Dithiolane Thiol Modifier for Oligonucleotide Immobilization Stability
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Solution Overview
Problem
Thiol-modified oligonucleotides used for DNA functionalization on gold surfaces are unstable under high temperature and high salt conditions, leading to displacement from the surface, limiting their applications in bio diagnostics and nanotechnology.
Innovation Solution
Development of cyclic dithiolane phosphoramidite derivatives that introduce multiple thiol groups, enhancing the stability of self-assembled monolayers (SAMs) on gold surfaces by forming stronger and more stable gold-sulfur bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single thiol group is used for oligonucleotide attachment on gold surface, then simplicity of modification is maintained, but stability of self-assembled monolayer decreases under high temperature and high salt conditions
Solution Approach 1:
The patent combines multiple thiol groups (di-thiol configuration) into a single oligonucleotide molecule, creating a multi-functional attachment system. This merging of multiple bonding sites within one molecule enables simultaneous formation of multiple gold-sulfur bonds, dramatically enhancing SAM stability while maintaining the simplicity of the modification approach through cyclic disulfide precursor incorporation during standard oligonucleotide synthesis.
2Reliability
If multiple thiol groups are introduced to enhance SAM stability, then reliability improves, but complexity of modification increases
Solution Approach 1:
The patent incorporates cyclic disulfide structures into the oligonucleotide sequence during standard phosphoramidite synthesis as a preliminary step. These cyclic disulfide precursors are integrated alongside normal nucleotides using conventional synthesis machinery, avoiding the need for complex post-synthesis modification procedures. The multi-thiol functionality is thus achieved through preliminary incorporation of specially designed monomers rather than complex subsequent steps.
Solution Approach 2:
The cyclic disulfide structure serves as an intermediary form that simplifies the modification process. During oligonucleotide synthesis, the cyclic disulfide monomer is incorporated in its protected form, which is then reduced in a simple post-synthesis step to generate the active multi-thiol configuration. This intermediary form enables easy incorporation during standard synthesis while facilitating subsequent activation to the desired multi-functional state.
3Ease of manufacture
If standard phosphoramidite synthesis is used without specialized monomers, then ease of manufacture is maintained, but ability to introduce multiple reactive thiol groups is limited
Solution Approach 1:
The patent develops universal cyclic disulfide phosphoramidite monomers that can be incorporated at any position within an oligonucleotide sequence using standard synthesis protocols. These multi-functional monomers serve multiple purposes: they act as normal nucleotide building blocks during synthesis, provide site-specific incorporation capability, and upon reduction, generate multiple reactive thiol groups for enhanced gold surface attachment. This universality allows the same monomer type to be used throughout the oligonucleotide chain with consistent behavior.
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 cyclic dithiolane modification significantly increases the stability of oligonucleotide SAMs on gold surfaces, preventing displacement even in challenging conditions, thus improving their suitability for bio diagnostics and nanotechnology applications.
Implementation Method 1
The thiol (R—SH) modified oligonucleotides serve as attractive tools with a vast number of potential applications in the field of nucleic acid chemistry such as it enables covalent attachment of variety of ligands... thiol has a strong specific interaction with gold surface to form reversible covalent bond with gold
Data Source
AI summary
The thiol modified oligonucleotides have vast number of applications in the field of nucleic acid chemistry. The conjugates generated by mono thiol groups are unstable at higher temperature, in high salt concentration buffers and in presence other thiols. There is strong need to develop a novel thiol modifier probes that can generate multiple thiol groups. Described herein are efficient processes and compounds, dithiolane phosphoramidites derivative and dithiolane succinyl supports. The advantage of our cyclic disulfide thiol modifier is multifold a) each incorporation introduces two thiol groups; b) it can be introduced at any desired site of oligonucleotides; c) The symmetrical branching nature of the spacer in the linker arm of dithiolane allows for clean oligo synthesis, where cleavage of the linker arm and thereby of loss of oligo chain is prevented. We have successfully made 20-mer oligonucleotide containing single dithiolane derivative at 3′, and 21-mer oligonucleotides containing single dithiolane derivative at 5′ or in the middle of the mixed base sequence. HPLC and ESI MS analysis of these oligonucleotides indicated satisfactory purity and correct composition of these oligos, respectively.