Systems and methods for biological analysis
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Solution Overview
Problem
Existing thermal cyclers face issues with temperature gradients and heat transfer delays within the sample block, leading to inconsistent PCR yields due to irregularities in the heat sink and sample block positioning, which affect the reliability of biological analysis data.
Innovation Solution
A thermal block assembly with a sample block, heating and cooling element, and heat sink design that includes projections for secure engagement, thermally conductive materials, and temperature sensors with thermal pads to ensure uniform heat distribution and minimize delays, along with a drip pan with an ejection mechanism to facilitate easy sample holder removal and reduce spill risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If screws or clamps are used to maintain the relative positions of the sample block, heating and cooling element, and heat sink, then the device structure is simple and easy to assemble, but temperature irregularities and heat transfer delays occur due to positioning irregularities
Solution Approach 1:
The device is divided into modular components (sample block, heating/cooling element, heat sink) that can be independently manufactured and then precisely positioned using protrusions and recesses. This segmentation allows for easier manufacturing of individual parts while maintaining precise relative positioning through the engagement features.
Solution Approach 2:
Protrusions and recesses serve as intermediary positioning features between the sample block, heating/cooling element, and heat sink. These features act as mechanical mediators that ensure precise alignment and consistent thermal contact without requiring complex fastening mechanisms like screws or clamps.
2Productivity
If the sample block changes temperature quickly between set points, then the PCR cycle time is reduced and productivity increases, but temperature gradients within the sample block cause different samples to experience different temperatures
Solution Approach 1:
The heating and cooling elements are designed with multiple independent heating/cooling zones that can be controlled separately. This allows different regions of the sample block to be heated or cooled at different rates, compensating for thermal gradients and ensuring uniform temperature distribution across all sample positions during rapid temperature transitions.
Solution Approach 2:
The thermal control system is segmented into multiple independent zones within the heating and cooling elements. Each zone can be independently controlled to maintain uniform temperature across the sample block during rapid cycling, preventing temperature gradients that would otherwise occur with single-zone control.
3Loss of time
If thermal contact between the heating and cooling element and sample block is improved, then heat transfer efficiency increases and time delays are reduced, but the device complexity increases due to additional thermal interface components
Solution Approach 1:
Thermal interface material is introduced as an intermediary substance between the heating/cooling element and the sample block. This material fills microscopic gaps and irregularities in the contacting surfaces, significantly improving thermal contact and reducing heat transfer delays without requiring complex mechanical modifications to the device structure.
Solution Approach 2:
The thermal interface properties are optimized by selecting materials with specific thermal conductivity, compliance, and thickness parameters. By carefully controlling these parameters, excellent thermal contact is achieved while keeping the interface layer thin enough to minimize additional thermal resistance and maintain rapid heat transfer.
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
The solution enhances the uniformity of temperature distribution across the sample block, reduces time delays in heat transfer, and simplifies the removal of the sample holder, thereby improving the reliability and efficiency of PCR processes and minimizing data inconsistencies.
Implementation Method 1
a heating and cooling element... configured to be thermally coupled to the heating and cooling element
Implementation Method 2
a heat sink including a surface... The surface includes a plurality of projections for engaging the heating and cooling element
Implementation Method 3
a heat sink including a surface
Data Source
AI summary
A thermal block assembly for use in a biological analysis system includes a sample block, a heating and cooling element, a heat sink including a surface, the surface including a plurality of projections for engaging the heating and cooling element to hold the heating and cooling element on the heat sink. A thermal block assembly for use in a biological analysis system includes a heating and cooling element, a sample block including a lower surface configured to be thermally coupled to the heating and cooling element, one or more temperature sensors configured to extend through the one or more slots of the lower surface of the sample block, and one or more thermal pads between the one or more temperature sensors and heating and cooling element.