Amperometric separation-free immunosensor for real-time environmental monitoring

Abstract

Immunoanalytical techniques have found widespread use due to the characteristics of specificity and wide applicability for many analytes, from large polymer antigens, to simple haptens, and even single atoms. Electrochemical sensors offer benefits of technical simplicity, speed and convenience via direct transduction to electronic equipment. Together, these two systems offer the possibility of a convenient, ubiquitous assay technique with high selectivity. However, they are still not widely used, mainly due to the complexity of the associated immunoassay methodologies. A separation-free immunoanalytical technique is described here, which has allowed for the analysis of atrazine in real time and in both quasi-equilibrium and stirred batch configurations. It illustrated that determinations as low as 0.13 M (28 ppb) could be made using equilibrium incubation with an analytical range of 0.1-10 M. Measurements could be made between 1 and 10 mM within several minutes using a real-time, stirred batch method. This system offers the potential for fast, simple, cost-effective biosensors for the analysis of many substances of environmental, biomedical and pharmaceutical concern.

Electrochemical Characterization of Commercial and Home-Made Screen-Printed Carbon Electrodes

“…The nature of these biosensors has been described elsewhere. [11,12] Briefly, PANI/PVS was deposited on the surface of the electrode and the potential was cycled the required number of times. No protein was immobilized onto the surface of the polymer.…”

Novel biosensor fabrication methodology based on processable conducting polyaniline nanoparticles

“…Drop-coating of the nanoPANI/DBSA dispersion onto electrodes was carried out as an alternative deposition method to the more commonly utilised electropolymerisation method [2][3][4][7][8][9][10][11][12]. Electropolymerisation is not a technique applicable to cost-effective mass production of biosensors.…”

“…In many instances, modification of electrodes with polyaniline has been applied in biosensing applications [2][3][4][5][6][7][8][9][10][11][12], where polyaniline can act as an effective non-diffusional mediating species coupling electrons directly from the enzyme redox site to the electrode. This allows for very effective direct electrical communication between the biomolecule and the electrode surface.…”

Antibody based methods for environmental and food analysis: a review

“…A polarisation fluoroimmunoassay for atrazine was optimised by structure changes of labelled antigen (Samsonova et al, 1994). Monoclonal antibodies raised against the same hapten-protein immunogens were produced in this laboratory and subsequently employed for development of piezoelectric (Pribyl et al, 2003) and amperometric (Killard et al, 2001) immunosensor. The monoclonal reagents incorporated into the immunoassay system were less sensitive compared with rabbit antibodies.…”