SPR Microarray Substrate Oxidation Resistance
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Solution Overview
Problem
Gold-coated glass slides used in surface plasmon resonance (SPR) detection for DNA analysis are prone to delamination when exposed to corrosive oxidizers during DNA printing processes, as Au—S bonds are vulnerable to aggressive oxidizers, necessitating a substrate that can withstand strong oxidizers.
Innovation Solution
A substrate with a first metal film (e.g., gold, silver, or copper) and a second thin metal film (e.g., Ti, Zr, Al, Cr, Hf, V, Ta, W, or Pb) where a reactive organosilane is covalently bonded to the second thin metal film through metal-oxygen-silicon bonds, allowing for chemical stability and extension of evanescent plasmon waves, enabling the use of aggressive oxidizers and monitoring of biomolecule interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold coated glass slides are used for SPR detection, then DNA analysis capability is provided, but the gold surface delaminates when exposed to corrosive oxidizers during DNA printing
Solution Approach 1:
A second thin metal film (Ti, Zr, Al, Cr, Hf, V, Ta, W, or Pb) is introduced as an intermediary layer between the gold first metal film and the organosilane. This intermediate metal film forms a protective interface that prevents direct contact between the gold and corrosive oxidizers, while still allowing the organosilane to bond through metal-oxygen-silicon bonds to the second metal film surface.
Solution Approach 2:
The invention creates a composite structure consisting of multiple metal films (gold + second metal) combined with organosilane molecules. This composite material system combines the SPR-generating capability of gold with the oxidation resistance and bonding capability of the second metal film and organosilane, achieving both stability and chemical resistance.
2Adaptability or versatility
If thiol chemistry is used to modify the gold surface, then DNA binding capability is achieved, but the Au-S bonds are vulnerable to aggressive oxidizers
Solution Approach 1:
The second thin metal film and organosilane combination serves as an intermediary between the gold surface and DNA molecules. Instead of DNA binding directly to gold through vulnerable Au-S bonds, the organosilane provides stable bonding to the second metal film, and DNA binds to the organosilane functional groups, creating a more oxidation-resistant bonding pathway.
Solution Approach 2:
The invention changes the chemical bonding parameters by transitioning from direct Au-S bonds to metal-oxygen-silicon bonds between the second metal film and organosilane. This parameter change in bond type and composition provides resistance to oxidative degradation while maintaining DNA binding functionality through the organosilane-DNA interaction.
3Object-affected harmful factors
If a second thin metal film is added to protect against oxidizers, then resistance to corrosive oxidizers is improved, but the device complexity increases
Solution Approach 1:
The second metal film is applied locally and selectively to specific regions or the entire surface where oxidation protection is needed, rather than uniformly modifying the entire device. This localized application minimizes the impact on overall device complexity while providing targeted protection where it is most needed.
Solution Approach 2:
The second metal film is deposited as an extremely thin layer (thin enough to allow plasmon wave extension), changing the thickness parameter to a value that provides protection without significantly increasing material usage or processing complexity. The thinness parameter allows the layer to be nearly transparent to the plasmon field while still providing chemical protection.
4Measurement precision
If the second thin metal film is made thin enough to allow plasmon wave extension, then SPR detection capability is maintained, but the protective function may be compromised
Solution Approach 1:
The second metal film thickness is optimized to provide just enough protection while maintaining plasmon wave extension. The thickness is not made excessively thick (which would block plasmons) but is sufficient to provide the necessary chemical barrier function, representing a balanced partial action that satisfies both requirements.
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 solution allows for the use of aggressive oxidizers in DNA printing processes while maintaining the stability of the gold surface, enabling effective monitoring of chemical interactions with DNA, RNA, or proteins through surface plasmon resonance methods.
Implementation Method 1
the first metal film can generate surface plasmons and the upper surface of the second thin metal film is used to form chemically stable bonds to the reactive organosilane
Implementation Method 2
The second thin metal film is sufficiently thin so as to allow extension of an evanescent plasmon wave from said first metal film
Implementation Method 3
a reactive organosilane covalently bonded to the second surface of the second thin metal film through metal-oxygen-silicon bonds
Implementation Method 4
converting the upper surface of the second thin metal film to the corresponding metal oxide; and reacting a functionalized organosilane with the metal oxide
Data Source
AI summary
An article, process, and method for surface plasmon resonance plates are described. A substrate is covered with a thin metal film onto which a second thin metal film is deposited. The surface of the second thin metal film is converted to the metal oxide which is used to covalently bond organosilanes to the surface. Reactive organosilanes containing terminal bonding groups are arranged in a plurality of spots that are surrounded by inert organosilanes. Biomolecule attachment to the binding group is detected or measured from surface plasmon signals from the first thin metal film.