Characterization and application of porous PHBV-based bacterial polymers to realize novel bio-based electroanalytical (bio)sensors

The establishment of novel disruptive technologies represents a common requirement for the sustainable development as reported in the 2030 agenda established by United Nations. As demonstrated by the Covid-19 pandemic, and furtherly highlighted by the current global challenges, i.e. precision agriculture, decentralized testing, personalized medicine, the field of portable devices is growing day-by-day. Relatively to the electrochemical portable strips, globally represented by glucose strips for diabetes patients, the use of plastic-based products is still very high. In this work, two bacterial polymers have been deeply characterized and compared with the gold standard polyester that is the most used material to produce printed electrochemical strips. In particular, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV with micro-fibrillated cellulose (MFC), namely PHBV/MFC, have been produced with different porosities and have been morphologically, mechanically and electrochemically characterized. Scanning electron microscopy, contact angle, tensil tests, cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, stripping voltammetry and chronoamperometry have been used to evaluate and confirm the suitability of PHBV-based substrates for future sustainable application in the (bio)electroanalytical field. In particular these novel substrates have been applied towards the development of two sensing platforms, namely iron ions and organophosphate pesticides. As shown, in comparison with the gold standard polyester for sensors and biosensors development, the use of PHBV-based substrates allowed to reach similar detection limit and repeatability. In particular, iron ions were detected down to 140 and 150 ppb and dichlorvos was detect with an inhibition biosensor down to 0.4 and 0.5 ppb, respectively for PHBV and PHBV/MFC. These novel substrates may represent a starting point towards the development of sustainable platforms for decentralized applications.