Gao Jiong, Zhang Shiyue, Xi Fengna
Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Third Hospital of Shanxi Medical University, Tongji Shanxi Hospital, Taiyuan 030032, China.
School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Molecules. 2025 Feb 6;30(3):746. doi: 10.3390/molecules30030746.
Homogeneous aptasensors that eliminate the need for probe labeling or immobilization hold significant potential for the rapid detection of tumor biomarkers. Herein, a homogeneous aptasensor with electrochemical (EC) and electrochemiluminescence (ECL) dual detection channels was developed by integrating nanochannel-based probe enrichment and DNase I cleavage for selective detection of the tumor biomarker, carbohydrate antigen 125 (CA125). A two-dimensional (2D) composite probe was prepared by assembling the CA125-specific aptamer and the cationic probe tris(2,2'-bipyridyl)Ru(II) (Ru(bpy)), which exhibited both EC and ECL properties, onto graphene oxide (GO) nanosheets (Ru(bpy)/Apt@GO). A vertically ordered mesoporous silica film (VMSF) with ultrasmall, uniform, and vertically aligned nanochannel arrays was rapidly grown on the inexpensive and disposable indium tin oxide (ITO) electrode, forming the detection interface. Due to the size exclusion effect of the ultrasmall nanochannels in VMSF, the Ru(bpy)/Apt@GO probe was unable to penetrate the nanochannels, resulting in no detectable Ru(bpy) signal on the electrode. Upon specific recognition of CA125 by the aptamer, an aptamer-CA125 complex was formed and subsequently detached from GO. DNase I then cleaved the aptamer-CA125 complex, releasing CA125 and allowing Ru(bpy) to dissociate into the solution. This enzymatic cleavage enabled CA125 to re-enter the binding cycle, amplifying the release of Ru(bpy) into the solution. The electrostatic adsorption of the cationic Ru(bpy) by VMSF significantly enhanced both the EC and ECL signals. The constructed aptasensor exhibited a linear EC detection range for CA125 from 0.1 U/mL to 100 ng/mL, with a limit of detection (LOD) of 91 mU/mL. For ECL detection, CA125 was detected over a range from 0.001 to 100 U/mL, with a LOD as low as 0.4 mU/mL. The developed aptasensor demonstrated excellent selectivity and was successfully applied to the dual-mode EC/ECL detection of CA125 in fetal bovine serum samples.
无需探针标记或固定的均相适体传感器在快速检测肿瘤生物标志物方面具有巨大潜力。在此，通过整合基于纳米通道的探针富集和DNase I切割技术，开发了一种具有电化学（EC）和电化学发光（ECL）双检测通道的均相适体传感器，用于选择性检测肿瘤生物标志物糖类抗原125（CA125）。通过将CA125特异性适体和具有EC和ECL特性的阳离子探针三（2,2'-联吡啶）钌（II）（Ru(bpy)）组装到氧化石墨烯（GO）纳米片上，制备了二维（2D）复合探针（Ru(bpy)/Apt@GO）。在廉价且一次性使用的氧化铟锡（ITO）电极上快速生长出具有超小、均匀且垂直排列的纳米通道阵列的垂直有序介孔二氧化硅膜（VMSF），形成检测界面。由于VMSF中超小纳米通道的尺寸排阻效应，Ru(bpy)/Apt@GO探针无法穿透纳米通道，导致电极上无可检测的Ru(bpy)信号。当适体特异性识别CA125时，形成适体-CA125复合物，随后从GO上脱离。然后DNase I切割适体-CA125复合物，释放出CA125并使Ru(bpy)解离到溶液中。这种酶切作用使CA125能够重新进入结合循环，放大Ru(bpy)向溶液中的释放。VMSF对阳离子Ru(bpy)的静电吸附显著增强了EC和ECL信号。构建的适体传感器对CA125的EC检测线性范围为0.1 U/mL至100 ng/mL，检测限（LOD）为91 mU/mL。对于ECL检测，CA自0.001至100 U/mL范围内可被检测到，LOD低至0.4 mU/mL。所开发的适体传感器表现出优异的选择性，并成功应用于胎牛血清样品中CA125的双模式EC/ECL检测。
