Silane-Based Monolayer for Oxide Surface Stability
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Solution Overview
Problem
Existing self-assembled monolayers (SAMs) on oxide surfaces are not robust enough to withstand harsh conditions and non-specific binding issues in waveguide-based assays, limiting their effectiveness in bio-sensing applications.
Innovation Solution
Development of a composite material with a monolayer on an oxide surface using trifunctional alkyl/alkenyl/alkynyl silane groups as spacer units and functional moieties for recognition ligands and terminal groups to minimize non-specific binding, providing stability and resistance to bio-fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If phospholipid bilayer membranes are used on oxide surfaces, then non-specific binding resistance is improved, but robustness and durability under harsh conditions deteriorates
Solution Approach 1:
The patent creates a composite structure by covalently attaching PEGylated alkylthiol molecules to an oxide surface through silane chemistry. This composite material combines the non-specific binding resistance of PEG chains with the robustness of covalent bonding to the oxide substrate, resolving the contradiction between membrane-like anti-fouling properties and durability under harsh conditions.
Solution Approach 2:
The patent introduces a silane-based intermediary layer that bridges the oxide surface and the PEGylated alkylthiol molecules. This intermediary enables covalent attachment of the PEG chains to the oxide surface, creating a stable hybrid structure that maintains both the protective properties of PEG and the robustness of covalent bonding.
2Object-affected harmful factors
If PEG-terminated alkylthiols are used on metal surfaces, then non-specific binding resistance is improved, but applicability to oxide surfaces deteriorates
Solution Approach 1:
The patent employs a silane-based intermediary that enables PEGylated alkylthiol molecules to be covalently attached to oxide surfaces. This intermediary adapts the metal-surface-compatible PEGylated alkylthiol chemistry to oxide surfaces, maintaining non-specific binding resistance while expanding applicability to oxide substrates.
Solution Approach 2:
The patent modifies the chemical parameters of the alkylthiol molecules by introducing PEG chains with specific lengths and ratios. By controlling the PEG chain length (e.g., PEG4, PEG8) and their proportion relative to the alkyl chain, the patent optimizes both non-specific binding resistance and compatibility with oxide surfaces.
3Ease of manufacture
If short attachment group SAMs are used, then ease of attachment to oxide surface is improved, but non-specific binding resistance in waveguide assays deteriorates
Solution Approach 1:
The patent systematically varies the parameters of the PEG chains, including their length (PEG4, PEG8, etc.) and the ratio of PEGylated to non-PEGylated alkylthiol molecules. By optimizing these parameters, the patent achieves both easy attachment to oxide surfaces and effective non-specific binding resistance in waveguide assay conditions.
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 new SAMs exhibit low non-specific binding and high stability, comparable to lipid bilayer membranes, allowing for reusable surfaces and improved bio-sensing capabilities, including detection of target species like Bacillus anthracis protective antigen with reduced background noise.
Implementation Method 1
a monolayer thereon the oxide surface, the monolayer including a first species of the formula X-Q-Z1 where X includes a silicon atom from a trifunctional alkyl/alkenyl/alkynyl silane group for attachment to the oxide surface, Q represents a central portion of the trifunctional alkyl/alkenyl/alkynyl silane group and serves as a spacer group of an alkane, or a combination of an alkane and one or more of an alkene or an alkyne group having greater than about 3 carbons, the spacer group promoting self assembly of a plurality of the species
Implementation Method 2
The advantages of their films include dense packing due to the hydrophobic interactions of the alkyl chains, as well as the hydrophilicity of the terminal polyethylene glycol units
Implementation Method 3
the hydrophilicity of the terminal polyethylene glycol units
Data Source
AI summary
The present invention provides a composite material including a substrate having an oxide surface, and, a continuous monolayer on the oxide surface, the monolayer including a silicon atom from a trifunctional alkyl/alkenyl/alkynyl silane group that attaches to the oxide surface, an alkyl/alkenyl/alkynyl portion of at least three carbon atoms, a polyalkylene glycol spacer group, and either a reactive site (e.g., a recognition ligand) or a site resistant to non-specific binding (e.g., a methoxy or the like) at the terminus of each modified SAM. The present invention further provides a sensor element, a sensor array and a method of sensing, each employing the composite material. Patterning is also provided together with backfilling to minimize non-specific binding.