Improved EIS Performance of an Electrochemical Cytosensor Using Three-Dimensional Architecture Au@BSA as Sensing Layer

Abstract

An ultrasensitive electrochemical cytosensor for quantitative determination of carcinoembryonic antigen (CEA)-positive tumor cells was developed using three-dimensional (3D) architecture Au@BSA microspheres as sensing layer with the conjugation of targeting molecule monoclonal anti-CEA antibody (anti-CEA). The prepared Au@BSA microspheres exhibited satisfactory biocompatibility for cell proliferation via evaluation from thiazolyl blue tetrazolium bromide (MTT) assay, providing a suitable platform for cell adhesion study. Attributed to the excellent electroconductivity of Au@BSA, amplified electrochemical signals could be obtained and resulted in the greatly enhanced detection sensitivity. Electrochemical testing techniques including electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) were applied to assess the optimal conditions, specificity, and detection performance of as-fabricated cytosensor. The attachment of CEA-positive BXPC-3 cells onto the anti-CEA immobilized sensing layer led to the increased EIS responses, which changed linearly in the cell concentration range from 5.2 × 10(1) to 5.2 × 10(7) cells mL(-1) with a detection limit of 18 cells mL(-1). This proposed cytosensing strategy revealed high specificity to CEA-positive cells, acceptable intra-assay precision, excellent fabrication reproducibility with the RSD of 3.5%, and good stability owing to the outside BSA biocompatible layer, developing a promising technique for early monitoring of tumor cells at a lower level.

Magnetic Fe3O4-Reduced Graphene Oxide Nanocomposites-Based Electrochemical Biosensing

“…The results indicated that GOx entrapped in the nanocomposites has an unchanged secondary structure and retains its biological activity. Electrochemical impedance spectroscopy (EIS) is a highly effective tool to measure the change of interface properties of the modified electrode surface during the fabrication process [31]. Figure 4( 6 ].…”

Protein-inorganic hybrid nanoflowers as ultrasensitive electrochemical cytosensing Interfaces for evaluation of cell surface sialic acid

“…GA is an ideal reagent, because it reacts immediately and quantitatively with primary amino groups to give stable imines, giving chemical activation. After the immediate and quantitative reaction with GA, the R et value sharply increased to 832 Ω (curve c), because of the formation of Schiff base structures and steric hindrance of kinetic solvent effect (Hu et al, 2013b). BSA, which has a large number of functional groups (e.g., À SH and À NH 2 ) (Hu et al, 2012), can be converted to a reactive interface by GA, where another layer of target biomolecules SNA was covalently immobilized on the surface of the BSA-incorporated Ag nanoflowers via Schiff base structures, the R et value increased to 1943 Ω (curve d).…”

“…In our previous work, we synthesized a series of metal@protein nanocomposites via a protein-mediated method, and used them as sensing platforms for the sensitive detection of cancer cells (Hu et al, 2013a(Hu et al, , 2013b. These hybrid nanocomposites have a range of advantages such as excellent conductivities, large surface areas, and nontoxicity.…”

Facile synthesis of mesoporous calcium carbonate particles with finger citron residue as template and their adsorption performances for Congo red

“…However, collecting and treating these templates are rather intricate, and sometimes require some special training. Plant leaf, possessing a feature of hierarchical and porous structure, as a kind of renewable and accessible biomass, has been used as template to synthesize metal carbide (Li et al, 2009), metal oxide (Huang et al, 2014), and noble metals (Hu et al, 2013).…”