Colorimetric Detection of Nitrosamines in Human Serum Albumin Using Cysteine-Capped Gold Nanoparticles

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Environmental Science

Background:

• Nitrosamines, such as N-nitroso diethylamine (NDEA), are significant pharmaceutical impurities and environmental contaminants.
• Their presence poses grave public health risks due to carcinogenic properties.

Purpose of the Study:

• To develop and validate cysteine-gold nanoparticles (CysAuNPs) for the colorimetric detection of NDEA.
• To investigate the interaction mechanism between NDEA and human serum albumin (HSA) using computational and experimental methods.

Main Methods:

• Synthesis and characterization of CysAuNPs using UV-visible absorption, fluorescence spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscopy (TEM).
• Colorimetric detection of NDEA in HSA using CysAuNPs.
• Molecular docking (MD) and molecular dynamic simulation (MDS) to study NDEA-HSA interactions.

Main Results:

• CysAuNPs exhibited absorbance at 377 nm and emission at 623 nm, with uniform spherical to nanoplate-like morphology.
• NDEA addition to HSA with CysAuNPs caused a significant increase in absorbance, indicating NDEA detection.
• The detection limit for NDEA in HSA was as low as 0.35 µM.

Conclusions:

• CysAuNPs provide a sensitive, cost-effective, and rapid colorimetric sensor for NDEA detection in biological samples.
• The study elucidated the interaction mechanism involving disulfide bond disruption and protein unfolding.
• This method offers a promising tool for monitoring nitrosamines in clinical and environmental settings.