Recently, many studies have demonstrated the significant advantages of loop-mediated isothermal amplification (LAMP) based methods over serological tests and PCR for rapid detection of microbial pathogens. Here, a rapid LAMP assay was developed to detect the hepatitis B virus (HBV) from DNA, and particularly, blood samples from infected patients using a commercially available master mix and portable real-time fluorometer. The final optimized fluorescence-based LAMP assay provided significant amplification time of less than 15 minutes compared with over 1 hour for PCR and an opened tube LAMP system described previously. Results indicated that fluorescence-based LAMP assay was more sensitive than PCR as a rapid, sensitive, efficient, and highly reliable approach for rapid detection of HBV.

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.

Gold nanoparticles (AuNPs) with an average particle size of about 7 nm and concentration of 1 mM were synthesized by gamma rays irradiation method using 0.5% carboxymethyl chitosan (CMC) as a stabilizer. The characteristics of AuNPs were verified using UV-vis spectrum and TEM (Transmission Electron Microscope) images. The synthesized AuNPs were intravenously injected into tail of mice with a dose of 1 mg AuNPs per mouse for investigation of the in vivo distribution of AuNPs at different times. The analytical results showed that there was no significant difference in the blood haematological and serum biochemical indexes between the mice administrated with AuNPs and the control group. The gold content in the samples determined by k0-neutron activation analysis (k0-NAA) method indicated that after injection 1 h, AuNPs were mainly accumulated in liver (64.92%), blood (31.33%) and a small amount in lungs (2.16%) and kidneys (1.60%). After 6 hrs post-injection, the content of AuNPs was almost not determined in the blood, but its accumulation was increased in livers with 88.85%, lungs with 8.55% and kidneys with 2.10%. After 12 hrs of intravenous administration, the content of AuNPs was found to be slightly reduced by 83.86% in liver, but it was almost unchanged in lungs and kidneys. The results obtained in this study clearly indicated the distribution and the retention time of AuNPs in the mice. The AuNPs synthetized by gamma rays irradiation may potentially be developed for application as an X-ray contrast agent in diagnosis and as antioxidant agent for liver protection.

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