Amino acids-incorporated nanoflowers with an intrinsic peroxidase-like activity.

Zhuo-Fu Wu,Qi-Sheng Huo,Cheng-Yan He,Heng Li,Ye Zhang,Zheng-Qiang Li,Lei Wang,Lei Chen,Ya-Li Ma,Zhi Wang

doi:10.1038/srep22412

Zhuo-Fu Wu, Qi-Sheng Huo + Show 8 more

Open Access

https://doi.org/10.1038/srep22412

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Abstract

Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years. A simple method is reported here for fabricating hybrid organic–inorganic nanoflowers using copper (II) ions as the inorganic component and natural amino acids as the organic component. The results indicate that the interactions between amino acid and copper ions cause the growth of the nanoflowers composed by C, N, Cu, P and O elements. The Cu ions and Cu(AA)n complexes containing Cu-O bond are present in the nanoflowers. The nanoflowers have flower-like porous structure dominated by the R groups of amino acids with high surface-to-volume ratios, which is beneficial for exerting its peroxidase-like activity depending on Fenton-like reaction mechanism with ABTS and Rhodamine B as the substrates. It is expected that the nanoflowers hold great promise as enzyme mimics for application in the field of biosensor, bioanalysis and biocatalysis.

Highlights

Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years
Numerous works have been devoted to the synthesis and characterization of the nano-structured materials[1,2,3,4,5,6]
Among of the nano-structured materials, the bio-inspired materials with micro- and nano-scale have been proposed as a big breakthrough on the design of advanced functional materials and have attracted much attention in recent years due to the huge advantage of the bio-molecules in directing and assembling the superstructures[7]

Summary

Results and Discussion

The nanoflowers have hierarchical structures with high surface-to-volume ratios. Figure 1d demonstrates that disordered fragments are formed without Asn. Depending on the difference of R groups, the peroxidase-like activities of amino acid-incorporated nanoflowers are compared and the results are as follows: “Positively charged R groups > Nonploar, aliphatic R groups > Aromatic R group > polar, uncharged R groups > negatively charged groups” (Table S1). On the basis of the difference of R groups, the specific activities of amino acid-incorporated nanoflowers using Rhodamine B as the substrate are compared and the results are as follows: “Positively charged R groups > Nonploar, aliphatic R groups > Aromatic R group > polar, uncharged R groups > negatively charged groups” (Table S2). Owing to the existence of Cu ions, the amino acids-incorporated nanoflowers exhibit intrinsic peroxidase-like activity by the self-assembly between amino acids and copper phosphate, while the protein-incorporated nanoflowers only present the enzymatic activity of protein component. We expect that these amino acid-inorganic hybrid nanoflowers will have important applications in biosensors, bioanalytical devices, pharmaceutical applications and industrial biocatalysis

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