Bacteria and cell cytocompatibility studies on coated medical grade titanium surfaces

Abstract

Acute and chronic osteomyelitis caused by staphylococci can be difficult to treat by conventional means and often has marked consequences for the patient. Current methods of treatment involve the use of systemic antibiotics, the local implantation of nondegradable drug carriers, and surgical debridement. A possible solution that could prevent initial bacterial adhesion could be to modify the implant surface with an antimicrobial coating while maintaining biocompatibility to host cells. This study describes the cytocompatibility evaluation of different coatings (poly(D,L-lactide) (PDLLA), politerefate (PTF), calcium phosphate/anodic plasma-chemical treatment (CaP/APC), polyurethane (PU), and polyvinylpyrollidone (PVP) on titanium surfaces with and without chlorhexidine diacetate (CHA) to Staphylococcus aureus, Staphylococcus epidermidis, and hTERT human fibroblasts. Surface characterization of the coatings showed no significant variation in the roughness or hydrophobicity of the coated surfaces, except the CaP/APC surface that was porous yet the smoothest, and PVP, PVP+CHA, and CaP/APC+CHA that were more hydrophilic in nature than the others. On the surfaces without CHA, both staphylococcal strains and spread fibroblasts were observed, but on the CHA impregnated surfaces few bacteria and no intact fibroblasts were seen. Flow cytometry found fewer bacteria in the media and on the surfaces containing CHA in comparison to the surfaces without CHA. The release kinetics varied from slow (over 200 h) to burst release: PDLLA>PTF>PU>CaP/APC=PVP. This study showed that PDLLA and PTF have the best potential as coatings on implants for drug delivery, as they were cytocompatible to hTERT fibroblasts, eluted CHA effectively, and passed mechanical testing. The actual release kinetics of PDLLA and PTF are important, as the amount of CHA present should remain above the minimal inhibitory concentration value for a limited time before disappearing completely.

Antibacterial iodine-supported titanium implants

“…Because systemic antibiotics often do not provide effective treatment for implant infections due to the phenomenon of drug resistance, it is important that the coating of the implant exhibit local antibacterial activity. In order to reduce the incidence of implant-associated infections, several biomaterial surface treatments have been proposed [18][19][20][21][22][23][24][25][26][27][28][29][30]. In particular, silver has raised the interest of many investigators because of its good antimicrobial action and low toxicity [30,[40][41][42][43].…”

“…Several biomaterial surface treatments have been proposed as a means of reducing the incidence of implant-associated infections. There has been investigation into the covalent attachment of polycationic groups [18,19]; ion implantation, such as F+ [20]; impregnating or loading chitosan nanoparticles with antimicrobial agents [21,22]; coating implant surfaces with polymers drug-loaded [23,24]; and coating implant surfaces with either quaternary ammonium compounds, human serum albumin, or silver ions [25][26][27][28][29][30]. However, there are several shortcomings of these proposed techniques including limited chemical stability, local inflammatory reactions due to material composition, and a lack of controlled release kinetics from the coatings.…”

Surgical site infection after total en bloc spondylectomy: risk factors and the preventive new technology

“…In order to reduce the incidence of implant-associated infections, several biomaterial surface treatments have been proposed [16][17][18]. There have also been reports on antibacterial alloy implants [19].…”

Surface Engineering for Bone Implants: A Trend from Passive to Active Surfaces

“…The coated antibiotic-HA-composite exhibited a reduced infection rate compared with CaP coatings in vivo [105]. In order to reduce the risk of antibiotic resistance also non-antibiotic organic compounds with antimicrobial activity like chlorhexidine, chloroxylenol, and poly(hexamethylenebiguanide) [106][107][108][109][110][111][112] have been investigated as potential alternatives. These organic molecules are commonly used for their broad spectrum of antimicrobial action and lower risk of drug resistance.…”