Synthesis of Layered, Graded Bioscaffolds - Structural Interfaces and Attachments in Biology - page 353

Fig. 16.8 Core-shell composite Young's modulus ( n ¼ 6) compares favorably to layered
composites theoretical prediction. The close agreement is indicative of integration of the mem-
brane shell with scaffold core. Shell thicknesses: 23, 45, 78, and 155 m. Error bars: Mean SD.

m

(Reproduced, with permission, from Caliari et al. [ 1 ])

After separate mechanical characterization of aligned CG scaffolds and CG
membranes, CG scaffold-membrane composites were fabricated and characterized
using membranes ranging in thicknesses from 23

m(1%
2 wrapped twice around scaffold). These scaffolds demonstrated dramatically
increased tensile moduli over CG scaffold controls (no membrane shell) with a 36-
fold increase observed for the 155

m(0.5%1 )to155

m m

mmembrane thickness. Experimental results were
compared to predictions from layered composites theory. Layered composites theory
has previously been used to accurately predict the tensile properties of multicompo-
nent materials based on the relative size of the individual components and their
separate moduli [ 1 ]. CG core-shell composite Young's modulus ðE composite Þ can be
predicted by the rule of mixtures as a function of scaffold core Young's modulus
ðE scaffold Þ , membrane shell Young's modulus E membrane ,compositeradius( r ), and
membrane thickness ( t )[ 1 ]:

m

!
þ E membrane 1 ð r t Þ

!

2 2

ðr tÞ

E composite ¼ E scaffold (16.1)

r 2 r 2

Experimental results correlate well with theoretical predictions, especially for
composites with the two thicker membranes (78, 155

m m) (Fig. 16.8 ). The close