Potential of hybrid iron oxide–gold nanoparticles as thermal triggers for pancreatic cancer therapy

Abstract

Theranostics are emerging platforms for rapid cancer diagnosis and therapy. Hybrid iron oxide–gold nanoparticles (HNPs) have shown potential as theranostics due to their ability for imaging using MRI, heating using laser irradiation and carrier abilities for drug molecules after surface functionalization. The ability of HNPs to act as localised nano-heaters has been well documented for tumour ablation applications where maximal heating effect is desired. However, the use of HNPs as thermal triggers for drug release requires more control over temperature output and careful consideration of heat dissipation. In this work we report the potential of HNPs to act as localised nano-heaters in vitro and document the cellular effect prior and post laser irradiation in human pancreatic adenocarcinoma (BxPC-3) cell lines. The data showed that after incubation of 50 μg mL⁻¹ HNPs, a thermal increase of up to 9 °C was observed in the cells after laser irradiation with the total area experiencing heat dissipation from the laser beam being 346 mm². Although the total temperature experienced by cells was below the perceived temperature for irreversible cell damage, after 24 h significant levels of HSP27 and HSP70 were evident with a drop in cell viability to 85%. This indicated that even with rapid irradiation at low temperatures the cells were undergoing stress. Upon I.T. injection in pancreatic xenograft models, a similar heating capacity was observed at identical concentration which also resulted in bulk tumour dissipation. The findings from this work highlight the factors which must be taken into consideration when designing HNPs as theranostics for heat triggered drug delivery.