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  • BioCompatability of Metal Coated Spheres

    Posted on July 11th, 2011 Microsphere Expert

    For those scientists who are looking to use silver coated materials such as silver coated microspheres in biomedical applications, it is important to understand whether they are bio-compatable.  A selection of abstracts and article references related to the biocompatability of silver follow:

    The Biocompatibility of Silver2

    The experiments reported have referred to some of the characteristics of the biocompatibility of Ag. Silver has been shown to display interactions with albumin, as an example of a plasma protein, quite different from those of most metals. Such studies shed further light on the complex issue of protein adsorption on biomaterials. It has also been demonstrated that Ag at concentrations < 1 ppm exerts a considerable influence on the activity of lactate dehydrogenase, this effect being reversed in the presence of albumin. A significant but transient increase in blood levels of Ag following intramuscular implantation of the metal has been observed. This is not reflected in any raised urine level. It is proposed that the richly vascular tissue immediately surrounding the implant in the acute phase of the response gives rise to the transient increase, but a subsequent decrease in vascularity reduces this possibility. It appears that Ag released from implants following this initial period substantially remains in the local area.2

    Lack of toxicologocial side-effects in silver-coated megaprostheses in humans1

    Deep infection of megaprostheses remains a serious complication in orthopedic tumor surgery. Furthermore, reinfection gets a raising problem in revision surgery of patients suffering from infections associated with primary endoprosthetic replacement of the knee and hip joint. These patients will need many revision surgeries and in some cases even an amputation is inevitable. Silver-coated medical devices proved their effectiveness on reducing infections, but toxic side-effects concerning some silver applications have been described as well. Our study reports about a silver-coated megaprosthesis for the first time and can exclude side-effects of silver-coated orthopedic implants in humans. The silver-levels in the blood did not exceed 56.4 parts per billion (ppb) and can be considered as non-toxic. Additionally we could exclude significant changes in liver and kidney functions measured by laboratory values. Histopathologic examination of the periprosthetic environment in two patients showed no signs of foreign body granulomas or chronic inflammation, despite distant effective silver concentrations up to 1626 ppb directly related to the prosthetic surface. In conclusion the silver-coated megaprosthesis allowed a release of silver without showing any local or systemic side-effects.1

    Specific Article References for the biocompatability of silver are below:

    • B. Jansen, M. Rinck, P. Wolbring, A. Strohmeier, T. Jahns, “In vitro evaluation of the antimicrobial efficacy and biocompatibility of a silver-coated central venous catheter,” J. Biomater. Appl. 9(July 1994):55-70; A. Oloffs, C. Grosse-Siestrup, S. Bisson, M. Rinck, R. Rudolph, U. Gross, “Biocompatibility of silver-coated polyurethane catheters and silver-coated Dacron material,” Biomaterials 15(August 1994):753-758.
    • L.C. Fung, A.E. Khoury, S.I. Vas, C. Smith, D.G. Oreopoulos, M.W. Mittelman, “Biocompatibility of silver-coated peritoneal dialysis catheter in a porcine model,” Perit. Dial. Int. 16(July-August 1996):398-405.
    • K.S. Tweden, J.D. Cameron, A.J. Razzouk, W.R. Holmberg, S.J. Kelly, “Biocompatibility of silver-modified polyester for antimicrobial protection of prosthetic valves,” J. Heart Valve Dis. 6(September 1997):553-561.
    • M. Boswald, K. Mende, W. Bernschneider, S. Bonakdar, H. Ruder, H. Kissler, E. Sieber, J.P. Guggenbichler, “Biocompatibility testing of a new silver-impregnated catheter in vivo,” Infection 27(1999):S38-S42 (Suppl 1).
    • M. Bosettia, A. Massèb, E. Tobinc and M. Cannas ” Silver coated materials for external fixation devices: in vitro biocompatibility and genotoxicity“  Biomaterials, Volume 23, Issue 3, February 2002, Pages 887-892.
    • 2 – Williams, D.F. “The biocompatibility of silver“, First International Conference on Gold and Silver in Medicine, Bethesa, MD, May 13-14, 1987.
    • Williams, R.L., Doherty, P.J., Vince, D.G., Grashoff, G.J. and Williams, D.F., The biocompatibility of silver, Critical Reviews in Biocompatibility, 5, 221, 1989.
    • 1 – Hardes J, Ahrens H, Gebert C, Streitbuerger A, Buerger H, Erren M, Gunsel A, Wedemeyer C, Saxler G, Winkelmann W, Gosheger G.  Biomaterials. 2007 Jun;28(18):2869-75. Epub 2007 Mar 3. “Lack of toxicological side-effects in silver-coated megaprostheses in humans.
    • T. B. Boitsova, L. V. Shapoval and N. V. Sirotinkin, “Chemical deposition of silver shells on the surface of hollow glass microspheres”, Journal of Materials Science, Volume 46, Number 3, 693-699, DOI: 10.1007/s10853-010-4796-6
    • Alex W. H. Lin, Christopher H. Loo, Leon R. Hirsch, Min-Ho Lee, Naomi J. Halas, Jennifer L. West, and Rebekah A. Drezek, “Nanoshells for integrated diagnosis and therapy of cancer“, Proc. SPIE 5593, 308 (2004); doi:10.1117/12.570267

    We would like to thank Elaine Lissner from the Parsemus Foundation for submitting the above references.

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