Adjusting the chlorhexidine content of calcium phosphate coatings by electrochemically assisted co-deposition from aqueous solutions

Abstract

Currently, a number of strategies to create either biologically active or antimicrobial surfaces of biomaterials are being developed and commercially applied. However, for metallic implants in contact with bone, both osteomyelitis and a fast and stable long-term fixation of implants are challenges to be overcome, especially in the case of bad bone quality. Therefore, the present work aims to develop compound coatings of calcium phosphate phases (CPP) and chlorhexidine (CHD) that combine bioactive properties with a strategy to prevent initial bacterial adhesion and thus offer a possible solution to the two major problems of implant surgery mentioned above. Using electrochemically assisted deposition of CPP on samples of Ti6Al4V together with the pH-dependent solubility of CHD, the preparation of coatings with a wide range of CHD concentrations (150 ng/cm(2) to 65 microg/cm(2)) from electrolytes with CHD concentrations between 50 and 200 microM was possible, thus allowing the adaptation of implant surface properties to different surgical and patient situations. Detailed SEM and FTIR analysis showed that coatings are formed by a co-deposition process of both phases and that CHD interacts with the deposition and transformation of CPP in the coating. For high CHD contents, coatings consist of CHD crystals coated by nano-crystalline hydroxyapatite.

Single-step pulsed electrodeposition of calcium phosphate coatings on titanium for drug delivery

“…difference could be probably due to the effect of the reverse pulses which may present a higher increase of the pH at the vicinity of the cathode. For that reason, PRP40_2CHX condition may reduce the solubility of CHX which will result in a higher concentration of CHX in the coating [32]. These results are in accordance with the major antibacterial activity observed by PRP40_2CHX condition, which is 13% greater against S. aureus and 47% for E. coli (Fig.…”

“…Then, chlorhexidine digluconate 20% (w/v) (Sigma-Aldrich) was incorporated into the electrolyte solution at different concentrations: 0.3, 0.6, 1.5, 3, 6 and 12 mM, for selected electrodeposition conditions. After the electrodeposition, samples were removed from the electrolytic cell, rinsed with distilled water and dried at room temperature [32].…”

“…Nevertheless, this hydrophobic layer might also prevent cell adhesion resulting in poor implant stability and osseointegration. An alternative approach for loading the antibacterial agent is by co-deposition with CaP, a methodology that incorporates CHX in the CaP coatings by adding CHX to the electrolyte used in the electrodeposition process [32].…”

Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

“…Scharnweber et al worked on biofunctionalization of titanium implant materials by immobilizing collagen type I and studied conformational changes caused by adsorptive immobilization [ 17 – 18 ]. Others worked on collagenous matrix coatings on titanium implants modified with decorin and chondroitin sulfate that enhanced osteoblast adhesion and increased expression of osteopontin (a bone-specific marker) [ 19 ].…”

Antimicrobial Prosthetic Surfaces in the Oral Cavity—A Perspective on Creative Approaches

“…Compounds containing chlorhexidine, a strong disinfectant that prevents initial bacterial adhesion, have been applied in calcium phosphate phases to titanium alloy (e.g., Ti6Al4V) surfaces [41]. These surfaces were formed by a co-deposition process of both phases where chlorhexidine interacted with the deposition and transformation of calcium phosphate phases in the coating.…”