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

Abstract

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.

Solid Electrochemiluminescence Sensor by Immobilization of Emitter Ruthenium(II)tris(bipyridine) in Bipolar Silica Nanochannel Film for Sensitive Detection of Oxalate in Serum and Urine

“…In recent years, electrochemiluminescence (ECL) sensors have gained significant attention for detecting oxalate ions [ 20 ]. ECL technology combines principles of electrochemistry and luminescence, where the core principle involves the generation of chemiluminescent substances on the electrode surface through electrochemical reactions, enabling the detection of target analytes [ 21 ]. ECL exhibits advantages such as high sensitivity, wide linear range, and low detection limit [ 22 , 23 , 24 ].…”

Vertical Silica Nanochannels and o-Phenanthroline Chelator for the Detection of Trace Fe(II)

“…Molecules with different characteristics can show distinct mass transport processes and physical phenomena at the nanoscale, which has been employed for the construction of novel electrochemical and electrochemiluminescence sensors with high sensitivity. , For example, when the size of charged nanochannels or nanopores is comparable to the Debye length (a few or tens of nanometers) in solution, counterions will be electrostatically attracted due to their interaction with the electrical double layer (EDL) near the charged surface of nanochannels or nanopores. − In addition, molecules confined in ultrasmall volume containers can be more easily detected compared to those in bulk solution, which arises from the ultrasmall volume and greatly increased concentration of molecules. − Vertically ordered mesoporous silica film (VMSF) consisting of uniform (commonly 2–3 nm in diameters) and numerous (10 12 pores cm –2 ) nanopores and ultrathin thickness (∼100 nm as usual) has been utilized to modify the electrode for sensitive and antifouling detection of various analytes of interests in real samples, such as metal ions, biomarkers, cells, and drug molecules in complex samples. − Thanks to the deprotonation of abundant silanol groups (p K a ∼ 2) inside nanochannels, ultrasmall volume (∼0.48 zL) of a nanochannel, and adjustable hydrophobic surface, VMSF has become an effective permselective electrode material in terms of charge, size, and complexation effects, which has aroused intensive fundamental research and sensing work so far. − To the best of our knowledge, exploitation of chelating agents for promoting the confined effect inside nanochannels of VMSF and further increasing the analytical performance has not yet been reported.…”

Highly Sensitive Electrochemical Determination of Butylated Hydroxyanisole in Food Samples Using Electrochemical-Pretreated Three-Dimensional Graphene Electrode Modified with Silica Nanochannel Film

“…For instance, vertically ordered mesoporous silica film (VMSF) has garnered attention due to its unique structure [39][40][41][42]. VMSF is composed of a vertical array of nanochannels perpendicular to the electrode, uniform nanochannel sizes (typically 2-3 nm in diameter), high pore density (up to 10 12 /cm 2 ), adjustable thickness (usually 50-200 nm), and good chemical stability [43][44][45]. Compared to the morphologies of other porous silica materials, these characteristics provide VMSF with rapid mass transfer capabilities and size and electrostatic sieving capabilities at the molecular level [46][47][48][49][50].…”