Sikder Prabaha, Grice Corey R, Lin Boren, Goel Vijay K, Bhaduri Sarit B
Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, Ohio 43606, United States.
Department of Physics & Astronomy, The University of Toledo, Toledo, Ohio 43606, United States.
ACS Biomater Sci Eng. 2018 Aug 13;4(8):2767-2783. doi: 10.1021/acsbiomaterials.8b00594. Epub 2018 Jul 18.
This Article reports the fabrication and evaluation of single-phase, silver-doped trimagnesium phosphate hydrate (Ag-TMPH) nanosheet coatings on polyetheretherketone (PEEK), a well-known material used to fabricate orthopedic and spinal implants. While PEEK has better biomechanical compatibility with bone compared to metallic implants, it is also quite inert. Therefore, it is a common practice to coat PEEK implants with conventional calcium phosphates (CaPs) to enhance cell attachment, proliferation and differentiation. As opposed to well-studied CaP compounds, relatively less-explored magnesium phosphates (MgPs) are also becoming interesting orthopedic biomaterials and is the prime focus in this research. The novel aspects of this paper are as follows. First, we report developing TMPH coatings within minutes with the help of microwave irradiation technology. Microwave irradiation plays an important role in the coating formation with accelerated kinetics. Scanning electron microscopy (SEM) confirmed the fabrication of approximately 650 nm thick TMPH coatings. The coatings resulted in submicron level surface roughness and in vitro cell studies confirmed enhanced MC3T3 cell adhesion within 4 h on such surfaces. The coatings also resulted in significant apatite formation after immersing in simulated body fluid for 7 days. Second, multifunctionality was achieved by doping TMPH coatings with Ag, thus rendering the coatings antibacterial. The antibacterial properties were evaluated against two most common infection-causing bacterial strains-Gram-negative and Gram-positive . The results indicated good bacterial resistance and bactericidal properties of the Ag-TMPH coatings. Third, in spite of Ag doping, the single-phase nature of the coatings were retained (without forming composite systems) with the help of the low-processing temperature of the microwave irradiation. The inductive coupled plasma technique confirmed that the doped single-phase TMPH coatings supported a uniform and controlled release of Ag ions over a period of 3 weeks. MTT assay evaluations and SEM micrographs confirmed no signs of cytotoxicity and healthy proliferation of cells in all cases. Quantitative real time PCR (qRT-PCR) indicated a significant rise in collagen (Col1) and osteocalcin (OCN) gene expression levels in the case of TMPH coated PEEK. Thus, microwave irradiation was successfully employed in forming multifunctional, that is, bioactive, cytocompatible, and antibacterial MgP coatings on PEEK.
本文报道了在聚醚醚酮（PEEK）上制备和评估单相银掺杂三水磷酸三镁（Ag-TMPH）纳米片涂层的过程。PEEK是一种用于制造骨科和脊柱植入物的知名材料。虽然与金属植入物相比，PEEK与骨具有更好的生物力学相容性，但它也相当惰性。因此，用传统的磷酸钙（CaP）涂覆PEEK植入物以增强细胞附着、增殖和分化是一种常见的做法。与研究充分的CaP化合物不同，研究相对较少的磷酸镁（MgP）也正成为有趣的骨科生物材料，并且是本研究的主要焦点。本文的新颖之处如下。首先，我们报告了借助微波辐照技术在几分钟内制备TMPH涂层。微波辐照在涂层形成过程中以加速动力学发挥重要作用。扫描电子显微镜（SEM）证实制备了约650 nm厚的TMPH涂层。这些涂层导致亚微米级的表面粗糙度，体外细胞研究证实MC3T3细胞在4小时内在此类表面上的附着力增强。将涂层浸入模拟体液7天后还导致了大量磷灰石形成。其次，通过用Ag掺杂TMPH涂层实现了多功能性，从而使涂层具有抗菌性。针对两种最常见的致病细菌菌株——革兰氏阴性菌和革兰氏阳性菌评估了抗菌性能。结果表明Ag-TMPH涂层具有良好 的抗菌性和杀菌性能。第三，尽管进行了Ag掺杂，但借助微波辐照的低加工温度，涂层的单相性质得以保留（未形成复合体系）。电感耦合等离子体技术证实，掺杂的单相TMPH涂层在3周内支持Ag离子的均匀和可控释放。MTT分析评估和SEM显微照片证实在所有情况下均无细胞毒性迹象且细胞健康增殖。定量实时PCR（qRT-PCR）表明，在TMPH涂覆的PEEK的情况下，胶原蛋白（Col1）和骨钙素（OCN）基因表达水平显著升高。因此，微波辐照成功用于在PEEK上形成多功能的，即具有生物活性、细胞相容性和抗菌性的MgP涂层。
