In-vitro investigation of green synthesized gold nanoparticle’s role in combined photodynamic and radiation therapy of cancerous cells

Abstract Gold nanoparticles (AuNPs) have been introduced for increasing the effectiveness of various cancer treatments such as radiation and photodynamic therapy. Instead of toxic chemicals, various natural compounds have been introduced for AuNPs synthesis. Here, gallic acid-coated AuNPs (Ga@AuNPs) with the average diameter of 17.9 ± 10 nm and surface charge of −16.2 ± 3.2 mV have been synthesised through easy and single-step chemical route and were characterised with transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV–Vis spectroscopy. The interaction of Ga@AuNPs and methylene blue (MB) photosensitisers was confirmed through various techniques such as FTIR spectroscopy, zeta potential investigation, and UV–vis spectroscopy. Based on our results, methylene blue was adsorbed to the surface of Ga@AuNPs through various amine and thiol functional groups. Upon laser radiation, a release of singlet oxygen species (ROS) from nanoformulation of methylene blue was more gradual than free methylene blue based on the determination of singlet oxygen in the present of 1,3-diphenylisobenzofuran (DPBF) radical scavenger. The Ga@AuNPs nanoparticles were not representing significant toxic effects toward cells. However, the synthesised nanoparticles could increase the effectiveness of radiation therapy or combined treatment of methylene blue mediated photodynamic and radiation therapy in an in-vitro investigation.