Antibacterial coating systems

The local application of antibiotics is a well-known procedure that has been in successful clinical use for more than 20 years. The most frequently used carrier substance for the antibiotic or other antibacterial substances is polymethylmethacrylate (PMMA). However, because PMMA is not resorbable, as much as 70% of the antibiotic dose is permanently sequestered in the PMMA cement and therefore not available to combat bacterial colonization. Antibacterial coatings of metal implants represent an attractive solution to simplify the local application of an antibacterial substance in fracture care. Several coating technologies have been investigated, involving different carrier materials as well as different antibacterial substances. A fully resorbable coating containing gentamicin sulphate has yielded promising results in animal studies and intramedullary tibial nails with this coating have already been implanted successfully in a few patients. In the future, the main developmental focus for antibacterial coatings for implants will lie in tailoring the release characteristics and the antibacterial substance to minimize the risk of breeding resistant bacterial strains while maximizing the efficacy of the coating.     

Gentamycin delivered from a PDLLA coating of metallic implants: In vivo and in vitro characterisation for local prophylaxis of implant-related osteomyelitis

Locally applied antibiotics support prophylaxis of highly feared implant associated infections. Implant coatings with poly(d,l-lactide) (PDLLA)/gentamicin seem to be a promising approach. Aims of this study were to analyse the release kinetics of gentamicin in vivo, in vitro, to analyse the antibacterial efficacy, the resistance development and its impact on osteoblasts. For the in vitro release experiments titanium implants were coated with PDLLA/gentamicin and the antibiotic release in aqueous solution was analysed at 20 time points (from 10 s to 110 days). For the in vivo experiments PDLLA/gentamicin-coated kirschner wires were implanted in the tibiae of 18 rats. Gentamicin concentration in the bone was analysed at several time points (n = 3 each, 1 h to 7 days). Bactericidal efficacy, bacterial adhesion on the implants and resistance development were tested. AP activity, cell count and CICP expression of osteoblasts were analysed. Gentamicin was released rapidly with an initial burst in aqueous solution and followed by a slow release. Similarly, in vivo gentamicin concentration reached a high peak initially followed by a decrease to a low level. No development of resistance was observed in the investigated setting, the antibacterial efficacy was not affected by the coating process and significantly fewer bacteria were attached to the implant. Osteoblasts were not negatively affected by the gentamicin released from the coating. PDLLA/gentamicin coating resulted in a desired antibiotic peak concentration within the bone. Bacterial adhesion was successfully prevented. No bacterial resistances were developed. This coating seems to be a suitable supplement for prophylaxis of implant-associated infections.     

Interfacial shear strength of bioactive‐coated carbon fiber reinforced polyetheretherketone after in vivo implantation

Despite the excellent osseointegration of carbon‐fiber‐reinforced polyetheretherketone (CFR/PEEK) with a surface hydroxyapatite (HA) coating, the bone‐implant interfacial shear strength of HA‐coated CFR/PEEK after osseointegration is unclear. We examined the interfacial shear strength of HA‐coated CFR/PEEK implants after in vivo implantation in a rabbit femur‐implant pull‐out test model. HA coating was performed by a newly developed method. Uncoated CFR/PEEK, HA‐coated blasted titanium alloy, and uncoated blasted titanium alloy were used as control implants. The implants were inserted into drilled femoral cortex, and pull‐out tests were conducted after 6 and 12 weeks of implantation to determine maximum interfacial shear strength. The HA‐coated CFR/PEEK (15.7 ± 4.5 MPa) and HA‐coated titanium alloy (14.1 ± 6.0 MPa) exhibited significantly larger interfacial shear strengths than the uncoated CFR/PEEK (7.7 ± 1.8 MPa) and the uncoated titanium alloy (7.8 ± 2.1 MPa) at 6 weeks. At 12 weeks, only the uncoated CFR/PEEK (8.3 ± 3.0 MPa) exhibited a significantly smaller interfacial shear strength, as compared to the HA‐coated CFR/PEEK (17.4 ± 3.6 MPa), HA‐coated titanium alloy (14.2 ± 4.8 MPa), and uncoated titanium alloy (15.0 ± 2.6 MPa). Surface analysis of the removed implants revealed detachment of the HA layer in both the HA‐coated CFR/PEEK and titanium alloy implants. The proposed novel HA coating method of CFR/PEEK significantly increased interfacial shear strength between bone and CFR/PEEK. The achieved interfacial shear strength of the HA‐coated CFR/PEEK implant is of the same level as that of grit‐blasted titanium alloy with HA. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1618–1625, 2012     

