This study is based on the principle that superparamagnetic iron oxide nanoparticles (Fe3O4) can be used to target a specific area given that their magnetic properties emerge when an external magnetic field is applied. Cerium oxide (CeO2), which causes oxidative stress by generating reactive oxygen species (ROS) in the environment of tumor cells, was synthesized on the surface of superparamagnetic iron oxide nanoparticles to produce nanoparticles that selectively kill cancer cells. In addition, hyaluronic acid (HA) was coated on the cerium’s surface to target CD44-overexpressing tumor cells, and natZr was chelated on the Fe3O4@CeO2 surface to show the usefulness of labeling the radioisotope 89Zr (T1/2 = 3.3 d). The synthesis of Fe3O4@CeO2 was confirmed by Fourier Transform-Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Field Emission-Transmission Electron Microscope (FE-TEM). The coating of HA was confirmed by FT-IR, X-ray Photoelectron. Spectroscopy (XPS), FE-TEM, Energy-Dispersive X-ray Spectroscopy (EDS) and Thermogravimetric Analysis (TGA)/Differential Scanning Calorimetry (DSC). The sizes of the prepared nanoparticles were confirmed through FE-TEM and Field Emission-Scanning Electron (FE-SEM) (sizes of 15 to 30 nm), and it was confirmed that natZr was introduced onto the surface of the nanoparticles using EDS. The particle size of the dispersed material was limited through Dynamic Light Scattering (DLS) to about 148 nm in aqueous solution, which was suitable for the (enhanced permeation and retention) EPR effect. It was confirmed that the HA-coated nanoparticles have good dispersibility. Finally, a cytotoxicity evaluation confirmed the ability of CeO2 to generate ROS and target the delivery of HA. In conclusion, Fe3O4@CeO2 can effectively inhibit cancer cells through the activity of cerium oxide in the body when synthesized in nano-sized superparamagnetic coral iron that has magnetic properties. Subsequently, by labeling the radioactive isotope 89Zr, it is possible to create a theranostic drug delivery system that can be used for cancer diagnosis.

In this study, we investigated the tumor targeting effect in cancer cells using triphenylphosphonium (TPP) cations, which are accumulated by differences in membrane potential, and folic acid (FA), which is selectively bound to overexpressed receptors on various cancer cells. We used Food and Drug Administration (FDA)-approved silica nanoparticles (SNPs) as drug carriers, and SNPs conjugated with TPP and FA (STFs) samples were prepared by introducing different amounts of TPP and FA onto the nanoparticle surfaces. STF-1, 2, 3, 4 and 5 are named according to the combination ratio of TPP and FA on the particle surface. To confirm the tumor targeting effect, 89Zr (t1/2 = 3.3 days) was coordinated directly to the silanol group of SNP surfaces without chelators. It was shown that the radiochemical yield was 69% and radiochemical purity was >99%. In the cellular uptake evaluation, SNPs with the most TPP (SFT-5) and FA (SFT-1) attached indicated similar uptake tendencies for mouse colon cancer cells (CT-26). However, the results of the cell internalization assay and measurement of positron emission tomography (PET) images showed that SFT-5 had more affinity for the CT-26 tumor than other samples the TPP ratio of which was lower. Consequently, we confirmed that TPP ligands affect target cancer cells more than FA, which means that cell membrane potential is significantly effective for tumor targeting.

This study evaluated the in vivo behavior and accumulation of silica particles in the form of wires, which were actively studied as drug carriers along with spheres, using positron emission tomography (PET). Wire-shaped silicon dioxide (SiO2) was synthesized at micro-size, using anodic aluminum oxide (AAO), a template, and folic acid (FA), which specifically binds folate receptors (FR) which are overexpressed in many cancers, and which was bound to the wire’s surface to confirm its possible use as a cancer diagnostic agent. In addition, for evaluation using PET, the positron-emitting nuclide 89Zr (t1/2 = 3.3 days) was directly bonded to the hydroxyl group (-OH) on the particle surface. The diameter and shape of the synthesized silica microwires (SMWs) were confirmed using SEM and TEM, the chemical bonding of FA was confirmed through FT–IR and NMR, and the labeling of 89Zr was measured by means of radio-thin-layer chromatography (TLC) measurement. Folic acid-conjugated SMWs (FA-SMWs) were found to have a low receptor-mediated uptake in cell internalization evaluation, but in PET studies, FA-SMWs stayed longer at the tumor site. In conclusion, we successfully synthesized a homogeneous silica microwire for drug delivery, we confirmed that the FA-conjugated sample remains at the tumor site for a relatively longer time, and we have reported the characteristic in vivo behavior of 89Zr-FA-SMWs.

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Ga-labeled capsaicin using a DOTA (1,4,7,10-tetraazocyclododecane-N,N',N″,N'″-tetraacetic acid) derivative [Ga-SCN-Benzyl(Bn)-DOTA-capsaicin] was studied for the diagnosis of breast cancers, such as MCF-7 and SK-BR-3. The standard compound, Ga-SCN-Bn-DOTA-capsaicin, was also prepared and characterized by spectroscopic analysis. The binding affinity ofGa-SCN-Bn-DOTA-capsaicin was evaluated by using breast cancer cell lines (MCF-7, SK-BR-3) and colon cancer cell (CT-26); the biodistribution was carried out by using MCF-7-bearing nude mice, after which the positron emission tomography (PET) images were obtained at different time intervals (15-120 minutes). Ga-SCN-Bn-DOTA-capsaicin showed a cellular uptake of 0.93% Injected Dose (ID) after 30 minutes of incubation, whereasGa-SCN-Bn-DOTA showed a lower uptake of 0.25% ID. The tumor-to-blood ID/g% ratios increased and were found to be 0.49, 0.22, and 0.77 for 15, 30, and 60 minutes, respectively. The small-animal PET study showed that the uptake of Ga-SCN-Bn-DOTA-capsaicin was higher in the tumor regions even at 30 minutes after injection. These results suggest thatGa-SCN-Bn-DOTA-capsaicin is a potential targeting agent for PET imaging of MCF-7.