Abstract
Gold nanoparticles capped by carboxymethyl chitosan (AuNPs/CM-chitosan) with particle sizes of 5.2–7.3 nm were successfully synthesized by the γ-irradiation of Au3+ solutions. Their characteristics were analysed by transmission electron microscope images, powder X-ray diffraction patterns, UV-visible spectroscopy, and Fourier transform infrared spectra. The antioxidant activity of AuNP/CM-chitosan was time dependent and much higher than that of ascorbic acid at the same concentration. On the other hand, the results of tail vein injection of AuNP/CM-chitosan in mice indicated that this product was not toxic to mice and that AuNPs were mainly distributed in liver tissue, at approximately 77.5%, 6 h after injection. The hepatoprotective activity of AuNP/CM-chitosan was also tested in acetaminophen-induced hepatotoxic mice by oral administration at daily doses of 0.5–2 mg/head. The results indicated that compared to the control, supplementation with 2 mg of AuNPs/head strongly reduced the aspartate aminotransferase and alanine aminotransferase indexes in the blood of the tested mice by approximately 66.5 and 69.3%, respectively. Furthermore, the MTT (3[4,5 dimetylthiazol-2-yl]-2,5-diphenyltetrazol bromide) assay on a liver cancer cell line (HepG2) clearly confirmed strong anticancer activity on HepG2 cells treated with 0.05–0.5 mM AuNPs and the tested cells did not survive after treatment with 0.5 mM AuNPs, while the growth of the normal cell line (L929) has no significant effect at the same treated concentration of AuNPs. The AuNP/CM-chitosan in the present study was synthesized by the γ-irradiation method without using any toxic-reducing chemical and stabilized in a natural biocompatible polymer. The strong antioxidant, hepatoprotective, and anticancer effects of this product may be supported to be used in the biomedical field.
Highlights
AuNPs have attracted increased attention and demonstrated promising effects and benefits in biosensor, bioimaging, and biomedical applications such as disease therapeutics, diagnostics, photothermal therapy, targeted delivery, and cancer treatment [1]
The MTT (3[4,5 dimetylthiazol-2-yl]-2,5-diphenyltetrazol bromide) assay on a liver cancer cell line (HepG2) clearly confirmed strong anticancer activity on HepG2 cells treated with 0.05–0.5 mM AuNPs and the tested cells did not survive after treatment with 0.5 mM AuNPs, while the growth of the normal cell line (L929) has no significant effect at the same treated concentration of AuNPs
The L929 cell viability decreased to 54.5% at the treated AuNP concentration of 0.5 mM. These results clearly revealed that AuNP/CN-chitosan synthesized by the γ-irradiation method had a low cytotoxicity effect in normal cell
Summary
AuNPs have attracted increased attention and demonstrated promising effects and benefits in biosensor, bioimaging, and biomedical applications such as disease therapeutics, diagnostics, photothermal therapy, targeted delivery, and cancer treatment [1]. There are several methods for the fabrication of AuNPs, such as radiolytic, chemical [6, 7], physical [8], and biological methods [9,10,11]. Among these methods, gamma ray irradiation was reported to be effective with several advantages. The reactions are carried out under normal conditions with high efficiency and synthesized AuNPs are highly pure and lack contamination by excessive chemical reductants and Au3+ ion residue. The gamma ray irradiation method can be favourably applied on a large scale and the production process meets the requirements for clean production [12,13,14]
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