Structuring of bioactive glass surfaces at the micrometer scale by direct casting intended to influence cell response

摘要

Defect-free bioactive glass surfaces with agrooved microstructure at the low micrometer scale wereachieved by a mold casting process. The process wasapplied to the well-known glass compositions 45S5 and13–93. Such microstructured surfaces may exhibit especiallyfavorable conditions for bone cell orientation andgrowth. The aim of the study was to assess the parameterrange for a successful casting process and thus to producesamples suitable to investigate the interaction betweenstructured surfaces and relevant cells. Viscous flow in itstemperature dependence and thermal analysis were analyzedto identify a suitable process window and to designa manageable time-temperature process scheme. Counteractingeffects such as formation of chill ripples, moldsticking and build-up of permanent thermal stress in theglass had to be overcome. A platinum gold alloy was chosenas mold material with the mold surface bearing themother shape of the microstructure to be imprinted onthe glass surface. First experiments studying the behaviorof osteoblast-like cells, seeded on these microstructuredglass surfaces revealed excellent viability and an orientationof the cells along the microgrooves. The presented resultsshow that direct casting is a suitable process to producedefined microstructures on bioactive glass surfaces.