DNA Catenane Biosensor with Cleavable Linkage for Rolling Circle Amplification
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Solution Overview
Problem
Mechanically interlocked DNA catenanes with strong linking duplexes are unsuitable as templates for rolling circle amplification (RCA) due to topological constraints, limiting their application in biosensing and detection systems.
Innovation Solution
Engineering a biosensor system where a stimuli-responsive RNA-cleaving DNAzyme cleaves one interlocked ring, releasing the topological constraint and allowing RCA to occur, enabling the detection of microorganisms like E. coli by converting the DNA catenane into a suitable template for amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a DNA catenane with a strong linking duplex is used as a template, then structural stability and mechanical interlocking are improved, but rolling circle amplification cannot occur due to topological constraints
Solution Approach 1:
The patent transforms the static, constrained DNA catenane structure into a dynamic system where the linking duplex can be selectively cleaved by a DNAzyme upon target binding. This dynamic transition allows the structure to switch from a stable but inactive state to an amplified signaling state, resolving the contradiction between structural stability and amplification capability
Solution Approach 2:
The patent segments the DNA catenane into functionally distinct components: a stable structural core (the interlocked rings) and a cleavable linkage region. This segmentation allows the majority of the structure to maintain stability while a specific segment can be modified to enable amplification when needed
2Measurement precision
If a DNA catenane structure is used for biosensing, then detection specificity is improved through mechanical interlocking, but detection sensitivity is limited due to lack of signal amplification
Solution Approach 1:
The patent incorporates a DNAzyme into the DNA catenane structure in advance, pre-positioning the amplification trigger within the structure itself. When the target binds to the DNAzyme, the amplification process is immediately activated, enabling sensitive detection while maintaining the specific recognition capabilities of the mechanically interlocked structure
Solution Approach 2:
The patent uses the DNAzyme as an intermediary element that bridges the specific target recognition function and the signal amplification function. The DNAzyme selectively binds the target and then catalyzes the cleavage event that triggers RCA, thereby translating specific recognition into amplified signal without compromising either specificity or sensitivity
3Reliability
If traditional detection methods like ELISA or PCR are used, then detection capability is achieved, but compatibility with complex biological samples and blood is limited
Solution Approach 1:
The patent designs a self-contained biosensing system where the DNA catenane with integrated DNAzyme performs target recognition, signal transduction, and amplification all in one structure. This self-service capability eliminates the need for complex sample preparation and multiple reagent additions, enabling direct detection in complex biological samples and blood without compromising detection reliability
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 system achieves ultra-sensitive detection of E. coli at concentrations as low as 10 cells/mL, with enhanced detection sensitivity and specificity, compatible with biological samples and blood, outperforming traditional methods like ELISA and PCR.
Implementation Method 1
a first single-stranded nucleic acid ring comprising a linkage that is cleaved by an enzyme from the microorganism target or by an enzyme that is activated by a molecule from the microorganism
Implementation Method 2
DNA can be engineered into catalysts (DNAzymes) and molecular receptors (DNA aptamers), making DNA a functionally versatile polymer. DNA, as a highly programmable material based on predictable Watson-Crick base-pairing interactions
Implementation Method 3
The present application further demonstrates that the linking-duplex feature enables the use of topologically interlocked architectures, such as DNA catenanes, for the design of amplified biosensors for bioanalytical applications
Data Source
AI summary
The present application is directed to biosensors and methods for detecting a microorganism target in a sample using a mechanically interlocked nucleic acid catanane, wherein an enzyme from the microorganism target or that is activated by a molecule from the microorganism target cleaves a linkage in a first single-stranded nucleic acid ring of the catanane structure, allowing rolling-circle amplification to occur and the presence of rolling-circle amplification products indicates the presence of the microorganism in the sample.