Gentamicin release from polymethylmethacrylate bone cements and Staphylococcus aureus biofilm formation

We measured the formation of a Staphylococcus aureus biofilm in vitro on unloaded and gentamicin-loaded bone cements (CMW3 and Palacos R) and related the formation to antibiotic release rates. All experiments were done in triplicate. Microbial growth on gentamicin-loaded cements occurred despite the release of antibiotic. Biofilm formation on gentamicin loaded CMW3 bone cement was one fourth to one fifth less than on the unloaded bone cement, while biofilm formation on Palacos R bone cement was not significantly affected by antibiotic loading. More gentamicin was released from CMW3 (79 mg) than from Palacos R (70 mg), but the percentage gentamicin released after one week relative to the total amount incorporated was significantly lower for CMW3 (4.7%) than for Palacos R (8.4%). After one day, subinhibitory concentrations of antibiotics were eluted from the cements. We concluded that antibiotic-loaded bone cement does not necessarily inhibit the formation of an infectious biofilm in vitro.     

Gentamicin release from polymethylmethacrylate bone cements and Staphylococcus aureus biofilm formation

We measured the formation of a Staphylococcus aureus biofilm in vitro on unloaded and gentamicin-loaded bone cements (CMW3 and Palacos R) and related the formation to antibiotic release rates. All experiments were done in triplicate. Microbial growth on gentamicin-loaded cements occurred despite the release of antibiotic. Biofilm formation on gentamicin loaded CMW3 bone cement was one fourth to one fifth less than on the unloaded bone cement, while biofilm formation on Palacos R bone cement was not significantly affected by antibiotic loading. More gentamicin was released from CMW3 (79 mg) than from Palacos R (70 mg), but the percentage gentamicin released after one week relative to the total amount incorporated was significantly lower for CMW3 (4.7%) than for Palacos R (8.4%). After one day, subinhibitory concentrations of antibiotics were eluted from the cements. We concluded that antibiotic-loaded bone cement does not necessarily inhibit the formation of an infectious biofilm in vitro.     

Gentamicin release from polymethylmethacrylate bone cements and Staphylococcus aureus biofilm formation

We measured the formation of a Staphylococcus aureus biofilm in vitro on unloaded and gentamicin-loaded bone cements (CMW3 and Palacos R) and related the formation to antibiotic release rates. All experiments were done in triplicate. Microbial growth on gentamicin-loaded cements occurred despite the release of antibiotic. Biofilm formation on gentamicin loaded CMW3 bone cement was one fourth to one fifth less than on the unloaded bone cement, while biofilm formation on Palacos R bone cement was not significantly affected by antibiotic loading. More gentamicin was released from CMW3 (79 mg) than from Palacos R (70 mg), but the percentage gentamicin released after one week relative to the total amount incorporated was significantly lower for CMW3 (4.7%) than for Palacos R (8.4%). After one day, subinhibitory concentrations of antibiotics were eluted from the cements. We concluded that antibiotic-loaded bone cement does not necessarily inhibit the formation of an infectious biofilm in vitro.     

Antimicrobial efficacy of gentamicin-loaded acrylic bone cements with fusidic acid or clindamycin added.

The increasing gentamicin resistance among bacteria in septic joint arthroplasty has stimulated interest in adding a second antibiotic into gentamicin-loaded bone cement. A first aim of this in vitro study is to investigate whether addition of fusidic acid or clindamycin to gentamicin-loaded bone cement has an additional antimicrobial effect against a collection of 38 clinical isolates, including 16 gentamicin-resistant strains. A modified Kirby-Bauer test, involving measurement of the inhibition zone around antibiotic-loaded bone cement discs on agar plates, was used to investigate whether adding a second antibiotic has an additional antimicrobial effect. Second, a selected number of strains was used to study their survival in an interfacial gap made in the different bone cements to mimic the gap between bone and cement as existing near a prosthesis. Gentamicin-loaded bone cement had an antimicrobial activity against 58% of the 38 bacterial strains included in this study, while 68% of the strains were affected by bone cement loaded with a combination of gentamicin and clindamycin. Bone cement loaded with the combination of gentamicin and fusidic acid had antimicrobial activity against 87% of the bacterial strains. In the prosthesis-related gap model, there was a clear trend toward less bacterial survival for gentamicin-loaded bone cement after adding clindamycin or fusidic acid. Addition of clindamycin or fusidic acid into gentamicin-loaded bone cement yields an additional antimicrobial effect. The combination gentamicin and fusidic acid was effective against a higher number of clinical isolates than the combination of gentamicin with clindamycin, including gentamicin-resistant strains.     

