Surface functionalization of Bioglass® with alkaline phosphatase

Bioglass (R) type 45S5 is the most widespread bioactive glass studied for its inorganic bioactivity and ability to affect cell behaviour. In this research work sintered Bioglass (R) substrates were functionalized with a biological molecule (the enzyme alkaline phosphatase ALP) in order to couple bioactive glass typical inorganic properties with biological signals. For the first time - ALP grafting has been performed on the standard Bioglass (R) composition, which is the most widely bioactive glass studied and currently commercialized in various forms. ALP was grafted to sintered Bioglass (R) glass-ceramic pellets both via silanization and via direct bonding to hydroxyl groups exposed on the surface. The presence of the biomolecule was investigated by means of XPS and its activity by enzymatic activity test. In vitro bioactivity of sintered Bioglass (R) at different steps of the functionalization process was investigated by soaking samples in simulated body fluid (SBF) for various experimental times. The possibility to graft ALP in an active state on sintered Bioglass (R) samples both via direct grafting and silanization routes has been demonstrated in the present research. ALP enhances and fastens in vitro bioactivity of the glass-ceramic. Surface functionalization of Bioglass (R) pellets is of interest as model for sintered Bioglass (R) derived scaffolds to be used in bone engineering. (C) 2015 Elsevier B.V. All rights reserved.