In vitro responses to electrosprayed alkaline phosphatase/calcium phosphate composite coatings.
Surface modification of titanium implants to improve their fixation in bone tissue is of great interest. We present a novel approach to enhance implant performance by applying important principles of bone mineralization to biomedical coatings. As an attempt to mimic the biphasic biomineralization process, both the enzyme alkaline phosphatase (ALP) and calcium phosphate (CaP) were immobilized onto Ti discs, thereby triggering enzymatically and physicochemically controlled biomineralization pathways. ALP, CaP and ALP-CaP composite coatings with preserved functionality of ALP were successfully deposited using electrospray deposition. In vitro soaking studies in cell culture medium revealed that crystal growth initially proceeded at a faster rate on CaP-coated Ti than on ALP-containing coatings, but mineral deposition onto ALP-coated Ti caught up with the calcification behaviour of CaP coatings upon long-term soaking. Cell culture experiments with osteoblast-like cells, however, demonstrated the opposite effect in mineral deposition on the electrosprayed CaP and ALP coatings. The ALP-CaP composite coatings showed delayed proliferation as well as accelerated mineralization in comparison to cells cultured on the CaP-coated and uncoated Ti. In conclusion, these in vitro results showed that the osteogenic potential of Ti can be stimulated by ALP-containing coatings.
Department of Periodontology and Biomaterials PB309, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
Lise T
LT
de Jonge
Jeroen J J P
JJ
van den Beucken
Sander C G
SC
Leeuwenburgh
Anouk A J
AA
Hamers
Joop G C
JG
Wolke
John A
JA
Jansen
D000469:Alkaline Phosphatase / Q000737:chemistry*; D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D008422:Materials Testing; D010006:Osteoblasts / Q000737:chemistry*; D010012:Osteogenesis / Q000502:physiology*; D051381:Rats
D018786:Bone Substitutes; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C020243:calcium phosphate; D000469:Alkaline Phosphatase