Oltean-Dan Daniel, Dogaru Gabriela-Bombonica, Jianu Elena-Mihaela, Riga Sorin, Tomoaia-Cotisel Maria, Mocanu Aurora, Barbu-Tudoran Lucian, Tomoaia Gheorghe
Department of Orthopedics and Traumatology, Iuliu Hatieganu University of Medicine and Pharmacy, 47 General Traian Mosoiu Street, 400132 Cluj-Napoca, Romania.
Department of Medical Rehabilitation, Iuliu Hatieganu University of Medicine and Pharmacy, 46-50 Viilor Street, 400347 Cluj-Napoca, Romania.
Micromachines (Basel). 2021 Oct 31;12(11):1352. doi: 10.3390/mi12111352.
Innovative nanomaterials are required for the coatings of titanium (Ti) implants to ensure the activation of Ti surfaces for improved osseointegration, enhanced bone fracture healing and bone regeneration. This paper presents a systematic investigation of biomimetic composite (BC) coatings on Ti implant surfaces in a rat model of a diaphyseal femoral fracture. Methodological approaches of surface modification of the Ti implants via the usual joining methods (e.g., grit blasting and acid etching) and advanced physicochemical coating via a self-assembled dip-coating method were used. The biomimetic procedure used multi-substituted hydroxyapatite (ms-HAP) HAP-1.5 wt% Mg-0.2 wt% Zn-0.2 wt% Si nanoparticles (NPs), which were functionalized using collagen type 1 molecules (COL), resulting in ms-HAP/COL (core/shell) NPs that were embedded into a polylactic acid (PLA) matrix and finally covered with COL layers, obtaining the ms-HAP/COL@PLA/COL composite. To assess the osseointegration issue, first, the thickness, surface morphology and roughness of the BC coating on the Ti implants were determined using AFM and SEM. The BC-coated Ti implants and uncoated Ti implants were then used in Wistar albino rats with a diaphyseal femoral fracture, both in the absence and the presence of high-frequency pulsed electromagnetic shortwave (HF-PESW) stimulation. This study was performed using a bone marker serum concentration and histological and computer tomography (micro-CT) analysis at 2 and 8 weeks after surgical implantation. The implant osseointegration was evaluated through the bone-implant contact (BIC). The bone-implant interface was investigated using FE-SEM images and EDX spectra of the retrieved surgical implants at 8 weeks in the four animal groups. The obtained results showed significantly higher bone-implants contact and bone volume per tissue volume, as well as a greater amount of newly formed bone, in the BC-coated Ti implants than in the uncoated Ti implants. Direct bone-implant contact was also confirmed via histological examination. The results of this study confirmed that these biomimetic composite coatings on Ti implants were essential for a significant enhancement of osseointegration of BC-coated Ti implants and bone regeneration. This research provides a novel strategy for the treatment of bone fractures with possible orthopedic applications.
钛（Ti）植入物的涂层需要创新的纳米材料，以确保钛表面的活化，从而改善骨整合、促进骨折愈合和骨再生。本文在大鼠股骨干骨折模型中，对Ti植入物表面的仿生复合（BC）涂层进行了系统研究。采用了通过常规连接方法（如喷砂和酸蚀）对Ti植入物进行表面改性的方法，以及通过自组装浸涂法进行先进的物理化学涂层的方法。仿生过程使用了多取代羟基磷灰石（ms-HAP）HAP-1.5 wt% Mg-0.2 wt% Zn-0.2 wt% Si纳米颗粒（NPs），这些纳米颗粒用I型胶原分子（COL）进行功能化，得到ms-HAP/COL（核/壳）纳米颗粒，将其嵌入聚乳酸（PLA）基质中，最后用COL层覆盖，得到ms-HAP/COL@PLA/COL复合材料。为了评估骨整合问题，首先，使用原子力显微镜（AFM）和扫描电子显微镜（SEM）测定Ti植入物上BC涂层的厚度、表面形态和粗糙度。然后，将涂有BC的Ti植入物和未涂覆的Ti植入物用于患有股骨干骨折的Wistar白化大鼠，分别在有无高频脉冲电磁短波（HF-PESW）刺激的情况下进行实验。本研究在手术植入后2周和8周，使用骨标志物血清浓度、组织学和计算机断层扫描（micro-CT）分析进行。通过骨-植入物接触（BIC）评估植入物的骨整合情况。在四个动物组中，在8周时使用回收的手术植入物的场发射扫描电子显微镜（FE-SEM）图像和能谱仪（EDX）光谱对骨-植入物界面进行了研究。获得的结果表明，与未涂覆的Ti植入物相比，涂有BC的Ti植入物具有更高的骨-植入物接触率和每组织体积的骨体积，以及更多的新形成骨。组织学检查也证实了直接的骨-植入物接触。本研究结果证实，这些Ti植入物上的仿生复合涂层对于显著增强涂有BC的Ti植入物的骨整合和骨再生至关重要。本研究为骨折治疗提供了一种可能用于骨科应用的新策略。
