Synthesis of gold and silver nanoparticles stabilized with glycosaminoglycans having distinctive biological activities

Abstract

Metal nanoparticles have been studied for their anticoagulant and anti-inflammatory efficacy in various models. Specifically, gold and silver nanoparticles exhibit properties that make these ideal candidates for biological applications. The typical synthesis of gold and silver nanoparticles incorporates contaminants that could pose further problems. Here we demonstrate a clean method of synthesizing gold and silver nanoparticles that exhibit biological functions. These nanoparticles were prepared by reducing AuCl(4) and AgNO(3) using heparin and hyaluronan as both reducing and stabilizing agents. The particles show stability under physiological conditions and narrow size distributions for heparin particles and wider distribution for hyaluronan particles. Studies show that the heparin nanoparticles exhibit anticoagulant properties. Additionally, either gold- or silver-heparin nanoparticles exhibit local anti-inflammatory properties without any significant effect on systemic hemostasis upon administration in carrageenan-induced paw edema models. In conclusion, gold and silver nanoparticles complexed with heparin demonstrated effective anticoagulant and anti-inflammatory efficacy, having potential in various local applications.

Figure 1

UV-visible spectra of gold (solid) and silver (dashed) nanoparticles synthesized by DAPHP molecules. The plasmon peak at ~533 nm confirms the presence of AuNPs, while the plasmon peak at ~400 nm corresponds to the formation of AgNPs. Arbitrary units (a.u.).

Figure 2

TEM image of Au-DAPHP capped gold nanoparticles show uniform size distribution at (a) 100kx and (b) 160kx. (c) Diffraction pattern of AuNPs show their corresponding FCC. (d) Particle size distribution (PSD) of AuNPs is 10 nm ± 3 nm.

Figure 3

TEM image of Ag-DAPHP capped silver nanoparticles at (a) 160 kx and (b) 340kx. (c) Diffraction pattern reveal FCC of AgNPs. (d) Particle size distribution (PSD) of AgNPs is 7 nm ± 3 nm.

Figure 4

UV-visible spectra of (a) gold and (b) silver nanoparticles synthesized by DAPHP molecules as a function of increasing NaCl concentration from 0 – 1 M. Arbitrary units (a.u.).

Figure 5

UV-visible spectra of purified and redispersed (a) gold and (b) silver nanoparticles synthesized by DAPHP molecules as a function of NaCl concentration from 0 – 150 mM. Arbitrary units (a.u.).

Figure 6

XPS spectra of Au-DAPHP and Ag-DAPHP naoparticles film form by drop coating film on Si (111) substrate. (a) Au 4f core level spectra of from Au-DAPHP, (b) N1s core level spectra from Au-DAPHP, (c) Ag 3d core level spectra from Ag-DAPHP, (d) N1s core level spectra from Ag-DAPHP. Arbitrary units (a.u.).

Figure 7

TEM image of drop coated film of Au-HA at (a) 75 kx, (b) 160kx, (c) with broad size distribution of ~5 – 30 nm. TEM image of Ag-HA nanoparticles at (d) 75 kx, (e) 125 kx (f) and size distribution from ~6 – 26 nm.

Figure 8

Effects of (a) Au-DAPHP (solid) and Ag-DAPHP (open) and (b) free DAPHP on aPTT in human plasma. The coagulation times for (c) Ag-HA or Ag-glucose, and (d) Au-HA or Au-glucose fell within the normal control ranges. Data represent mean ± SEM, n = 6. Concentration of DAPHP was based on carbazole assay and concentrations of sugars were 6.7 μM.

Figure 9

Effects of free DAPHP, Au-DAPHP and Ag-DAPHP on carrageenan-induced paw edema in rats as compared to Indomethacin. Significant inhibition of carrageenan-induced paw edema was shown for Au- or Ag-glucose, Au-HA or Ag-HA versus heparin (A and B). In contrast, Au-DAPHP and Ag-DAPHP nanoparticles administered locally in the paw did not exhibit any systemic effect on aPTT as compared to locally administered heparin (C and D). Data represent mean ± SEM, n = 5 per group.