Ratiometric nonfluorescent CRISPR assay utilizing Cas12a-induced plasmid supercoil relaxation.

Most CRISPR-based biosensors rely on labeled reporter molecules and expensive equipment for signal readout. A recent approach quantifies analyte concentration by sizing λ DNA reporters via gel electrophoresis, providing a simple solution for label-free detection. Here, we report an alternative strategy for label-free CRISPR-Cas12a, which relies on Cas12a trans-nicking induced supercoil relaxation of dsDNA plasmid reporters to generate a robust and ratiometric readout.

Adeno-associated virus genome quantification with amplification-free CRISPR-Cas12a.

Efficient manufacturing of recombinant Adeno-Associated Viral (rAAV) vectors to meet rising clinical demand remains a major hurdle. One of the most significant challenges is the generation of large amounts of empty capsids without the therapeutic genome. There is no standardized analytical method to accurately quantify the viral genes, and subsequently the empty-to-full ratio, making the manufacturing challenges even more complex.

Low-rate smartphone videoscopy for microsecond luminescence lifetime imaging with machine learning.

Time-resolved techniques have been widely used in time-gated and luminescence lifetime imaging. However, traditional time-resolved systems require expensive lab equipment such as high-speed excitation sources and detectors or complicated mechanical choppers to achieve high repetition rates. Here, we present a cost-effective and miniaturized smartphone lifetime imaging system integrated with a pulsed ultraviolet (UV) light-emitting diode (LED) for 2D luminescence lifetime imaging using a videoscopy-based virtual chopper (V-chopper) mechanism combined with machine learning.

Unidirectional trans-cleaving behavior of CRISPR-Cas12a unlocks for an ultrasensitive assay using hybrid DNA reporters containing a 3' toehold.

CRISPR-Cas12a can induce nonspecific trans-cleavage of dsDNA substrate, including long and stable λ DNA. However, the mechanism behind this is still largely undetermined. In this study, we observed that while trans-activated Cas12a didn't cleave blunt-end dsDNA within a short reaction time, it could degrade dsDNA reporters with a short overhang.

Flexible sensor patch for continuous carbon dioxide monitoring.

Monitoring and measurement of carbon dioxide (CO) is critical for many fields. The gold standard CO sensor, the Severinghaus electrode, has remained unchanged for decades. In recent years, many other CO sensor formats, such as detection based upon pH-sensitive dyes, have been demonstrated, opening the door for relatively simple optical detection schemes.