ASTM Committee on F4 Medical and Surgical Materials and Devices, Division IV, Tissue Engineered Medical Products (TEMPs), Biomaterials and Biomolecules for TEMPs Subcommittee (F4.42) has been developing standards for characterizing natural materials used in TEMPs. Natural materials include alginate, chitosan, collagen and hyaluronate. These materials support cell growth and differentiation on TEMPs substrates and scaffolds. Natural materials have been used in a variety of applications, including encapsulation, cell seeding, development of “memory” biomaterials, as well as degradable scaffolds, growth factor/nucleic acid delivery vehicles, and as a carrier to improve product handling characteristics. These materials have typically been very poorly characterized as to their chemical, physical and biological properties. This has resulted in variability in the products produced from these starting materials. The development of Standard Guides and Test Methods for characterizing natural materials is anticipated to reduce the variability of these starting materials and to aid in the assessment of the safety of the subsequent TEMPs.
Three Standard Guides for characterizing the natural materials that are used as starting materials in the production of TEMPs have been developed and approved as ASTM standard guides. The first guide deals with Alginate, while the second guide deals with Chitosan and Chitosan salts. A third guide was recently approved for the characterization of Type I collagen used for surgical implants and substrates for TEMPs. Standard test methods are under development for the use of 1H-NMR to determine the molecular weight of alginate and the degree of deacetylation of chitosan.
Planned future documents will include guides to characterize additional types of collagen and hyaluronate, as well as the development of additional standard test methods for characterizing the natural materials.