ZnO nanoplatforms for multifunctional biomolecules sensors

ZnO nanostructured thin films consisting of dense 2D arrays of ZnO nanorings and/or nanorods have been fabricated on different substrates by using a hybrid approach of nanosphere colloidal lithography, self assembled monolayer deposition, metal-organic chemical vapour deposition and/or wet chemistry synthesis. The biosensing capability of the nanostructured films has been tested by integrating the ZnO thin films either to glass coverslips or to quartz piezoelectric sensors, in order to detect their changes upon the biomolecules uptake, respectively in the optical properties, by scanning laser confocal microscopy (SLCM), as well as in the mass load and the viscoelastic properties, by quartz crystal microbalance with dissipation monitoring (QCM-D). As proof of working, the adsorption processes of two model proteins, such as albumin and lysozyme, having opposite isoelectric values at the physiological pH of 7.4, have been investigated as function of various experimental parameters, related to the properties of both the sensing substrate (e.g., surface topography and chemistry) and the analyte solution (protein nature, bulk concentration, pH and ionic strength). Theoretical models of the proteins coverage and average orientation into the adlayers formed on the differently nanostructured ZnO thin films have been obtained by angular resolved XPS analysis. Finally, preliminary results of the surface functionalization of the nanostructured ZnO films by supported lipid bilayers are also shown, as promising and advanced biomimetic ZnO-based biosensors.