Doymus Burcu, Kerem Gizem, Yazgan Karatas Ayten, Kok Fatma Nese, Önder Sakip
Department of Molecular Biology and Genetics, Istanbul Technical University, ITU, Istanbul, Turkey.
Department of Biomedical Engineering, Yildiz Technical University, Esenler, Istanbul, Turkey.
J Biomater Appl. 2021 Jan;35(6):655-669. doi: 10.1177/0885328220977765. Epub 2020 Dec 6.
Bacterial infections and lack of osseointegration may negatively affect the success of titanium (Ti) implants. In the present study, a functional coating composed of chitosan (CS) microspheres and nano hydroxyapatite (nHA) was prepared to obtain antimicrobial Ti implants with enhanced bioactivity. First, the chitosan microspheres were fixed to Ti surfaces activated by alkali and heat treatment, then nHA coatings were precipitated onto these surfaces. Ciprofloxacin was loaded into the microspheres using two different procedures; encapsulation and diffusion. Scanning electron microscopy micrographs of the modified Ti surfaces showed that the coating was successfully deposited onto the Ti surfaces and stable for 30 days in PBS. The drug was completely released from free microspheres loaded by encapsulation in 21 days whereas only 89% release was observed after immobilization. The burst release also decreased from ca. 55% to ca. 35%. The release was further reduced following the nHA precipitation. The modified Ti surfaces showed antimicrobial activity based on the bacterial time-kill assay using , but the efficiency was affected by both nHA precipitation and drug loading strategy. Highest antimicrobial activity was seen in the samples without nHA layer, and when the drug was loaded by diffusion. Fourier transform infrared spectroscopy and X-ray diffraction analyses revealed that nHA on the surface enhanced HA growth in simulated body fluid for 3 weeks, showing increased osseointegration potential. Therefore, the proposed coating may be used to prevent Ti implant failure originated from bacterial infection and/or low bioactivity.
细菌感染和骨结合不足可能会对钛（Ti）植入物的成功产生负面影响。在本研究中，制备了一种由壳聚糖（CS）微球和纳米羟基磷灰石（nHA）组成的功能涂层，以获得具有增强生物活性的抗菌Ti植入物。首先，将壳聚糖微球固定在经过碱处理和热处理活化的Ti表面，然后在这些表面上沉淀nHA涂层。使用两种不同的方法将环丙沙星载入微球中：包封法和扩散法。改性Ti表面的扫描电子显微镜照片显示，涂层成功沉积在Ti表面，并且在PBS中稳定30天。通过包封载入游离微球中的药物在21天内完全释放，而固定化后仅观察到89%的释放。突释也从约55%降至约35%。nHA沉淀后释放进一步减少。基于使用的细菌时间杀灭试验，改性Ti表面显示出抗菌活性，但效率受到nHA沉淀和药物载入策略的影响。在没有nHA层且通过扩散载入药物的样品中观察到最高的抗菌活性。傅里叶变换红外光谱和X射线衍射分析表明，表面的nHA在模拟体液中促进了HA生长3周，显示出增加的骨结合潜力。因此，所提出的涂层可用于预防源自细菌感染和/或低生物活性的Ti植入物失败。
