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Encapsulating NHC-capped copper(i) complexes inside cyclodextrin for catalysis in living cells.
Francisca Figueiredo1, Hugo Madec2, Pierre Mesdom1
1Chimie ParisTech, PSL Université, CNRS, Institute of Chemistry for Life and Health Sciences 75005 Paris France gilles.gasser@chimieparistech.psl.eu kevin.cariou@chimieparistech.psl.eu https://www.gassergroup.com.
Researchers developed non-toxic copper catalysts for reactions within living cells. Encapsulating copper(i) N-heterocyclic carbene (NHC) catalysts in cyclodextrins (CD) preserved their activity while reducing toxicity, enabling new cellular chemistry.
Area of Science:
- Bioinorganic Chemistry
- Catalysis
- Chemical Biology
Background:
- Metal-based catalysis is crucial for developing non-natural chemical reactions within living organisms.
- Current catalysts often rely on expensive and rare heavy metals, limiting their broader application.
- There is a significant need for catalysis using accessible first-row metals for in vivo applications.
Purpose of the Study:
- To develop non-toxic, first-row metal-based catalysts for intracellular chemical reactions.
- To investigate the use of cyclodextrin (CD) encapsulation to mitigate the toxicity of copper(i) N-heterocyclic carbene (NHC) catalysts.
- To demonstrate the preserved catalytic activity of CD-encapsulated NHC-copper complexes for specific chemical transformations.
Main Methods:
- Synthesis and characterization of copper(i) N-heterocyclic carbene (NHC) catalysts.
- Encapsulation of NHC-copper complexes within modified cyclodextrins (CDs).
- Evaluation of catalyst cytotoxicity towards CT26 cells.
- Assessment of catalytic activity for pinacol boronate ester deprotection in vitro and in living cells.
Main Results:
- Cyclodextrin encapsulation rendered toxic copper(i) NHC complexes harmless to CT26 cells at high concentrations.
- The catalytic activity of CD-encapsulated NHC-copper complexes was maintained.
- The catalysts enabled the release of phenol-based fluorophores via deprotection of pinacol boronate ester groups, both extracellularly and intracellularly.
- Fluorophore production in cells using CD-NHC-copper catalysts surpassed that of cellular machinery alone and endogenous reactive oxygen species (ROS).
Conclusions:
- Cyclodextrin encapsulation is an effective strategy to reduce the toxicity of metal-based catalysts for intracellular applications.
- NHC-copper catalysts encapsulated in CDs offer a promising platform for developing new bioorthogonal reactions.
- This approach expands the toolkit for chemical biology and in vivo catalysis using earth-abundant metals.
