Miniaturized inkjet-printed flexible ion-selective sensing electrodes with the addition of graphene in PVC layer for fast response real-time monitoring applications.

In this letter, we propose a miniaturization scheme of inkjet printed ionic sensing electrodes by adding graphene into the ion-selective PVC film not only to reduce the impedance of the ionic liquid layer of the electrode but also to increase the electrode capacitance for the reduction of the response time. Based on the scheme, we present a fully inkjet-printed electrochemical ion-selective sensor comprising a working electrode and reference electrode, which are inkjet-printed Ag NPs/PEDOT:PSS-graphene/PVC-graphene and Ag/AgCl/ionic liquid PVC-graphene layer structures, respectively. The printed ion-selective working electrode has been miniaturized to a size of 22,400 μm equivalent to a square shape of ∼150 × 150 μm comparable to the size of a human cell.

Inkjet-printed flexible non-enzymatic lactate sensor with high sensitivity and low interference using a stacked NiO/NiO-Nafion nanocomposite electrode with clinical blood test verification.

In this paper, we present a flexible, inkjet-printed, non-enzymatic lactate sensor with high sensitivity and specificity, using a stacked nickel oxide-Nafion nanocomposite/nickel oxide working electrode. Instead of deploying a pure Nafion film on the top of the nickel oxide particles, the nickel oxide-Nafion nanocomposite layer in the new electrode scheme functions not only as an anti-interfering layer but also a reactive layer and the bottom pure nickel oxide layer free from interfering substances mainly participates in the redox reaction to enhance the sensing current. Experimental results show that the sensor with a working electrode printed using a 30 μL NiO ink and a mixture of 30 μL NiO and 4 μL Nafion ink can exhibit an anti-interference ability of >95%, a sensitivity of 20.