Micro-fluidic Device Thermal Segmentation for POCT
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Solution Overview
Problem
Existing micro-fluidic systems for Point of Care Testing face challenges in miniaturizing heating and cooling solutions, leading to bulky designs that are not cost-effective for small form factor applications, especially at sensitive bio-diagnostic temperatures and photon counting sensitivities.
Innovation Solution
Integration of a photodetector circuit with both heating and cooling elements, such as a Peltier cooler, within a single micro-fluidic device, where the heating element is thermally conductive to the detection chamber and the cooling element is thermally conductive to the photodetector, allowing for precise temperature control and reduced noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If separate heating or cooling elements are used in a bulky manner, then temperature control capability is improved, but device size and cost increase making it unsuitable for miniaturized POCT applications
Solution Approach 1:
The patent combines both heating and cooling functionality into a single integrated micro-fluidic device. The heating element (resistive heater) and cooling element (Peltier cooler) are integrated on the same substrate, allowing simultaneous or independent operation to achieve precise temperature control while minimizing device size and complexity
Solution Approach 2:
The micro-fluidic device is designed to perform multiple functions: temperature control (both heating and cooling), fluid transport, and detection. The integrated design allows the same device structure to serve both thermal regulation purposes and analytical measurement, reducing overall system complexity
2Measurement precision
If the photodetector is cooled to reduce noise, then measurement sensitivity is improved, but the micro-fluidic sample temperature may be affected
Solution Approach 1:
The device is segmented into distinct thermal zones: the photodetector area is cooled by the Peltier element to reduce noise, while the micro-fluidic chamber area is heated by the resistive heater to maintain sample temperature. This spatial segmentation allows independent temperature control of different functional regions
Solution Approach 2:
Different parts of the device have different thermal characteristics optimized for their specific functions. The photodetector region is designed to be cooled for low-noise operation, while the micro-fluidic chamber is designed to be heated for proper sample reaction conditions. Each region's thermal properties are locally optimized
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
Enables ultra-sensitive measurements at elevated temperatures like 37°C while maintaining low noise levels, facilitating cost-effective, miniaturized, and disposable Point of Care Testing solutions without affecting the micro-fluidic sample temperature.
Implementation Method 1
Cooling of the photon counting sensor may be achieved by dedicated cooling elements. For example, cooling of a sense SPAD to around −30° C. will enable about two orders lower noise count compared to room temperature.
Implementation Method 2
A defined temperature may be achieved by heaters.
Data Source
AI summary
A micro-fluidic device includes an integrated photodetector circuit. The integrated photodetector circuit includes at least one photodetector. The micro-fluidic device also includes a micro-fluidic cartridge. The micro-fluidic cartridge includes at least one detection chamber connected to a micro-channel to receive a liquid to be tested. The micro-fluidic cartridge is arranged on the integrated photodetector circuit such that the at least one detection chamber is aligned with the photodetector. The micro-fluidic device further includes a heating element thermally conductive to the detection chamber and operable to alter a temperature of the liquid to be tested. The micro-fluidic device additionally includes a cooling element thermally conductive to the photodetector and operable to alter a temperature of the photodetector.