Electrochemical Biosensor Using CRISPR/Cas13a for Rapid RNA Detection
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Solution Overview
Problem
Current methods for detecting SARS-CoV-2 RNA, such as RT-PCR and CRISPR-based optical detection, face limitations in point-of-care applications due to complexity, time requirements, and sensitivity issues, particularly in monitoring low concentrations of viral RNA for early detection of infections.
Innovation Solution
An electrochemical biosensor is developed that utilizes a nanocomposite containing molybdenum disulfide, graphene, and chitosan with a flower-shaped gold nanostructure, combined with the CRISPR/Cas13a system, which allows for the detection of SARS-CoV-2 RNA without nucleic acid amplification, enhancing sensitivity and reducing test time by immobilizing reporter RNA on the electrode and using a Cas13a-crRNA complex to induce current reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RT-PCR technology is used for detecting SARS-CoV-2 RNA, then detection sensitivity and specificity are improved, but test time and operational complexity increase
Solution Approach 1:
The patent extracts and removes the nucleic acid amplification step from the detection process. By using CRISPR/Cas13a trans-cleavage activity directly on extracted RNA, the method achieves high sensitivity detection without requiring RT-PCR amplification, thereby reducing test time while maintaining detection capability
Solution Approach 2:
The patent replaces the complex mechanical amplification system of RT-PCR with a biochemical detection system based on CRISPR/Cas13a trans-cleavage. This substitution eliminates the need for thermal cycling and amplification reagents, simplifying the process and reducing test time while maintaining detection sensitivity
2Measurement precision
If CRISPR-based optical detection is used, then detection sensitivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the optical detection system with an electrochemical detection system. By using electrochemical biosensors to measure the trans-cleavage activity of Cas13a, the method eliminates bulky and expensive optical components while maintaining high detection sensitivity and enabling point-of-care applications
Solution Approach 2:
The patent creates an electrical signal copy of the biochemical reaction instead of using optical signals. The trans-cleavage activity of Cas13a is transduced into an electrochemical signal through the interaction with the electrode-modified biosensor, providing a simpler and more portable detection method
3Loss of time
If electrochemical biosensor without amplification is used, then test time is reduced, but detection sensitivity for low concentration RNA decreases
Solution Approach 1:
The patent uses a composite electrode structure modified with multiple materials (graphene, chitosan, gold nanoparticles) to enhance the electrochemical signal. This composite structure increases the surface area and electrical conductivity of the electrode, amplifying the detection signal without requiring nucleic acid amplification, thereby maintaining sensitivity while reducing test time
Solution Approach 2:
The patent optimizes the electrochemical parameters including electrode potential, scan rate, and buffer composition to maximize signal detection. By carefully controlling these parameters, the biosensor achieves high sensitivity detection of low concentration RNA directly without amplification, balancing speed and accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The biosensor achieves high-sensitivity detection of SARS-CoV-2 RNA at low concentrations, enabling rapid and accurate monitoring of COVID-19 without pre-amplification, with a linear dynamic range of 1.0×10−1 fg/ml to 1.0×105 fg/ml and limits of detection as low as 4.4×10−2 fg/ml for the ORF and S genes, suitable for point-of-care diagnostics.
Implementation Method 1
an electrode which has been modified with a nanocomposite (NC) containing molybdenum disulfide (MoS2), graphene, and chitosan (CHT)
Implementation Method 2
a flower-shaped gold nanostructure (AuNF) are deposited
Implementation Method 3
which can detect an RNA such as SARS-CoV-2 with high sensitivity through a CRISPR/Cas13a trans-cleavage reaction
Data Source
AI summary
The present invention relates to an electrochemical biosensor for detecting a target RNA, and the present invention can detect a very small amount of target RNA with high sensitivity without a nucleic acid amplification reaction through a CRISPR/Cas13a trans-cleavage reaction, thereby having an advantage of being useful for point-of-care diagnostic testing of fast-spreading RNA-based infectious diseases such as COVID-19.