Copal Bone Cement Is More Effective in Preventing Biofilm Formation than Palacos R-G

Bone cements loaded with combinations of antibiotics are assumed more effective in preventing infection than bone cements with gentamicin as a single drug. Moreover, loading with an additional antibiotic may increase interconnectivity between antibiotic particles to enhance release. We hypothesize addition of clindamycin to a gentamicin-loaded cement yields higher antibiotic release and causes larger inhibition zones against clinical isolates grown on agar and stronger biofilm inhibition. Antibiotic release after 672 hours from Copal bone cement was more extensive (65% of the clindamycin and 41% of the gentamicin incorporated) than from Palacos R-G (4% of the gentamicin incorporated). The higher antibiotic release from Copal resulted in a stronger and more prolonged inhibition of bacterial growth on agar. Bacterial colony counting and confocal laser scanning microscopy of biofilms grown on the bone cements suggest antibiotic release reduced bacterial viability, most notably close to the cement surface. The gentamicin-sensitive Staphylococcus aureus formed gentamicin-resistant small colony variants on Palacos R-G and therefore Copal more effectively decreased biofilm formation than Palacos R-G. Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.     

Silver oxide‐containing hydroxyapatite coating has in vivo antibacterial activity in the rat tibia

Bacterial infection is a serious postoperative complication of joint replacement. To prevent infections related to implantation, we have developed a novel antibacterial coating with Ag‐containing hydroxyapatite (Ag‐HA). In the present study, we examined the antibacterial activity of Ag‐HA implant coatings in the medullary cavity of rat tibiae. Forty 10‐week‐old rats received implantation of Ag‐HA‐ or HA‐coated titanium rods, then were inoculated with ～1.0 × 10² colony‐forming units of methicillin‐resistant Staphylococcus aureus. Bacterial counts were calculated for rats euthanized at 24, 48, and 72 h postoperatively. Serum levels of Ag (in the Ag‐HA group only) were calculated for rats euthanized at 24, 48, 72 h and 4 weeks. Radiographic evaluations of bone infection were also performed at 4 weeks. Tibiae from both groups showing infection were evaluated histologically. Significant differences in bacterial counts were seen at 24, 48, and 72 h. Mean concentrations of Ag in serum peaked about 48 h after implantation, then gradually decreased. Mean radiographic scores for infection were significantly lower with Ag‐HA implants than with HA implants. Histological examination showed better results for abscesses, bone resorption, and destruction of cortical bone around Ag‐HA‐coated implants. These results indicate that Ag‐HA coatings may help prevent surgical‐site infections associated with joint replacement. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1195–1200, 2013     

Effect on infection resistance of a local antiseptic and antibiotic coating on osteosynthesis implants: an in vitro and in vivo study.

