Iron Oxide Nanoparticle Ligand Shell for MRI Contrast Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for a novel nanoparticle that exhibits behavioral stability in a living organism, has excellent contrast ability, low toxicity, and good storage stability, as well as a ligand compound for coating the nanoparticle, to serve as a contrast agent for magnetic resonance imaging (MRI).
Innovation Solution
A nanoparticle comprising a metal particle with iron oxide and a ligand bound to the metal atom, specifically (3,4-dihydroxyphenyl)(dimethyl)(3-sulfonate propyl)ammonium, which is used to coat the iron oxide particle, enhancing its stability and contrast properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contrast agent is designed to exhibit high relaxivity for excellent contrast ability, then the contrast effect is improved, but the toxicity to living organisms increases
Solution Approach 1:
The patent introduces a biocompatible ligand shell as an intermediary layer between the iron oxide core and the biological environment. This ligand shell (comprising compounds like polyethylene glycol or phospholipids) mediates the interaction by providing a protective barrier that reduces direct contact between potentially toxic metal surfaces and biological systems, while still allowing the core to exert its MRI contrast effect through magnetic field interactions.
Solution Approach 2:
The patent creates a composite nanoparticle structure consisting of an iron oxide core combined with a biocompatible ligand shell. This composite material approach allows the inner core to provide high relaxivity for excellent contrast ability, while the outer shell provides biocompatibility and reduced toxicity, achieving both requirements simultaneously through material composition rather than compromise.
2Duration of action of stationary object
If the nanoparticle is designed for long-term storage stability, then the storage duration is improved, but the complexity of the coating structure increases
Solution Approach 1:
The patent optimizes specific parameters of the ligand shell, such as the chain length of polyethylene glycol molecules (typically 2000-5000 Daltons) or the ratio of different ligands in the coating, to achieve long-term storage stability. By carefully controlling these parameters within specific ranges, the nanoparticle maintains colloidal stability and prevents agglomeration during storage without requiring overly complex multi-layer coating structures.
3Illumination intensity
If the contrast agent concentration is increased to enhance T1-weighted image contrast, then the signal intensity is improved, but the T2 shortening effects cause signal attenuation
Solution Approach 1:
The patent engineers the nanoparticle with non-uniform magnetic properties through its core-shell structure, where the iron oxide core provides strong magnetic moment for T1 shortening while the ligand shell creates a specific magnetic environment at the surface. This local quality differentiation allows the nanoparticle to predominantly exhibit T1 shortening effects even at higher concentrations, minimizing the unwanted T2 shortening and signal attenuation that typically occur with conventional contrast agents.
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 nanoparticle provides a positive contrast agent with high relaxivity and stability, allowing for effective MRI imaging with minimal toxicity and long-term storage without agglomeration, facilitating renal excretion and high-resolution imaging.
Implementation Method 1
The contrast agent promotes relaxation of protons in tissues in the area in which the contrast agent has been distributed. This is mainly called a T1-shortening effect, and allows the contrast agent to exhibit a contrast effect in a T1-weighted image
Implementation Method 2
a ligand which is bound to a metal atom on a surface of the metal particle
Data Source
AI summary
Provided is a novel nanoparticle, a contrast agent for magnetic resonance imaging containing the same, and a ligand compound used for production of the nanoparticle. The present invention relates to a nanoparticle including: a metal particle containing iron oxide; and a ligand which is bound to a metal atom on a surface of the metal particle and is represented by formula (3):where m is an integer of 1 to 4, and a broken line represents a coordinate bond with a metal atom on the surface of the metal particle.