Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission

peer-reviewedHere for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor), and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 mu A and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply.PUBLISHEDpeer-reviewe

Optimierung von Redoxpolymeren für Biosensoren und Biobrennstoffzellen und ihre Stabilisierung auf Elektrodenoberflächen

Im Rahmen dieser Arbeit wurde eine neue, optimierte Synthesestrategie für die modlulare Herstellung von Redoxpolymeren auf Basis einer Epoxidöffnungsreaktion entwickelt. Es wurden Methoden zur Stabilisierung von Redoxpolymerfilmen durch Quervernetzung und Methoden zur selektiven Quervernetzung mittels geschützter Quervernetzer entwickelt. Durch Trennung der Osmiumkomplexsynthese von der Polymerrückgratsynthese war es möglich, das Formalpotential der verwendeten Osmiumkomplexe an den Kofaktor PQQ anzupassen. Außerdem konnten die Redoxpolymere durch Modifikation mit Phenothiazinen für Bioanodenanwendungen optimiert werden. Abschließend wurde ein voltammetrischer pH-Sensor auf Basis zweier Redoxpolymere hergestellt und charakterisiert

Direct electron transfer of trametes hirsuta laccase adsorbed at unmodified nanoporous gold electrodes

The enzyme Trametes hirsuta laccase undergoes direct electron transfer at unmodified nanoporous gold electrodes, displaying a current density of 28 mu A/cm(2). The response indicates that ThLc was immobilised at the surface of the nanopores in a manner which promoted direct electron transfer, in contrast to the absence of a response at unmodified polycrystalline gold electrodes. The bioelectrocatalytic activity of ThLc modified nanoporous gold electrodes was strongly dependent on the presence of halide ions. Fluoride completely inhibited the enzymatic response, whereas in the presence of 150 mM Cl-, the current was reduced to 50% of the response in the absence of Cl-. The current increased by 40% when the temperature was increased from 20 degrees C to 37 degrees C. The response is limited by enzymatic and/or enzyme electrode kinetics and is 30% of that observed for ThLc co-immobilised with an osmium redox polymer. (C) 2012 Elsevier B.V. All rights reserved

PQQ-sGDH bioelectrodes based on Os-complex modified electrodeposition polymers and carbon nanotubes

Graphite electrodes were modified with specifically designed Os-complex modified electrodeposition polymers exhibiting a formal potential of the polymer-bound complex of about 0 to 20 mV (vs. Ag/AgCl/3 M KCl) which is only about 100 mV anodic of the formal potential of pyrroloquinoline quinone (PQQ) in PQQ-dependent glucose dehydrogenase (PQQ-GDH). The efficiency of wiring the polymer-entrapped PQQ-GDH was dependent on the nature of the polymer backbone, the crosslinking with bifunctional crosslinkers and the co-entrapment of multi-walled carbon nanotubes. Due to the limited long-term stability a new polymer synthesis strategy was adapted using the same Os-complex but providing enhanced crosslinking capabilities by introducing epoxide functions at the polymer backbone. Related bioelectrodes showed enhanced glucose-dependent current and a stability of at least 3 days of continuous operation