In Vitro Synthesis of Calcium Nanoparticles Using the Protein Cage of Apoferritin


Article Preview

Recently the creation of calcium compounds with a highly controlled ultrastructure is noted as next generation materials for biomedical applications. Here we propose the novel method for synthsizing calcium nanoparticles using iron strange protein, apoferritin. Apoferritin was incubated in saturated Ca(HCO3)2 solution at 18 °C. Temperature of the reaction solution was then increased to 37 °C and left for 2 hours to make CaCO3 sedimentated. After removing the sediments in the bulk solution by centrifugation, the supernatant was concentrated. Saturated Ca(HCO3)2 was added to it and the mixed solution was incubated at 37 °C for 30 min. This process was repeated four times. With a Transmission Electron Microscope (TEM), nearly spherical particles with a diameter of about 6 nm were observed to form in the cavity of apoferritin. The nanoparticles were observed to have a lattice structure of spacing about 0.22 nm with high resolution TEM. With Energy Dispersive X-ray spectroscopy (EDS) analysis, the peak of Ca (Kα; 3.7 keV) was detected from a synthesized nanoparticle. According to the solvent condition, nanoparticles formed in the apoferritin cavity would be CaCO3.



Key Engineering Materials (Volumes 361-363)

Main Theme:

Edited by:

Guy Daculsi and Pierre Layrolle




H. Fukano et al., "In Vitro Synthesis of Calcium Nanoparticles Using the Protein Cage of Apoferritin", Key Engineering Materials, Vols. 361-363, pp. 183-186, 2008

Online since:

November 2007




[1] T.J. Webster et al. Biomaterials 22, 1327-1333 (2001).

[2] M. Okuda et al. Biotechnology and Bioengineering 84, 187-194 (2003).

[3] M. Okuda et al. Nano Letters 5, 991-993 (2005).

[4] S. Takeda, M. Ohata, S. Ebina, and K. Nagayama Biochem. Biophys. Acta 1174, 218-220 (1993).

[5] H. Yoshimura, T. Scheybani, W. Baumeister, and K. Nagayama, Langmuir 10, 3290-3295 (1995).

[6] S. H. Banyard, D. K. Stammers, and P. M. Harrison Nature 271, 282-284 (1978).

[7] J. Polanams, A. D. Ray, and R. K. Watt Inorganic Chemistry 44, 3203-3209 (2005). Fig. 3 EDS spectrum of an Ca core (a) Unstained STEM image of cores, (b) EDS spectrum at position 001 (b) -1) and 002 (b) - 2) in (a). Scale bar is 30 nm.

Fetching data from Crossref.
This may take some time to load.