Nanohole Array Sensor for Colorimetric DNA Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nanoscale sensors for detecting DNA bases, antigen-antibody interactions, and pathogens face challenges due to limited sensitivity, requiring complex and costly equipment for wavelength shifting measurements, and struggle with random particle sizes and positions, leading to inconsistent results.
Innovation Solution
A sensor with a large-area high-density array of nanoscale Lycurgus cups or nanoholes, featuring a thin metal film and nanoparticles on the sidewalls, allowing for colorimetric sensing observable with the naked eye, offering unprecedented sensitivity and integration with microfluidic devices for biochemical detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LSPR sensors use colloidal plasmonic particles, then sensitivity is improved, but particle size and position become random and difficult to control
Solution Approach 1:
The patent segments the plasmonic structure into a periodic array of nanoholes rather than using random colloidal particles. This segmentation into ordered units allows precise control of size and position while maintaining the plasmonic resonance properties needed for sensitivity.
Solution Approach 2:
The patent applies local quality by creating uniform nanoholes with specific dimensions (e.g., 200 nm diameter, 500 nm depth) at regular intervals across the substrate. Each nanohole has controlled local properties that collectively provide both precision and sensitivity.
2Measurement precision
If EOT substrates use sub-wavelength holes in optically thick metal surfaces, then high sensitivity is achieved, but fabrication becomes expensive and time consuming
Solution Approach 1:
The patent employs inexpensive fabrication techniques such as nanosphere lithography and standard thin-film deposition that can produce large areas of nanohole arrays rapidly. This replaces expensive electron beam lithography and focused ion beam milling, making the sensor economically viable for widespread use.
Solution Approach 2:
The patent optimizes key parameters including nanohole diameter (200 nm), depth (500 nm), and center-to-center spacing (350 nm) to achieve high sensitivity while enabling scalable fabrication. These parameter choices balance performance with manufacturability.
3Measurement precision
If SPR sensors use Kretschmann configuration, then sensitivity is improved, but specialized high precision equipment is required
Solution Approach 1:
The patent replaces the complex mechanical and optical alignment requirements of Kretschmann SPR (which requires precise angle tuning and prism coupling) with a straightforward normal-incidence transmission measurement through nanoholes. This substitution eliminates the need for specialized equipment while maintaining high sensitivity through plasmonic resonance.
Solution Approach 2:
The patent creates a simplified copy of the SPR measurement principle using nanohole transmission instead of prism-based evanescent wave coupling. The essential plasmonic resonance phenomenon is preserved, but the measurement geometry is copied into a simpler, more accessible configuration that uses standard microscopy equipment.
4Measurement precision
If LSPR sensors use colloidal particles, then sensitivity is improved, but complex image analysis is required to extract usable data
Solution Approach 1:
The patent exploits the fact that plasmonic resonance in the nanohole array produces distinct color changes in the transmitted light that are directly observable and correlate with analyte concentration. This colorimetric output can be captured by standard cameras and analyzed using simple image processing, eliminating the need for complex spectral analysis of scattered light from individual particles.
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 sensor achieves 100 times better sensitivity than existing nanoplasmonic devices, enabling accurate DNA hybridization detection, protein-protein interaction analysis, and pathogen detection, even in resource-poor settings, without the need for high-precision spectrometers, using visible color photography for results.
Implementation Method 1
surface plasmon resonance ('SPR') based devices are increasingly being used for detecting DNA bases
Implementation Method 2
Localized surface plasmon resonance ('LSPR') sensors, based on colloidal plasmonic particles
Implementation Method 3
the resonance peak wavelength shift ('PWS') for most of the sensors known in the art is on the order of only a few nanometers
Implementation Method 4
Another known method to obtain high sensitivity plasmonic resonance is to make sub-wavelength holes in optically thick metal surfaces, commonly referred to as extraordinary optical transmission ('EOT') substrates
Data Source
AI summary
Apparatus and methods are disclosed that are configured to permit nanoplasmonic spectroscopy sensing in the form of colorimetric sensing. An example apparatus involves: (a) an array layer having a top surface and a bottom surface, wherein a plurality of nanoholes are defined in the top surface of the array layer, wherein the plurality of nanoholes each have at least one sidewall surface and a bottom surface, (b) a thin metal film disposed on the top surface of the array layer and on the bottom surface of each of the plurality of nanoholes, and (c) a plurality of nanoparticles disposed on the at least one sidewall surface of the plurality of nanoholes.