第30卷第4期 2010年12月
化学传感器 CHEMICALS
SENSORS
Vol. 30, No. 4 Dee.2010
DNA在SiO,纳米粒子薄膜表面的单分子行为研究
般晓燕，何彦·
（湖南大学化学化工学院，化学生物传略与计量学国家置点实验室，湖南长沙410082）
要：基于应用全内反射荧光显微镜，利用YOYO-1标记的入-DNA分子作为探针研究了SiO,纳米粒子摘
薄膜的表面性质，在不同的pH值下，考察了pH值对单个DNA分子在其表面行为（自由运动和吸附)的影响，并采用接触角（CA)和原子力显微镜（AtomicForceMicroscope，AFM)表征了SiO,纳米粒子薄膜表面的性质。实验表明，随着pH值的降低，DNA分子在其表面的吸附率随之增大。DNA分子在SiO,纳米粒子薄膜表面的吸附行为是静电作用和疏水作用共同作用的结果，但是起主导作用的是疏水作用。此外，相同pH值下，与文献中报道的DNA在玻片上的吸附率相比，DNA在SiO,纳米粒子薄膜表面的吸附率要大得多，这是由
于SiO,纳米粒子的比表面积大，表面活性位点多，且疏水性能强的缘故。关键词：单分子：全内反射荧光；DNA；SiO,纳米粒子
MotionandabsorptionofDNAmoleculeonthesilicananoparticle
filesurfacesstudiedusingsinglemoleculemicroscopy
Yin Xiao-yan，HeYan
( State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, College of Chemistry and
Chemical Engineering, Changsha 410082, China)
Abstract: Silica nanoparticle films were characterized using objectivetype total intermal reflection microscopy(TIRFM) with YOYO1 labeled single ADNA molecule as a probe, and the results were compared with CA and eenasdoosaaanaae (ooaaroo molecules were randomly diffusing and freely moving on the silica nanoparticle film surface at pH8.20. As pH de-creased, the DNA molecules were gradually dragged and adsorbed onto the silica nanoparticle film surface, The kinetics of adsorption/desorption of individual DNA molecules were examined to elucidate the contributions of hydrophobic interaction and electrostatic repulsion, and the driving forces were found to be mainly hydrophobic in-teraction. However, at the same pH, the fraction of DNA molecules adsorbed on the silica nanoparticle film surface is much larger than that on the glass surface, It is because that the total surface area of the silica nanoparticle film is larger than the bare glass surface and the silica nanoparticle has more active sites for DNA molecule adsorption/des-orption.
Key words: singlemolecule; total intemal reflection fluorescence; DNA; silica nanoparticle
原子、分子和宏观体系之间的纳米粒子所组成
引言 0
随着科学技术的突飞猛进，材料科学在人们生产、生活的各个领域中起着越来越重要的作用，一直是人类社会技术进步，社会发展的基础。所谓纳米材料是指三维空间尺度至少有一维处于纳米量级(1~100nm)的材料，它是由尺寸介于
*通讯联系人，Email:yanhe2021@gmail.com 万方数据
的新一代材料，具有比表面积大、表面结合能极强[3]等特点，导致了它具有传统固体材料所不具有的许多特殊性能，如高硬度、高强度、高韧性、高表面活性等等。因此，纳米材料在国防、电子、化工、核技术、航空、冶金、轻工、医药等领域中具有重要的应用价值，故近年来这一领域形成了新