The purpose of this study was to acquire information about the effect of an antibacterial and biodegradable poly-L-lactide (PLLA) coated titanium plate osteosynthesis on local infection resistance. For our in vitro and in vivo experiments, we used six-hole AO DC minifragment titanium plates. The implants were coated with biodegradable, semiamorphous PLLA (coating about 30 microm thick). This acted as a carrier substance to which either antibiotics or antiseptics were added. The antibiotic we applied was a combination of Rifampicin and fusidic acid; the antiseptic was a combination of Octenidin and Irgasan. This produced the following groups: Group I: six-hole AO DC minifragment titanium plate without PLLA; Group II: six-hole AO DC minifragment titanium plate with PLLA without antibiotics/antiseptics; Group III: six-hole AO DC minifragment titanium plate with PLLA + 3% Rifampicin and 7% fusidic acid; Group IV: six-hole AO DC minifragment titanium plate with PLLA + 2% Octenidin and 8% Irgasan. In vitro, we investigated the degradation and the release of the PLLA coating over a period of 6 weeks, the bactericidal efficacy of antibiotics/antiseptics after their release from the coating and the bacterial adhesion of Staphylococcus aureus to the implants. In vivo, we compared the infection rates in white New Zealand rabbits after titanium plate osteosynthesis of the tibia with or without antibacterial coating after local percutaneous bacterial inoculations at different concentrations (2 x 10(5)-2 x 10(8)): The plate, the contaminated soft tissues and the underlying bone were removed under sterile conditions after 28 days and quantitatively evaluated for bacterial growth. A stepwise experimental design with an "up-and-down" dosage technique was used to adjust the bacterial challenge in the area of the ID50 (50% infection dose). Statistical evaluation of the differences between the infection rates of both groups was performed using the two-sided Fisher exact test (p < 0.05). Over a period of 6 weeks, a continuous degradation of the PLLA coating of 13%, on average, was seen in vitro in 0.9% NaCl solution. The elution tests on titanium implants with antibiotic or antiseptic coatings produced average release values of 60% of the incorporated antibiotic or 62% of the incorporated antiseptic within the first 60 min. This was followed by a much slower, but nevertheless continuous, release of the incorporated antibiotic and antiseptic over days and weeks. At the end of the test period of 42 days, 20% of the incorporated antibiotic and 15% of the incorporated antiseptic had not yet been released from the coating. The antibacterial effect of the antibiotic/antiseptic is not lost by integrating it into the PLLA coating. The overall infection rate in the in vivo investigation was 50%. For Groups I and II the infection rate was both 83% (10 of 12 animals). In Groups III and IV with antibacterial coating, the infection rate was both 17% (2 of 12 animals). The ID50 in the antibacterial coated Groups III and IV was recorded as 1 x 10(8) CFU, whereas the ID50 values in the Groups I and II without antibacterial coating were a hundred times lower at 1 x 10(6) CFU, respectively. The difference between the groups with and without antibacterial coating was statistically significant (p = 0.033). Using an antibacterial biodegradable PLLA coating on titanium plates, a significant reduction of infection rate in an in vitro and in vivo investigation could be demonstrated. For the first time, to our knowledge, we were able to show, under standardized and reproducible conditions, that an antiseptic coating leads to the same reduction in infection rate as an antibiotic coating. Taking the problem of antibiotic-induced bacterial resistance into consideration, we thus regard the antiseptic coating, which shows the same level of effectiveness, as advantageous.     

载银与载庆大霉素硅灰石涂层体外抗菌性能的对比研究

目的 制备具有长效药物缓释效果的骨科抗菌植入材料表面涂层.方法 采用等离子体喷涂技术在钛合金表面沉积硅灰石涂层.一组试样在浓度为重量百分率5%的硝酸银溶液中浸泡24 h获得载银硅灰石涂层,另一组试样通过与装载庆大霉素的胶原溶液发生接枝反应制得载庆大霉素硅灰石涂层.两种涂层的性能通过抗菌剂体外溶液释放实验、抗会黄色葡萄球菌的抑菌环实验和成骨细胞接触培养毒性实验进行表征.结果 成功制备载银与载庆大霉素硅灰石涂层.载银硅灰石涂层均匀释放银离子达50 d;涂层抗金黄色葡萄球菌能力可维持40 d以上.载庆大霉素硅灰石涂层呈爆发性释放庆大霉素,涂层抗会黄色葡葡球菌能力可以维持18 d.两种涂层均不影响成骨细胞在其表面的黏附、增殖以及碱性磷酸酶活性的表达.结论 载银硅灰石涂层与载庆大霉素硅厌石涂层相比,抗菌剂释放较均匀、抗菌时效较长,更具临床应用前景.     

Release of gentamicin from a tricalcium phosphate bone implant.

The impregnation and elution of gentamicin antibiotic from a commercially available porous beta-tricalcium phosphate (TCP) bone implant material (Vitoss, Orthovita, Inc.) was investigated in vitro. Sustained local antibiotic release is an attractive method for the prevention of infection following surgery. The purpose of this study was to evaluate the use of the naturally forming clot that occurs within a porous tissue scaffold when combined with autologous blood or bone marrow aspirate (BMA) as a method for achieving controlled drug delivery. The diffusion of antibiotic from porous TCP scaffolds was studied using water, clotted blood, or BMA as impregnating fluids. Incorporation of the drug into the porous scaffold using clotted blood or BMA as a binder produced slowed release relative to aqueous impregnated and dried samples. Modifications were made to the elution method to simulate restricted diffusion due to surrounding clotted blood, tissue, or bone that would occur in vivo. These modified methods simulated release in a surgical site and showed long release profiles, with significant amounts of antibiotic being released for up to 2 weeks. We concluded that adding gentamicin with autologous BMA is a promising method of controlling drug release.     

