Impedimetric Biosensor for Real-Time DNA Mutation Detection
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Solution Overview
Problem
Current DNA sensing technologies face challenges such as the need for high-end instrumentation, incompatibility with high-throughput assays, requirement of additional chemicals, lack of sensor-regeneration capacity, and insufficient dynamic information on hybridization or denaturation events, making them inefficient for fast, cheap, and repetitive detection of single-nucleotide polymorphisms (SNPs).
Innovation Solution
A method and device using impedimetric real-time monitoring with chemically induced denaturation of DNA/RNA bioparticles, where a functionalized surface coated with probe DNA/RNA is exposed to an electrolytic solution, and impedance measurements are taken before and after denaturation, allowing for the calculation of denaturation-time constants to detect and quantify point mutations without labels or auxiliary chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microarrays are used for SNP detection, then massively parallelized readout is achieved, but reaction time increases to at least 16 hours and dynamic information on DNA binding kinetics is completely lost
Solution Approach 1:
The patent replaces the mechanical/optical readout system of microarrays with an electronic detection system based on field-effect transistors (FETs). The FETs detect DNA hybridization events through electrical signal changes caused by charge redistribution at the gate insulator, enabling real-time monitoring without the time-consuming optical detection processes of microarrays.
Solution Approach 2:
The patent changes the detection parameter from optical signals (fluorescence) to electrical signals (impedance, gate current). This parameter change enables continuous real-time monitoring of DNA binding kinetics while maintaining high-throughput capability, as electrical measurements can be performed rapidly and repeatedly without adding chemicals or labels.
2Measurement precision
If fluorescent labelling of target DNA is performed, then detection sensitivity is improved, but device complexity and cost increase due to sophisticated optical readout techniques
Solution Approach 1:
The patent substitutes the complex optical readout system with a simple electrical measurement system. The FET-based sensor detects DNA presence and hybridization states through changes in electrical impedance or gate current, eliminating the need for fluorescent labels, lasers, optics, and complex image processing systems while maintaining detection sensitivity.
Solution Approach 2:
The patent utilizes the intrinsic negative charge of DNA molecules themselves as the detection mechanism. The DNA charges the gate insulator of the FET, creating an electrical signal that directly reports on DNA presence and binding state. This self-service approach eliminates the need for external labels or auxiliary chemicals, simplifying the system while preserving detection capability.
3Measurement precision
If established denaturation-based approaches are used, then mutation detection is achieved, but expensive instrumentation and fluorescent labels are required
Solution Approach 1:
The patent replaces expensive optical instrumentation and fluorescent labeling systems with inexpensive electrical measurement equipment. The FET-based sensor detects DNA denaturation and hybridization through electrical signal changes, enabling mutation detection using simple voltage and current measurements rather than complex optical systems.
Solution Approach 2:
The patent uses the intrinsic electrical properties of DNA (negative charge) to generate detection signals without requiring fluorescent labels or expensive reagents. The DNA molecules themselves serve as the signal source by modulating the electrical characteristics of the FET, eliminating the need for costly labeling chemicals and reducing overall system cost.
4Measurement precision
If real-time PCR with melting-curve analysis is performed, then SNP detection is achieved, but fluorescent labels and expensive instrumentation are required
Solution Approach 1:
The patent eliminates the need for fluorescent labels by using the intrinsic charge of DNA to generate electrical detection signals. The FET sensor directly detects DNA hybridization and denaturation events through changes in gate current or impedance, making the detection process label-free and reducing chemical consumption compared to real-time PCR methods.
5Loss of time
If DNA switching method on gold electrodes is used, then real-time monitoring without fluorescent labelling is achieved, but labels are still involved on probe DNA
Solution Approach 1:
The patent eliminates all labels from both probe and target DNA by utilizing the intrinsic charge of DNA molecules for detection. The FET-based sensor detects hybridization events through electrical signal changes caused by the charges of the DNA molecules themselves, achieving complete label-free operation unlike the gold electrode method that still requires labels on probe DNA.
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
This approach enables label-free, fast, reliable, and cost-effective detection and characterization of point mutations, suitable for multiple analyses and repetitive use of the sensor, providing accurate and reproducible results.
Implementation Method 1
measuring a first impedance value within the electrolytic solution, adding a chemical to the electrolytic solution which is able to achieve denaturation of the target DNA and/or RNA, then measuring a second impedance value within the flow cell after completion of the denaturation
Implementation Method 2
adding a chemical to the electrolytic solution which is able to achieve denaturation of the target DNA and/or RNA, then measuring a second impedance value within the flow cell after completion of the denaturation of the target DNA and/or RNA
Data Source
AI summary
A method an system is disclosed for the detection and/or allocation of at least one point mutation in target DNA and/or RNA duplexes. The method comprises obtaining a functionalized surface which is coated with probe DNA and/or RNA whereto target DNA and/or RNA duplexes are attached, contacting said functionalized surface to an electrolytic solution having a neutral pH in a flow cell and measuring a first impedance value within said electrolytic solution, and then adding a chemical to the electrolytic solution which is able to achieve denaturation of the target DNA and/or RNA. The method further comprises measuring a second impedance value within the flow cell after completion of the denaturation of the DNA and/or RNA target, and then obtaining a value representative for the impact of the chemical on the impedance of the electrolytic solution. The amount and/or allocation of point mutation(s) within the target DNA and/or RNA is then determined by calculating the denaturation-time constant based on the difference between the first and second impedance value and taking into account the impact of the chemical by third impedance value.