Abschätzung der biologischen aktivität von chemisch immobilisiertem rhBMP-2 auf titanoberflächen in vivo

Translated title of the contribution: Assesment of the biological activity of chemically immobilized rhBMP-2 on titanium surfaces in vivo

G. Voggenreiter, K. Hartl, S. Assenmacher, M. Chatzinikolaidou, H. P. Jennissen, H. M. Rumpf

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Previously it has been shown that recombinant human bone morphogenetic protein (rhBMP-2) can be chemically immobilized by "anchor molecules" on titanium surfaces for serving as a drug delivery device. This opened the question of whether the insoluble immobilized rhBMP-2 retained its activity in comparison to the same amount of soluble rhBMP-2 included with the implant samples. Elcctropolished titanium miniplates (10 × 6 × 0.8 mm) were "surface-enhanced" by a novel treatment with chromosulfuric acid and then coated with a total amount of 150-200 ng rhBMP-2 prepared by recombinant technology. Periosteal flaps (7 × 20 mm) were detached and isolated from the anterior surface of the tibiae of adult rabbits and wrapped around the titanium sample plates which were then implanted in the M. gastrocnemius. In the first experimental group various controls without rhBMP-2 were combined (n = 12). In the second experimental group implants with chemically immobilized rhBMP-2 (n = 8) were compared with implants to which non-immobilized soluble rhBMP-2 was added (n = 8). Animals were sacrificed after 28 days and a quantitative evaluation was carried out by means of serial sections. Untreated control plates showed bone formation in 2/12 implants, rhBMP-2 coated implants in 6/8 and implants with free rhBMP-2 administered subperiostally in 8/8 cases. In the case of rhBMP-2 coated implants the induced bone had direct contact to the implant in all cases while in the group with free administered rhBMP-2 the bone had no contact to the implant in two cases, but was separated by a fibrous capsule. Bone volume, bone surface area, and trabecular number displayed no difference between the two rhBMP-2-groups. However, in the biocoated group a tendency to an increase in the bone-implant contact area was evident. No differences in osteoid area, osteoid perimeter and eroded perimeter were detected. We conclude that in the case of non-immobilized rhBMP-2 there is the danger lor formation of fibrous tissue between the implant and the newly formed bone and in addition the generation of ectopic bone at inappropriate places. In contrast chemically immobilized rhBMP-2 does not have these drawbacks and at the same time displays a biological activity on surfaces similar to that of soluble rhBMP-2 demonstrating that biomaterial surfaces can be tailored for a selective and specific interaction with the target tissue.

Translated title of the contributionAssesment of the biological activity of chemically immobilized rhBMP-2 on titanium surfaces in vivo
Original languageGerman
Pages (from-to)942-948
Number of pages7
JournalMaterialwissenschaft und Werkstofftechnik
Volume32
Issue number12
DOIs
Publication statusPublished - Dec 2001
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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