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Abstract：
Polydopamine nanoparticles (PDA NPs) are widely utilized in the field of biomedical science for surface functionalization because of their unique characteristics, such as simple and low-cost preparation methods, good adhesive properties, and ability to incorporate amine and oxygen-rich chemical groups. However, challenges in the application of PDA NPs as surface coatings on electrode surfaces and in conjugation with biomolecules for electrochemical sensors still exist. In this work, we aimed to develop an electrochemical interface based on PDA NPs conjugated with a DNA aptamer for the detection of glycated albumin (GA) and to study DNA aptamers on the surfaces of PDA NPs to understand the aptamer-PDA surface interactions using molecular dynamics (MD) simulation. PDA NPs were synthesized by the oxidation of dopamine in Tris buffer at pH 10.5, conjugated with DNA aptamers specific to GA at different concentrations (0.05, 0.5, and 5 μM), and deposited on screen-printed carbon electrodes (SPCEs). The charge transfer resistance of the PDA NP-coated SPCEs decreased, indicating that the PDA NP composite is a conductive bioorganic material. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed that the PDA NPs were spherical, and dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy data indicated the successful conjugation of the aptamers on the PDA NPs. The as-prepared electrochemical interface was employed for the detection of GA. The detection limit was 0.17 μg/mL. For MD simulation, anti-GA aptamer through the 5\'terminal end in a single-stranded DNA-aptamer structure and NH2 linker showed a stable structure with its axis perpendicular to the PDA surface. These findings provide insights into improved biosensor design and have demonstrated the potential for employing electrochemical PDA NP interfaces in point-of-care applications.
摘要：
聚多巴胺纳米粒子(PDANPs)因其独特的特性被广泛应用于生物医学领域的表面功能化,如简单和低成本的制备方法，良好的粘合性能，以及结合胺和富氧化学基团的能力。然而,在将PDANP用作电极表面的表面涂层以及与生物分子结合用于电化学传感器的应用中仍然存在挑战。在这项工作中,我们旨在开发一种基于与DNA适体偶联的PDANP的电化学界面,用于检测糖化白蛋白(GA),并利用分子动力学(MD)模拟研究PDANP表面的DNA适体,以了解适体-PDA表面相互作用.PDANP是通过在pH10.5的Tris缓冲液中氧化多巴胺合成的，与不同浓度（0.05、0.5和5μM）的GA特异性DNA适体缀合，并沉积在丝网印刷碳电极(SPCE)上。PDANP涂覆的SPCE的电荷转移电阻降低，表明PDANP复合材料是导电的生物有机材料。透射电子显微镜（TEM）和扫描电子显微镜（SEM）证实PDANPs呈球形，和动态光散射（DLS），傅里叶变换红外光谱(FTIR),和拉曼光谱数据表明适体在PDANP上的成功缀合。所制备的电化学界面用于GA的检测。检出限为0.17μg/mL。对于MD模拟，抗GA适体通过单链DNA适体结构和NH2接头的5'末端显示出稳定的结构，其轴垂直于PDA表面。这些发现提供了对改进的生物传感器设计的见解，并证明了在即时护理应用中采用电化学PDANP接口的潜力。
