# Copper- and Iron-Based Nanoflowers in Cancer Theranostics
## 2 Synthesis Methods for Copper- and Iron-Based Nanoflowers
### Hydrothermal Method
Specifically, Fe\({}_{3}\)O\({}_{4}\) nanoflower-SC showed an 83.66% improvement over hollow Fe\({}_{3}\)O\({}_{4}\) and a 10.70% increase over regular Fe\({}_{3}\)O\({}_{4}\) nanoflowers. Additionally, incorporating dispersants into Fe\({}_{3}\)O\({}_{4}\) nanoflowers reduced agglomeration, further enhancing their magnetothermal performance [76]. Despite these advantages, Mn\({}_{0.5}\)Zn\({}_{0.5}\)Fe\({}_{2}\)O\({}_{4}\) nanoparticles [77] outperform hollow Fe\({}_{3}\)O\({}_{4}\) in ILP, benefiting from Mn\({}^{2+}\) doping, which optimizes magnetothermal performance. [PERSON] and colleagues developed nanoflower-like Bi\({}_{2}\)CuO\({}_{4}\) via a one-step hydrothermal method, leveraging its large surface area to adsorb aptamers and create a signal probe in a sandwich structure on the sensing interface. This enabled enhanced electrochemical signal detection and amplification. The resulting ratiometric biosensor, using Al-MOF, Ce-MOF, and Bi\({}_{2}\)CuO\({}_{4}\), achieved an ultra-sensitive detection of HER2 within 0.001-20.0 ng/mL and can detect other tumor markers by altering the aptamer type, showing high universality and promising clinical application potential [78]. The synthesis of copper bismuth oxysulfide (BiCuOS) nanoflowers (NFs) using oleylamine and sodium citrate as a surfactant and a reducing agent in a one-step hydrothermal process was reported. The nanoflowers consist of bismuth oxide nanoplates arranged in nanoarrays on CuS bases, which enhances optical absorption under NIR light. With a point of zero charge (PZC) near the acidic tumor pH (~5.5), these BiCuOS NFs can absorb NIR light to induce hyperthermia in cancer therapy and act as laser cavity mirrors. Additionally, they can carry chemotherapeutic drugs like doxorubicin, enabling combined chemo-photothermal therapy for improved anticancer efficacy [79]. [PERSON] et al., investigated iron oxide-based magnetic nanoflowers in an in vitro study on breast cancer cells (MDA-MB-231). These monodispersed, temperature-sensitive nanoflowers, synthesized via hydrothermal methods, were tested for magnetic fluid hyperthermia (MFH) effects. The results showed that MFH, in the presence of magnetic nanoclusters, killed nearly 87% of cancer cells within 30 min, highlighting nanoflowers as a promising alternative to traditional single-domain magnetic nanoparticles for cancer treatment [80]. [PERSON] and colleagues synthesized Co(OH)\({}_{2}\)/FeOOH/WO\({}_{3}\) nanofibers (NFs) using a one-step hydrothermal method, demonstrating dual-function enzyme activity with enhanced peroxidase and catalase-like properties. The interactions between the NFs and hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)) were studied using EPR, XPS, and UV-vis techniques. The NFs exhibited pH-dependent activity: peroxidase-like at acidic pH and catalase-like at basic pH. At acidic pH, they generated hydroxyl radicals, while at basic pH, they produced oxygen. The production of hydroxyl radicals and oxygen varied with NF concentration. The study also assessed their anticancer potential for photodynamic therapy (PDT) based on catalase-like activity and oxygen production. This work paves the way for the development of active nanozymes for biosensors and cancer therapy [81].