Bacterial Biofilm Formation on Resorbing Magnesium Implants

Charyeva, Olga; Neilands, Jessica; Svensäter, Gunnel; Wennerberg, Ann

doi:10.4236/ojmm.2015.51001

Cited by 13 publications

(16 citation statements)

References 28 publications

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“…In addition, these could be neutralized by wound liquid or by the blood flow to create a moderately alkaline niche where bacteria could thrive while being protected from the host immune cell attack. In agreement with this notion, in a recent in vitro study bacterial biofilms were developing on serum and phosphate buffer treated magnesium alloy surfaces . Based on these observations, it is conceivable that a corroding magnesium‐organic environment interface could provide a niche where bacteria could initially settle and thrive as a first step toward biofilm formation.…”

Section: Discussionmentioning

confidence: 64%

“…In agreement with this notion, in a recent in vitro study bacterial biofilms were developing on serum and phosphate buffer treated magnesium alloy surfaces. 65 Based on these observations, it is conceivable that a corroding magnesium-organic environment interface could provide a niche where bacteria could initially settle and thrive as a first step toward biofilm formation. However, in vivo imaging and electron microscopic analysis in this study additionally demonstrated the spreading of the infection into peri-implant tissue pockets.…”

Section: Discussionmentioning

confidence: 99%

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Susceptibility of metallic magnesium implants to bacterial biofilm infections

Rahim

Rohde

Rais

et al. 2016

J Biomedical Materials Res

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Magnesium alloys have promising mechanical and biological properties as biodegradable medical implant materials for temporary applications during bone healing or as vascular stents. Whereas conventional implants are prone to colonization by treatment resistant microbial biofilms in which bacteria are embedded in a protective matrix, magnesium alloys have been reported to act antibacterial in vitro. To permit a basic assessment of antibacterial properties of implant materials in vivo an economic but robust animal model was established. Subcutaneous magnesium implants were inoculated with bacteria in a mouse model. Contrary to the expectations, bacterial activity was enhanced and prolonged in the presence of magnesium implants. Systemic antibiotic treatments were remarkably ineffective, which is a typical property of bacterial biofilms. Biofilm formation was further supported by electron microscopic analyses that revealed highly dense bacterial populations and evidence for the presence of extracellular matrix material. Bacterial agglomerates could be detected not only on the implant surface but also at a limited distance in the peri-implant tissue. Therefore, precautions may be necessary to minimize risks of metallic magnesium-containing implants in prospective clinical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1489-1499, 2016.

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Section: Discussionmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Susceptibility of metallic magnesium implants to bacterial biofilm infections

Rahim

Rohde

Rais

et al. 2016

J Biomedical Materials Res

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“…The effects of dissolution and osmotic pressure decline over 2 days, however the pH shift may also have a negative effect on S. epidermidis growth over the 7-day period. The impact on the planktonic population may be less significant due to reduced exposure to these factors (13,29). …”

Section: Discussionmentioning

confidence: 99%

Thin magnesium layer confirmed as an antibacterial and biocompatible implant coating in a co-culture model

Zaatreh

Haffner

Strauss

et al. 2017

Molecular Medicine Reports

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Implant-associated infections commonly result from biofilm-forming bacteria and present severe complications in total joint arthroplasty. Therefore, there is a requirement for the development of biocompatible implant surfaces that prevent bacterial biofilm formation. The present study coated titanium samples with a thin, rapidly corroding layer of magnesium, which were subsequently investigated with respect to their antibacterial and cytotoxic surface properties using a Staphylococcus epidermidis (S. epidermidis) and human osteoblast (hOB) co-culture model. Primary hOBs and S. epidermidis were co-cultured on cylindrical titanium samples (Ti6Al4V) coated with pure magnesium via magnetron sputtering (5 µm thickness) for 7 days. Uncoated titanium test samples served as controls. Vital hOBs were identified by trypan blue staining at days 2 and 7. Planktonic S. epidermidis were quantified by counting the number of colony forming units (CFU). The quantification of biofilm-bound S. epidermidis on the surfaces of test samples was performed by ultrasonic treatment and CFU counting at days 2 and 7. The number of planktonic and biofilm-bound S. epidermidis on the magnesium-coated samples decreased by four orders of magnitude when compared with the titanium control following 7 days of co-culture. The number of vital hOBs on the magnesium-coated samples was observed to increase (40,000 cells/ml) when compared with the controls (20,000 cells/ml). The results of the present study indicate that rapidly corroding magnesium-coated titanium may be a viable coating material that possesses antibacterial and biocompatible properties. A co-culture test is more rigorous than a monoculture study, as it accounts for confounding effects and assesses additional interactions that are more representative of in vivo situations. These results provide a foundation for the future testing of this type of surface in animals.

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“…These findings were in line with reports of cytotoxic effects of magnesium in vitro against mammalian cells and bacteria that appeared to be mainly due to pH increases. 32,44,45 Whereas pH increases are the result of magnesium corrosion and magnesium hydroxide production it is conceivable that in comparison to pure crystalline magnesium hydroxide additional components such as proteins or phosphates in metallic magnesium implant corrosion layers could enhance the biocompatibility in vivo. 46,47 The findings do not entirely exclude the possibility that under particular conditions magnesium corrosion, excess Mg 21 ions or moderate pH increases could stimulate the differentiation of osteogenic cells.…”

Section: Discussionmentioning

confidence: 99%

Differential magnesium implant corrosion coat formation and contribution to bone bonding

Rahim

Weizbauer

Evertz

et al. 2016

J Biomedical Materials Res

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Magnesium alloys are presently under investigation as promising biodegradable implant materials with osteoconductive properties. To study the molecular mechanisms involved, the potential contribution of soluble magnesium corrosion products to the stimulation of osteoblastic cell differentiation was examined. However, no evidence for the stimulation of osteoblast differentiation could be obtained when cultured mesenchymal precursor cells were differentiated in the presence of metallic magnesium or in cell culture medium containing elevated magnesium ion levels. Similarly, in soft tissue no bone induction by metallic magnesium or by the corrosion product magnesium hydroxide could be observed in a mouse model. Motivated by the comparatively rapid accumulation solid corrosion products physicochemical processes were examined as an alternative mechanism to explain the stimulation of bone growth by magnesium-based implants. During exposure to physiological solutions a structured corrosion coat formed on magnesium whereby the elements calcium and phosphate were enriched in the outermost layer which could play a role in the established biocompatible behavior of magnesium implants. When magnesium pins were inserted into avital bones, corrosion lead to increases in the pull out force, suggesting that the expanding corrosion layer was interlocking with the surrounding bone. Since mechanical stress is a wellestablished inducer of bone growth, volume increases caused by the rapid accumulation of corrosion products and the resulting force development could be a key mechanism and provide an explanation for the observed stimulatory effects of magnesium-based implants in hard tissue.

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Bacterial Biofilm Formation on Resorbing Magnesium Implants

Cited by 13 publications

References 28 publications

Susceptibility of metallic magnesium implants to bacterial biofilm infections

Susceptibility of metallic magnesium implants to bacterial biofilm infections

Thin magnesium layer confirmed as an antibacterial and biocompatible implant coating in a co-culture model

Differential magnesium implant corrosion coat formation and contribution to bone bonding

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