Facile Approach to Develop Peptide-Stabilized CdS/CdSe Quantum Dots for Cellular Imaging.

This study presents a mild, one-pot synthetic approach for the synthesis of multicolor, water soluble, photo luminescent CdS and CdSe quantum dots (QDs). To achieve this goal, cyclic peptides containing cysteine residues are rationally designed and synthesized. Among the peptides tested, those containing two cysteine residues exhibit superior stabilizing properties, ensuring the solubility and long-term stability of the QDs in aqueous solutions for several months. The newly synthesized QDs exhibit unique excitation-dependent multicolor photoluminescence with a quantum yield of 20.55% and 45.50% for CdS and CdSe, respectively, providing versatility for imaging applications. Cellular uptake studies using HCT 116 cells reveal effective internalization of the QDs into both the cytoplasm and nucleus, highlighting their potential applications in bioimaging and drug delivery. This green synthesis approach underscores the crucial role of peptide chemistry in nanoparticle stabilization, paving the way for the development of functional nanomaterials tailored for specific uses in bioimaging and nanomedicine.