Fluorescence Biochip Sensor Reuse via Index Matching
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Solution Overview
Problem
Current fluorescence biochip detection methods suffer from significant light loss due to chromophores emitting towards a higher refractive index medium, limiting collection efficiency, and existing solutions are costly as they require new sensors for each analysis.
Innovation Solution
A method and device that utilize a substrate partially transparent to emission wavelengths, with a filter to reject excitation wavelengths and ensure index continuity between the substrate and sensor, allowing for efficient light capture and reuse of the sensor for subsequent analyses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If chromophores are placed at the glass-air interface to emit light, then emission intensity towards air increases, but light collection efficiency decreases because approximately 80% of light emission is lost in the glass slide
Solution Approach 1:
A coupling medium with refractive index matching the glass substrate is introduced between the chromophores and the sensor. This intermediary eliminates the glass-air interface, allowing light to pass from the glass into the coupling medium without total internal reflection, thereby capturing light that would otherwise be lost and improving collection efficiency to approximately 70-80%.
Solution Approach 2:
The refractive index parameter of the medium between the substrate and sensor is changed from air (n≈1.0) to a coupling medium matching the glass refractive index (n≈1.5). This parameter change eliminates the optical impedance mismatch, allowing efficient light transmission and resolving the contradiction between emission intensity and collection efficiency.
2Device complexity
If optics with limited numerical aperture are used to collect light, then device complexity is reduced, but light collection efficiency is limited to a few percent
Solution Approach 1:
The coupling medium acts as an intermediary that redirects light emitted at high angles (which would normally be lost due to limited numerical aperture) back into the sensor. By eliminating total internal reflection at the glass-air interface, the system can collect light over a wider angular range without requiring complex high-NA optics.
Solution Approach 2:
Instead of trying to capture light with complex high-NA optics, the invention inverts the approach by modifying the interface itself to allow light to escape into the sensor medium. This simple interface modification achieves high collection efficiency without increasing optical system complexity.
3Loss of energy
If the sensor is used as the substrate to capture light directly, then light collection efficiency improves, but cost increases because each analysis requires a new sensor
Solution Approach 1:
The system is segmented into two separate components: a reusable sensor and a disposable substrate with chromophores. The substrate is separated from the sensor after each analysis, allowing the expensive sensor to be reused while only the inexpensive substrate is discarded. This resolves the contradiction by achieving high collection efficiency through the coupling medium while maintaining cost-effectiveness through component separation.
Solution Approach 2:
The substrate containing the chromophores is discarded after single use, while the sensor is recovered and reused for subsequent analyses. This approach maintains high light collection efficiency while minimizing cost by replacing only the inexpensive substrate rather than the expensive sensor.
4Measurement precision
If a filter is interposed between the substrate and sensor to reject excitation wavelength, then measurement precision improves by separating excitation and emission, but device complexity increases
Solution Approach 1:
The coupling medium serves as an additional intermediary layer that, combined with the optical filter, enhances the separation between excitation and emission wavelengths. The filter is integrated into the optical path between substrate and sensor, providing precise wavelength discrimination while maintaining a relatively simple overall device structure.
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 enhances light collection efficiency and reduces costs by allowing the sensor to be reused, enabling effective imaging and detection of fluorescence with improved fidelity and resolution.
Implementation Method 1
interposing between the chromophores and the sensor a filter for rejecting the excitation wavelength, this filter being transparent at the emission wavelength
Implementation Method 2
detecting the fluorescence emitted by chromophores attached to a substrate of the biochip, and more precisely for imaging and detecting the fluorescence emitted by chromophores
Implementation Method 3
using a substrate at least partially transparent to the emission wavelength of the chromophores
Implementation Method 4
ensuring at least partial index continuity between the substrate and the sensor
Data Source
Figure 1~8
AI summary
The invention relates to an imaging method and device for detecting fluorescence from a biochip, by illuminating chromophores associated with probes (14) of a substrate (12) placed on a sensor (10) having photodetectors of the CCD or CMOS type for example, a filter for rejecting the chromophore excitation light being provided between the probes (14) and the sensor. According to the invention, the substrate (12) can be removed from the sensor (10) after use so as to allow the sensor to be reused.