Magnetic graphene oxide and vertically-ordered mesoporous silica film for universal and sensitive homogeneous electrochemiluminescence aptasensor platform

Herein, we demonstrated a convenient and highly sensitive homogeneous electrochemiluminescence (ECL) aptasensor platform by combination of magnetic composite probe and vertically-ordered mesoporous silica films (VMSF). Magnetic composite probe composed of biorecognition element (target-specific aptamer), ECL signal reporter (Ru(bpy)32+) and large-scale magnetic graphene oxide (M−GO), can be prepared by simple incubation, magnetic separation and redispersion prior to use. High-affinity and specific binding between target and aptamer can detach aptamer from M−GO and simultaneously release the slight amount of Ru(bpy)32+ into a solution, which can be sensitively detected by VMSF modified indium tin oxide (VMSF/ITO) due to the excellent electrostatic preconcentration capacity of VMSF. In this sensing system, detectable signal of Ru(bpy)32+ can be remarkably amplified by VMSF/ITO and meanwhile background signal can be reduced by the adsorption capacity of M−GO and size exclusion property of VMSF/ITO, effectively promoting the analytical performance of the present homogeneous ECL aptasensor. The applicability and universality of this sensing platform was confirmed by employing alpha fetoprotein (AFP) and prostate specific antigen (PSA) as the target models and their detection limits were 0.08 pg/mL and 9.6 pg/mL, respectively. Furthermore, the designed homogeneous ECL aptasensor platform is label-free, immobilization-free, low-cost, and free of additional electrode modification and sample pretreatment procedures, rendering a simple sensing strategy for quantitative determination of various biomarkers in clinical diagnosis by adapting the specific aptamer.