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Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
A sandwich sensor based on molecularly imprinted polymers and aptamers for highly specific dual detection mode of
Qiaoyan Wang1, Wei Wen1, Zhe Meng2
1State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, National Demonstration Center for Experimental Chemistry Education, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, 750021, China.
Abstract:
Developing a highly sensitive and specific carcinoembryonic antigen (CEA) detection method is of great significance for rapid screening, monitoring, and evaluation of tumors. This study developed a sandwich sensor based on dual recognition modes (molecular imprinting and aptamer) and dual detection modes (persistent luminescence and colorimetry) for CEA detection, effectively improving the selectivity and detection accuracy of the sensor. Firstly, magnetic molecularly imprinted polymers (m-MIPs) targeting CEA were synthesized with Fe3O4 nanoparticles as the magnetic core, and the persistent luminescent nanoparticles (PLNPs) ZnGa2O4:Cr3+ (ZGC) were immobilized onto the m-MIPs to construct the m-MIPs/ZGC as the first recognition probe. Subsequently, MOF-5@PP ~ Apt was synthesized as the second recognition probe. During detection, the high selectivity of imprinted cavities was utilized to achieve efficient capture of the target molecule CEA. Based on the high affinity between aptamers and CEA, the sandwich-structured m-MIPs/ZGC@CEA@MOF-5@PP ~ Apt was formed. Due to the overlap between the absorption range of MOF-5 (220-275 nm) and the excitation range of ZGC (220-300 nm), the persistent luminescence intensity of ZGC at 700 nm is weakened by competitive excitation absorption. The decrease in persistent luminescence intensity exhibits a good linear correlation with CEA concentration. In addition, the color change intensity of phenolphthalein in the supernatant under weakly alkaline conditions was also well correlated with CEA concentration. The results indicate the linear ranges for persistent luminescence and colorimetric determination were 1-2000 ng L- 1 (R2 = 0.9967), corresponding to a detection limit of 0.45 ng L- 1, and 2.5-50 µg L- 1 (R2 = 0.9865), corresponding to a detection limit of 0.95 µg L- 1, respectively. This dual-recognition and dual-signal sensing platform integrates the merits of m-MIPs, aptamers and PLNPs, offering a reliable dual-modal strategy for accurate CEA quantification in complex samples.
