MOEMS Microchannel Microwave Heating for Rapid Sample Processing
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Solution Overview
Problem
Current microfluidic systems face inefficiencies in heating chemical reactor volumes within channels, as they also heat the entire substrate, leading to prolonged cooling times and increased processing times for reactions like PCR and immunoassay analysis.
Innovation Solution
The method employs microwave absorption using a low-power Co-planar waveguide or microwave transmission line to instantaneously heat aqueous samples within microchannel flow channels on a micro-optical-electro-mechanical system (MOEMS) device, where the microwaves pass through non-heating wall sections and carrier fluids, allowing for efficient energy deposition directly to the samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heating methods (joule-heating from trace resistors) are used to heat chemical reactor volumes in microfluidic channels, then the substrate and carrier fluid are also heated, but this causes prolonged cooling times and increased processing times
Solution Approach 1:
The invention segments the heating function by introducing microwave radiation that selectively heats only the aqueous sample partitions within the microfluidic channel, while the substrate and carrier fluid remain unheated. This spatial segmentation of thermal energy deposition resolves the contradiction by achieving rapid heating of the target volume without unnecessarily heating surrounding materials that would require cooling.
Solution Approach 2:
The microwave heating method applies local quality by concentrating thermal energy exclusively in the aqueous sample regions where it is needed for chemical reactions. The substrate and carrier fluid maintain their original thermal properties and do not accumulate heat, eliminating the cooling bottleneck that plagues conventional heating methods.
2Temperature
If conventional heating methods are used, then the entire substrate is heated, but this leads to heat accumulation and much longer cooling periods
Solution Approach 1:
The invention extracts the heating function from the substrate and applies it directly to the aqueous sample partitions through microwave radiation. By taking out the heating action from the substrate context and applying it selectively to the sample, the system achieves rapid thermal energy deposition without the penalty of heating the entire substrate mass that would require prolonged cooling.
Solution Approach 2:
Microwave radiation serves as an intermediary energy delivery mechanism that passes through the substrate and carrier fluid to deposit thermal energy directly into the aqueous sample partitions. This intermediary approach enables precise spatial control of heating, improving processing speed by avoiding heat accumulation in the substrate.
3Loss of time
If microwave heating is used, then energy is deposited directly into aqueous samples, but the substrate and carrier fluid are not heated
Solution Approach 1:
The invention converts the typically problematic property of water's strong microwave absorption into a beneficial feature. The high dielectric loss of aqueous samples, which would normally cause heating of surrounding materials, is instead exploited to achieve selective and efficient energy deposition directly into the sample partitions, dramatically reducing processing time.
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 significantly reduces processing times by an order of magnitude, minimizing substrate heating and enabling real-time processing for applications such as bacterial, viral, and chemical detection, as well as on-chip synthesis of chemical complexes and nanoparticles.
Implementation Method 1
The present invention provides a method of near-instantaneous thermal energy deposition into the aqueous chemical reactor partitions or streams utilizing microwave absorption of energy from a coincident low power Co-planar waveguide (CPW) or microwave transmission line.
Implementation Method 2
Microwave heating of aqueous solutions exhibits excellent energy deposition due to the polarization of the water molecules.
Implementation Method 3
The microchannel flow channel has a wall section that receives the microwaves and enables the microwaves to pass through wall section of the microchannel flow channel without being appreciably heated by the microwaves.
Data Source
AI summary
Apparatus for heating a sample includes a microchip; a microchannel flow channel in the microchip, the microchannel flow channel containing the sample; a microwave source that directs microwaves onto the sample for heating the sample; a wall section of the microchannel flow channel that receives the microwaves and enables the microwaves to pass through wall section of the microchannel flow channel, the wall section the microchannel flow channel being made of a material that is not appreciably heated by the microwaves; a carrier fluid within the microchannel flow channel for moving the sample in the microchannel flow channel, the carrier fluid being made of a material that is not appreciably heated by the microwaves; wherein the microwaves pass through wall section of the microchannel flow channel and heat the sample.