Infection is one of the most important causes of
titanium implant failure in vivo A developing prophylactic method involves the immobilization of
antibiotics, especially
vancomycin, onto the surface of the
titanium implant. However, these methods have a limited effect in curbing multiple
bacterial infections due to
antibiotic specificity. In the current study,
enoxacin was covalently bound to an
amine-functionalized Ti surface by use of a
polyethylene glycol (PEG) spacer, and the bactericidal effectiveness was investigated in vitro and in vivo The
titanium surface was
amine functionalized with
3-aminopropyltriethoxysilane (APTES), through which PEG spacer molecules were covalently immobilized onto the
titanium, and then the
enoxacin was covalently bound to the PEG, which was confirmed by X-ray photoelectron spectrometry (XPS). A spread plate assay, confocal
laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to characterize the antimicrobial activity. For the in vivo study, Ti implants were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and implanted into the femoral medullary cavity of rats. The degree of
infection was assessed by radiography, micro-computed tomography, and determination of the counts of adherent bacteria 3 weeks after surgery. Our data demonstrate that the
enoxacin-modified PEGylated Ti surface effectively prevented bacterial colonization without compromising cell viability, adhesion, or proliferation in vitro Furthermore, it prevented MRSA
infection of the Ti implants in vivo Taken together, our results demonstrate that the use of
enoxacin-modified Ti is a potential approach to the alleviation of
infections of Ti implants by multiple bacterial species.