CyTTHA Chelators for Stable Lanthanide Complexes
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Solution Overview
Problem
Current metal chelators for biomedical applications, particularly for imaging and therapeutics, face challenges in achieving high thermodynamic and kinetic stability, rapid complexation under mild physiological conditions, and versatility in binding a wide range of metal ions, especially for lanthanide ions like Eu(III) and Tb(III), while also requiring efficient synthesis and modification for functionalization.
Innovation Solution
Development of a class of lanthanide chelators based on cyclohexyl triethylenetetraamine hexaacetic acid (cyTTHA) with functionalization using 7-aminoquinolinone or 7-amino-4-trifluoromethyl-2-(1H)-quinolinone sensitizer chromophores, enabling the formation of luminescent complexes with exceptional quantum yields, high absorptivity, and fast metal complexation rates, along with a modular synthesis for multifunctional metal complexes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If macrocycle chelators like DOTA and NOTA are used to achieve excellent kinetic stability, then kinetic inertness is improved, but metallation requires prolonged reaction at high temperatures and low pH, limiting use with antibody conjugates and radioisotopes with short half-lives
Solution Approach 1:
The chelator is divided into two functional parts: a macrocyclic core (1,4,7-triazacyclononane) providing kinetic stability, and a pendant arm (acetic acid group) enabling mild-condition metallation. This segmentation allows each part to optimize its function independently.
Solution Approach 2:
The chelator transitions from a rigid macrocycle-only structure to a dynamic system where the pendant arm can flex and rotate to facilitate metal coordination under mild conditions, while the macrocyclic core maintains structural integrity for kinetic stability.
2Speed
If DTPA variants are used to achieve favorable formation kinetics, then metallation speed is improved, but kinetic inertness becomes extremely poor
Solution Approach 1:
The invention merges the beneficial features of DTPA (fast formation kinetics) with the stable macrocyclic core (1,4,7-triazacyclononane) to achieve both rapid metallation and excellent kinetic stability simultaneously, resolving the contradiction between speed and reliability.
3Adaptability or versatility
If bifunctional chelators are designed to bind multiple metal ions, then versatility is improved, but the ability to meet stringent requirements for clinical application is compromised
Solution Approach 1:
The chelator is designed with universal functionality to bind multiple metal ions (Ga, In, Tl, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) while maintaining the kinetic stability and mild-condition metallation required for clinical applications, achieving both versatility and reliability.
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 cyTTHA-based chelators provide luminescent complexes with exceptional brightness and stability, suitable for time-gated biosensing and microscopy, enabling efficient detection and imaging applications by forming stable and bright lanthanide complexes that can be easily synthesized and modified for various biomedical uses.
Implementation Method 1
A coordination complex is the product of a Lewis acid-base reaction in which neutral or anionic organic ligands form coordinate covalent bonds with a central metal atom or ion.
Implementation Method 2
Molecules that coordinate to Gd(III) are used as contrast agents for magnetic resonance imaging (MRI). A particular class of coordination compounds binds to lanthanide ions like Tb(III) or Eu(III) and contain organic chromophores that act to sensitize lanthanide-centered luminescence.
Implementation Method 3
Lanthanide luminophores have photophysical properties such as ms-scale excited state lifetimes and multiple, narrow-line emission bands that make them uniquely suited for use in high throughput screening (HTS) in drug discovery, immunoassays and live-cell microscopy.
Data Source
AI summary
A variety of compounds are provided capable of chelating a metal, in particular a lanthanide such as Eu(III) and Tb(III). Luminescent complexes of the compound and a metal ion are also provided, in particular luminescent metal complexes are provided containing a lanthanide such as Eu(III) or Tb(III) and a compound described herein. In some aspects, the luminescent complexes are capable of exhibiting bright emissions with high quantum yields. Methods of making the compound are provided. Methods of using the compounds and luminescent complexes are also provided, for example for imaging and therapeutic applications.