Synthesis of Urchin-Shaped Gold Nanoparticles Utilizing Green Reducing and Capping Agents at Different Preparation Conditions: An In Vitro Study

Employing environmentally friendly reducing and capping materials to synthesize gold nanoparticles is an exciting research point. However, the used materials usually need a long reduction time that can take days. In this work, the instantaneous production of small-sized (less than 20 nm) gold nanoparticles is investigated using ascorbic acid, gelatin, and a mixture of the two agents at different preparation conditions (at room temperature; 20 ± 3 °C and near boiling temperature; 95 ± 3 °C). Particle size analysis, as well as transmission electron microscopy, were used to assess the produced particles’ physical characteristics. The structural changes and optical characteristics of the nanoparticles were monitored using UV–visible spectroscopy. Fourier Transform Infrared spectroscopy (FTIR) was used to establish the presence of a gelatin coating over the gold nanoparticles. The morphology of the produced nanoparticles at 95 ± 3 °C was spherical with a size ranging from 8–18 nm, whereas urchin-shaped nanoparticles ranging from 24–100 nm were formed at 20 ± 3 °C reaction temperature. The presence of hydroxyl and amine groups associated with the gelatin was confirmed using FTIR. This could be a step for wider usage of green synthesized nanogold particles in several applications.