Abstract
in this study, a potentiometric urea biosensor through the immobilization of urease enzyme onto chitosan (CH)/Co3O4 and CH/Fe3O4 hybrid nano-biocomposites have been fabricated on glass filter paper. A copper wire of diameter 250 pm has been attached with nanoparticles in order to extract the voltage output signal. A physical absorption method has been adopted to immobilize the surface of CH/Co3O4 and CH/Fe3O4 hybrid nano-biocomposites. Urea biosensor based on magnetic nanoparticles (MNPs) was utilized for the estimation of urea concentration in blood and urine. Blood and urine samples of 25 healthy and 25 sick volunteers were collected and after that urease/ Fe3O4-CH/Cu biosensor electrode or urease/Co3O4-CH/Cu biosensor electrode with 20 mu L urease immobilization was used for estimation of blood and urine urea. The potentiometric sensitivity was measured over the concentration range 0.1 - 6.00 ppm; and the limit of detection is 0.073 ppm. The response time, efficiency and accuracy of this biosensor is 280 seconds, 50 samples and 94 - 99%, respectively. The concentration of urea in 100 times diluted blood and urine sample was found to be 4.1 x 10(-4) and 3.84x 10(-4) M, respectively. The magnetic study shows that coercivity of both the samples is found to be a few oersteds which make them very promising candidates for a variety of applications in biomedical as well as recording technology.