NTA Linkers with SAM Anchoring for Stable SPR/LSPR Protein Binding
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Solution Overview
Problem
Current SPR and LSPR technologies face challenges in achieving stable and efficient immobilization of proteins on sensor surfaces, with issues such as slow dissociation of immobilized components and idiosyncratic drift in flow cells, which affect the reliability and accuracy of protein-protein interaction analysis.
Innovation Solution
The development of nitrilotriacetic acid (NTA) linkers with customizable spacers and attachment sites, allowing for robust and stable immobilization of proteins on SPR and LSPR sensors, using a method that includes a substrate coated with a metal layer and NTA linkers to bind ligands and analytes, enhancing the detection of molecular binding events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If NTA sensor chips are used for protein immobilization, then immobilization stability is improved, but slow and continuous dissociation of immobilized components occurs
Solution Approach 1:
The patent introduces a self-assembled monolayer (SAM) composed of thiol-containing groups attached to the gold surface as an intermediary layer. This SAM acts as a mediator between the gold surface and the NTA-protein complex, providing a stable platform that prevents continuous dissociation while maintaining immobilization stability. The alkane groups in the SAM extend away from the gold surface to provide appropriate spacing and orientation for the NTA groups.
2Adaptability or versatility
If commercial NTA sensor chips are used, then repeated immobilization and regeneration are enabled, but idiosyncratic drift of flow cells occurs
Solution Approach 1:
The patent segments the sensor chip surface into distinct functional layers: a self-assembled monolayer (SAM) layer for stable anchoring, and a NTA-functionalized layer for protein binding. This segmentation allows the SAM layer to provide a stable, drift-free reference surface while the NTA layer performs the intended protein immobilization and regeneration cycles, thereby eliminating flow cell drift issues.
3Stability of the object's composition
If direct covalent coupling using amino groups is used for protein immobilization, then stable surface is achieved, but high binding capacity is compromised
Solution Approach 1:
The patent applies local quality by creating a surface with heterogeneous functional groups: the SAM layer provides stable anchoring at the gold surface interface, while the NTA groups at the distal end of the alkane chains provide high-capacity histidine tag binding. This spatial differentiation of functional qualities allows simultaneous achievement of surface stability and high binding capacity.
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 NTA linkers provide a stable and efficient method for protein immobilization, reducing non-specific binding and improving the signal-to-noise ratio in SPR and LSPR analysis, thereby enhancing the accuracy and reliability of protein-protein interaction studies.
Implementation Method 1
Ni2+ immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support
Implementation Method 2
a self-assembled monolayer (SAM) composed of a thiol containing group attached to the gold surface
Data Source
AI summary
Described are devices, compounds and methods for detecting an analyte in a sample. More particularly this disclosure provides SPR and LSPR sensors modified by NTA linkers for binding a ligand and/or analyte. The NTA linkers of the disclosure typically include a head (or “anchoring site”) for coupling to a surface of the SPR or LSPR sensor, a spacer, and one or more attachment sites on a distal end or ends of the spacer which couple to a ligand. The head may include a thiol for coupling the linker to a surface of the SPR or LSPR sensor. The spacer may be a carbon chain. PAG or PEG chain, or matrix material. The one or more attachment sites may be a nitrilotriacetic acid (NTA) moiety capable of chelating a transition metal ion and binding the ligand.