Department of Hepatology, Taiyuan Third People's Hospital, Taiyuan 030012, China.
School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Molecules. 2023 Oct 5;28(19):6935. doi: 10.3390/molecules28196935.
The labeling-free and immobilization-free homogeneous aptamer sensor offers advantages including simple operation, low cost, and high sensitivity, demonstrating great potential in rapid detection of tumor biomarkers in biological samples. In this work, a labeling-free and immobilization-free homogeneous aptamer sensor was conveniently fabricated by combining size exclusion and charge-selective penetration of a nanochannel-modified electrode and two-dimensional (2D) nanorecognition probe which can realize selective and highly sensitive detection of alpha-fetoprotein (AFP) in serum. Vertically ordered mesoporous silica film (VMSF) with ultra-small, uniform, and vertically aligned nanochannels was easily grown on the simple, low-cost, and disposable indium tin oxide (ITO) electrode. Through π-π interaction and electrostatic force, the AFP aptamer (Apt) and electrochemical probe, tris(bipyridine)ruthenium(II) (Ru(bpy)), were coloaded onto graphene oxide (GO) through simple incubation, forming a 2D nanoscale recognition probe (Ru(bpy)/Apt@GO). Owing to the size exclusion effect of VMSF towards the 2D nanoscale probe, the electrochemical signal of Ru(bpy)/Apt@GO could not be detected. In the presence of AFP, the specific binding of AFP to the aptamer causes the dissociation of the aptamer and Ru(bpy) from GO, resulting in their presence in the solution. The efficient electrostatic enrichment towards Ru(bpy) by negatively charged VMSF allows for high electrochemical signals of free Ru(bpy) in the solution. Linear determination of AFP ranged from 1 pg/mL to 1000 ng/mL and could be obtained with a low limit of detection (LOD, 0.8 pg/mL). The high specificity of the adapter endowed the constructed sensor with high selectivity. The fabricated probe can be applied in direct determination of AFP in serum.
无标记和无固定化的均相适体传感器具有操作简单、成本低、灵敏度高等优点，在生物样品中快速检测肿瘤标志物方面具有巨大潜力。在这项工作中，通过将纳米通道修饰电极的尺寸排阻和电荷选择渗透与二维（2D）纳米识别探针相结合，方便地制备了无标记和无固定化的均相适体传感器，该传感器可以实现对血清中甲胎蛋白（AFP）的选择性和高灵敏度检测。具有超小、均匀和垂直排列纳米通道的垂直有序介孔硅膜（VMSF）很容易在简单、低成本和一次性的氧化铟锡（ITO）电极上生长。通过π-π相互作用和静电力，将 AFP 适体（Apt）和电化学探针三（联吡啶）钌（II）（Ru（bpy））通过简单孵育共载入氧化石墨烯（GO）上，形成二维纳米识别探针（Ru（bpy）/Apt@GO）。由于 VMSF 对二维纳米探针的尺寸排阻效应，无法检测 Ru（bpy）/Apt@GO 的电化学信号。在 AFP 存在的情况下，AFP 与适体的特异性结合导致适体和 Ru（bpy）从 GO 上解离，从而使其存在于溶液中。带负电荷的 VMSF 对 Ru（bpy）的有效静电富集允许溶液中游离 Ru（bpy）具有高电化学信号。AFP 的线性测定范围为 1 pg/mL 至 1000 ng/mL，检测限（LOD，0.8 pg/mL）低。适配器的高特异性赋予了构建的传感器高选择性。所制备的探针可直接用于血清中 AFP 的测定。
