A technique to immobilize bioactive proteins, including bone morphogenetic protein-4 (BMP-4), on titanium alloy.
Immobilization of biomolecules on surfaces enables both localization and retention of molecules at the cell-biomaterial interface. Since metallic biomaterials used for orthopedic and dental implants possess a paucity of reactive functional groups, biomolecular modification of these materials is challenging. In the present work, we investigated the use of a plasma surface modification strategy to enable immobilization of bioactive molecules on a "bioinert" metal. Conditions during plasma polymerization of allyl amine on Ti-6Al-4V were varied to yield 5 ("low")- and 12 ("high")-NH2/nm2. One- and two-step carbodiimide schemes were used to immobilize lysozyme, a model biomolecule, and bone morphogenetic protein-4 (BMP-4) on the aminated surfaces. Both schemes could be varied to control the amount of protein bound, but the one-step method destroyed the activity of immobilized lysozyme because of crosslinking. BMP-4 was then immobilized using the two-step scheme. Although BMP bound to both low- and high-NH2 surfaces was initially able to induce alkaline phosphatase activity in pluripotent C3H10T1/2 cells, only high amino group surfaces were effective following removal of weakly bound protein by incubation in cell culture medium.
Puleo
D A
DA
Center for Biomedical Engineering, University of Kentucky, Lexington 40505-0070, USA. puleo@uky.edu
Kissling
R A
RA
Sheu
M S
MS
D000327:Adsorption; D000497:Alloys / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001709:Biotechnology / Q000379:methods*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000737:chemistry* / Q000378:metabolism*; D002460:Cell Line; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008809:Mice, Inbred C3H; D009113:Muramidase / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D001672:Biocompatible Materials; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D009113:Muramidase