Poly-L-lysine/hydroxyapatite/carbon nanotube hybrid nanocomposite applied for piezoelectric immunoassay of carbohydrate antigen 19-9

Hybrid composites are of special scientific interest for biochemical applications wherein the abilities to modulate the morphology and property of the hybrid material are important. In this paper, the formation of poly-L-lysine/hydroxyapatite/carbon nanotube (PLL/HA/CNT) hybrid nanoparticles is described and a general design strategy for an immunosensing platform has been proposed on the basis of PLL/HA/CNT nanocomposite adsorption of antibodies. Quartz crystal microbalance (QCM) used as a model transducer and the detection performances of the resulting immunosensor were investigated by use of the immuno-system of carbohydrate antigen 19-9 (CA19-9), an important indicator in the diagnosis of clinical cancers. The hybrid nanocomposite was characterized by the transmission electron microscope (TEM), scanning electron microscope (SEM) and Fourier transform-infrared (FT-IR) spectrum measurements. The frequency response characteristics for the processes of immobilization and immunoreaction of anchored anti-CA19-9 antibodies were studied in detail. It was found that the developed sensing interface has some advantages such as the activation-free immobilization and the high antigen-binding activities of antibodies. The as-prepared immunosensor can allow for the determination of CA19-9 in the concentration range of around 12.5-270.0 U ml(-1). Such an interface design with the hybrid nanocomposite should be tailored as a new alternative used for biosensor design.

杂化复合材料在生化应用中具有特殊的科学研究价值，在这些应用中，调节杂化材料的形态和性能的能力至关重要。本文描述了聚-L -赖氨酸/羟基磷灰石/碳纳米管（PLL/HA/CNT）杂化纳米粒子的形成，并基于PLL/HA/CNT纳米复合材料对抗体的吸附，提出了一种免疫传感平台的通用设计策略。以石英晶体微天平（QCM）作为模型传感器，利用碳水化合物抗原19 - 9（CA19 - 9）这一临床癌症诊断的重要指标的免疫系统，研究了所得免疫传感器的检测性能。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）和傅里叶变换红外（FT - IR）光谱测量对杂化纳米复合材料进行了表征。详细研究了固定化过程以及锚定的抗CA19 - 9抗体免疫反应的频率响应特性。研究发现，所开发的传感界面具有一些优势，例如抗体无需激活即可固定以及具有高抗原结合活性。所制备的免疫传感器能够测定浓度范围约为12.5 - 270.0 U/ml的CA19 - 9。这种采用杂化纳米复合材料的界面设计应作为生物传感器设计的一种新的替代方案进行定制。