A Printed, Paper-based, Disposable and Recyclable RNA Sensor based on CRISPR/Cas – CRISCOFET

Like RNA vaccines, our CRISCOFET proposal is revolutionary: it does not need gene amplification. CRISCOFET combines five recent technologies, CRISPR/Cas (clustered regular interspaced short palindromic repeats), EGOFETs (electrolyte-gated organic field-effect transistors), xurography, printed CMOS and green printable paper coating to propose a breakthrough in RNA detection, going from biomolecular machinery to organic electronics/conventional electronics hybridization, on biosourced and recyclable paper sheet.
RNA detection and quantification are extremely useful to identify RNA virus infections, as illustrated by the recent pandemic caused by SARS-CoV-2, but they are also used to monitor bacterial proliferation in food or after infection in humans or animals, or to monitor the evolution of diseases because a specific gene is expressed or because miRNAs are produced.
CRISPR/Cas are new bioactive ribonucleoparticles made of two parts: a Cas protein and an RNA (named CRISPR RNA i.e., crRNA). The system is easily programmable by changing the sequence of the crRNA: a new target, a new crRNA. Its function is to fix specific RNA sequence by hybridization with crRNA, then to activate an RNAse activity. This project proposes a detection of the RNAse activity by using the programmed unraveling of an RNA hydrogel.
EGOFETs are innovative organic field-effect transistors for which an electrolyte is placed between the gate electrode and the organic semiconductor. As for all FETs, the gate capacitance drives the current flowing through the transistor. We propose to functionalize the gate with a hydrogel crosslinked by RNA strands. Upon CRISPR/Cas RNAse activity, the gel collapses, that is sensed by a change in capacitance, amplified by the transistor into a change in current.
The approach we propose would contribute to make RNA point-of-care tests more available and easier to deploy on a large scale, more sensitive, giving immediate result, biosourced and recyclable.