DSLR Imaging System for Microfluidic Thermal Melt Detection
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Solution Overview
Problem
Current imaging systems for monitoring nucleic acid diagnostic assays and biological processes are limited by accuracy, precision, and cost-effectiveness, particularly in microfluidic devices where real-time PCR and thermal melt analysis are performed.
Innovation Solution
The use of a digital single lens reflex (DSLR) camera with a large CMOS sensor, LED excitation sources, and a specific illumination configuration to create an imaging system that can track flow and perform thermal melt measurements, allowing for improved data efficiency and precision in imaging within microfluidic channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging systems are used for monitoring nucleic acid diagnostic assays, then the systems can perform basic imaging functions, but the accuracy and precision are limited
Solution Approach 1:
The imaging system is designed to perform multiple functions including flow tracking, thermal melt analysis, and real-time PCR monitoring using a single integrated system. The same imaging system with LED excitation sources and CMOS sensor is used for different assay types, eliminating the need for separate specialized systems while maintaining high measurement precision across all functions.
2Measurement precision
If high resolution imaging is performed to improve measurement precision, then accuracy improves, but data transfer bandwidth and storage requirements increase
Solution Approach 1:
The system extracts and processes only the essential imaging data required for thermal melt analysis and flow tracking. By focusing on specific parameters such as fluorescence intensity changes over temperature and flow velocity measurements, the system reduces the volume of data that needs to be transferred and stored while maintaining high measurement precision for the critical assay parameters.
3Measurement precision
If conventional sensors are used for thermal melt detection, then the system structure is simpler, but the detection resolution is insufficient
Solution Approach 1:
The system replaces conventional mechanical or contact-based temperature sensing with optical detection using fluorescence-based thermal melt analysis. The imaging system captures fluorescence intensity changes as DNA melts, providing high-resolution thermal melt detection without physical contact. This substitution enables precise detection of melting temperatures and transitions while maintaining system integrity.
4Difficulty of detecting and measuring
If multiple illumination sources are used to improve observation of reaction dynamics, then measurement capability improves, but device complexity increases
Solution Approach 1:
The system uses LED excitation sources that can be activated in periodic sequences to excite different fluorescent dyes at different wavelengths. By alternating between blue LED (470±40nm) for SYBR Green and red LED (630±20nm) for other fluorophores, the system achieves multi-color fluorescence imaging capability without requiring all illumination sources to be active simultaneously, thus reducing overall system complexity while maintaining comprehensive reaction dynamics observation.
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 configuration enhances the accuracy and precision of nucleic acid assays by enabling flow tracking and thermal melt analysis with reduced data transfer bandwidth and storage needs, while also allowing for better control of PCR and thermal melt processes through improved observation of reaction dynamics.
Implementation Method 1
The illumination system includes a first LED (light emitting diode) having a first central wavelength of about 470+−40 nanometers (nm) and configured to excite a first fluorescent dye
Implementation Method 2
a first fluorescent dye having a second central wavelength of about 530+−50 nm and a second LED having a third central wavelength of about 630+−20 nm and configured to excite a second fluorescent dye having a fourth central wavelength of about 680+−50 nm
Data Source
AI summary
This invention relates to systems and methods for imaging sample materials within a microfluidic device during an assay reaction process. In accordance with certain aspects of the invention, images are formed with a pixel array and a region of interest (“ROI”) is defined within the pixel array. Image values, such as fluorescent intensity, can be computed as averages of individual pixel values within the ROI. Where the ROI is subject to non-uniform conditions, such as non-uniform heating, the ROI can be divided into sub-ROIs which are sufficiently small that the condition is uniform within the sub-ROI.