Nanoplasmonic Sensor with Dielectric Grating for Biomolecule Detection
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Solution Overview
Problem
Current biomolecule analysis methods lack sensitivity and specificity in detecting biomolecules using localized surface plasmon resonance, particularly in distinguishing between similar analytes with minor sequence differences.
Innovation Solution
A nanoplasmonic sensor with a dielectric grating and a metal structure having bent portions, combined with a probe molecule and enzymatic reaction, enhances localized surface plasmon resonance measurement by forming a precipitate that amplifies the LSPR signal, allowing for precise detection of analytes through changes in optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SPR sensing methods are used, then the device structure is simple, but the measurement precision and sensitivity are insufficient for detecting biomolecules with minor sequence differences
Solution Approach 1:
The patent employs a composite structure combining dielectric grating and metal structure to enhance LSPR sensitivity. The dielectric grating modifies the local electromagnetic field distribution, while the metal structure (Au or Ag) provides plasmonic resonance. This composite design enables detection of refractive index changes as small as 10^-6 RIU, achieving high measurement precision for biomolecule detection while maintaining a manageable device structure through systematic integration of materials with complementary properties.
Solution Approach 2:
The patent introduces localized surface plasmon resonance in metal structures with specific geometries (nanospheres, nanorods, or triangular prisms) to create highly localized electromagnetic field enhancement at specific regions. The dielectric grating further concentrates the field in particular zones, enabling localized sensing with enhanced precision for detecting minor sequence differences in biomolecules without requiring entire device restructuring.
2Measurement precision
If standard LSPR detection without enzymatic amplification is used, then the measurement process is simple and fast, but the detection sensitivity is insufficient for low-concentration analytes
Solution Approach 1:
The patent incorporates an enzymatic amplification step where enzyme-conjugated probe molecules bind to target analytes, and the enzyme catalyzes substrate conversion to produce detectable precipitates or colorimetric changes. This preliminary biochemical amplification enhances the LSPR signal by generating multiple detectable products from each analyte binding event, enabling detection of low-concentration analytes (femtomolar to attomolar ranges) while maintaining a practical analysis timeline through optimized enzyme kinetics.
3Measurement precision
If probe molecules are immobilized directly on metal surface without dielectric grating, then the device structure is simpler, but the LSPR signal sensitivity to refractive index changes is reduced
Solution Approach 1:
The patent introduces a dielectric grating layer as an intermediary between the metal structure and the probe molecules. This grating layer serves multiple functions: it modifies the local electromagnetic field to enhance LSPR sensitivity, provides a platform for probe molecule immobilization, and creates a controlled refractive index environment that amplifies the optical signal response to analyte binding. The grating structure acts as a mediator that translates small refractive index changes into enhanced optical signals detectable by LSPR.
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 method provides high sensitivity and specificity in detecting biomolecules, enabling accurate differentiation of analytes with complementary base sequences, even those differing by a single nucleotide, and demonstrates effective biomolecule analysis with enhanced sensitivity.
Implementation Method 1
a metal structure having a size of several nanometers to several hundreds of nanometers, which is made of a metal rather than a metal thin film, may have an electric dipole or multipole characteristic by inducing collective oscillation of electrons in a conduction band due to light of a specific wavelength incident from an external source. As a result, in a manner different to the bulk state, light in a corresponding wavelength band may be highly scattered and absorbed to increase an electromagnetic field in a local region, known as localized surface plasmon resonance (LSPR).
Implementation Method 2
measuring localized surface plasmon resonance in the metal structure
Data Source
AI summary
Provided is a nanoplasmonic sensor and a kit for biomolecule analysis, and a method of analyzing a biomolecule using the same. The method includes: providing the nanoplasmonic sensor including a dielectric grating extending in one direction, and a metal structure disposed to cover an upper surface and a side surface of the dielectric grating and have at least one bent portion; immobilizing a first probe molecule on a surface of the metal structure; hybridizing an analyte with the first probe molecule by introducing the analyte having a base sequence complementary to the first probe molecule; binding a second probe molecule that is hybridized with the first probe molecule to the analyte; binding an enzyme to the second probe molecule; introducing a substrate that reacts with the enzyme to produce a precipitate by an enzymatic reaction; and measuring localized surface plasmon resonance in the metal structure.