Heat Dissipation of Hybrid Iron Oxide-Gold Nanoparticles in an Agar Phantom

Abstract

Hybrid iron oxide-gold nanoparticles (HNPs) have shown potential in cancer therapy as agents for tumour ablation and thermal switches for targeted drug release. Heat generation occurs by exploitation of the surface plasmon resonance of the gold coating, which usually occurs at the maximum UV absorption wavelength. However, lasers at such wavelength are often expensive and highly specialised. Here, we report the heating and monitoring of heat dissipation of HNPs suspended in agar phantoms using a relatively inexpensive Ng: YAG pulsed 1064 nm laser source. The particles experience heating of up to 40°C with a total area of heat dissipation up to 132.73 mm 2 from the 1 mm diameter irradiation point after 60 seconds. This work reports the potential and possible drawbacks of these particles for translation into cancer therapy based on our findings.

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T2 Contrast Agent

“…The presence of Au provides two main advantages: (i) a wellknown and versatile platform for surface functionalization, the gold−thiol chemistry, and (ii) gold adds plasmonic features to the superparamagnetic NPs that can be exploited for multimodal imaging, such as contrast for CT (computed tomography) and SERS (surface enhanced Raman spectroscopy) imaging in vivo, 13 and photothermal therapy. 17 Our primary motivation is to develop magnetic nanoparticles that can be used as nontoxic, cell-degradation resistant MRI contrast agents, e.g., for long-term follow-up studies of transplanted stem cells or for in vitro and in vivo studies to follow tumor growth of NP-loaded tumor cells. The magnetoresponsive Au/Fe NPs described in this work combine the capability of cell internalization shown by mixed-ligand gold nanoparticles 5,18,19 with magnetic features.…”

Thermally triggered theranostics for pancreatic cancer therapy

“…The HNP preparation and characterisation has been reported previously [21,22] along with their ability to undergo triggered heating upon laser irradiation in agar phantoms [17,34], in vitro and in situ in tumour bearing mouse cadavers [35,36]. Drug attachment was carried out at three drug:HNP weight ratios (5:1, 2.5:1 and 1:1 based on Fe weight of HNP) for all four bisnaphthalamide based drugs.…”

“…In order to exploit the thermo-responsive properties of these formulations, laser irradiation was used. Extensive previous studies have been carried out in order to optimize the laser treatment duration in order to achieve temperatures that are likely to initiate drug release without adverse effects to tissue [34,35]. Figure 6 A 1 shows a tumour excised from a control group mouse.…”

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

“…Previously we reported the controllable heating capacity and resultant dissipation aer irradiation of HNPs in agar phantoms at varied concentrations. 21 These studies suggested that the HNPs used (50 nm) would be useful for stimuli responsive drug release as their heating could be controlled via alteration of irradiation time and concentration. In order for HNPs to be used to thermally trigger drug release it is important that their temperature rise is not sufficient to cause any thermal degradation of drug or widespread heat dissipation at high temperatures which would affect healthy tissue.…”

“…Studies on the thermal potential and heat dissipation of HNPs for stimuli responsive drug delivery have been reported, however the majority of these have been either been carried out using computer modelling 22 or in the use of agar phantoms 21,23 and little studies have shown heating abilities aer cellular internalization. Whilst gel phantoms are designed to mimic physiological tissue there is an increasing need to fully understand the heating ability and effect on surroundings experienced aer irradiation in more realistic conditions either in vitro or in vivo.…”