传感器类型
荧光生物传感器
检测对象
荧光素(fluorescein,DMSO溶液)、肌红蛋白(myoglobin,FITC标记,50 mM磷酸盐缓冲液pH 7.0)
检测原理
该检测基于分子印迹聚合物(MIP)微点/纳米丝阵列的特异性识别。MIP前驱体在模板存在下经投影光刻和纳米压印聚合,形成与荧光素或肌红蛋白互补的结合位点;去除模板后,目标分子重新结合到MIP位点。荧光素本身具有荧光,肌红蛋白则用FITC标记,结合后在480 nm激发下发射527 nm荧光。荧光显微镜采集图像,用ImageJ计算MIP与NIP荧光强度比IF=FI_MIP/FI_NIP。纳米丝高长径比使印迹位点暴露于表面,提高传质和结合容量,因此荧光信号随目标浓度增加而增强;竞争性结合中非荧光类似物会占据位点并降低荧光。
检测灵敏度
原文未报告 LOD、线性范围、灵敏度斜率或相关系数。
效应效果
荧光素多孔MIP微点洗涤后消除92%初始荧光,75 μM荧光素孵育后恢复62%,IF=3;重复孵洗变化在10%以内。与荧光素二乙酸酯竞争时,MIP荧光随竞争物浓度降低,NIP几乎无竞争。纳米丝MIP微点荧光强度约为普通多孔点的4倍,IF由3提高到13。肌红蛋白MIP对FITC-肌红蛋白的IF=4.3;细胞色素C非特异结合高20%但IF=0,血红蛋白IF=1.5,表明特异性。阵列经数月重复孵洗无降解。作者认为其合成简便、成本低、稳定性好,适合生物传感器和生物芯片。
传感器的构成
- 基底/纳米模具:阳极氧化铝(Al2O3)多孔层(孔径约150 nm)与铝片,作为纳米压印模具并承载模板固定;玻璃片(glass slide)用于多孔微点阵列。
- 玻璃基底活化:MAPTMS(methacryloylamido-propyl trimethoxysilane)处理玻璃片,提供光聚合界面,用于多孔MIP微点阵列。
- 表面活化/模板固定:APTES((3-aminopropyl)triethoxysilane)硅烷化引入氨基,FITC或肌红蛋白(myoglobin)经戊二醛(glutaraldehyde)共价固定于Al2O3孔壁,作为印迹模板。
- 识别元件:分子印迹聚合物(MIP)纳米丝/微点,由4-VPy、MMA、TRIM、DPAP(荧光素体系)或HEMA、MAA、TEGDMA、DPAP(肌红蛋白体系)光聚合形成,提供特异性结合位点。
- 信号标记物:荧光素(fluorescein)或FITC标记肌红蛋白(FITC-myoglobin),结合后产生荧光信号。
- 读出层:荧光显微镜(Leica DMI6000 B,480 nm激发/527 nm发射)读取荧光强度。
中文摘要
显微镜投影光刻与纳米压印、分子印迹相结合,用于快速微制备分子印迹聚合物(MIP)阵列,形成微米级纳米丝岛。使用10×物镜和承载所需图案的光掩模,可轻松获得直径70–90 μm的微点。微点由平行纳米丝组成,具有高长径比,直径约150 nm、长度数微米,通过在多孔氧化铝上进行纳米压印获得。阵列分别以小分子荧光素或蛋白质肌红蛋白为模板进行分子印迹。荧光素MIP阵列能够特异性识别目标分子,并通过荧光显微镜加以证明。与非纳米结构多孔微点相比,纳米丝微点的结合容量和印迹因子提高四倍,印迹因子(IF)达到13。以肌红蛋白为模板对纳米丝阵列进行印迹也是可行的,可获得较高的印迹因子4.3。通过投影光刻获得的此类合成受体纳米结构微阵列在生物传感器和生物芯片开发中具有巨大潜力。
英文摘要
Microscope projection photolithography is combined with nanomolding and molecular imprinting for the fast microfabrication of molecularly imprinted polymer (MIP) arrays in the form of micrometric islands of nanofilaments. Dot diameters from 70-90 μm are easily obtained using a 10× objective and a photomask carrying the desired pattern. The dots are composed of parallel nanofilaments of a high aspect ratio, 150 nm in diameter and several micrometers in length, which are obtained through a nanomolding procedure on porous alumina. The arrays are molecularly imprinted with the small molecule fluorescein or with the protein myoglobin. The fluorescein MIP arrays are able to specifically recognize their target, as demonstrated by fluorescence microscopy. A four-fold increase in binding capacity and imprinting factor (IF = 13) is obtained compared to non-nanostructured porous dots. Imprinting of the nanofilament arrays with the protein myoglobin as the template is also possible and allows for a high imprinting factor of 4.3. Such nanostructured microarrays of synthetic receptors obtained by projection photolithography have great potential in biosensor and biochip development.