CRISPR/Cas13a as a viral nucleic acid detection mechanism for POC testing

Until the development of the CRISPR-based platforms, SHERLOCK and DETECTR, no molecular diagnostic technique existed that is accurate, fast (i.e. detection within a few hours), inexpensive and portable. Without the need for patient samples to be shipped to laboratories, these nucleic acid detection mechanisms have the potential to revolutionize the world of molecular diagnostics as they bring the ability to provide a rapid and accurate diagnosis to people all over the world, including the most rural and isolated areas. Hence, SHERLOCK and DETECTR can act as a key driver in reducing outbreaks of infectious diseases, and in general disease monitoring. SHERLOCK stands for ‘specific high-sensitivity enzymatic reporter unlocking’. It exploits the “collateral effects” of Cas13a’s ribonuclease activity in combination with isothermal amplification to detect RNA in a patient’s sample. This article details: (i) the mechanism of SHERLOCK and the progression between its first and second versions, (ii) its limitations as an all-around multiplexing technique, and (iii) the bioethical implications that need to be acknowledged alongside its development and eventual public use. The emergence of the novel SHERLOCK platform has the power to impact millions of lives through early viral detection, and it is crucial to understand its mechanism in order to optimize its applications. This will impact the future of point-of-care diagnostic testing, especially for emerging and re-emerging viruses such as dengue virus and Zika virus. However, its limitations and bioethical implications also need to be addressed to ensure that a system is in place that will maintain the integrity of the application’s original purpose and the safety of its users.