Highly Stable Gold Nanoparticle Functionalized by Aspirin in an Aqueous Solution: Evaluation of Its Stability at Different Temperatures and pH Values

Aspirin, also called O-acetylsalicylic acid (ASA), was used to functionalize gold nanoparticles (AuNPs), resulting in a well-dispersed aqueous solution with stability maintained for over 3 months in this study. The stability, size, and shape of the formed AuNPs were investigated using UV-Visible spectrophotometer (UV-Vis), transition electron microscope (TEM), and dynamic light scattering (DLS). The functional groups capping AuNPs were investigated by Fourier Transform infrared spectroscopy (FTIR). In this work, AuNPs were spherical with an average diameter of 13 ± 1.2 nm. The UV-Visible results showed a strong SPR peak around 544 nm. In addition, the behaviour of aspirin-AuNPs in aqueous medium within different pH values (pH 1.8 – 11.3), and chemical stability with time, and various temperature values (25 °C, 40 °C, 60 °C, and 70 °C) were carried out in this study. The first goal of this work is to prepare AuNPs with good stability using aspirin as a capping ligand in the presence of NaBH4 to control size distribution and prevent any aggregation of AuNPs. Second, to ascertain the pH and temperature values at which the AuNPs will become unstable. Overall, aspirin is a weak acid that is only slightly soluble in water. Therefore, AuNPs lead to a significant increase in its solubility, which is another important issue for drug solubility nowadays. Accordingly, aspirin can be used at the lowest possible dose using AuNPs in the future.

Highly Stable Gold Nanoparticle Functionalized by Aspirin in an Aqueous Solution: Evaluation of Its Stability at Different Temperatures and pH Values Keywords:

Gold Nanoparticles , Stability , aspirin , O-acetylsalicylic acid Solubility , Temperature