# Copper- and Iron-Based Nanoflowers in Cancer Theranostics
## 4 Synthesis Methods and Applications of Flower-like Copper- and Iron-Based Nanostructures
### Copper-Based NFs  
Copper-based NFs also play an important role in the development of novel theranostic modalities for cancer. [PERSON] et al., synthesized CuS-MnS\({}_{2}\) NFs via a hydrothermal process followed by calcination thermal treatment. Biomedical applications on human ovarian carcinoma A2780 cells, human hepatocyte LO2 cells and MIHA cells, human non-small cell lung cancer H460 cells, and human lung adenocarcinoma A549 cells were examined along with the NFs' anticancer mechanism. Cells were incubated with CuS-MnS\({}_{2}\) NFs and exposed to 808 nm laser irradiation for 15 min along with a fluorescent agent in order to test cell viability. As was expected, higher doses of NFs showed better efficiency. At the highest concentration tested (1 mg mL\({}^{-1}\)), A2780 cells showed the lowest viability around 65%, H460 70% and A549 around 90%. Compared to cancer cells, healthy human cells MIHA and LO2 were not affected, suggesting that CuS-MnS\({}_{2}\) exhibits good biocompatibility. Further tests were conducted, proving that necrotosis might be the main anticancer mechanism of CuS-MnS\({}_{2}\) NFs paired with NIR irradiation [117]. CuS NFs conjugated with nanographene oxide (NGO) and folic acid (FA) were tested for their efficacy in PTT by [PERSON] et al. In their study, the produced NFs showed 46.2% photothermal efficiency (light-to-heat conversion), while only within 5 min of exposure at 980 nm laser irradiation, a temperature of 63.1 \({}^{\circ}\)C was accomplished. Notable cytotoxicity was exhibited towards human cervix adenocarcinoma and human ovarian adenocarcinoma cells [118]. Table 5 presents copper-based nanoflowers synthesized by different processes, and Table 6 presents the synthesized copper nanoflowers under diverse reaction conditions and their main findings. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type of** & **Synthesis** & **Size (nm)** & **Application** & **Reference** \\
**Nanoflower** & **Method** & **Size (nm)** & **Application** & **Reference** \\ \hline CuS–MnS\({}_{2}\) & Hydrothermal & 400 & Contrast agent (MRI), photothermal (PTT) and photodynamic (PDT) agent against ovarian cancer & [117] \\ NGO–FA–CuS & Hydrothermal & 40 & Theranostic agent & [118] \\ Cu-EGCG-ICG- & \begin{tabular}{c} Self-assembly \\ \end{tabular} & 217 \(\pm\) 18.1 & PTT and chemotherapy agent & [119] \\ Cu\({}_{7.2}\)S\({}_{4}\)/5 MoS\({}_{2}\) & Solvothermal & 200 & \begin{tabular}{c} Theranostic agent \\ (PTT, PDT, CT) \\ \end{tabular} & [120] \\ Hollow CuS & \begin{tabular}{c} Laser-assisted \\ ablation/ion- \\ exchange \\ \end{tabular} & 30–120 & \
\begin{tabular}{c} Theranostic agent \\ PTT and chemotherapy agent \\ \end{tabular} & [121] \\ Cu\({}_{3}\)SnS\({}_{4}\) & Hydrothermal & n.a. & (PEC) detection of human cytochrome c & Enzyme-like action for cancer cell detection and ROS-mediated & [23] \\ Gallic acid–Cu(II) & Self-assembly & 9200 &
\begin{tabular}{c} Anticancer activity \\ against breast and lung cancer cell lines \\ \end{tabular} & [122] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Copper-based nanoflowers synthesized by different processes.