Consistent quasistatic and acoustic elasticity determination of poly‐L‐lactide‐based rapid‐prototyped tissue engineering scaffolds

Abstract

This paper is concerned with reliable and physically sound elasticity determination of rapid-prototyped tissue engineering scaffolds made of poly-L-lactide (PLLA), with and without small portions of tricalcium phosphate (TCP) inclusions. At the level of overall scaffolds, that is, that of several millimeters, multiple uniaxial loading-unloading (quasistatic) tests were performed, giving access to the scaffolds' Young's moduli, through stress-strain characteristics during unloading. In addition, acoustic tests with 0.05 MHz frequency delivered an independent access to elastic properties, in terms of the normal components of the scaffolds' stiffness tensors. The latter strongly correlate, in a linear fashion, with the Young's moduli from the unloading tests, revealing porosity independence of Poisson's ratio. The magnitude of the latter is in full agreement with literature data on polymers. Both of these facts underline that both ultrasound tests and quasistatic unloading tests reliably provide the elastic properties of tissue engineering scaffolds.

Influence of internal pore architecture on biological and mechanical properties of three‐dimensional fiber deposited scaffolds for bone regeneration

“…It has to be noted that the macroporous structure influences the properties of the whole scaffold . Mechanical properties of the 3D constructs were characterized by static compression tests and dynamic mechanical analysis (DMA) studies (rotational rheometer).…”

“…), which is required for tissue constructs. The obtained porosity level is a good compromise between mechanical and biological properties . High porosity and pore size of 480 µm are known to result in greater bone ingrowth .…”

“…It was found that in scaffolds with smaller pores, the tendency was tilted toward cell growth rather than ECM secretion, resulting in over confluence during the middle and late stages of differentiation; consequently, the extent of ECM secretion decreased compared with scaffolds with larger pores . However, high porosity resulted also in diminished mechanical properties, thereby setting an upper functional limit for pore size and porosity is required . Moreover, to get good fusion between layers, the pore size in the Z direction is compromised.…”

Viscoelastic behaviour of hydrogel-based composites for tissue engineering under mechanical load

“…To reduce the effect of viscous dissipation, quasi-static unconfined compression tests [16] were performed at very a low strain rate (∼0.3 millistrains s…”

“…s −1 [16]. The tangent Young's modulus (E) was calculated from the initial linear part of the slope of the stress-strain curve, i.e.…”