INORGANIC PATHWAYS FOR BIOSYNTHESIS - A MOLECULAR-ORBITAL MODELING APPROACH

Selective adherence on bioactive glass surfaces of various biological molecules associated with osteogenesis appears to be responsible for t he correlation of in vitro reaction kinetics with the rate of bone bon ding. Chemical interaction of organic molecules with hydrated silica i s also important in osteogenesis and bone mineralization and affects, in as yet an unknown manner, extracellular bond and cartilage matrix f ormation. The AM-1 molecular orbital method is used to calculate the r eaction pathways for bond formation between alanine and trisiloxane ri ngs to simulate organic interactions with hydrated silica. The results show that there are low energy reaction pathways for the organic-inor ganic bonding. Different types of interfacial bonds can be formed depe nding upon the structure and orientations of the organic or inorganic molecules. The differences in reaction pathways and binding energies f or formation of -Si-O-C- linkages with the amino acids versus formatio n of -Si-N- bonds may account for the variety of biochemical effects o bserved for silicon in nature and for bioactive glass.