Reagentless Electrochemical Detection of Tumor Biomarker Based on Stable Confinement of Electrochemical Probe in Bipolar Silica Nanochannel Film

The convenient construction of carbon-based electrochemical immunosensors with high performance is highly desirable for the efficient detection of tumor biomarkers. In this work, an electrochemical immunosensor was fabricated by integrating a biofunctionalized mesoporous silica nanochannel film with a carbon-based electrode, which can enable the sensitive determination of carcinoembryonic antigen (CEA) in serum. The commonly used carbonaceous electrode, glassy carbon electrode (GCE), was employed as the supporting electrode and was pre-treated through electrochemical polarization to achieve the stable binding of a vertically ordered mesoporous silica film with amino groups (NH2-VMSF) without the use of any adhesive layer. To fabricate the immunorecognition interface, antibodies were covalently immobilized after the amino groups on the outer surface of NH2-VMSF was derivatized to aldehyde groups. The presence of amino sites within the high-density nanochannels of NH2-VMSF can facilitate the migration of negatively charged redox probes (Fe(CN)63-/4-) to the supporting electrode through electrostatic adsorption, leading to the generation of electrochemical signals. In the presence of CEA, the formation of immunocomplexes on the recognitive interface can reduce the electrochemical signal of Fe(CN)63-/4- on the supporting electrode. Based on this principle, the sensitive electrochemical detection of CEA was achieved. CEA can be determined to range from 0.01 ng mL−1 to 100 ng mL−1 with a limit of detection of 6.3 pg mL−1. The fabricated immunosensor exhibited high selectivity, and the detection of CEA in fetal bovine serum was achieved.

Section: Introductionmentioning

confidence: 99%

Sensitive Electrochemical Detection of Carcinoembryonic Antigen Based on Biofunctionalized Nanochannel Modified Carbonaceous Electrode

Zhou,

Wang,

et al. 2024

“…Owing to the uniform pore size, as well as large specific surface area and good mechanical stability, VMSFs have emerged as superior protective layer on the electrode surface and simultaneously allows the effective diffusion of small molecules (analytes or probes), greatly minimizing contamination of the complex matrix on the electrode and maintaining the electrode performance [ 27 , 28 , 29 , 30 , 31 ]. Moreover, VMSFs with many tiny nanochannels can confine various nanomaterials, such as metals [ 32 , 33 , 34 ], polymers [ 35 ], graphene quantum dots (GQDs) [ 36 ], and electrochemical probes [ 37 , 38 , 39 ], to fabricate a functional sensing interface. These exceptional characteristics of VMSFs provide a universal anti-fouling electroanalytical platform for direct determination in complicated real matrix [ 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

N-Doped Graphene Quantum Dots Confined within Silica Nanochannels for Enhanced Electrochemical Detection of Doxorubicin

Zhang,

Zhou,

Yan

et al. 2023

Herein, we describe a fast and highly sensitive electrochemical sensor for doxorubicin (DOX) detection based on the indium tin oxide (ITO) modified with a binary material consisting of vertically-ordered mesoporous silica films (VMSFs) and N-doped graphene quantum dots (NGQDs). VMSFs, with high permeability and efficient molecular transport capacity, is attached to the ITO electrode via a rapid and controllable electrochemical method, which can serve as a solid template for the confinement of numerous NGQDs through facile electrophoresis. By virtue of the excellent charge transfer capacity, π-π and electrostatic preconcentration effects of NGQDs, as well as the electrostatic enrichment ability of VMSF, the presented NGQDs@VMSF/ITO shows amplified electrochemical signal towards DOX with a positive charge, resulting in good analytical performance in terms of a wide linear range (5 nM~0.1 μM and 0.1~1 μM), high sensitivity (30.4 μA μM−1), and a low limit of detection (0.5 nM). Moreover, due to the molecular sieving property of VMSF, the developed NGQDs@VMSF/ITO sensor has good selectivity and works well in human serum and urine samples, with recoveries of 97.0~109%, thus providing a simple and reliable method for the direct electrochemical analysis of DOX without complex sample pretreatment procedures.

“…Other malignancies, such as melanoma, gastric cancer, breast cancer, ovarian cancer, lung cancer, and pancreatic cancer, may also result in elevated CEA levels. Therefore, CEA serves as an important broad-spectrum tumor biomarker with widespread applications in cancer screening, early diagnosis, and postoperative monitoring [ 3 , 4 , 5 ]. For example, changes in CEA levels can be used to evaluate the effectiveness of treatment, predict patient prognosis, and monitor cancer recurrence.…”

Section: Introductionmentioning

confidence: 99%

Immunosensor with Enhanced Electrochemiluminescence Signal Using Platinum Nanoparticles Confined within Nanochannels for Highly Sensitive Detection of Carcinoembryonic Antigen

Zhang,

et al. 2023

Rapid, highly sensitive, and accurate detection of tumor biomarkers in serum is of great significance in cancer screening, early diagnosis, and postoperative monitoring. In this study, an electrochemiluminescence (ECL) immunosensing platform was constructed by enhancing the ECL signal through in situ growth of platinum nanoparticles (PtNPs) in a nanochannel array, which can achieve highly sensitive detection of the tumor marker carcinoembryonic antigen (CEA). An inexpensive and readily available indium tin oxide (ITO) glass electrode was used as the supporting electrode, and a layer of amino-functionalized vertically ordered mesoporous silica film (NH2-VMSF) was grown on its surface using an electrochemically assisted self-assembly method (EASA). The amino groups within the nanochannels served as anchoring sites for the one-step electrodeposition of PtNPs, taking advantage of the confinement effect of the ultrasmall nanochannels. After the amino groups on the outer surface of NH2-VMSF were derivatized with aldehyde groups, specific recognition antibodies were covalently immobilized followed by blocking nonspecific binding sites to create an immunorecognition interface. The PtNPs, acting as nanocatalysts, catalyzed the generation of reactive oxygen species (ROS) with hydrogen peroxide (H2O2), significantly enhancing the ECL signal of the luminol. The ECL signal exhibited high stability during continuous electrochemical scanning. When the CEA specifically bound to the immunorecognition interface, the resulting immune complexes restricted the diffusion of the ECL emitters and co-reactants towards the electrode, leading to a reduction in the ECL signal. Based on this immune recognition-induced signal-gating effect, the immunosensor enabled ECL detection of CEA with a linear range of 0.1 pg mL−1 to 1000 ng mL−1 with a low limit of detection (LOD, 0.03 pg mL−1). The constructed immunosensor demonstrated excellent selectivity and can achieve CEA detection in serum.