Biochip Multimode Waveguide for Low-Background Fluorescence
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Solution Overview
Problem
Existing biochip devices face challenges in real-time hybridization signal detection due to high background fluorescence from solution molecules, limiting sensitivity and dynamic range, and require precise optical coupling that is mechanically challenging.
Innovation Solution
A biochip device with a multimode waveguide using substantially non-directional coupling means and mode filter means to excite only surface-bound chromophores, reducing background fluorescence by filtering out guided modes with ineffective indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical coupling methods are used to excite the waveguide, then coupling precision can be achieved, but mechanical complexity and alignment difficulty increase significantly
Solution Approach 1:
The patent extracts the directional coupling requirement from the system by introducing substantially non-directional coupling means. This allows excitation light to be coupled into the waveguide without requiring precise angular alignment or sub-micrometer positioning, thereby eliminating complex mechanical alignment systems while maintaining effective optical coupling.
Solution Approach 2:
The patent changes the angular parameter of the incident light from highly collimated (conventional method requiring sub-micrometer precision) to a broader angular distribution (substantially non-directional). This parameter change enables coupling into multiple guided modes simultaneously, reducing sensitivity to alignment precision and simplifying the mechanical design.
2Measurement precision
If evanescent wave excitation is used to eliminate background fluorescence, then sensitivity improves, but optical coupling precision requirements become extremely stringent
Solution Approach 1:
The patent converts the harmful effect of requiring high precision coupling into a benefit by deliberately using substantially non-directional coupling means that excite multiple guided modes. This approach maintains the evanescent wave excitation mechanism for sensitivity while accepting broader angular distributions, thereby eliminating the need for extremely stringent optical coupling precision.
Solution Approach 2:
The patent introduces dynamic flexibility in the optical coupling system by using substantially non-directional coupling means. Instead of requiring static, precise alignment, the system accepts a range of incident angles and dynamically couples light into various guided modes, making the system more robust to manufacturing tolerances and easier to implement.
3Productivity
If fluorescent molecules in solution are present at high concentration, then hybridization signal can be detected, but background fluorescence increases and limits dynamic range
Solution Approach 1:
The patent segments the excitation field into multiple guided modes with different evanescent field distributions. By using substantially non-directional coupling means, the system creates a spatial segmentation where only surface-bound chromophores (in the evanescent field region) are excited, while fluorescent molecules in the bulk solution remain unexcited, thereby eliminating background fluorescence while maintaining hybridization signal detection.
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
Enhances sensitivity and dynamic range for real-time hybridization signal detection by minimizing background fluorescence and simplifying optical coupling requirements.
Implementation Method 1
a substrate constituted by at least one plate of material forming a multimode waveguide and carrying chromophore elements suitable for emitting fluorescence in response to excitation by guided waves having an evanescent portion
Implementation Method 2
excitation by guided waves having an evanescent portion
Implementation Method 3
it includes coupling means for coupling excitation light with the waveguide in the form of guided waves, the coupling means being substantially non-directional
Implementation Method 4
carrying chromophore elements suitable for emitting fluorescence in response to excitation by guided waves
Implementation Method 5
mode filter means to excite only surface-bound chromophores, reducing background fluorescence by filtering out guided modes with ineffective indices
Data Source
AI summary
A biochip device comprising a substrate constituted by at least one plate of material forming a multimode planar waveguide and carrying chromophore elements suitable for emitting fluorescence in response to excitation by guided waves having an evanescent portion, the device being characterized in that it includes coupling means for coupling excitation light with the waveguide in the form of guided waves, the coupling means being substantially non-directional.