Enzymatically mediated fluorescent copper nanocluster generation for tyramine determination

Area of Science:

• Biochemistry
• Nanomaterials Science
• Analytical Chemistry

Background:

• Enzymatic reactions offer versatile pathways for synthesizing novel materials.
• Fluorescent nanomaterials are valuable tools in analytical chemistry and biosensing.
• Tyramine is a biogenic amine found in food, with implications for food quality and safety.

Purpose of the Study:

• To develop a method for the enzymatic generation of fluorescent nanomaterials.
• To utilize these nanomaterials for the sensitive quantification of tyramine.
• To characterize the synthesized nanoclusters and elucidate their formation mechanism.

Main Methods:

• Enzymatic synthesis of fluorescent copper nanoclusters using tyramine oxidase and tyramine.
• Characterization of nanoclusters using Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray spectroscopy (EDX), and X-ray Photoelectron Spectroscopy (XPS).
• Spectroscopic analysis of fluorescence properties (excitation/emission wavelengths) and optimization of reaction conditions (buffer, pH).

Main Results:

• Fluorescent copper nanoclusters were successfully synthesized via enzymatic reaction.
• The fluorescence intensity of the nanoclusters correlated linearly with tyramine concentration (1.0·10⁻⁵ to 2.5·10⁻⁴ M).
• The method demonstrated high sensitivity (Limit of Detection [LOD] = 6.3·10⁻⁶ M) and precision (Relative Standard Deviation [RSD] = 3%).

Conclusions:

• The reducing properties of p-hydroxybenzaldehyde, a product of the enzymatic reaction, facilitate nanocluster formation.
• This enzymatic approach provides a robust and sensitive method for tyramine quantification.
• The developed method was successfully applied to determine tyramine content in sausage samples.