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Abstract Background The skin is both a target and a potential conduit for the delivery of drugs, but its cornified cell layer resists penetration by most molecules. This study investigated the potential of superparamagnetic iron oxide nanoparticles to facilitate the transdermal delivery of anticancer agents. Results Chemotherapeutic cancer drugs were applied with or without nanoparticles to the skin of hairless mice, and their ability to penetrate the skin was assessed using fluorescence microscopy and tumor growth. Nanoparticles enhanced the penetration of the skin by doxorubicin and 5-fluorouracil as determined by fluorescence microscopy and growth retardation of experimental melanoma in immunocompetent, syngeneic mice. This drug enhancement did not require conjugation or encapsulation of the drugs by the nanoparticles—simple co-administration sufficed. Nanoparticles applied topically to melanomas increased the cytotoxicity and immune cell infiltration induced by co-administered 5-fluorouracil, and also reduced vascularization of the tumors independently of 5-fluorouracil. Conclusion Correctly formulated superparamagnetic iron oxide nanoparticles can facilitate the chemotherapeutic effectiveness of cytotoxic drugs on skin tumors by both increasing their transdermal penetration and ameliorating host–tumor interactions. This enhancement of skin penetration occurs without the need for conjugation or encapsulation of the co-administered drugs, and so will likely be applicable to other drugs, also.

Radiosensitization effects caused by high atomic number (Z) metallic nanoparticles have been extensively explored with a wide range of X-ray based radiotherapy beams that seem to provide intriguing results for potential clinical applications. In this study, the radiobiological consequences of gold nanoparticles (AuNPs), superparamagnetic iron oxide nanoparticles (SPIONs), Platinum Nanodendrites (PtNDs) and Bismuth Oxide Nanorods (BiNRs) on Human Colon Carcinoma cells (HCT 116) irradiated with 150 MeV proton beams were investigated. Cell survival and reactive oxygen species (ROS) generation were measured. BiNRs demonstrates the highest sensitization enhancement ratio (SER) of 4.93 followed by PtNDs with SER value of 3.08. Meanwhile, AuNPs and SPIONs depict SER values around 2.64 and 1.95 respectively. The ROS generation corresponded to the level of radiosensitization with the highest ROS obtained for BiNRs and followed by PtNDs, AuNPs and SPIONs. In conclusion, high Z nanoparticles possess the potential to be clinically applied in proton beam therapy. Keywords: Gold nanoparticles, Superparamagnetic iron oxide nanoparticles, Platinum nanoparticles, Bismuth nanoparticles, Radiosensitization, Proton beam

Nanomedicine is an emerging field with great potential in disease theranostics. We generated sterically stabilized superparamagnetic iron oxide nanoparticles (s-SPIONs) with average core diameters of 10 and 25 nm and determined the in vivo biodistribution and clearance profiles. Healthy nude mice underwent an intraperitoneal injection of these s-SPIONs at a dose of 90 mg Fe/kg body weight. Tissue iron biodistribution was monitored by atomic absorption spectroscopy and Prussian blue staining. Histopathological examination was performed to assess tissue toxicity. The 10 nm s-SPIONs resulted in higher tissue-iron levels, whereas the 25 nm s-SPIONs peaked earlier and cleared faster. Increased iron levels were detected in all organs and body fluids tested except for the brain, with notable increases in the liver, spleen, and the omentum. The tissue-iron returned to control or near control levels within 7 days post-injection, except in the omentum, which had the largest and most variable accumulation of s-SPIONs. No obvious tissue changes were noted although an influx of macrophages was observed in several tissues suggesting their involvement in s-SPION sequestration and clearance. These results demonstrate that the s-SPIONs do not degrade or aggregate in vivo and intraperitoneal administration is well tolerated, with a broad and transient biodistribution. In an ovarian tumor model, s-SPIONs were shown to accumulate in the tumors, highlighting their potential use as a chemotherapy delivery agent.