Chitosan-capped gold nanoparticles for selective and colorimetric sensing of heparin

Zhanguang Chen,Zhen Wang,Jinbin Liu,Xi Chen,Haixiong Xu

doi:10.1007/s11051-013-1930-9

Abstract

In this contribution, novel chitosan-stabilized gold nanoparticles (AuNPs) were prepared by mixing chitosan with citrate-reductive AuNPs under appropriate conditions. The as-prepared chitosan-stabilized AuNPs were positively charged and highly stably dispersed in aqueous solution. They exhibited weak resonance light scattering (RLS) intensity and a wine red color. In addition, the chitosan-stabilized AuNPs were successfully utilized as novel sensitive probes for the detection of heparin for the first time. It was found that the addition of heparin induced a strong increase of RLS intensity for AuNPs and the color change from red to blue. The increase in RLS intensity and the color change of chitosan-stabilized AuNPs caused by heparin allowed the sensitive detection of heparin in the range of 0.2–60 μM (~6.7 U/mL). The detection limit for heparin is 0.8 μM at a signal-to-noise ratio of 3. The present sensor for heparin detection possessed a low detection limit and wide linear range. Additionally, the proposed method was also applied to the detection of heparin in biological media with satisfactory results.Electronic supplementary materialThe online version of this article (doi:10.1007/s11051-013-1930-9) contains supplementary material, which is available to authorized users.

Highlights

Heparin, known as the most negatively charged biological macromolecule (Rabenstein 2002; Althaus et al 2013; Linhardt and Toida 2004; Whitelock and Iozzo 2005), is a highly sulfated linear glycoaminoglycan consisting of repeating units of 1?4-linked pyranosyluronic acid and 2-amino-2-deoxyglucopyranose residues
It is reasonable that the diameter of chitosan-stabilized AuNPs is smaller than 1/20 of the incident wavelengths in the scan range such that the signal would only come from resonance light scattering (RLS) (Miller 1978)
To compare the light scattering spectra of chitosanstabilized AuNPs with that of chitosan-stabilized AuNPs-heparin conjugates, it can be concluded that the assembly of chitosan-stabilized AuNPs results in great enhancement of RLS intensity of chitosanstabilized AuNPs

Summary

Introduction

Known as the most negatively charged biological macromolecule (Rabenstein 2002; Althaus et al 2013; Linhardt and Toida 2004; Whitelock and Iozzo 2005), is a highly sulfated linear glycoaminoglycan consisting of repeating units of 1?4-linked pyranosyluronic acid and 2-amino-2-deoxyglucopyranose residues. Heparin plays an important role in the regulation of various normal physiological and pathological processes such as cell growth and differentiation, inflammation, immune defense, lipid transport and metabolism, and blood coagulation (Althaus et al 2013; Whitelock and Iozzo 2005; Mackman 2008; Williams and Davies 2001). The proper therapeutic dosing concentration range of heparin is 2–8 U/mL (17–67 lM) during cardiovascular surgery and 0.2–1.2 U/mL (1.7–10 lM) in the postoperation period and long-term therapy (Zhan et al 2010). Close monitoring and quantification of heparin in serum are of vital importance for regulation of the physiological process and for clinical applications during surgery and the postoperative therapy period

Methods

Results

Conclusion