DETECTION OF CADMIUM-RESISTANT RHIZOBACTERIA USING PIEZOELECTRIC NANOBIOSENSOR

Abstract

Traditionally, enzyme-linked immunosorbent assay (ELISA) is used for the interaction study of antibody–antigen ( Ab – Ag ) along with Western blot, immunofluorescence and flow cytometry. These are the processes which give the result at the end on the basis of amount of bound label. Piezoelectric quartz crystal microbalance (QCM) has more advantages like elimination of the use of the enzyme or radioactive-labelled material, simple concept, rapid turn-around time, cost effectiveness and easy automation over traditional techniques. Efforts are being made to enhance the efficacy of QCM biosensor by employing appropriate nanomaterials. In the present piece of work silver nanoparticles were prepared, characterized and applied on AT-cut gold-coated quartz crystal to get more surface area and hence more Ag – Ab complex. The gold electrode of quartz crystal modified with silver nanoparticles was exposed to antibody (anti-Rhizobacteria) and finally to the corresponding antigen (Rhizobacteria). The change in the resonant frequency of quartz crystal of QCM was measured after each modification. The sharp decrease in resonant frequency reflects the interaction of Rhizobacteria with its corresponding antibody (anti-Rhizobacteria). The signals obtained from such a nanobiosensor were compared with ELISA. A similar selectivity and higher sensitivity along with less time was observed with the developed QCM nanobiosensor.