Label free urea biosensor based on organic electrochemical transistors

Abstract

The quantification of urea is of the utmost importance not only in medical diagnosis, where it serves as a potential indicator of kidney and liver disfunction, but also in food safety and environmental control. Here, we describe a urea biosensor based on urease entrapped in a crosslinked gelatin hydrogel, deposited onto a fully printed PEDOT:PSS-based organic electrochemical transistor (OECT). The device response is based on the modulation of the channel conductivity by the ionic species produced upon urea hydrolysis catalyzed by the entrapped urease. The biosensor shows excellent reproducibility, a limit of detection as low as 1 μM and a response time of a few minutes. The fabrication of the OECTs by screen-printing on flexible substrates ensures a significant reduction in manufacturing time and costs. The low dimensionality and operational voltages (0.5 V or below) of these devices contribute to make these enzymatic OECT-based biosensors as appealing candidates for highthroughput monitoring of urea levels at the point-of-care or in the field.

Semiconducting Small Molecules as Active Materials for p‐Type Accumulation Mode Organic Electrochemical Transistors

“…Organic electrochemical transistors (OECTs), as depicted schematically in Figure , have been widely explored for interfacing organic electronics with biologically and medically relevant systems. [ 1,2 ] The burgeoning field of organic bioelectronics has seen OECTs employed in a wide range of applications from neural interface devices for epileptogenic centers, [ 3 ] to biological analyte detection, [ 4–7 ] cardiac monitoring, [ 8 ] whole cell interface monitoring, [ 9,10 ] pH sensing, [ 11 ] in ion pumps, [ 12 ] and electronic plants. [ 13 ] While OECTs traditionally have comprised the conducting polymer mixture poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), semiconducting polymers have more recently been implemented as the active material in OECTs.…”

Flexible Printed Organic Electrochemical Transistors for the Detection of Uric Acid in Artificial Wound Exudate

“…Label-free biosensors based on organic (semi-) conductive polymers may represent ideal devices to be interfaced with wound environment: they detect complex biological signals in aqueous media and translate them into an electronic output; they are operated at low voltages and require low power sources and they can be fabricated into flexible materials [23][24][25] with large-area techniques such as screen printing [26][27][28][29] and inkjet printing [30] on lowcost substrates (paper, plastic foils, textiles). Moreover, they can be manufactured as impalpable patches adhering on the skin to record physiological signals.…”

Assessment of Gold Bio-Functionalization for Wide-Interface Biosensing Platforms

“…Therefore, the aim of the study herein presented is to determine which is the minimum biorecognition element concentration requested to achieve a sufficiently high surface coverage. Interestingly, it has been demonstrated that it is possible to reduce to one tenth the biorecognition elements concentration without impacting on the analytical performances, thus optimizing the biofunctionalization protocol of the SiMBiT platform as well as of other bioelectronic devices [ 22 , 23 , 24 ]. This study paves the way toward a multiplexing single molecule technology that will open to a massive use of high-throughput array-based assay not only in clinical laboratory analysis but also in point-of-care and low resources settings.…”