# Copper- and Iron-Based Nanoflowers in Cancer Theranostics
## 4 Synthesis Methods and Applications of Flower-like Copper- and Iron-Based Nanostructures
### Iron-Based NFs
Their results showed that the produced NFs had great potential as a negative and a positive contrast agent in MRI, thus contributing to a more spot-on diagnosis and reducing the chances of the misdiagnosis of other entities as cancerous tumors [110]. [PERSON] et al., produced PEG-coated Fe\({}_{3}\)O\({}_{4}\) NFs through the solvothermal method with easy dimension control for the diagnosis and therapy of breast cancer. Moreover, it was proven that the magnetization of the Fe NFs has a linear relationship with their size, making them excellent for imaging purposes and monitoring therapeutic performance [111]. Therapeutic action against breast cancer cells is also supported by [PERSON] et al. In their study, \(\gamma\)Fe\({}_{2}\)O\({}_{3}\)@Au NFs were produced and tested in vivo on mice. It was observed that the produced NPs had a great tumor accumulation and gradual concentration decrease at the 6, 24 and 48 h time stamps post injection. The NF's anticancerous properties were only apparent when applied in combination with laser irradiation. In other cases, in which the separate use of \(\gamma\)Fe\({}_{2}\)O\({}_{3}\)@Au NFs or laser irradiation was applied, tumor growth was not influenced. Tumor necrosis was triggered as soon as two days post injection, and no regrowth was observed during the course of 12 days post injection [112]. Furthermore, [PERSON] et al., examined the effect of iron oxide NFs encapsulated in thermosensitive fluorescent liposomes for the hyperthermia treatment of lung adenocarcinoma. In their experiments, NFs managed to easily pass through the lung cancer cells' membranes due to the high biocompatibility provided by the surrounding lipid capsule, therefore accumulating in their cytoplasm. As mentioned before, cytotoxicity showed a negligible effect without a source of radiation, in this case, MHT, thus reinforcing the synergetic effect of NFs [83]. Similarly, iron NFs encapsulated with the polymer PS-PAA have also been examined as multimodal nanoplatforms on one of the most aggressive types of cancer: brain glioblastoma. [PERSON] et al., developed IONFs@PS-b-PAA for PTT, MRI and magnetic particle imaging (MPI) [113]. [PERSON] et al., synthesized iron oxide-gold nanoparticles (GIONFs) with great optical properties and biocompatibility and tested them as a PTT agent. In their study, the effect of GIONFs on cholangiocarcinoma(CAA), an aggressive type of cancer affecting the bile duct, was examined. The synergetic use of the produced NFs with NIR laser irradiation resulted in an increase in the tumor's temperature, indicating the high heating capacity of GIONFs. In vitro testing on CAA cells showed that GIONFs do not induce hemolysis. In vivo PTT experiments revealed that a dose of 200 \(\mu\)g GIONFs only reduced the stiffness of the tumor but did not induce its regression. A dose of 700 \(\mu\)g GIONFs showed a partial tumor regression, suggesting that GIONFs should have an auxiliary role in cancer therapeutics [114]. [PERSON] et al., created iron oxide NFs with an outer Cu\({}_{2}\)O shell with multimodal properties including PTT, MHT and PDT. The produced nanomaterials were tested on human prostate adenocarcinoma PC3 cells both in vitro and induced on mice. The in vitro sole use of laser irradiation, magnetic frequencies or nanoparticles showed a negligible effect on PC3 cells. Comparing PTT and MHT, the first showed excellent results, reaching 90% cytotoxicity in 5 min with a concentration of 1.6 mM Cu and 250 \(\mu\)M Fe, while the latter reached only 15% cytotoxicity. It was observed that the effect of NFs in PTT is dose-dependent, even in low concentrations; for example, in 0.16 mM Cu and 25 \(\mu\)M Fe, the NPs showed great results. Taking into consideration that PDT's cytotoxicity depends on oxygen production, IONF@CuSs are eligible for this application due to the production of reactive oxygen species (ROS), especially under laser irradiation. Overall, IONF@CuS provides multiple theranostic applications, especially in PTT [115].