Feasibility of plasmonic cellular vehicles for photoacoustic applications

Gold nanorods (GNRs) are attractive as contrast agents for biomedical applications, such as the photothermal ablation or the photoacoustic (PA) imaging of cancer, due to their biocompatibility, ease of bioconjugation and high optical absorbance in the near-infrared (NIR). An innovative approach to reach tumor tissues may rest on the use of cellular vehicles loaded with GNRs. However, the feasibility of GNRs for cell tracking has not been fully explored. In this preliminary study, J774A.1 macrophages were treated with PEGylated GNRs with a cationic profile to gain insight into the cellular viability and the intracellular uptake. The cytotoxicity test was performed by the colorimetric WST-8 assay while the intracellular amount of gold was quantified by spectrophotometry. Finally, we verified the quality of the PA signals emitted from GNRs taken up by murine macrophages and then embedded in biomimetic scaffolds, under pulsed wave irradiation.