Tissue engineering pore size distribution

Another useful thermal characterization technique is thermal compression in which a polymer fabric or biotextile is subjected to different loads at different temperatures. The thickness, pore size, and distribution can be monitored at each condition to prepare ideal scaffolds for tissue engineering. PolyCethylene terephthalate) (PET) nonwoven fiber scaffolds have been prepared for tissue engineering by thermal compression and simultaneous characterization. Applying pressure near the T of the polymer ( 70°C) yielded better control of the pore size distribution and smaller pore sizes, which led to faster and wider proliferation of Irophoblast andNIH 3T3 cells on the scaffold [9]. 

Three key elements determine the potential and applications of a hollow-fiber membrane (1) pore size and pore size distribution, (2) selective layer thickness, and (3) inherent properties (chemistry and physics) of the membrane material. Pore size and its distribution usually determine membrane applications, separation factor, or selectivity. The selective layer thickness determines the membrane flux or productivity. Material chemistry and physics govern the intrinsic permselectivity for gas separation and pervaporation, fouling characteristics for RO (reverse osmosis), UF (ultrafiltration), and MF (microfiltration) membranes, chemical resistance for membranes used in harsh environments, protein and drug separation, as well as biocompatibUity for biomedical membranes used in dialysis and biomedical and tissue engineering. 

The ultimate tensile test results showed that the samples electrospun with a negative polarity voltage broke at one half the strain, 28% vs. 60%, and only achieved a UTS of 0.23 MPa, one half the positive polarity s 0.51 MPa. While the total porosity of the samples was insignificantly different (74.5% 1.3% positive and 77.4% 1.8% negative), the distribution of pore sizes determined by mercury porosimetry was less uniform for positive samples, with a strong peak at a pore diameter of 5 pm. SEM pictures seemed to show that at the nanostructure level the fibers branched differently. These properties of the fabric were significantly different in ways that may affect its use as a tissue engineering scaffold. 

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