Synthesis and characterization of biocompatible acetaminophen stabilized gold nanoparticles

Gold nanoparticles (AuNPs) are extensively used in the field of biological and biomedical research. The non-toxic, biocompatible AuNPs are widely used in both in vivo and in vitro studies. The toxicity of AuNPs are varied and dependent on the reducing agent, synthesizing method, size and shape. The present study describes the synthesis and characterization of gold nanoparticles using acetaminophen through the bright sunlight mediated photochemical method and the biocompatibility of synthesized gold nanoparticles were analysed through the in vitro studies. The AuNPs synthesis was carried out in 20 min at biological pH 7.4. The physicochemical properties of acetaminophen stabilized gold nanoparticles (A-AuNPs) were analyzed by the ultraviolet (UV)-visible spectroscopy, high resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), zeta potential, fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) techniques. The maximum surface plasmon resonance absorption spectrum of acetaminophen stabilized gold nanoparticles was obatained at 529 nm. The electron microscopic observation of A-AuNPs showed spherical shape with the average particle size of 16.5 nm. The in vitro hemocompatibility of A-AuNPs was evaluated by hemolytic assay and erythrocyte sedimentation rate (ESR) estimation. The hemolysis was 2.54% and ESR was 11 mm h⁻¹ at a maximum tested concentration of 250 μg ml⁻¹ on human red blood cells (RBCs). The biocompatibility of A-AuNPs was tested on normal Vero and A549 lung cancer cell lines by MTT assay, lactate dehydrogenase (LDH) leakage assay and apoptosis analysis by acridine orange/ethidium bromide (AO/EtBr) fluorescence staining. The viability of Vero and A549 cells were 86.24% and 90.44% respectively on treatment with 250 μg ml⁻¹ concentration of A-AuNPs. The LDH assay showed 16.12% and 15.0% leakage from Vero and A549 cells in maximum concentration. Further, the results of apoptosis analysis strongly supported the biocompatibility of A-AuNPs. In summary, the cost effective, one-step synthesized A-AuNPs have good hemocompatibility and biocompatibility prpoperty, therefore they can be safely used in biological applications. (paper)