# Copper- and Iron-Based Nanoflowers in Cancer Theranostics
## 6 Conclusions  
Cancer is currently one of the main causes of death internationally. Its complex nature has been gradually revealed, while many imaging and therapeutic modalities have been developed. Advanced modalities in cancer theranostics with a low price range and high yield efficiency are pressing issues. A novel type of materials, nanomaterials like NPs, is being studied as a plausible solution to this problem. NFs are NPs that resemble flowers on the nanoscale. Although a typical NF's structure consists of inorganic materials, many organic components can be added to enhance their properties, such as enzymes and drugs, thus creating HNFs.  
The field of flower-like hierarchical nanomaterials has seen significant advancements, focusing on synthetic techniques, growth mechanisms, particle size distribution, morphology, and their chemical, physical, and optical properties to enhance catalytic, energy-related, and biomedical applications. Various inorganic nanoflowers have been synthesized through physical, chemical, biological, and hybrid methods. Over the past two decades, research on these materials has surged, with increasing publications emphasizing their benefits, such as their high surface-to-volume ratio, strong adsorption capacity, high loading efficiency, and excellent catalytic performance. Efforts have been made to optimize their morphology and size distribution for specific applications by controlling factors like reagents, reaction time, temperature, and metal ratios.  
In the last couple of decades, NFs based on copper or iron have been under the microscope for the production of novel nanomaterials. Due to their excellent biocompatibility, high drug loading ability, low cost, facile synthesis and, most importantly, magnetic and photothermic properties, Fe- and Cu-based NFs can be used as drug nanoplatforms, PTT/MHT/PDT agents and MRI contrast agents. NFs have been synthesized through various methods, including physical, chemical, biological, and hybrid approaches. The optimization of their morphology and size distribution is of great importance for specific applications, by adjusting, for example, reaction conditions such as reagent type and quantity, reaction time, temperature, and metal ratios. By altering synthetic pathways, simple, cost-effective, and environmentally friendly methods have been developed that seem to be suitable for industrial applications too. Such NFs possess unique functionalities and hold promise for use in cancer theranostics. Investigations into alloy, core-shell, and surface-modified NFs are anticipated to expand the range of multi-metallic compositions with modified structures, and future research may focus on integrating multiple nanostructured materials. These studies have uncovered numerous unique functionalities and potential applications. Future research on nanomaterials is likely to involve combining multiple nanostructured materials, such as CoS nanoflowers coated with gallic acid, manganese sulfide, and graphene oxides, to unlock new functionalities and expand their applications.  
Conceptualization, A.T. and G.Z.K.; methodology, all authors; software, all authors; validation, A.T. and G.Z.K.; investigation, all authors; data curation, A.V.; writing--original draft preparation, A.V., D.A.G. and P.E.; writing--review and editing, A.T. and G.Z.K.; visualization, A.T. and G.Z.K.; supervision, A.T.; project administration, A.T. and G.Z.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflicts of interest.