Gadolinium MRI Contrast Agents with Zinc-Binding Units
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Solution Overview
Problem
Current MRI imaging agents, particularly those using Gadolinium, suffer from low relaxivity and rapid renal excretion, limiting their ability to specifically target and detect zinc ions in biological tissues, which are crucial for understanding diseases like Alzheimer's and cancer, due to their nonspecificity and low molecular weight.
Innovation Solution
Development of novel MRI imaging agents containing a central Gadolinium(III) 1,4,7,10-tetraazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) moiety with two zinc(II) binding units, such as di-2-picolylamine, that increase relaxivity by binding to serum albumin and enhancing water exchange rates around the Gadolinium core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low molecular weight Gadolinium contrast agents (DTPA or DOTA derivatives) are used, then renal excretion is rapid and the agents are easy to administer, but they exhibit low relaxivity and nonspecific targeting
Solution Approach 1:
The patent combines Gadolinium-DOTA complex with a high molecular weight polymeric carrier (polyethylene glycol or polyacrylic acid backbone with amine groups). This composite structure integrates the contrast-enhancing properties of Gd-DOTA with the high relaxivity and prolonged circulation of polymeric carriers, resolving the contradiction between rapid excretion and low relaxivity
Solution Approach 2:
The invention merges two functional components: (1) the Gadolinium-DOTA chelate complex that provides MRI contrast, and (2) the polymeric carrier that provides high molecular weight characteristics for prolonged circulation and enhanced relaxivity. The polymer contains multiple amine groups that coordinate with Gadolinium ions, creating a hybrid contrast agent that achieves both rapid clearance and high relaxivity
2Adaptability or versatility
If additional functionality is added to selectively target metal ions, then specificity improves, but device complexity increases
Solution Approach 1:
The patent introduces zinc-binding units (dipicolylamine or tris(pyridylmethyl)amine groups) at specific locations on the polymeric carrier structure. These localized functional groups provide selective zinc ion binding capability without requiring complete redesign of the entire ligand structure, thus achieving specificity while controlling complexity
Solution Approach 2:
The polymeric carrier serves multiple functions simultaneously: (1) provides high molecular weight for prolonged circulation, (2) contains multiple amine groups for Gadolinium coordination, (3) incorporates zinc-binding units for selective metal ion targeting, and (4) offers multiple attachment points for contrast agent molecules. This multi-functionality reduces the need for separate specialized components
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 agents exhibit higher T1 relaxivity, allowing for effective detection at lower concentrations and improved imaging of small biological targets with reduced toxicity and adverse effects, offering enhanced pharmacokinetic profiles compared to existing compounds.
Implementation Method 1
The new agents exhibit higher T1 relaxivity, allowing for effective detection at lower concentrations
Implementation Method 2
enhancing water exchange rates around the Gadolinium core
Implementation Method 3
binding to serum albumin and enhancing water exchange rates around the Gadolinium core
Data Source
AI summary
In some aspects, the present disclosure provides novel ligands, which may be used to make novel MRI contrast agents for the detection of zinc. In further aspects, by the present disclosure also provides methods of using as imaging agents and compositions thereof.