Gold(III)-NHC Complexes Stabilize Anticancer Activity and Thiol Detection
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Solution Overview
Problem
Current metal-based anticancer drugs, such as platinum(II) and ruthenium(II) complexes, face challenges like severe side effects and drug resistance, while gold(III) complexes are unstable under physiological conditions, limiting their effectiveness in cancer treatment.
Innovation Solution
Development of gold(III) complexes with N-heterocyclic carbene ligands that stabilize Au(I) and provide dual anti-cancer and fluorescent switch-on properties, synthesized using specific methods involving H2N^N^N ligands and silver triflate, enabling effective cancer treatment and thiol detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold(III) complexes are used for cancer treatment, then anti-cancer activity is improved, but stability under physiological conditions deteriorates
Solution Approach 1:
The patent combines gold(III) center with N-heterocyclic carbene (NHC) ligands and N^N^N ligands to create composite coordination complexes. This composite structure leverages the stabilizing effect of NHC ligands on Au(I) while maintaining the anti-cancer activity of Au(III), resolving the contradiction between activity and stability
Solution Approach 2:
The patent changes the oxidation state parameter from Au(I) to Au(III) while using NHC ligands to stabilize the higher oxidation state. This parameter change enables the complex to maintain both the desired anti-cancer activity of Au(III) and the stability typically associated with Au(I)-NHC complexes
2Reliability
If platinum(II) and ruthenium(II) complexes are used as anticancer drugs, then anti-cancer efficacy is improved, but side effects and drug resistance worsen
Solution Approach 1:
The patent creates gold(III)-NHC complexes that can function through multiple mechanisms: they can target DNA like traditional agents, but also target specific proteins and enzymes such as thioredoxin reductase. This multi-functionality provides anti-cancer efficacy while potentially reducing resistance development
Solution Approach 2:
The NHC ligands act as intermediaries that mediate the interaction between the gold center and biological targets. These ligands stabilize the complex in physiological conditions while allowing controlled interaction with cancer cells, reducing harmful side effects
3Illumination intensity
If fluorescent ligands are used in Au(III) complexes for thiol detection, then fluorescence emission is improved, but emission is quenched by Au(III) 5d x2-y2 orbital
Solution Approach 1:
The patent creates a dynamic system where the fluorescence state changes in response to thiol detection. The complex transitions from a quenched state (Au(III) with fluorescent ligand) to an active fluorescent state upon reduction by thiols, enabling detection while managing the quenching effect
Solution Approach 2:
The patent converts the harmful quenching effect into a useful detection mechanism. The quenching of fluorescence by Au(III) is not eliminated but rather utilized as the basis for thiol detection - when thiols reduce Au(III) to Au(I), the fluorescence is restored, providing a switch-on signal for detection
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 gold(III)-NHC complexes exhibit stable anti-cancer activity, inhibit tumor growth, and serve as effective probes for thiol detection, displaying similar efficacy to cisplatin with reduced side effects and enhanced stability.
Implementation Method 1
Gold(III) complexes are always unstable under physiological conditions and will be reduced to Au(I) or even Au(0) by physiological thiols.
Implementation Method 2
N-heterocyclic carbene (NHC) ligand(s) is able to stabilize Au(I) against reduction to Au(0) and/or demetalation under physiological conditions.
Implementation Method 3
If the ligand is highly fluorescent, intraligand emission would be quenched due to the presence of low energy Au(III) 5d x2-y2 orbital. Upon reduction of Au(III) to Au(I) by thiols, the fluorescent ligand(s) will be released and switch on the emission.
Data Source
Figure 1(A)
Figure 1(B)
Figure 2(A)~2(B)
AI summary
Provided herein is a method of synthesis of Au(III)-NHC complexes, a pharmaceutical composition comprises thereof. Also provided herein are the methods for the treatment and prevention of cancer/tumor in patients in need thereof by the administration of the Au(III)-NHC complexes. Also provided is method of detecting thiol in a biological system. The Au(III)-NHC complexes possess anticancer activity such as the induction of cell death, inhibition of cellular proliferation, inhibition of thioredoxin reductase activity, and inhibition of tumor growthin vivo.