Preparation and Application of a Novel Composite Nanoparticle as a Protein Fluorescence Probe

ABSTRACT

A novel composite nanoparticle has been prepared by an in situ polymerization method under ultrasonic irradiation. The nano‐CdS has been prepared, then the polymerization of acrylic acid (AA) was carried out by initiator potassium persulfate (KPS) under ultrasonic irradiation. The surface of the composite nanoparticles was covered with abundant carboxylic groups (–COOH). The nanoparticles are water‐soluble, stable and biocompatible. The fluorescence intensity of the composite nanoparticles is significantly increased in the presence of micro protein at pH 5.50. Based on this, a new fluorescence probe was developed for the determination of proteins including BSA, HSA, and human γ‐IgG. The fluorescence emission is measured at λ_em/λ_ex = 580/400 nm. Under the optimum conditions, the response is linearly proportional to the concentration of proteins. The linear range is 0.1–40 µg mL⁻¹ for BSA, 0.2–25 µg mL⁻¹ for HSA and 0.1–15 µg mL⁻¹ for human γ‐IgG. The method has been applied to the determination of the total protein in human serum samples collected from the hospital and the results are in good agreement with those reported by the hospital, which indicates that the method presented here is not only sensitive, simple, inexpensive but also reliable.

Keywords:

• Composite nanoparticle
• CdS
• PAA
• Protein
• Fluorescence probe

ACKNOWLEDGMENTS

This project is supported by Natural Foundation of Education Commission of Anhui Province (2003kj145, 2001kj114ZD), Natural Foundation of Anhui Province (03044904) and Foundation of Anhui Normal University for Young Teacher (2002xqn45).

Notes

Note: Human γ‐IgG, 2.0 µg mL⁻¹; CdS‐PAA nanoparticles, 5.0 × 10⁻⁴ mol L⁻¹; pH 5.50.