Search

In this paper, aldehyde-terminated ionic liquid was synthesized and used to fabricate a novel label-free electrochemical immunosensor for the determination of hepatitis B surface antigen. This sensor was formed from a gold electrode which was modified with a composite film containing the aldehyde-functionalized ionic liquid incorporated into nafion and anti-hepatitis B surface antigen antibody probes. Aldehyde-functionalized ionic liquid was used not only as a substrate for antibody immobilization, but also as a good material with high electrical conductivity, which greatly simplified the process of sensor fabrication. The proposed sensor exhibited a good performance in a linear range from 0.05 to 15 ng mL −1 with a detection limit of 20 pg mL −1 ( S / N =3) and provided a novel strategy for clinical detection due to satisfying stability, selectivity and reproducibility. [ABSTRACT FROM AUTHOR]

In this work, a novel and convenient strategy for synthesis of a well-defined polymer containing both aldehyde and ferrocene functional groups by grafting 4-hydroxybenzaldehyde and ferrocenecarboxylhydrazide onto linear poly (vinylbenzyl chloride) was developed. The designed polymer film (polymer CAF) could be used as a new support matrix for fabrication of a label-free electrochemical immunosensor with high sensitivity, good stability and repeatability. With human IgG as an analyte model, the proposed electrochemical immunosensor showed a linear concentration range from 0.1 to 20 ng mL −1 with a detection limit of 0.07 ng mL −1 (S/N=3). Moreover, interfering proteins including HSA, IgM, and IgE were added into the analyte, the developed immnnosensor can detect human IgG with high specificity. [ABSTRACT FROM AUTHOR]

A label-free electrochemical immunosensor based on Nafion/carbon nanotubes (CNTs)/charged pyridinecarboxaldehyde composite film was developed for the detection of hepatitis B surface antigen. Nafion/CNTs/charged pyridinecarboxaldehyde nanocomposites were prepared by dispersing charged pyridinecarboxaldehyde and CNTs in Nafion solution. The nanocomposites were cast on the electrode surface to form aldehyde-terminated composite film that can covalently bind antibody on the film without using other reagent. The immunosensor response was linearly changed with hepatitis B surface antigen concentration in the range from 0.1 to 25 ng ml −1 with a detection limit (signal/noise ratio = 3) of 0.04 ng ml −1 . Some important advantages such as simple preparation, good stability, reproducibility, and selectivity of the immunosensor were achieved. [ABSTRACT FROM AUTHOR]

This paper reports a label-free electrochemical immunosensor for the determination of aflatoxin B1 (AFB1), which is based on a gold electrode modified by a biocompatible film of carbon nanotubes/poly(diallyldimethylammoniumchloride)/Pd–Au nanoparticles (CNTs/PDDA/Pd–Au). The nanocomposite was characterized by transmission electron microscopy and the electrochemical behavior of modified electrodes was investigated by cyclic voltammetry. The CNTs/PDDA/Pd–Au nanocomposites film showed good electron transfer ability, which ensured high sensitivity to detect AFB1 in a range from 0.05 to 25 ng mL −1 with a detection limit of 0.03 ng mL −1 obtained at 3σ (where σ is the standard deviation of the blank solution, n = 10). The proposed immunosensor provides a simple tool for AFB1 detection. This strategy can be extended to any other antigen detection by using the corresponding antibodies. [ABSTRACT FROM AUTHOR]

In this work, a novel sulfur-containing compound with aldehyde groups was synthesized, which was used to immobilize antibodies through the covalent bonding of the aldehyde groups with amino groups, in which no additional chemical cross-linker is required. Human IgG was used as a model analyte to fabricate the electrochemical immunosensor. Using the proposed immunosensor, IgG was detected within the range from 0.01 to 25 ng mL −1 with a detection limit of 0.003 ng mL −1 obtained by 3 S/N. The simple electrochemical immunosensor had a good specificity, stability and reproducibility. [ABSTRACT FROM AUTHOR]

Using poly-(epichlorohydrin) and 4-pyridinecarboxaldehyde, we synthesized a new aldehyde-functionalized polymer, which was applied to simplify antibody immobilization on the electrode surface, in which no additional chemical cross-linking is required. Combined with the advantages of graphene, a label-free electrochemical immunosensor based on graphene/aldehyde-containing polymer film for α-fetoprotein detection was fabricated. α-Fetoprotein was detected within the range from 0.05 to 35 ng mL − 1 with a detection limit of 0.02 ng mL − 1 obtained by 3 S/N. The proposed immunosensor is easy, label-free, specific and thus provides a good diagnostic tool for detection of α-fetoprotein and other cancer markers. [ABSTRACT FROM AUTHOR]

A new polymer bearing aldehyde groups was designed and synthesized by grafting 4-pyridinecarboxaldehyde onto poly(epichlorohydrin). Antibodies can be directly immobilized on the surface of the polymer film through the covalent bonding of aldehyde groups of the film with amino groups of antibodies. In this study, human immunoglobulin G (IgG) was used as a model analyte for the fabrication of an electrochemical impedance immunosensor. Using the proposed immunosensor, IgG in the range from 0.1 to 80 ng ml −1 was detected with a detection limit of 0.07 ng ml −1 (signal/noise [S/N] = 3). In addition, the electrochemical impedance immunosensor displays good stability and reproducibility. [ABSTRACT FROM AUTHOR]

In this work, a novel thiol aromatic aldehyde was synthesized. It can be used as a substrate to directly immobilize antibodies on a gold electrode, for which no additional chemical cross-linker is required. It was also applied as a linker to prepare Fe 3 O 4 @Au/PAMAM/Ab 2 –horseradish peroxidase bioconjugates, which introduced multiple enzymes onto a sensing interface owing to the high surface-to-volume ratio of Fe 3 O 4 @Au nanoparticles and many functional groups of the poly(amidoamine) dendrimer (PAMAM). The introduced multiple enzymes greatly improved the detection signal. Under optimal conditions, the proposed electrochemical immunosensor exhibited desirable performance for detection of IgG in the range 0.005–50 ng ml −1 with a detection limit of 3 pg ml −1 based on a signal-to-noise ratio of 3. It has great potential application in the area of clinical analysis. [ABSTRACT FROM AUTHOR]

Abstract: Antibodies can be directly immobilized on the surface of dialdehyde cellulose film through the covalent bonding of the aldehyde groups of the dialdehyde cellulose with amino groups of antibodies. In this work, human IgG was used as a model analyte to fabricate an electrochemical immunosensor. Using the proposed immunosensor, we detected IgG within the range from 0.5 to 45ng/mL with a detection limit of 0.3ng/mL (S/N=3). The electrochemical immunosensor had a good specificity, stability and reproducibility. This strategy may pave a simple way to fabricate an electrochemical immunosensor in other applications. [Copyright &y& Elsevier]