RFD-CD2 DNAzyme for Clostridium difficile Detection
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Solution Overview
Problem
Current methods for detecting Clostridium difficile infections are labor-intensive, time-consuming, and lack specificity, with existing DNAzyme probes being limited to diagnosing specific strains, failing to provide a universal solution for diverse C. difficile strains.
Innovation Solution
Development of a catalytic nucleic acid probe, RFD-CD2, with a nucleotide sequence selected from specific SEQ ID NOs, capable of cleaving a nucleic acid substrate and generating a fluorogenic signal upon contacting C. difficile, allowing for the detection of diverse pathogenic strains with high sensitivity and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR methods are used to detect toxin-coding genes, then sensitivity is improved, but the ability to distinguish active toxin production from asymptomatic carriers deteriorates
Solution Approach 1:
The patent uses an RNA-cleaving DNAzyme as an intermediary molecular tool that specifically recognizes and binds to C. difficile RNA targets. This DNAzyme acts as a mediator between the bacterial RNA and the detection system, enabling specific detection of active toxin production rather than just gene presence. The DNAzyme's catalytic activity generates a detectable signal only when bound to its specific RNA target, providing information about active toxin production.
2Loss of time
If enzyme immunoassays are used to detect toxins rapidly, then detection time is reduced, but sensitivity deteriorates
Solution Approach 1:
The patent replaces the enzyme-based immunoassay system with a DNAzyme-based catalytic system. Instead of using enzyme-substrate reactions to generate signals, the invention uses DNAzyme-catalyzed RNA cleavage reactions. This substitution maintains rapid detection capabilities while improving sensitivity through the high specificity of nucleic acid base pairing and the catalytic amplification effect of the DNAzyme.
3Measurement precision
If GDH detection is performed to achieve rapid and sensitive testing, then detection sensitivity is improved, but the ability to distinguish toxigenic strains from non-toxigenic strains deteriorates
Solution Approach 1:
The patent applies local quality by designing the DNAzyme to recognize specific local sequences within C. difficile RNA that are unique to toxigenic strains. Rather than detecting a universal marker like GDH present in all strains, the DNAzyme targets specific RNA regions that differ between toxigenic and non-toxigenic strains, providing localized sequence-specific recognition that enables strain differentiation.
4Reliability
If conventional culture and cytotoxicity assays are used as gold standard methods, then diagnostic accuracy is improved, but labor intensity and time consumption increase
Solution Approach 1:
The patent implements self-service through the autonomous catalytic activity of the DNAzyme. The DNAzyme automatically binds to its target RNA and catalyzes the cleavage reaction without requiring manual intervention, complex equipment, or skilled operators. The system generates its own detectable signal through the catalytic reaction, eliminating the need for labor-intensive processing steps required by conventional culture and cytotoxicity assays.
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
RFD-CD2 achieves a limit of detection as low as 100 CFU/mL, making it suitable for rapid diagnosis of C. difficile infections across various strains, offering a universal DNAzyme probe for diagnosing CDI with improved sensitivity and specificity compared to previous probes.
Implementation Method 1
RFD-CD2, with a nucleotide sequence selected from specific SEQ ID NOs, capable of cleaving a nucleic acid substrate and generating a fluorogenic signal
Data Source
AI summary
This disclosure relates to catalytic nucleic acids, catalytic nucleic acid probes, biosensors, and kits for detecting the presence of Clostridium difficile. Also provided are methods for detecting the presence of Clostridium difficile in a test sample, using the catalytic nucleic acids, catalytic nucleic acid probes, biosensors, and kits.