Eu3+-induced clusterization of non-emissive cysteine into bright green assemblies.
Eu3+ coordination with L-cysteine results in a significant increase in luminescence, with a 56-fold increase in quantum yield compared to Eu3+ alone.
Where it sits
this study against the rest of the matrixyl corpusSummary and findings
This study investigates the effect of Eu3+ coordination on L-cysteine, focusing on the resulting clusterization and emission properties. The findings indicate a 56-fold increase in quantum yield to 14% compared to Eu3+ alone. The research highlights the unique interaction between Eu3+ and cysteine in generating luminescent materials.
Abstract
Clusteroluminescence (CL) offers an effective strategy for generating emission from nonconjugated, heteroatom-rich molecules, yet simple, biocompatible CL systems derived from natural building blocks remain scarce. Here, we report that coordination of Eu3+ with intrinsically non-emissive L-cysteine (Cys) induces clusterization and activates intense green emission. Under basic conditions, Eu3+ promotes the formation of hierarchical Eu-Cys clusters that exhibit a broad emission centered at ∼525 nm, a large Stokes shift (∼150 nm), excitation-dependent emission, and a 56-fold increase in quantum yield (14%) relative to Eu3+ alone. Combined spectroscopic and microscopic analyses reveal that the emission originates from clustered Cys domains rather than Eu-centered excited states, with Eu3+ functioning primarily as a structural node that rigidifies heteroatom-rich assemblies and suppresses nonradiative decay. Control experiments with other metal ions and amino acids reveal a pronounced coordination specificity, highlighting the unique cooperative interplay between Eu3+'s high coordination propensity and cysteine's thiol-containing ligand topology. This rare-earth-ion-induced clusterization strategy extends CL to single, non-aromatic amino acids into the emissive framework, and providing a general approach for constructing luminescent materials from simple biomolecules.
Background
The study addresses the challenge of generating emission from nonconjugated, heteroatom-rich molecules using clusteroluminescence (CL). Prior research has shown limited biocompatible CL systems derived from natural building blocks. This study is significant as it explores the potential of Eu<sup>3+</sup> coordination with L-cysteine to create luminescent materials.
Methods
The study employs spectroscopic and microscopic analyses to evaluate the emission properties of Eu-Cys clusters. Specific conditions include basic pH to promote cluster formation. Not reported in abstract.
Results
The primary finding is a 56-fold increase in quantum yield (14%) when L-cysteine is coordinated with Eu<sup>3+</sup>. The emission occurs at approximately 525 nm, with a Stokes shift of about 150 nm. Control experiments indicate specificity in coordination.
Interpretation
This study presents a novel method for enhancing luminescence in non-emissive amino acids, which could have implications for material science. However, the clinical relevance is uncertain as the findings are based on chemical analyses rather than biological applications. The study does not report on potential confounding factors or limitations.
Key findings
- 56-fold increase in quantum yield (14%) relative to Eu3+ alone.
- Emission centered at ∼525 nm.
- Large Stokes shift of ∼150 nm.
Limitations
- Not reported in abstract.
- No human data provided.
- Study does not detail specific experimental conditions.