Gold nanoparticles for photothermal therapy – Influence of experimental conditions on the properties of resulting AuNPs

• Published in: Journal of drug delivery science and technology 2024-11, Vol.101, p.106215, Article 106215
• Main Authors: Amaral, Mariana Neves, Nunes, Daniela, Fortunato, Elvira, Martins, Rodrigo, Rodrigues, Carla, Faísca, Pedro, Ferreira, Hugo Alexandre, Coelho, João M.P., Gaspar, M. Manuela, Reis, Catarina Pinto
• Format: Article
• Language: English
• Subjects: Cancer; Gold nanoflowers; Gold nanoparticles; Hyperthermia; Novel therapies; Photothermal agents; Photothermal therapy
• ISSN: 1773-2247
• DOI: 10.1016/j.jddst.2024.106215

Gold nanoparticles (AuNPs)-mediated Photothermal Therapy (PTT) is a minimally-invasive therapeutic approach that uses AuNPs to convert light into heat, leading to the thermal ablation of tumors. Thus, the efficacy of this strategy strongly relies on the photothermal conversion potential of AuNPs. The ability to convert light into heat can be enhanced by tuning the physicochemical and optical properties of AuNPs. This can be achieved by changing the conditions of AuNP's synthesis, such as the order of addition of reagents. The present work entails to explore how varying the order of reagents addition modulates the properties of AuNPs, particularly enhancing the photothermal conversion potential of the resulting AuNPs and consequently, improving PTT efficacy. For this, eleven different AuNPs' nanoformulations were synthetized following different sequences of addition of reagents. These nanoformulations were characterized regarding their physicochemical properties namely size, surface charge, gold concentration, surface morphology and maximum absorbance wavelength. In addition, their thermal activation profiles were determined in vitro. Furthermore, the biocompatibility of different nanoformulations was also assessed. Three nanoformulations, with the most favorable photothermal activation profiles (AuNPs 2, 3 and 7), were then selected for preliminary in vitro safety and efficacy assays using a panel of cell lines. These three nanoformulations were deemed safe in vitro at the tested concentrations. At 250 μM of gold content, and after an incubation period of 4 h, followed by 5 min irradiation with a laser emitting at 808 nm (7.96 W/cm2), AuNPs 7 significantly reduced the cell viability of all cancer cell lines tested (MCF-7, HCT-116 and A375) by ≥ 45 %. However, such cytotoxic effect was not observed for the human keratinocyte cell line (HaCat), thus demonstrating its specificity towards cancer cells. Overall, the results herein presented reinforce that the order of reagents addition is highly important for achieving adequate AuNPs for PTT. [Display omitted] •Production of AuNPs without toxic agents, using L-ascorbic acid and rosmarinic acid.•The order of reagents addition in the synthesis of AuNPs influences their properties.•Silver nitrate, L-ascorbic and rosmarinic acids have unique roles in AuNPs synthesis.•Low concentration of AuNPs caused temperature increase of 15 °C over 10 min.•Laser-activated AuNPs had superior cytotoxicity against different cancer