Abstract
Aptamer- or antibody-based sensing protocols have been reported for detecting carcinoembryonic antigen (CEA), but most exhibit complicated procedures or multiple reactions. In this work, we developed a one-step aptasensing protocol for the spectrometric determination of CEA based on 4-nitrophenol (4-NP)-loaded magnetic mesoporous silica nanohybrids (MMSNs) for bioresponsive controlled-release applications. To fabricate such a responsive–controlled sensing system, single-stranded complementary oligonucleotides relative to the CEA-specific aptamer were first modified on the aminated MMSN. Thereafter, 4-NP molecules blocked the pores with the assistance of the aptamers via a hybridization reaction. The introduced target CEA specifically reacted with the hybridized aptamer, thus detaching from the MMSN to open the gate. The loaded 4-NP molecules were released from the pores, as determined using ultraviolet–visible (UV–vis) absorption spectroscopy after magnetic separation. Under optimum conditions, the absorbance increased with an increase in the target CEA in the sample and exhibited a good linear relationship within the dynamic range of 0.1–100 ng mL−1, with a detection limit of 46 pg mL−1. Moreover, this system also displayed high specificity, good reproducibility, and acceptable accuracy for analyzing human serum specimens, in comparison with a commercialized human CEA-enzyme-linked immunosorbent assay (ELISA) kit.
Highlights
A tumor biomarker, e.g., alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), or cancer antigen 15-3 (CA 15-3), is anything present in, or produced by, cancer cells in the body, relating to cancer or certain benign conditions [1,2,3]
GTG GTA T-30
Magnetic mesoporous silica nanoparticles are used as nanocontainers for the loading of the 4-nitrophenol tracer
Summary
A tumor biomarker, e.g., alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), or cancer antigen 15-3 (CA 15-3), is anything present in, or produced by, cancer cells in the body, relating to cancer or certain benign (noncancerous) conditions [1,2,3]. Only low amounts of soluble CEA can be detected in serum. Protocols based on aptasensors and immunoassays have been developed for the quantitative monitoring of CEA, e.g., radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay, chemiluminescent immunoassay, and electrochemical immunoassay techniques [7,8]. Yu et al developed a pressure-based biosensor integrated with a flexible pressure sensor and an electrochromic device for a visual immunoassay of CEA [9]. Tang et al designed a surface-enhanced Raman-scattering-based
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