Effect of Phase Composition of Calcium Phosphate (CaP) on Bioactivity of Osteon-like Composite Scaffolds

doi:10.15541/jim20150366

Abstract

Abstract:

From compositional perspective, natural bone is a kind of inorganic and organic composite material; while from structural perspective, the basic structural unit of cortical bone is vascularized osteon. In this study, based on the biomimetic principle, a tissue-engineered construct was created to stimulate the basic building block of cortical bone-osteon with complex structure. To achieve this goal, a bi-layered polycaprolactone (PCL)/CaP composite scaffold was produced via a novel two-step fabrication process in the combination of electrospinning and twin screw extrusion. Its inner hollow tube was made of electrospun nanofibers, allowing the formation of a confluent layer of endothelial cells (MS-1) to resemble the Haversian canal, and its outer layer consisted of spiral PCL/CaP microfilament with high porosity, facilitating the proliferation and differentiation of pre-osteoblasts (MC3T3-E1) to form bone-like tissues. To explore the effect of material composition on scaffold bioactivity, three composite scaffolds with different outer layers were fabricated, including PCL, PCL/biphasic calcium phosphate (BCP) and PCL/β-tricaclium phosphate (β-TCP). And then the influences of scaffold composition on the behaviors of pre-osteoblasts were further investigated. Compared to PCL and PCL/β-TCP, significantly more cell growth and higher calcium deposition are found on PCL/BCP scaffolds, precisely controlling the spatial distribution of different cells. Taken together, this bi-layered PCL/BCP scaffold partially mimics the complex structure of osteon, showing a promising potential in the orthopedic application.

Key words: calcium phosphate, phase composition, composite, osteon, twin screw extrusion

CLC Number:

R318

CHEN Xue-Ning, FAN Hong-Song, WANG Hong-Jun. Effect of Phase Composition of Calcium Phosphate (CaP) on Bioactivity of Osteon-like Composite Scaffolds[J]. Journal of Inorganic Materials, 2016, 31(1): 107-112.

Figures/Tables 5

Fig. 1 (a) Two-step fabrication process to create bi-layered scaffolds with (b-c) compact and (d-e) separate microfilaments. Methylene blue staining showed cell attachment in (f) compact, (g) separate, and (h) inner tube-free filaments

Fig. 2 SEM images of (a-b) cross-section of bi-layered scaffold, (c) nanofibrous layer of hollow tube, (d) porous structure inside the filament, and (e-g) surface structure of filament made of stock materials with different PEG amounts

Fig. 3 The growth of MC3T3-E1 cells seeded in microfilament layers of bi-layered (a,d) PCL/BCP, (b,e) PCL/TCP and (c,f) PCL scaffolds at (a-c) day 1 and (d-f) day 7

Fig. 4 Alizarin Red staining showed the osteogenic differentiation of MC3T3-E1 cells seeded in microfilament layers of bi- layered scaffolds(a) and quantification of calcium deposition on scaffolds with different composition (b)

Fig. 5 Bi-layered scaffold controlled the spatial distribution of different cells (a) A confluent layer of MS-1 cells was lined inside the nanofibrous hollow tube. (b) MC3T3-E1 cells were seeded in outer microfilament layer to form cell-rich tissue

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