Robust Peptide-Functionalized Gold Nanoparticles via Ethynyl Bonding for High-Fidelity Bioanalytical Applications.

Area of Science:

• Nanotechnology
• Bioconjugation Chemistry
• Materials Science

Background:

• Gold nanoparticle (AuNP) bioconjugates are crucial for biosensing, cell imaging, and biomedical research.
• Existing Au-S bond strategies are susceptible to ligand exchange interference from biothiols in biological settings.
• This instability limits the reliability of AuNP-based tools in complex environments.

Purpose of the Study:

• To develop a rapid and robust conjugation strategy for peptide-functionalized AuNP conjugates (PFCs).
• To enhance the stability and resistance of AuNP conjugates against biological interference, particularly biothiols.
• To validate the efficacy of the new conjugation method in a biological assay.

Main Methods:

• Utilized the gold-carbon triple bond (Au-C≡C) for rapid conjugation (within two minutes).
• Investigated the stability of Au-C≡C PFCs under various conditions (biothiols, high salt, pH, temperature).
• Employed molecular dynamics simulation and X-ray photoelectron spectroscopy (XPS) to elucidate the conjugation mechanism.

Main Results:

• Au-C≡C PFCs demonstrated superior stability and resistance to biothiols compared to traditional Au-S PFCs.
• The conjugates maintained excellent stability across a wide range of salt concentrations, pH values, and temperatures.
• Au-C≡C PFCs significantly enhanced signal fidelity in an intracellular caspase imaging assay.

Conclusions:

• The Au-C≡C conjugation strategy offers a robust and fast alternative for creating stable AuNP nanoprobes.
• This method overcomes the limitations of Au-S bonds, improving reliability in complex biological environments.
• The developed AuNP conjugates have broad potential for advanced biosensing, imaging, and biomedical applications.