Issue 12, 2015

Ca2+-induced self-assembly of Bombyx mori silk sericin into a nanofibrous network-like protein matrix for directing controlled nucleation of hydroxylapatite nano-needles

Abstract

Bone biomineralization is a well-regulated protein-mediated process where hydroxylapatite (HAP) crystals are nucleated with preferred orientation within the self-assembled protein matrix. Mimicking this process is a promising approach to the production of bone-like protein/mineral nanocomposites for bone repair and regeneration. Towards the goal of fabricating such nanocomposites from sericin, a protein spun by Bombyx mori (B. mori) silkworm, and bone mineral HAP, for the first time we investigated the chemical mechanism underpinning the synergistic processes of the conformational change/self-assembly of B. mori sericin (BS) as well as the nucleation of HAP on the resultant self-assembled BS matrix. We found that BS, rich in anionic amino acid residues, could bind Ca2+ ions from the HAP precursor solution through electrostatic attraction. The Ca2+ binding drove the conformational change of BS from random coils into β-sheets and its concomitant self-assembly into the interconnected nanofibrous network-like protein matrix, which initiated the nucleation and growth of HAP crystals. HAP crystals directed by the resultant self-assembled BS matrix grew preferentially along their crystallographic c-axis, leading to the formation of HAP nano-needles. The HAP nano-needles in the self-assembled BS matrix were subsequently aggregated into globules, probably driven by the hydrogen bonding between C[double bond, length as m-dash]O groups of BS and O–H groups of HAP nano-needles. The present work sheds light on the chemical mechanisms of BS self-assembly and the controlled mineralization directed by the self-assembled matrix. We also found that the resultant nanocomposites could promote the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. Thus our work also generates a biomimetic approach to bone-like silk protein/mineral nanocomposite scaffolds that can find potential applications in bone repair and regeneration.

Graphical abstract: Ca2+-induced self-assembly of Bombyx mori silk sericin into a nanofibrous network-like protein matrix for directing controlled nucleation of hydroxylapatite nano-needles

Supplementary files

Article information

Article type
Paper
Submitted
24 Nov 2014
Accepted
27 Jan 2015
First published
17 Feb 2015

J. Mater. Chem. B, 2015,3, 2455-2462

Ca2+-induced self-assembly of Bombyx mori silk sericin into a nanofibrous network-like protein matrix for directing controlled nucleation of hydroxylapatite nano-needles

M. Yang, G. Zhou, Y. Shuai, J. Wang, L. Zhu and C. Mao, J. Mater. Chem. B, 2015, 3, 2455 DOI: 10.1039/C4TB01944J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements