Mediator-free microfluidics biosensor based on titania–zirconia nanocomposite for urea detection

Abstract

Urease (Urs) and glutamate dehydrogenase (GLDH) co-immobilized onto titania-zirconia (TiO 2-ZrO 2) nanocomposite and integrated with microfluidics mediator-free sensor have been utilized for urea detection. The PDMS microchannels have been sealed with a glass substrate comprising of reference (Ag/ AgCl), counter (ITO) and working (Urs-GLDH/TiO 2-ZrO 2 /ITO) electrodes. This mediator-free microfluidics urea sensor shows linearity as 5-100 mg/dL with improved sensitivity as 2.74 mA [Log mM] 21 cm 22 and detection limit of 0.07 mg/dl (0.44 mM) using 3s b /m criteria. The Reynolds number has been found to be as 0.166, indicating that fluid flow is completely laminar, controllable and the pressure drop across the microchannels is found to be as 3.5 6 10 3 Pa.

Anti-epidermal growth factor receptor conjugated mesoporous zinc oxide nanofibers for breast cancer diagnostics

“…Thus, the results of these studies indicate that both bioelectrodes show a surface controlled process. 34 The variation of the peak (anodic and cathodic) current for both bioelectrodes as a function of the square root of the scan rate follows eqn (1)- (4): …”

Influence of immobilization strategies on biosensing response characteristics: A comparative study

“…During the potential sweep of cyclic voltammetry these excess electrons are responsible for the increased current. As the cholesterol concentration increases there is a growth in the number of released electrons, which leads to an enhancement in the redox current [26]. The calibration curves show a linear increase in the peak oxidation current with increasing cholesterol concentration for all the three bio-electrodes (Fig.…”

“…The variations of the peak current, for all the three bio-electrodes, show a linear variation with square root of scan rate indicating that the reaction is governed by a quasi-reversible diffusion electron process [26]. Surface coverage ( ) of ionic species for all the bio-electrodes were computed using Brown-Anson model which is given by the following equation [21]:…”

A highly efficient urea detection using flower-like zinc oxide nanostructures

“…A key parameter in fabrication of the amperometric biosensor is the identification of a suitable matrix which not only provides fast electron communication feature but also offers A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 4 high surface area for high enzyme loading [19][20][21][22][23][24]. Amongst various matrices, nanostructured metal oxides are extensively exploited due to their unique properties including high surface to volume ratio, good stability, favourable orientation for the immobilization of specific enzyme etc.…”