Double Nanohole Plasmonic Trap for Single Protein Manipulation
Solution Overview
Problem
Current methods for trapping and manipulating smaller biological and nanoparticles are challenging due to increased difficulty in trapping nonresonant dielectric particles as size decreases, often requiring tethering and introducing steric hindrance and experimental complexity.
Innovation Solution
A double-hole setup using a double nanohole assembly with a plasmonic layer, where the optical radiation source irradiates the nanohole assembly, and an optical system detects changes in optical power to identify trapping states, allowing for the direct manipulation of nanoparticles without tethering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional perturbative optical trapping is used to trap smaller particles, then trapping capability is achieved, but the laser power needed scales with the inverse fourth power of particle size, making it impractical for nanoparticles
Solution Approach 1:
The patent changes the optical parameters by using a dual-aperture configuration that creates a localized intensity maximum between the holes. This transforms the trapping mechanism from relying on high overall power to utilizing concentrated local field enhancement, enabling nanoparticle trapping with much lower laser powers
Solution Approach 2:
The optical trap is segmented into two separate apertures (holes) in the metal film. This segmentation creates a specific field distribution pattern with a intensity maximum between the holes, allowing efficient trapping of nanoparticles without requiring high overall laser power
2Measurement precision
If tethering methods are used to trap smaller particles, then trapping is achieved, but steric hindrance and hydrodynamic effects are introduced
Solution Approach 1:
The patent extracts the tethering element from the system entirely. By using direct optical trapping through the dual-aperture configuration, particles are trapped without any physical tethers or linkers, eliminating steric hindrance and hydrodynamic effects that would otherwise interfere with particle behavior
Solution Approach 2:
The mechanical tethering system is replaced with an optical trapping system. Instead of using physical linkers to attach particles to substrates, the patent uses localized optical fields to directly manipulate and trap particles, eliminating mechanical constraints
3Measurement precision
If tethering methods are used to trap smaller particles, then trapping is achieved, but experimental complexity increases due to the need for binding
Solution Approach 1:
The patent removes the complex binding and tethering requirements from the experimental setup. Direct optical trapping through the dual-aperture structure eliminates the need for surface functionalization, antibody attachment, or other complex biochemical procedures
Solution Approach 2:
Complex mechanical and biochemical tethering systems are replaced with a simple optical trapping mechanism. The dual-aperture metal film structure creates the trap through its geometric configuration alone, requiring no additional components or procedures
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
Enables sensitive trapping and sensing of single particles, including proteins and nanoparticles, with reversible trapping and high signal-to-noise ratio, capable of unfolding proteins and detecting interactions at the single molecule level.
Implementation Method 1
optical trapping, which uses the momentum change of light scattering to impart forces on small objects
Implementation Method 2
uses the momentum change of light scattering to impart forces on small objects
Implementation Method 3
double nanohole assembly includes two nanoholes defined in a plasmonic layer
Data Source
AI summary
Molecules or particle having a hydrodynamic radius as small as 3.5 nm can be trapped using a double-nanohole structure defined in a metal film or other metallic layer. Application of a suitable optical radiation flux to the double-nanohole structure can provide a folding and/or binding of protein molecules that can be identified based on changes in optical transmission. Varying nanohole transmissions can thus be associated with trapping, binding and unfolding of biological particles. The double-nanohole defines cusps, but such cusps can be defined in other ways as well.