Microarray Melting Curve Analysis for SNP Detection
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Solution Overview
Problem
Microarray techniques face challenges with promiscuous binding, leading to reduced accuracy and repeatability due to the inability to optimize hybridization temperatures for all probes simultaneously, resulting in errors in gene expression profiling and SNP analysis.
Innovation Solution
A method and apparatus for performing melting curve analyses on microarrays, using temperature-controlled fluid circulation and advanced fluorescence analysis techniques like FRET, FLIM, and FCS to detect and quantify target DNA binding, allowing for precise measurement of melting temperatures and reduction of noise caused by misbinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microarray techniques are used for high throughput analysis, then productivity is improved, but measurement precision deteriorates due to promiscuous binding
Solution Approach 1:
The patent applies preliminary action by performing a melting curve analysis before final detection. The method involves heating the microarray to progressively higher temperatures to denature non-specifically bound target DNA before the actual measurement, ensuring that only perfectly matched DNA-probe complexes remain bound during detection. This preliminary denaturation step eliminates promiscuous binding artifacts while maintaining high throughput capability.
2Measurement precision
If hybridization temperature is optimized for specific probes, then measurement precision is improved, but device complexity increases due to inability to optimize all probes simultaneously
Solution Approach 1:
The patent applies parameter changes by utilizing temperature as a dynamic parameter to differentiate between specific and non-specific binding. Instead of optimizing hybridization temperature for each individual probe (which would be extremely complex), the method uses a progressive heating approach where the melting temperature serves as a discriminatory parameter. Perfectly matched complexes remain bound at higher temperatures while mismatched complexes denature, allowing single temperature control to achieve high precision for all probes simultaneously.
3Measurement precision
If promiscuous binding is reduced by selective probe design, then measurement precision is improved, but manufacturing precision deteriorates due to lack of standardization
Solution Approach 1:
The patent applies the taking out principle by extracting and removing non-specifically bound target DNA from the system through thermal denaturation. By progressively heating the microarray to melting temperatures, the method selectively removes promiscuously bound DNA-probe complexes while leaving perfectly matched complexes intact. This extraction of unwanted binding artifacts eliminates the need for highly standardized probe design, as the thermal denaturation step universally removes non-specific binding regardless of probe sequence variations.
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
Improves the accuracy of gene expression profiling and SNP analysis by eliminating noise from misbound target DNA, enabling precise measurement of perfectly matched DNA and confirming the presence of SNPs, and allows for the reuse of microarrays and samples.
Implementation Method 1
Melting curve analysis involves the use of heat to break the hydrogen bonds holding double stranded nucleic acids (most often DNA) together so that the double stranded form melts apart ('dissociates') into two single stranded products.
Implementation Method 2
In practice, special dyes such as SYBR Green I are among those used to monitor the exact temperature at which melting occurs. SYBR Green fluoresces 1000 times more when intercalated between double stranded DNA verses floating free in solution.
Data Source
AI summary
A method and apparatus for performing melting curve analyses of nucleic acids on a microarray is described. The present method includes varying the temperature of a fluid on a microarray to dissociate and remove target DNA, scanning the mircoarray for fluorescence, collecting the target DNA removed from the microarray, and reusing the collected target DNA and the microarray. The apparatus of the present disclosure includes a microarray stage, a light source and detector, and a temperature controller, wherein the temperature controller is configured to adjust the temperature of a fluid within a sample chamber on the microarray such that the temperature of the fluid is varied during the analysis such that target DNA is dissociated from the microarray, and wherein the light source is directed to the microarray and the resulting fluorescence is perceived by the detector.