Sodium silicate bonded borate glass scaffolds for tissue engineering

Borate and silicate glass particles and microspheres with size distributions in the range of approximately 100–400 micron were loosely compacted and bonded by sodium silicate solution to prepare resorbable, porous glass constructs with porosity 30–50%. Conversion of the binding borate glass to hydroxyapatite was investigated by measuring the weight loss of the constructs in a solution of 0.25 M K2HPO4 with a pH value of 9.0 at 37 C, as a function of time. Almost full conversion of the borate glass to hydroxyapatite was achieved in less than 6 days. X-ray diffraction revealed an initially amorphous product that subsequently crystallized to hydroxyapatite