1. INTRODUCTION AND OBJECTIVES
Infections Free Titanium Implant Surfaces
D. Khvostenko1, S. VanOosten1, J. Mitchell2, J. Ferracane3, H. Davis3, P. Arnold4, C. Tamerler1.
1-Bionegineering Research Center, University of Kansas, Lawrence, KS; 2-Colledge of Dental Medicine, Midwestern University, Glendale, AZ; 3-School of Dentistry, Oregon Health and Science University; 4-Dept. of Neurosurgery, University of Kansas Medical Center, Kansas city, KS.
INTRODUCTION AND OBJECTIVES
RESULTS
RESULTS (CONTD.)
DISCUSSIONS
Fibroblasts viability on TiBP-AMP treated Ti surface
Infections that are associated with implants represent a major cause of implant failures. Implant materials provide an ideal surface to the growth of common pathogens which could be acquired shortly after the surgery or at a later stage of therapy. Failure to adequately treat these bacterial infections may result in severe complications. Systemic antibiotic therapy brings additional challenges one of which is the potential development and spread of antibiotic-resistant pathogens. Unfortunately, many studies demonstrate that the time for resistance development becomes shorter than time needed for a new drug development. The antibiotic resistance is increasingly becoming a critical problem in the field of implantology with the infections are remaining as one of the primary reasons for implant rejection due to bacterial biofilm forming at the implant-socket interface. Thus, there is a strong need for a new approach for creating antibacterial implant surfaces.
TiBP-AMP on surface
Titanium Implant
We are suggesting a novel so-called “multifactorial” approach, where at the implant-socket interface we can benefit from using multiple antimicrobial agents with different antimicrobial mechanisms. The multiple mechanisms approach is proven to reduce bacterial resistance development, and our approach also offers prolonged periods of displayed antimicrobial action. As antimicrobial agents here we are combining Antimicrobial Peptide (AMP) – immediate short term action and Bioactive Glass (BAG) – long term action. We hypothesize that multiple antimicrobial action mechanisms from those agents will significantly reduce the likelihood of resistance development in most common bacterial strains responsible for implants failure (S. mutans and S. epidermitis).
In-solution activity of TiBP-AMP against S. mutans and S. epidermidis
The current results show that TiBP-AMP on Ti surface is very effective against both bacterial strains (~ 90% reduction in bacterial colonization in comparison to bare Ti surface).
At the same time TiBP-AMP functionalized Ti surfaces provide a great substrate for Fibroblasts attachment and spreading: both AlamarBlue and MTT assays show a significant increase in metabolic rate (related to viability) of the cells on TiBP-AMP biofunctionilized surface (similar to cells on Collagen treated surface) in comparison to bare surface.
While Fibroblasts cell count for TiBP-AMP treated surface is slightly less than for Collagen or bare surfaces, cells on TiBP-AMP surfaces are more spread, resulting in higher Ti sample surface coverage, in comparison to bare surface.
MIC (for S. mutans)=50µM and MIC (for S. epidermidis)=8µM
Bacterial attachment to TiBP-AMP treated Titanium surface
CONCLUSIONS
Control (no TiBP-AMP)
TiBP-AMP treated
Biofunctialization of implant Titanium surfaces with TiBP-AMP chimeric peptide is a very promising way to prevent post-operative infection diseases by successfully preventing S. mutans and S. epidermidis attachment to implant surfaces.
TiBP-AMP on Ti surface was also shown to promote fibroblasts cells spreading and their viability, potentially increasing the rate of tissues healing around an implant.
S. mutans
ACKNOWLEDGEMENTS
S. epidermidis
The author would like to express the gratitude to all the collaborators of this project for their help.
Authors gratefully acknowledge the funding support by National Institute of Health (NIH), Musculoskeletal Tissue Engineering Research Grant 5R21AR at the University of Kansas.
MATERIALS AND METHODS
In Phase I of the work we are focusing on TiBP-AMP. The experimental procedures include:
In-solution antimicrobial activity of TiBP-AMP against S. mutans and S. epidermidis strains;
Antimicrobial activity of TiBP-AMP decorated Ti samples against same strains (Analysis of fluorescent images of stained biofilms);
Fibroblast cells viability on TiBP-AMP decorated Ti surfaces (MTT and AlamarBlue assays);
Evaluation of Fibroblast cells attachment and spreading (analysis of fluorescent images of actin stained cells on the surface).
In Phase II, we consider conducting the similar tests for BAG and BAG decorated with AMP, assembled on Ti surface
REFERENCES
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Yazici, H., H. Fong, B. Wilson, E. E. Oren, F. A. Amos, H. Zhang, J. S. Evans, M. L. Snead, M. Sarikaya and C. Tamerler (2013). "Biological response on a titanium implant-grade surface functionalized with modular peptides." Acta Biomater 9(2):
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