Organic-inorganic hybrid nanoflowers: The known, the unknown, and the future

Organic-inorganic hybrid nanoflowers (HNFs) are hierarchical flower-shaped microstructures that are assembled by nanoscale petal-like nanosheets composed of both organic and inorganic constituents. Generally, inorganic parts of HNFs are transition metal phosphates and organic components are mostly enzymes and proteins; however, non-protein molecules could be also used as organic phase in some types of newly described HNFs. Recent findings indicate that they are constructed through the coordination between organic and inorganic components. HNFs are mainly used for efficient biocatalysis and highly sensitive biosensing, while they have also some other noteworthy applications such as antimicrobial agents, antigen careers, and delivery platforms for anticancer drugs. It is believed that the high surface-to-volume ratio of HNFs could tackle mass transfer limitations leading to enhance the activity of their organic constituents. The environment-friendly route of synthesis and stabilization of biomolecules upon storage are the advantages of enzyme-based HNFs. In the present review, the focuses are on designs, preparations, formation mechanisms, and remarkable applications of the conventional forms and also magnetic, multi-component, and enzyme-free HNFs. Considering the fact that HNFs are in the early stages of development, the unknown aspects and future directions of research in this field are also discussed.