4 research outputs found
Development of impedimetric immunosensors for the detection of a range of antigens of biological or biomedical significance
This PhD project was funded by the European Union Framework 6 ELISHA
programme as part of the ELISHA programme. The aim of the research was focused
towards the development of point-of-care, simple, cost-efficient and reliable
impedimetric immunosensors for the rapid detection of important antigens such as
ciprofloxacin and digoxin. Through the cooperation of the 9 involved partners a
number of protocols have been developed for sensor fabrication and sample testing
that allow both rapid and reliable detection of a range of antigens. This work
describes in depth, the use of polymers and cyclic voltammetry for electrode surface
modification, the use of the avidin-biotin system for antibody immobilisation and
finally the use of Electrochemical Impedance Spectroscopy for antigen detection. We
report here the successful development of electrochemical impedimetric carbon based
immunosensors for the detection of free-form and chelated ciprofloxacin (both in
laboratory buffer and milk), digoxin and green fluorescent protein. It was observed
during this work that unavailability of sufficient quantities of the monoclonal
antibodies could lead to early sensor saturation and hence a less extended antigen
detection range, while very low quantities of immobilised antibodies could also give
rise to erroneous results. The immunosensors towards ciprofloxacin detected the
respective antigen when this was present between 1 ng ml-1 and 10 μg ml-1 in PBS
buffer and 0.1 ng ml-1 to 10 μg ml-1 when the antigen was added to milk samples. The
developed digoxin immunosensors could detect digoxin between the concentrations of
0.1 ng ml-1 and 10 μg ml-1. Lower detection limits where observed for the sensors
targeting GFP which could detect their respective antigen at concentrations as low as
100 pg ml-1. The tested concentration range of the latter sensors was extended up to
100 ng ml-1
Development of impedimetric immunosensors for the detection of a range of antigens of biological or biomedical significance
This PhD project was funded by the European Union Framework 6 ELISHA programme as part of the ELISHA programme. The aim of the research was focused towards the development of point-of-care, simple, cost-efficient and reliable impedimetric immunosensors for the rapid detection of important antigens such as ciprofloxacin and digoxin. Through the cooperation of the 9 involved partners a number of protocols have been developed for sensor fabrication and sample testing that allow both rapid and reliable detection of a range of antigens. This work describes in depth, the use of polymers and cyclic voltammetry for electrode surface modification, the use of the avidin-biotin system for antibody immobilisation and finally the use of Electrochemical Impedance Spectroscopy for antigen detection. We report here the successful development of electrochemical impedimetric carbon based immunosensors for the detection of free-form and chelated ciprofloxacin (both in laboratory buffer and milk), digoxin and green fluorescent protein. It was observed during this work that unavailability of sufficient quantities of the monoclonal antibodies could lead to early sensor saturation and hence a less extended antigen detection range, while very low quantities of immobilised antibodies could also give rise to erroneous results. The immunosensors towards ciprofloxacin detected the respective antigen when this was present between 1 ng ml-1 and 10 μg ml-1 in PBS buffer and 0.1 ng ml-1 to 10 μg ml-1 when the antigen was added to milk samples. The developed digoxin immunosensors could detect digoxin between the concentrations of 0.1 ng ml-1 and 10 μg ml-1. Lower detection limits where observed for the sensors targeting GFP which could detect their respective antigen at concentrations as low as 100 pg ml-1. The tested concentration range of the latter sensors was extended up to 100 ng ml-1.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Labeless Immunosensor Assay for Fluoroquinolone Antibiotics Based Upon an AC Impedance Protocol.
This paper describes the construction of a labeless immunosensor for the
antibiotic ciprofloxacin and its interrogation using an AC impedance protocol.
Commercial screen-printed carbon electrodes were used as the basis for the
sensor. Polyaniline was electrodeposited onto the sensors and then utilized to
immobilize a biotinylated antibody for ciprofloxacin using classical avidin-
biotin interactions. Electrodes containing the antibodies were exposed to
solutions of antigen and interrogated using an AC impedance protocol. The
faradaic component of the impedance of the electrodes was found to increase with
increasing concentration of antigen. Control samples containing a non-specific
IgG antibody were also studied and calibration curves obtained by subtraction of
the responses for specific and non-specific antibody-based sensors, thereby
eliminating the effects of non-specific adsorption of antigen
Labeless AC impedimetric antibody-based sensors with pg ml-1 sensitivities for point-of-care biomedical applications.
This paper describes the development and characterisation of labeless
immunosensors for (a) the cardiac drug digoxin and (b) bovine serum albumin
(BSA). Commercial screen-printed carbon electrodes were used as the basis for
the sensors. Two methods were used to immobilise antibodies at the electrode
surface. Aniline was electropolymerised onto these electrodes to form a thin
planar film of conductive polyaniline; the polyaniline film was then utilised as
a substrate to immobilise biotinylated anti-digoxin using a classical avidin-
biotin affinity approach. As an alternative approach, poly(1,2-diaminobenzene)
was electrodeposited onto the carbon electrodes and this modified surface was
then sonochemically ablated to form an array of micropores. A second
electropolymerisation step was then used to co-deposit conductive polyaniline
along with antibodies for BSA within these pores to produce a microarray of
polyaniline protrusions with diameters of several μm, containing entrapped anti-
BS