Zirconia-poly(propylene imine) dendrimer nanocomposite based electrochemical urea biosensor

• A novel zirconia-polypropylene imine dendrimer nanocomposite was synthesised.
• The nanocomposite was electro-co-deposited on screen printed carbon electrode.
• The nanocomposite was used as platform for the immobilisation of urease enzyme.
• The biosensor detected urea in the micromolar range in the presence of interferences.

In this article we report a selective urea electrochemical biosensor based on electro-co-deposited zirconia-polypropylene imine dendrimer (ZrO2-PPI) nanocomposite modified screen printed carbon electrode (SPCE). ZrO2 nanoparticles, prepared by modified sol–gel method were dispersed in PPI solution, and electro-co-deposited by cyclic voltammetry onto a SPCE surface. The material and the modified electrodes were characterised using FTIR, electron microscopy and electrochemistry. The synergistic effect of the high active surface area of both materials, i.e. PPI and ZrO2 nanoparticles, gave rise to a remarkable improvement in the electrocatalytic properties of the biosensor and aided the immobilisation of the urease enzyme. The biosensor has an ampereometric response time of ∼4 s in urea concentration ranging from 0.01 mM to 2.99 mM with a correlation coefficient of 0.9985 and sensitivity of 3.89 μA mM−1 cm−2. The biosensor was selective in the presence of interferences. Photochemical study of the immobilised enzyme revealed high stability and reactivity.