN, we employ a droplet microfluidic platform to perform thousands of parallel SHERLOCK reactions in nanoliter droplets. CARMEN’s potential for high-throughput infectious disease screening is demonstrated through the design of detection assays for large panels of clinically relevant viral and bacterial pathogens, as well as resistance markers. With WATSON, we maximize the sensitivity of SHERLOCK by targeting multiple tiled regions across a single pathogen genome. The clinical significance of WATSON is demonstrated by applying it to the detection of plasma circulating cell-free DNA in tuberculosis, highlighting its potential as a liquid biopsy test for infectious disease management.Ph.D

A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes

International audienc

Genome-wide tiled detection of circulating Mycobacterium tuberculosis cell-free DNA using Cas13

In this work, the authors developed a multiplexed, minimally invasive, CRISPR-Cas13-based approach to detect Mycobacterium tuberculosis cell-free DNA in the plasma of active pulmonary tuberculosis patients

Massively multiplexed nucleic acid detection using Cas13

The overwhelming majority of globally circulating pathogens go undetected, undermining patient care and hindering outbreak preparedness and response. To enable routine surveillance and comprehensive diagnostic applications, there is a need for detection technologies that can scale to test many samples while simultaneously testing for many pathogens. Here, we develop Combinatorial Arrayed Reactions for Multiplexed Evaluation of Nucleic acids (CARMEN), a platform for scalable, multiplexed pathogen detection. In the CARMEN platform, nanoliter droplets containing CRISPR-based nucleic acid detection reagents self-organize in a microwell array to pair with droplets of amplified samples, testing each sample against each CRISPR RNA (crRNA) in replicate. The combination of CARMEN and Cas13 detection (CARMEN-Cas13) enables robust testing of >4,500 crRNA-target pairs on a single array. Using CARMEN-Cas13, we developed a multiplexed assay that simultaneously differentiates all 169 human-associated viruses with ≥10 published genome sequences and rapidly incorporated an additional crRNA to detect the causative agent of the 2020 COVID-19 pandemic. CARMEN-Cas13 further enables comprehensive subtyping of influenza A strains and multiplexed identification of dozens of HIV drug-resistance mutations. CARMEN’s intrinsic multiplexing and throughput capabilities make it practical to scale, as miniaturization decreases reagent cost per test >300-fold. Scalable, highly-multiplexed CRISPR-based nucleic acid detection shifts diagnostic and surveillance efforts from targeted testing of high-priority samples to comprehensive testing of large sample sets, greatly benefiting patients and public health. ©202