We describe a process allowing the patterning of fully stretchable organic electrochemical transistors (OECTs). The device consists of an active stretchable area connected with stretchable metallic interconnections. The current literature does not provide a complete, simple and accurate process using the standard thin film microelectronic techniques allowing the creation of such sensors. An innovative patterning process based on the combination of laser ablation and thermal release tape ensures the fabrication of highly stretchable metallic lines – encapsulated in polydimethylsiloxane – from conventional aluminium tape. State-of-the-art stretchability up to 70% combined with ultra-low mOhms resistance is demonstrated. We present a photolithographic process to pattern the organic active area onto stretchable substrate. Finally the formulation of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) is tuned to achieve an OECT with a maximum stretchability of 38% while maintaining transconductance up to 0.35 mS and channel current as high as 0.2 mA.

Vincent J Vezzaa, Adrian Butterwortha, Perrine Lasserrea, Ewen O Blaira, Alexander MacDonalda, Stuart Hannaha, Christopher Rinaldib, Paul A Hoskissonc, Andrew C Wardd, Alistair Longmuire, Steven Setforde, Eoghan CW Farmerf, Michael...

A B S T R A C TA multifunctional sensor that responds to all -static/quasi-static or dynamic temperature or force -is reported. The sensor is based on a ferroelectric poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE)) capacitor connected to the gate of organic field-effect transistor (OFET). Both, the P(VDF-TrFE) capacitance and the output voltage of the P(VDF-TrFE)/OFET sensor exhibit a logarithmic response to static compressive force, leading to higher sensitivity for small forces. In addition, both the P(VDF-TrFE) capacitance and the output voltage of the P (VDF-TrFE)/OFET sensor exhibit a linear dependence on the static/constant temperature. Response to static force or temperature is observed irrespective of whether P(VDF-TrFE) is in ferroelectric or paraelectric states, confirming that piezo/pyroelectricity is not essential when monitoring static events. The piezo/pyroelectricity become activated during dynamic events (dynamic force or temperature) when the ferroelectric P(VDF-TrFE)/ OFET sensor is used. The obtained results indicate different sensing mechanisms for static and dynamic stimuli. Consequently, by choosing P(VDF-TrFE) layers in ferroelectric or paraelectric states a route for differentiating between the static and dynamic stimuli may exist.

Antimicrobial resistance (AMR) is an issue of upmost global importance, with an annually increasing mortality rate and growing economic burden. Poor antimicrobial stewardship has resulted in an abundance and diverse range of antimicrobial resistance mechanisms. To tackle AMR effectively, better diagnostic tests must be developed in order to improve antibiotic stewardship and reduce the emergence of antibiotic resistant organisms. This study employs a low-cost, commercially available screen printed electrode modified with an agarose-based hydrogel deposit to monitor bacterial growth using the techniques of electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) giving rise to a new approach to measuring susceptibility. Susceptible and drug resistant Staphylococcus aureus strains were deposited onto agarose gel modified electrodes which contained clinically important antibiotics to establish growth profiles for each bacterial strain and monitor the influence of the antibiotic on bacterial growth. The results show that S. aureus is able to grow on electrodes modified with gel containing no antibiotic, but is inhibited when the gel modified electrode is seeded with antibiotic. Conversely, methicillin-resistant S. aureus (MRSA; the drug resistant strain) is able to grow on gel modified electrodes containing clinically relevant concentrations of antibiotic. Results show rapid growth profiles, with possible time to results for antibiotic susceptibility < 45 minutes, a significant improvement on the current gold standards of at least 1-2 days.