Innovative chips based on palladium thin films deposited on plastic substrates have been tested in the Kretschmann surface plasmon resonance (SPR) configuration. The new chips combine the advantages of a plastic support that is interesting and commercially appealing and the physical properties of palladium, showing inverted surface plasmon resonance (ISPR). The detection of DNA chains has been selected as the target of the experiment, since it can be applied to several medical early diagnostic tools, such as different biomarkers of cancers or cystic fibrosis. The results are encouraging for the use of palladium in SPR-based sensors of interest for both the advancement of biodevices and the development of hydrogen sensors.

This work deals with the development of a disposable electrochemical biosensor for the specific detection of short DNA sequences. The sensor is an amperometric transducer with three planar electrodes, comprising a working, a counter and a pseudo-reference electrode, all made of a gold layer over a polycarbonate substrate. For the development of the genosensor, the working electrode was modified using thiol-tethered 33-mer DNA probe by chemisorptions, in a concentration range from 0.1 mu M to 5 mu M. Immobilization of ssDNA on gold surface was monitored with electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) in Fe(CN)(6)(4-/3-) and Ruthenium(II)/(III) solutions. The time dependence of ssDNA probe immobilization was also studied. The hybridization detection is then compared with EIS and DPV measurement

In this work, cell adhesion and electroporation effects have been studied through impedance measurements. Chinese Hamster Ovary (CHO-K1) cells have been plated and grown adherent to multi-electrode arrays and then stimulated to obtain the electroporation. We used Electrochemical Impedance Spectroscopy (EIS) measurements to analyze the impedance variation that occurs with cell adhesion and, consequently, to obtain the intrinsic electrical parameters of the electrode-cell interface through a lumped parameter model. The whole model allows to estimate the correction factor β and the sealing resistance Rseal, both dependent on the cell coverage and adhesion. The electroporation has been performed after cell adhesion, using a custom stimulation bench, able to evaluate the cell-electrode coupling and to stimulate an individually addressable site. By performing EIS measurements, before and after the electroporation, cell status, adhesion and membrane resistance can be detected. From measurements, an impedance decrease as a function of pulse amplitude can be noted. The proposed equivalent electrical model allows to evaluate the variation in membrane conductance due to pores formation. Moreover, average pore radius between 0.5 nm and 2.2 nm, increasing with pulse amplitude, was estimated