@article{mohammad_katkam_wei_2022, title={A Sensitive and Nonoptical CRISPR Detection Mechanism by Sizing Double-Stranded lambda DNA Reporter}, volume={11}, ISSN={["1521-3773"]}, url={https://doi.org/10.1002/anie.202213920}, DOI={10.1002/anie.202213920}, abstractNote={AbstractCRISPR‐based biosensors often rely on colorimetric, fluorescent, or electrochemical signaling mechanism, which involves expensive reporters and/or sophisticated equipment. Here, we demonstrated a simple, inexpensive, nonoptical, and sensitive CRISPR‐Cas12a‐based sensing platform to detect ssDNA targets by sizing double‐stranded λ DNA as novel report molecules. In this platform, the size reduction of λ DNA was quantified by gel electrophoresis analysis. We hypothesize that the massive trans‐nuclease activity of Cas12a toward λ DNA is due to the presence of single‐stranded looped structures along the λ DNA sequence. In addition, we observed a strong binding affinity between Cas12a and λ DNA, which further promotes the trans‐cleavage activity and helps achieve sub‐picomolar detection sensitivity, ≈100 times more sensitive than the fluorescent counterpart. The concept of utilizing the physical size change of λ DNA unlocks the possibility of using a variety of dsDNA as CRISPR reporters.}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Mohammad, Noor and Katkam, Shrinivas S. and Wei, Qingshan}, year={2022}, month={Nov} } @article{mohammad_katkam_wei_2022, title={Recent Advances in Clustered Regularly Interspaced Short Palindromic Repeats-Based Biosensors for Point-of-Care Pathogen Detection}, volume={7}, ISSN={["2573-1602"]}, url={https://doi.org/10.1089/crispr.2021.0146}, DOI={10.1089/crispr.2021.0146}, abstractNote={Infectious pathogens are pressing concerns due to their heavy toll on global health and socioeconomic infrastructure. Rapid, sensitive, and specific pathogen detection methods are needed more than ever to control disease spreading. The fast evolution of clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics (CRISPR-Dx) has opened a new horizon in the field of molecular diagnostics. This review highlights recent efforts in configuring CRISPR technology as an efficient diagnostic tool for pathogen detection. It starts with a brief introduction of different CRISPR-Cas effectors and their working principles for disease diagnosis. It then focuses on the evolution of laboratory-based CRISPR technology toward a potential point-of-care test, including the development of new signaling mechanisms, elimination of preamplification and sample pretreatment steps, and miniaturization of CRISPR reactions on digital assay chips and lateral flow devices. In addition, promising examples of CRISPR-Dx for pathogen detection in various real samples, such as blood, saliva, nasal swab, plant, and food samples, are highlighted. Finally, the challenges and perspectives of future development of CRISPR-Dx for infectious disease monitoring are discussed.}, journal={CRISPR JOURNAL}, author={Mohammad, Noor and Katkam, Shrinivas Siddhivinayak and Wei, Qingshan}, year={2022}, month={Jul} }