Nanowire Photodetectors for High-Resolution Biomolecule Detection
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Solution Overview
Problem
Current biomolecule detection technologies face limitations in spatial resolution, sensitivity, and environmental sensitivity, particularly in DNA sequencing applications, where high spatial pitch and limited sensitivity of matrix photodetectors and DNA sequencers lead to inefficiencies and detection errors.
Innovation Solution
A device comprising a substrate with nanowires extending between electrodes, an encapsulation layer, and a functionalization surface with biological detection probes, allowing for selective capture and optical detection of biomolecules through fluorescence changes, with nanowires acting as nanophotodetectors to generate electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If matrix photodetectors with spatial pitch greater than 1 μm are used, then device complexity is reduced, but measurement precision deteriorates due to insufficient spatial resolution for high-density parallel detection
Solution Approach 1:
The detection device is segmented into multiple independent nanowire photodetectors arranged in parallel, each capable of independent detection. This segmentation allows high spatial resolution across the array while keeping each individual nanowire detector relatively simple in structure, resolving the contradiction between overall device complexity and measurement precision.
Solution Approach 2:
The patent transitions from planar photodetector arrays to three-dimensional nanowire structures extending vertically between electrodes. This dimensional change enables higher detection density and spatial resolution without proportionally increasing planar device complexity, as detections occur along the vertical nanowire axis rather than requiring dense two-dimensional pixel packing.
2Ease of manufacture
If conventional photodetectors are used, then ease of manufacture is improved, but sensitivity deteriorates due to insufficient sensitivity for sequence detection after small number of amplifications
Solution Approach 1:
The patent changes the physical parameters of the photodetector by reducing its dimensions to the nanoscale and utilizing quantum-confined structures. These parameter changes dramatically increase the surface-to-volume ratio and quantum efficiency, enabling single-molecule detection sensitivity while maintaining compatibility with standard semiconductor fabrication processes for ease of manufacture.
3Measurement precision
If field-effect transistors are used for biomolecule detection, then sensitivity is improved, but reliability deteriorates due to sensitivity to environmental parameters such as pH, temperature, and interactions with non-target biomolecules
Solution Approach 1:
The patent introduces an interface layer as an intermediary between the nanowire photodetector and the sample environment. This interface layer protects the sensitive nanowire from direct exposure to pH, temperature fluctuations, and non-target biomolecules, while still allowing optical signals to pass through for detection. This resolves the contradiction by maintaining sensitivity to target biomolecules while providing robustness against environmental interference.
4Productivity
If DNA sequencers based on nanopores are used, then productivity is improved through rapid detection, but reliability deteriorates due to sensitivity to environmental parameters and need for redundancy
Solution Approach 1:
The patent replaces the mechanical nanopore-based detection system with an optical detection system using nanowire photodetectors. This substitution maintains rapid detection capability through optical signal transduction while eliminating the mechanical system's vulnerability to environmental parameters, thereby improving reliability without sacrificing productivity.
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 enables sensitive, parallel, and robust detection of biomolecules with reduced environmental sensitivity, allowing for faster and more accurate analysis, including DNA sequencing, with improved spatial resolution and reduced need for redundancy.
Implementation Method 1
each nanowire forms a nanophotodetector of light emitted at the functionalization surface, the light detected by each nanowire inducing an electrical detection signal in the detection circuit
Implementation Method 2
the fluorescent marker being capable of emitting a fluorescence light, in the detection spectral band, when it is illuminated by the excitation light
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2C
AI summary
The invention is a device for detecting at least one target biomolecule. The device comprises a substrate 10 having a first electrode 11, a multilayer structure 20 having a second electrode 21, and nanowires 30 extending between the first and second electrodes. Each nanowire has a homojunction, heterojunction, or Schottky junction between the first and second electrodes. The multilayer structure extends between the nanowires and a sample 2 capable of containing a target biomolecule 4. The multilayer structure has a functionalization surface 25 in contact with the sample. When light is emitted at the functionalization surface, for example, fluorescence light, at least one nanowire 30 enables light detection. The fluorescence light can indicate the presence or absence of a target biomolecule 4 on the functionalization surface 25.