Carboxymethyl-sagocellulose-stabilized Fe₃O₄ nanoparticles with 5-fluorouracil as photothermal agents for tumor ablation

Background: There is a continuous growth of interest in the development of nano-drug delivery systems that could combine therapy and diagnosis of cancer. 

Results: Novel multifunctional superparamagnetic iron oxide nanoparticles (SPIONs, chemically Fe₃O₄) conjugated with carboxymethyl sagocellulose (CMSC), and 5-fluorouracil (Fe₃O₄-CMSC-5FU) were synthesized. The conjugated nanoparticles have the magnetic properties of the SPIONs, which allows the nanoparticles to be localized at the target area by applying an external magnetic field. SPIONs generate heat upon exposure to laser lights, resulting in a photothermic effect. The drug-loading efficiency of 5-FU into the SPIONs-CMSC conjugated nanoparticles was 70 to 84% w/w which could release the drug at intracellular pH (5.4) of cancer cells and resist drug release at pH 7.2. In vivo studies using mice models confirmed the nanoparticles could efficiently deliver 5-FU only to the cancer cells and the anticancer effect was enhanced by laser-induced hyperthermia. 

Conclusions: The combination of targeted delivery of 5-FU with photothermal therapy (PTT) looks promising for selective killing of cancer cells. Furthermore, SPIONs are an excellent contrasting agent for use in computerized tomography (CT) imaging for determining the tumor location and monitoring the progress of the therapy. The focus of this work was the oncological application of multifunctional Fe₃O₄-CMSC-5FU nanoparticle conjugates, with an emphasis on therapeutic, diagnostic and prognostic purposes.