Revista de técnicas analíticas y bioanalíticas

Abstracto

New Direct Competition Free but Not Label Free Immunosensor Method for IgG Determination

Elisabetta Martini, Mauro Tomassetti and Luigi Campanella

In the present study, to reduce the excessively long time required for each “competition” measurement performed using the customary competitive immunosensors, an innovative “direct”, i.e. competition free, immunosensor method for IgG determination, was developed. Unlike what is usually reported in the literature for the latter type of immunosensor devices, which are usually “label free”, that is, which do not use a marker since the signal is often obtained directly as a result of immunocomplex formation, in the present competition free method, an enzymatic marker was again used to perform robust electro-enzyme measurement, while the transducer used was of the classic gas diffusion potentiometric type. The new immunosensor affords a considerable reduction in analysis time, but maintains good repeatability and selectivity and so IgG analysis in human milk and serum was successfully performed using it. For the immunosensor developed, a systematic study was also performed to ensure its complete analytical characterisation using standard solutions of IgG and a comparison involving a classical “competitive” ELISA type immunosensor was also performed. Lastly a short excursus on label free immunosensor methods reported in the literature is included to justify the choice made in the present research.