The effect of mixing on gentamicin release from polymethylmethacrylate bone cements

We compared the release of gentamicin from 6 different commercially available, antibiotic-loaded PMMA bone cements used for vacuum- and hand-mixed cement using a Cemvac vacuum mixing system. We also measured the release of gentamicin after manual addition of the antibiotic to different commercial, unloaded bone cements after hand-mixing. The porosity of cements was reduced in all vacuum-mixed cements, as compared with hand-mixed cements, concurrent with a statistically significant reduction (3 of 6) or increase (1 of 6) in the total amounts of gentamicin released. The total gentamicin release was studied in 3 of the brands after manual addition and mixing of the antibiotics. We found that the release of antibiotics was lower than in samples made from industrial mixing. In conclusion, the manual addition and mixing of gentamicin in PMMA bone cements leads to a lower release of antibiotics than that in corresponding commercially available antibiotic-loaded cements, while vacuum-mixing only leads to a minor reduction in antibiotic release, as compared to hand-mixing.     

The effect of mixing on gentamicin release from polymethylmethacrylate bone cements

We compared the release of gentamicin from 6 different commercially available, antibiotic-loaded PMMA bone cements used for vacuum- and hand-mixed cement using a Cemvac vacuum mixing system. We also measured the release of gentamicin after manual addition of the antibiotic to different commercial, unloaded bone cements after hand-mixing. The porosity of cements was reduced in all vacuum-mixed cements, as compared with hand-mixed cements, concurrent with a statistically significant reduction (3 of 6) or increase (1 of 6) in the total amounts of gentamicin released. The total gentamicin release was studied in 3 of the brands after manual addition and mixing of the antibiotics. We found that the release of antibiotics was lower than in samples made from industrial mixing. In conclusion, the manual addition and mixing of gentamicin in PMMA bone cements leads to a lower release of antibiotics than that in corresponding commercially available antibiotic-loaded cements, while vacuum-mixing only leads to a minor reduction in antibiotic release, as compared to hand-mixing.     

The effect of mixing on gentamicin release from polymethylmethacrylate bone cements

We compared the release of gentamicin from 6 different commercially available, antibiotic-loaded PMMA bone cements used for vacuum- and hand-mixed cement using a Cemvac vacuum mixing system. We also measured the release of gentamicin after manual addition of the antibiotic to different commercial, unloaded bone cements after hand-mixing. The porosity of cements was reduced in all vacuum-mixed cements, as compared with hand-mixed cements, concurrent with a statistically significant reduction (3 of 6) or increase (1 of 6) in the total amounts of gentamicin released. The total gentamicin release was studied in 3 of the brands after manual addition and mixing of the antibiotics. We found that the release of antibiotics was lower than in samples made from industrial mixing. In conclusion, the manual addition and mixing of gentamicin in PMMA bone cements leads to a lower release of antibiotics than that in corresponding commercially available antibiotic-loaded cements, while vacuum-mixing only leads to a minor reduction in antibiotic release, as compared to hand-mixing.     

Nanopartikuläres Silber

BACKGROUND: Multiresistant bacteria have become an important problem in prosthetic joint infections. Their frequent resistance against gentamicin, which is commonly used in antibiotic-loaded bone cements, makes a new prophylaxis necessary. METHODS: PMMA-cement was loaded with 1% nanoparticulate silver and its antibacterial activity tested in vitro against gentamicin-resistant MRSE and MRSA strains as well as being compared to the activity of plain and gentamicin-loaded bone cements. A quantitative elution testing was also done to study the potentially cytotoxic effects of NanoSilver cement. RESULTS: Unloaded and PMMA-cement loaded with 2% gentamicin did not exhibit any antibacterial activity against MRSE and MRSA. At 1%, NanoSilver cement completely inhibited the proliferation of MRSA and MRSE. NanoSilver bone cement did not show any significant differences compared to the non-toxic control group. CONCLUSIONS: If these promising in vitro results can be confirmed in vivo, NanoSilver bone cement may be of considerable value in total joint arthroplasty.     

