Cell Adhesion on Surface-Functionalized Magnesium

Abstract

The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance.

Sputtered Si and Mg doped hydroxyapatite for biomedical applications

“…Our findings are supported by data from Wagener et al [51] who demonstrated that MG63 osteosarcoma cells showed lower cell numbers and inhibited cell spreading when seeded directly on pure magnesium or on differently coated Mg. It was reported that the local rise in Mg level does not seem to have a significant impact on osteosarcoma cell proliferation [31,51]. High Mg levels can, however, inhibit deposition of Ca phosphate mineral matrix [52].…”

Biodegradable Ceramics Consisting of Hydroxyapatite for Orthopaedic Implants

“…Degradation of Mg in contact with human physiological solution involves hydrogen decomposition and an elevated pH at the implant surface. Both factors can strongly affect initial osteoblast adhesion and delay cell spreading and proliferation [47]. In this study, the TM-1 coating was less affected by the SBF corrosive attack, probably leading to lesser hydrogen decomposition.…”

“…It was expected that the coatings containing Mg would show lower cell numbers than of uncoated Ti6Al4V. It has already been demonstrated that cell adhesion and proliferation of MG63 osteosarcoma cells is inhibited in direct contact with pure Mg surfaces or Mg-based coatings [47,48]. A possible explanation for this could be due to the Mg ions being released from the surface of the implant.…”

Investigation of the Oxidation Mechanism of Dopamine Functionalization in an AZ31 Magnesium Alloy for Biomedical Applications

“…Cell adhesion is unlikely to occur directly on the implant. Thus, an appropriate surface treatment is needed [5]. For this treatment, several biomimetic coatings are investigated: Aminopropyltriehtoxysilane, vitamin C (AV), carbonyldiimidazole (CDI), stearic acid (SA), aminated hydroxyethyl cellulose, gelatin, and peptides [5][6][7][8][9].…”