Multilayer Magnetic Bead Coating for Stable Nucleic Acid Extraction
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Solution Overview
Problem
Existing biological material extraction magnetic beads face challenges with low dispersibility and efficiency due to aggregation and detachment of biological materials under physical and chemical loads, leading to decreased nucleic acid extraction efficiency.
Innovation Solution
A magnetic bead with a multilayer coating structure comprising a magnetic metal powder, an inorganic oxide layer, a gold layer, and an immobilization layer bonded via an Au-S bond, which enhances binding affinity and stability, preventing detachment and aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a colloid holding a ligand is used as an extraction carrier, then binding ability to biological material is achieved, but dispersibility in dispersion medium decreases and aggregation occurs under physical and chemical loads
Solution Approach 1:
The patent uses a composite structure consisting of magnetic beads coated with multiple layers including inorganic oxide layer, organic layer, and self-assembled monolayer. This composite material approach combines the advantages of different materials to achieve both strong binding ability and stable dispersibility, resolving the contradiction between reliability and stability of composition.
Solution Approach 2:
The patent modifies surface parameters by controlling the thickness and composition of coating layers, adjusting hydrophobicity/hydrophilicity balance, and optimizing ligand density. These parameter changes enable the extraction carrier to maintain both binding ability and dispersibility under various physical and chemical loads.
2Productivity
If physical and chemical loads are applied to the extraction carrier, then biological material extraction process is completed, but biological material may detach or extraction carrier may aggregate
Solution Approach 1:
The patent applies beforehand cushioning by creating a protective multilayer coating structure on magnetic beads before extraction. The inorganic oxide layer provides mechanical strength, the organic layer provides chemical stability, and the self-assembled monolayer with ligands provides specific binding protection. This protective structure prevents detachment and aggregation during subsequent extraction processes.
Solution Approach 2:
The patent uses thin film coatings (inorganic oxide layer, organic layer, self-assembled monolayer) that provide flexibility and protection to the magnetic beads. These thin films maintain binding stability under physical and chemical loads while allowing the extraction process to proceed efficiently.
3Reliability
If ligand density is increased to improve binding affinity, then capture efficiency increases, but dispersibility decreases
Solution Approach 1:
The patent applies local quality by creating a self-assembled monolayer where ligands are localized at the outermost surface while the underlying layers maintain dispersibility. The inorganic oxide layer and organic layer provide a stable base structure, while the self-assembled monolayer provides high binding affinity locally at the surface, resolving the contradiction between binding affinity and dispersibility.
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 multilayer coated magnetic beads improve nucleic acid extraction efficiency by maintaining binding affinity and stability under various loads, preventing detachment and aggregation, and ensuring high purification yields and corrosion resistance.
Implementation Method 1
an immobilization layer that is bonded to a surface of the gold layer via an Au-S bond and contains a compound having a ligand or a ligand binding site
Data Source
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AI summary
A biological material extraction magnetic bead contains: a magnetic metal powder; an inorganic oxide layer that covers a particle surface of the magnetic metal powder and contains an inorganic oxide; a base layer that covers a surface of the inorganic oxide layer and contains a gold ion reducing agent or a catalyst for a gold ion reduction reaction; a gold layer that covers a surface of the base layer and contains gold; and an immobilization layer that is bonded to a surface of the gold layer via an Au-S bond and contains a compound having a ligand or a ligand binding site.