Development of dental biosensor using nano-technology

本研究采用石英晶体微天平（QCM）对激光烧蚀沉积的羟基磷灰石（HA）和天然磷灰石（NA）薄膜进行了体外细胞相容性研究和蛋白质吸附的原位测量，为了研究钛种植体的良好表面形态，采用ArF准分子激光器在钛种植体表面制备HA和NA薄膜，并制作QCM传感器在360℃下热辐射1h。退火后，通过X射线衍射（XRD）对HA薄膜的化学成分进行了表征。用能谱分析（EDX）观察了HA和NA膜在钛盘上的表面形态。随后，原代小鼠成骨细胞（PMO）培养的光盘或无膜。通过DNA含量测定、碱性磷酸酶活性测定和骨钙素生成测定观察细胞增殖和分化情况。使用27-Hz QCM监测膜与磷酸盐缓冲液中的几种蛋白质之间的亲和力。XRD显示在退火条件下Ti和QCM传感器上的结晶HA和NA膜。对于NA膜，除了Ca和P之外，EDX还显示Na和Mg的峰。PMO生长速度快，有较高的ALP和OCN时，生长在NA膜比HA膜或Ti。NA膜QCM传感器对几种蛋白质的吸附量明显高于HA膜和非膜QCM传感器，说明激光烧蚀沉积的NA膜对蛋白质的上级吸附能力强，与细胞具有良好的细胞相容性。所获得的结果可能会导致更有效的牙科植入物的发展。

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.