Development of dental biosensor using nano-technology

本研究利用石英晶体微天平（QCM）对激光烧蚀沉积的羟基磷灰石（HA）和天然磷灰石（NA）薄膜进行体外细胞相容性和原位蛋白质吸附测量，以研究钛牙种植体更好的表面构象。采用充放电速率为10 Hz的ArF准分子激光在钛盘和QCM传感器上制备了HA和NA薄膜，并在360℃下进行热辐射退火1 h。退火后，用x射线衍射（XRD）对HA薄膜的化学成分进行了表征。用能量色散分析（EDX）观察了钛盘上HA和NA膜的表面构象。随后，小鼠原代成骨细胞（PMO）在带膜或不带膜的椎间盘上培养。采用DNA检测、碱性磷酸酶活性（ALP）检测和骨钙素（OCN）检测观察细胞的增殖和分化情况。使用27 hz QCM监测膜与磷酸盐缓冲液中几种蛋白质之间的亲和力。XRD结果表明，在退火条件下，Ti和QCM传感器表面形成了结晶的HA和NA薄膜。EDX显示Na膜除Ca和P峰外，还有Na和Mg峰。与HA膜和Ti膜相比，在NA膜中生长的PMO生长速度更快，ALP和OCN也更高。有NA膜的QCM传感器对几种蛋白质的吸收量显著高于无HA膜和HA膜的QCM传感器。基于这些发现，激光烧蚀沉积的NA膜由于具有良好的蛋白质吸收能力，与细胞具有良好的细胞相容性。获得的结果可能导致开发更有效的牙种植体。

This study examined in vitro cytocompatibility and in situ measurements of protein adsorption using the quartz crystal microbalance (QCM) to thin hydroxyl apatite (HA) and natural apatite (NA) films deposited by laser ablation, in order to investigate better surface conformation of titanium dental implants.Thin HA and NA films on titanium discs and the QCM sensor were made using an ArF excimer laser operating at a repletion rate of 10 Hz and annealed by heat radiation at 360℃ for 1 h. After annealing, the chemical composition of the HA film was characterized by X-ray diffraction (XRD). The surface conformation of the HA and NA films on the titanium disc was observed by energy dispersive analysis (EDX). Subsequently, primary mouse osteoblast (PMO) was cultured on the discs with or without film. Cell proliferation and differentiation were investigated by DNA assay, alkaline phosphatase activity (ALP) assay and osteocalcin production (OCN) assay. The affinity between the films and several proteins in the phosphate buffer was monitored using a 27-Hz QCM.XRD showed crystalline HA and NA films on the Ti and QCM sensor under the annealing conditions. EDX showed peaks of Na and Mg in addition to Ca and P for the NA film. PMO grew faster and had higher ALP and OCN when grown in NA films than on HA films or Ti. The absorbed amount of several proteins on the QCM sensor with NA film was significantly higher than that of HA film and non-film.Based on these findings, NA film deposited by laser ablation shows excellent cytocompatibility with cells owing to the superior absorption of protein. The results obtained could lead to the development of more effective dental implants.