NIST Reference Material Scaffolds for Tissue Engineering
Carl G. Simon Jr.
The National Institute of Standards and Technology (NIST) has deployed Reference Material (RM) scaffolds for tissue engineering: a series of well-characterized 3D tissue scaffolds with differing porosities (RM 8395, RM 8396 and RM 8397) (Fig. 1). Customers will use these RMs as calibration standards during characterization of tissue engineering scaffold devices to enable inter-lab comparison of measurements. The reference scaffolds were made by a freeform fabrication approach (precision extrusion deposition) because this technique affords precise control of scaffold structure. Poly(-caprolactone) was used to fabricate the scaffolds because it is stable during storage and has been cleared for use in tissue engineering implants. The scaffold structural parameters of strut diameter, strut spacing and porosity and have been characterized. The targeted strut diameter was 200 m for all three RMs. However, the targeted strut spacing was varied as 200 m for 8395, 300 m for 8396 and 450 m for 8397, resulting in porosities of 47%, 60% and 69%, respectively. These parameters were selected because they span the common range of pore sizes typically required for tissue engineering applications. The reference scaffolds have been a part of ASTM s committee F04.42 Biomaterials and Biomolecules for Tissue Engineered Medical Products under Working Group WK6507 Reference Scaffolds for Tissue Engineering .