Balasundaram Ganesan, Webster Thomas J
Division of Engineering, Brown University, Providence, Rhode Island 02912, USA.
J Biomed Mater Res A. 2007 Mar 1;80(3):602-11. doi: 10.1002/jbm.a.30954.
Peptide sequences such as lysine-arginine-serine-arginine (KRSR) selectively bind transmembrane proteoglycans (e.g. heparin sulfate) of osteoblasts (bone-forming cells) and are, therefore, actively being investigated for orthopedic applications. Further, nanophase materials (or materials with grain or particle sizes less than 100 nm) are promising new materials that promote new bone growth more than compared to conventional (that is, micron grain or particle size) materials. To combine the above two promising approaches for improving orthopedic implants, the objective of this in vitro study was to functionalize titanium (Ti) surfaces (both nanophase and conventional) with KRSR peptides and study their osteoblast cell adhesive properties. Materials were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. Results of this in vitro study provided evidence of increased osteoblast adhesion on nanophase compared to conventional Ti whether functionalized with KRSR or not. Results further showed that the immobilization of KRSR onto Ti (both nanophase and conventional) increased osteoblast adhesion compared to respective nonfunctionalized Ti and those functionalized with the negative control peptide KSRR. Most importantly, osteoblast adhesion on nonfunctionalized nanophase Ti increased compared to conventional Ti functionalized with KRSR. Further, select initial osteoblast adhesion was observed to occur at particle boundaries for any type of nanophase and conventional Ti formulated in this study. In summary, results provided evidence that not only should nonfunctionalized nanophase Ti be further studied for improved orthopedic applications but so should nanophase Ti functionalized with KRSR.
诸如赖氨酸 - 精氨酸 - 丝氨酸 - 精氨酸（KRSR）这样的肽序列能够选择性地结合成骨细胞（骨形成细胞）的跨膜蛋白聚糖（如硫酸肝素），因此，正被积极研究用于骨科应用。此外，纳米相材料（即晶粒或颗粒尺寸小于100纳米的材料）是有前景的新型材料，与传统材料（即微米级晶粒或颗粒尺寸的材料）相比，能更有效地促进新骨生长。为了结合上述两种改善骨科植入物的有前景的方法，本体外研究的目的是用KRSR肽对钛（Ti）表面（包括纳米相和传统表面）进行功能化处理，并研究其对成骨细胞的黏附特性。通过X射线光电子能谱、扫描电子显微镜和原子力显微镜对材料进行了表征。本体外研究结果表明，无论是否用KRSR进行功能化处理，与传统Ti相比，纳米相Ti上的成骨细胞黏附均有所增加。结果还表明，与各自未功能化的Ti以及用阴性对照肽KSRR功能化的Ti相比，将KRSR固定到Ti（纳米相和传统Ti）上可增加成骨细胞的黏附。最重要的是，与用KRSR功能化的传统Ti相比，未功能化的纳米相Ti上的成骨细胞黏附有所增加。此外，在本研究中制备的任何类型的纳米相和传统Ti中，均观察到部分初始成骨细胞黏附发生在颗粒边界处。总之，结果表明，不仅应进一步研究未功能化的纳米相Ti以改善骨科应用，用KRSR功能化的纳米相Ti也应如此。
