CRISPR-Cas systems in diagnostics: A comprehensive assessment of Cas effectors and biosensors

The development of rapid, sensitive, specific and accurate diagnostic tests is essential for improving the treatment outcome of diseases. In the majority of disease diagnosis, nucleic acid-based tests are accepted as a gold standard. In general, these tests provide reliable results, yet they require highly trained personnel and specialized equipmentation. With the introduction of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems in diagnostic applications, achieving breakthrough improvements in diagnostic tests is now possible. The specific target sequence recognition ability and trans-cleavage activity of certain Cas proteins enable novel applications of these systems in the development and improvement of diagnostic tests. These improvements and innovations allow for improved sensitivity, specificity and accuracy of point-of-care tests while keeping their costs at affordable levels. In this review, a comprehensive analysis of the common CRISPR-Cas systems used in diagnostic applications and the utilization of these systems in the design of novel biosensors is provided.