Preparation and characterization of heparin-modified gold nanoparticles

Jing WAN; Jinghua CHEN

ABSTRACT

BACKGROUND:

Macromolecules modified gold nanoparticles can be used in therapeutics, diagnostics, and other aspects, but most reports mainly focuses on the preparation of protein, DNA and small molecules of sugar modified gold nanoparticles, and the research on polysaccharide modified gold nanoparticles is superficial.

OBJECTIVE:

To prepare heparin-modified gold nanoparticles, studying their particle size and ultraviolet absorption spectra, and to determine the optimum reaction condition. DESIGN, TIME AND

SETTING:

The comparative observation of the experiment was performed at the Biotechnology Pharmaceutical Laboratory of School of Chemical Engineering in Wuhan University of Technology from April 2007 to September 2008. MATERIALS Gold nanoparticles were prepared and preserved at 4 ℃.

METHODS:

Heparin with an aldehyde group (HEP-CHO) as reducing end was prepared by nitrous acid degradation method. HEP-CHO was further reacted with dimethyl sulfoxide solution containing 0.05 mL and 0.5 mL glacial acetic acid to synthesize heparin with thiol-group (HEP-SH) through reductive amination reaction. Heparin was then orientated immobilized in four bottles of dimethyl sulfoxide solution containing 0.5 mL glacial acetic acid by adding the thiol-group of HEP-SH and sodium cyanoborohydride for 2, 4, 6, and 24 hours. The obtained products were added in gold nanoparticle solution, and the heparin was fixed on the surface of gold nanoparticles by Au-S bonds. MAIN OUTCOME

MEASURES:

① Maximum ultraviolet absorbance of gold nanoparticles before and after heparin modified; ② Average grain size of gold nanoparticles and heparin-modified gold nanoparticles.

RESULTS:

Gold nanoparticles with good particle size were prepared by using a rate of sodium citrate to chloroauric acid was 61 (mol/mol). The reductive amination reaction yield was higher when the more acetic acid was added to the solvent. The products were increased within 6 hours and 24 hours, but the difference was not significant. The average grain size and maximum ultraviolet absorbance of gold nanoparticles were 10 nm and 522 nm, and those of heparin-modified gold nanoparticles were 20 nm and 529 nm.

CONCLUSION:

Heparin-modified gold nanoparticles with good particle size are prepared, and the size can effect on the maximum ultraviolet absorbance. The optimum reaction condition for heparin immobilization is using a rate of dimethyl sulfoxide to acetic acid is 81 (mol/mol) as solvent of heparin, and the reaction time is 6 hours.