Ultrasensitive SARS-CoV-2 diagnosis by CRISPR-based screen-printed carbon electrode

A critical review of microfluidic systems for CRISPR assays

“…Such samples, of course, contained much less impurities and background species compared to clinical samples. As expected, most assays using synthetic nucleic acids as starting sample did not report extraction and purification systems steps (for example, see Zeng et al 50 or Wu et al 82 ). Two exceptions were a commercial magnetic bead-based extraction kit used by Bruch et al 51 to purify synthesized RNA (from synthesis buffer) and a commercial silica bead, spin-column-based extraction kit used by Bai et al 83 to purify target from the products of a commercial synthesis kit.…”

“…Chen et al 85 developed a microfluidic chip with pre-loaded RAA reagents for on-chip amplification. The analyte was displaced to the RAA amplification chamber using centrifugal force induced by a low-speed rotation (800 rpm) for 15 s. The amplicon was then transferred to the detection chamber using 3000 rpm for 15 s. Wu et al 82 presented a similar centrifugal-driven chip in which RAA and CRISPR-based detection occurred in the same chamber. Chen et al 76 used the automated system described earlier (chip, magnetic beads, and motorized arm) to effect transfer of purified sample into a chamber for RPA.…”

“…A few studies separated the cis -cleavage step from the subsequent trans -cleavage. Wu et al 82 performed RT-RPA in a tube and later added Cas12a into the same tube. They then transferred the activated enzyme onto a screen-printed electrode (containing reporters) for trans -cleavage.…”

Alternative platform for COVID-19 diagnosis based on AuNP-modified lab-on-paper

“…Recently, several platforms for COVID-19 diagnostics have been developed. [4][5][6][7][8][9] Lateral-flow test strips are commonly used for detecting SARS-CoV-2 antigen 10,11 the test strips are composed of many components laminated onto a sheet of plastic backing, an absorbance pad and a basal substrate. This platform is similar to a sandwich-ELISA assay, 12,13 requiring different antibody and sample preparation steps.…”

Rapid determination of SARS-CoV-2 nucleocapsid proteins based on 2D/2D MXene/P–BiOCl/Ru(bpy)32+ heterojunction composites to enhance electrochemiluminescence performance

“…The novel coronavirus disease 2019 (COVID-19), a cluster of atypical pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been known as a highly contagious disease. Owing to the rapid spread and multiple routes of transmission of SARS-CoV-2, it is a great challenge to guard against [ [1] , [2] , [3] , [4] , [5] ]. The clinical symptoms of COVID-19 disease include fever, cough, fatigue, shortness of breath, loss of smell and gastrointestinal symptoms, all these are similar to the common symptoms of influenza [ 6 ].…”