In-vitro-Freisetzung von Antibiotika aus SmartSet HV- und Palacos R-Knochenzement und deren Einfluss auf die mechanischen Eigenschaften

BACKGROUND: The continuing emergence of new bone cements with additional antibiotics makes it important to establish which one will provide the most favourable antibiotic elution. An in vitro antibiotic elution and mechanical study was therefore carried out to compare a newer bone cement, SmartSet, with the established Palacos R cement. METHODS: Samples were prepared with each cement adding 1 g gentamicin, 1 g of vancomycin, or 1 g of gentamicin and vancomycin. The samples were analysed using fluorescence polarisation immunoassay. Mechanical tests were performed to determine whether any significant degradation in the cement strength occurred following addition of the antibiotic. RESULTS: With regards to gentamicin release Palacos R eluted significantly more antibiotic over the study period than SmartSet (p<0.001). Both cements eluted significantly more gentamicin when two antibiotics were added. With respect to vancomycin release there was no significant difference. Palacos R was significantly stronger than SmartSet in the 4-point bending test when the gentamicin + vancomycin antibiotic groups were compared (p=0.01). Palacos R also demonstrated a higher elastic modulus than SmartSet when the gentamicin and gentamicin + vancomycin groups were compared (p=0.03, p=0.005). CONCLUSIONS: Gentamcin shows better release characteristics from Palacos R. Both cements exhibited synergistic release of combined antibiotics.     

Liquid gentamicin and vancomycin in bone cement: a potentially more cost-effective regimen

This study investigated the use of liquid gentamicin, a much less costly antibiotic (<1/20 the price of tobramycin) with a broad antimicrobial spectrum, alone and in combination with vancomycin in bone cement. Standardized cement specimens loaded with 480 mg of liquid gentamicin, 4 g of powdered vancomycin, or both antibiotics were tested for elution characteristics, bioactivity, compressive strength, and porosity. Vancomycin elution was enhanced by 146% with the addition of gentamicin liquid, and gentamicin elution was enhanced by 45% when combined with vancomycin. Bioassay confirmed the bactericidal activity of the released antibiotics. Adding liquid gentamicin increased porosity, whereas adding vancomycin did not. Compressive strength decreased by 13%, 37%, and 45% in specimens containing vancomycin, liquid gentamicin, and both antibiotics, respectively. Despite inferior mechanical properties, the temporary nature of cement beads and spacers makes the liquid gentamicin-vancomycin mixture a potentially more cost-effective regimen in bone cement to treat musculoskeletal infections.     

Experimental study of acrylic resin coated gentamicin tablets for local antibiotic therapy

Gentamicin tablets were prepared and evaluated for local antibiotic therapy. Two types of tablet were used. One, a slow release tablet, was coated with acrylic resin (Eudragit R.S.) and another was non-coated. The release of gentamicin from the coated tablets can be controlled by changing the thickness of the film coating. The thickness of the film coating was adjusted to release gentamicin within three weeks when placed in Ringer's solution. Coated tablets were inserted into the bone marrow of rabbits. Thereafter, daily excretion of gentamicin was measured in the urine for three weeks. Constant excretion of gentamicin was seen for ten to fourteen days, which suggests the release of gentamicin from the bone marrow. Plasma concentrations were very low, thus precluding side effects. Non-coated tablets were inserted to the bone marrow by the same method as above. Plasma concentrations of gentamicin peaked in one hour and then rapidly decreased. This pattern is similar to that seen with intramuscular administration. As acrylic resin was non-absorbable material in vivo, the tissue reactions around coated tablets were examined. Histological findings at three weeks, six weeks and six months after insertion, respectively, did not show any severe tissue reactions. The possible use of local therapy by coated antibiotic tablets for bone infections is discussed.     

Preparation of gentamicin-loaded electrospun coating on titanium implants and a study of their properties in vitro

Purpose

Implant-related infections are disastrous complications in the clinic, and there are no effective therapies. In this preliminary study, gentamicin-loaded coating on titanium implants was prepared using the electrospinning technique, and some properties of the coating titanium implants were studied.

Methods

We adopted the electrospinning technique to prepare gentamicin-coated titanium implants. The surface structure of the coating implants was observed using scanning electron microscope. An elution study was performed to determine the release behavior of the gentamicin from the coating. The antibacterial efficacy and quantitative analysis of the bacterial adhesion of Staphylococcus aureus were evaluated in vitro, and the cytotoxicity of the coated titanium implants on osteoblasts was investigated in vitro.

Results

The morphology of the gentamicin-coated titanium implants exhibited nanofibers, and the release of gentamicin showed an initial gentamicin burst followed by a slow release. The gentamicin-coated titanium implants had a persistent antibacterial efficacy for 1 week and significantly reduced the adhesion of the Staphylococcus aureus compared with bare titanium implants in vitro. There was no cytotoxicity observed in vitro for the gentamicin-coated implants.

Conclusion

The gentamicin-coated titanium implants, which were prepared using an electrospinning technique, present many advantages and may be considered to prevent and treat the implant-related infections.