Block copolymer based hybrid materials for direct electrochemical biosensing of nucleic acids and hemoproteins

该项目旨在开发实验上可用的无试剂电化学方法，用于鉴定和定量核酸和血色素蛋白。循环肿瘤DNA、RNA或microRNA水平可作为不同类型癌症的诊断和预后方法的衡量标准。同时，在用抗癌药物治疗癌细胞的过程中，会有相当数量的细胞色素c释放，这一水平可以用来衡量某种药物的效率，筛选新的潜在候选药物，或者反过来，作为细胞对抗癌治疗的抵抗力的指标。同时检测和定量这两种生物标志物可以显著提高抗癌治疗的效率，针对不同患者之间的(细微)差异，并有助于开发个性化药物的策略。直接电化学分析的灵敏度严格取决于分析物在工作电极中的整合程度，在我们的情况下是纳米复合材料。为此，将使用碳纳米材料(碳纳米管或氧化石墨烯)、贵金属纳米颗粒(金或银纳米颗粒)和两亲性嵌段共聚物的组合。因此，我们首先关注基于均匀溶解的碳纳米材料和贵金属纳米颗粒的有机/无机纳米复合材料的制备原理。所使用的两亲性两嵌段共聚物将起到三重作用。首先，由于碳纳米材料与疏水嵌段之间的疏水相互作用，它们被用作碳纳米材料的分散剂。此外，材料的亲水性(和离子)部分可用于络合金属离子，然后还原为金属纳米颗粒。最后，在合适的底物上沉积后，两嵌段共聚物作为基质材料与目标生物分子进行特定的相互作用。碳纳米材料的作用是提高整个复合材料的导电性和电子转移的效率。最后，金属纳米颗粒的存在有望催化电化学反应。总之，这些效应将协同作用，为核酸和细胞色素C的直接电化学分析提供相当大的生物传感器灵敏度和选择性。在这个项目的过程中，彻底的生物分析性能将涉及到对嵌段共聚物/碳纳米材料/金属纳米颗粒杂化材料的最佳结构和组成的系统研究。随后，将使用最好的工作结构来评估生物传感器的特性，然后开发用于实际样品(全血、血浆或血清)直接电化学分析的应用策略。

The project aims at the development of experimentally available reagentless electrochemical methods for identification and quantification of nucleic acids and hemoproteins. The level of circulating tumor DNA, RNA, or micro RNA can be taken as a measure for diagnostic and prognostic approaches to different types of cancer. Simultaneously, a considerable release of hemoprotein cytochrome c occurs during the treatment of cancer cells with anti-cancer drugs, and this level can then be taken as measure for the efficiency of a certain drug, the screening of new potential drug candidates or, in turn, as an indicator for cell resistance towards anti-cancer therapy. Simultaneous detection and quantification of both these biomarkers could considerably increase the efficiency of anti-cancer therapy with respect to (subtle) differences between different patients and help in developing strategies for personalized medicine.The sensitivity of direct electrochemical analysis strictly depends on the degree of integration of the analyte within the working electrode, in our case a nanocomposite material. For this purpose, a combination of carbon nanomaterials (carbon nanotubes or graphene oxide), noble metal nanoparticles (gold or silver nanoparticles), and amphiphilic block copolymers will be used. Therefore, we first focus on principles of organic/inorganic nanocomposite fabrication based on uniformly solubilized carbon nanomaterials and, eventually, noble metal nanoparticles. The employed amphiphilic diblock copolymers will serve a triple role. First, they are used as dispersing agent for the carbon nanomaterial due to hydrophobic interactions between the latter and the hydrophobic block. Further, the hydrophilic (and ionic) part of the material can be used to complex metal ions, followed by reduction to metal nanoparticles. Finally, after deposition on suitable substrates the diblock copolymer serves as matrix material for specific interaction with target biomolecules. The role of the carbon nanomaterial is to improve conductivity of the entire composite and the efficiency of electron transfer. Finally, the presence of metal nanoparticles is expected to catalyze electrochemical reactions. In total, these effects will synergistically provide a considerable improvement of biosensor sensitivity and selectivity for direct electrochemical analysis of both nucleic acids and cytochrome c.During the course of this project, a thorough examination of bioanalytical properties will involve a systematic investigation towards optimal construction and composition of the block copolymer/carbon nanomaterial/metal nanoparticle hybrid material. Subsequently, best working constructs will be used to assess biosensor characteristics, followed by the development of application strategies for direct electrochemical analysis of real samples (whole blood, plasma or serum).