Composite biocatalytic nanoflower
Self-assembly of a nanoflower with high surface area
A bio-inspired approach for the synthesis of flower-like copper phosphate crystals was proposed in this study. Herein, polydopamine (PDA) was applied to result in the self-assembly of crystals. The flower-like copper phosphate, composed of individual copper phosphate crystals possess self-assembled flowerlike architectures. The flower-like copper phosphate had a specific surface area of 1646.4 m2/g, much higher than irregular copper phosphate crystals of 245.3 m2/g. This method is expected to have many potential applications including catalysis science, antibacterial materials, and biological research.
Formation of PDA/Cu3(PO4)2·3H2O. a) Proposed mechanism, comprising four steps. Gray spheres indicate PDA molecules. Blue spheres indicate copper ions. Blue petals indicate the crystals of Cu3(PO4)2·3H2O. Step 1: PDA form complexes with copper ions; Step 2: forming small agglomerates with primary crystals; Step 3: PDA bonding with primary agglomerates; Step 4: continuous growth. b) fledglingPDA/Cu3(PO4)2·3H2O flowers (concentration of dopamine: 3 mg/L); c) grown PDA/Cu3(PO4)2·3H2O nanoflowers (the concentration of dopamine: 30 mg/L).
Graphene oxide-enzyme hybrid nanoflowers for water soluble dye and micropollutant degradation
Highly efficient enzyme immobilization on carbon-based conductive supports could provide wide applications in energy and environmental areas. Here, we synthesized a 3D flower-like structured self-assembly hybrid nanocomposite with copper phosphate, laccase, graphite oxide (GO) and carbon nanotubes (CNTs) via a facile one-pot strategy under mild conditions. The prepared nanocomposite exhibited very high enzyme loading and improved laccase activity. During the formation of the nanocomposite, the copper phosphate-laccase petals were intertwined by CNTs, and GO nanosheets were further coated on the “petal” surface. Such a configuration ensured high enzyme loading between the GO sheets and good mass transfer efficiency between immobilized enzyme and substrate, which was confirmed by the kinetics test. We further deposited the immobilized enzyme onto electrodes and observed significantly improved direct electron transfer efficiency. Furthermore, better organic dyes and micropollutant degradation performances were observed with the immobilized laccase. In addition, the nanoflower can also lead to highly efficient immobilization of carbonic anhydrase. This novel enzyme immobilization approach provides significant opportunities to exploit its properties in various energy and environmental applications.
Preparation procedure and proposed crystal growth process: (a) primary crystallization of the copper phosphate and laccase; (b) growth of the copper phosphate lamella; (c) inter-connect of separated lamellas and (d) crystal growth and the formation of final flower-like structure
SEM images of the nanoflowerr
Research team: Vicki Chen
Collaborators: Prof. Yatao Zhang
Duan, L., Wang, H., Hou, J., Zhang, Y. and Chen, V., 2015. A facile, bio-inspired synthetic route toward flower-like copper phosphate crystals with high specific surface area. Materials Letters, 161, pp.601-604.