Resorbable defect analog PLGA scaffolds using CO₂ as solvent: Structural characterization

Abstract

After tooth extraction, the immediate wound treatment by implanting an exact copy of the root could prevent alveolar bone atrophy. The implant should have an interconnected porosity in order to promote tissue in-growth. This communication reports a novel method to realize such net-shaped porous scaffolds fabricated within a few minutes. Porosity and micro-architecture are evaluated by Hg-porosimetry and by image analysis of electron and light microscopy as well as by computed micro-tomography. The total porosity of the scaffold corresponds to (63 +/- 3)%, mainly related to open interconnected porosity. Micro-tomography, as a noninvasive 3D method, is best suited to uncover pores of about 100 microm, a diameter especially important for tissue in-growth. The differentiation between open and closed porosity, however, depends on the method chosen. This effect is attributed to the spherical pores with an orifice only detected in the 3D analysis. Consequently, the closed porosity is overestimated by 8% evaluating 2D images. Finally, the mean pore diameter is found to be 106 and 100 microm for 2D and 3D analysis, respectively. Although the porosity of the scaffold needs to be further optimized for clinical applications, the procedure proposed is a promising route in manufacturing open porous implants without the use of any organic solvent.

Diffusion in Musculoskeletal Tissue Engineering Scaffolds: Design Issues Related to Porosity, Permeability, Architecture, and Nutrient Mixing

“…There are several methods to determine the porosity of a scaffold and quite often more than one method is used to verify results obtained by the other method. 39,64,113 A popular technique is the use of mercury intrusion porosimetry (MIP) 12,33,39,51,65,70,72,83,105,113,115 in which void volume is determined by forcing mercury into the pores under pressure. This technique is based on the principle that the pressure required to force a nonwetting liquid such as mercury into pores, against the resistance imparted by liquid surface tension, is indicative of pore size and void volume.…”

Quantitative architectural description of tissue engineering scaffolds

“…63,64 Attempts at quantitative measurements are equally varied. For instance, Maspero et al 65 used maximum pore/solid distances as a measurement of interconnectivity. Despite measuring these distances as between only 12?5 and 25 mm (compare this with the suggested interconnect sizes of 80 mm given in the literature), 38 the authors conclude that the interconnectivity of the scaffold studied would be sufficient to allow tissue ingrowth and vasculature, with no test of this hypothesis.…”

Growth Factors and Signalling Molecules for Cartilage Tissue Engineering – from Embryology to Innovative Release Strategies for Guided Tissue Engineering

“…Thus, the rapid increase of PGE 2 could be the result of the release out of the porous shell, whereas the later PGE 2 values could be the result of the release out of the core. Regarding the degradation of the microspheres we hypothesized that the slow erosion of the surfaces results in a semi-permeable membrane which delays the release of degradation products and thus results in autocatalytic processes, amplifying the degradation inside the material (Heidemann et al, 2002, Maspero et al, 2002, Gabler et al, 2007. Fig.…”