https://www.imtek.de/data/lehrstuehle/app/dokumente/publikationen/publpdf2008/kerzenmacher-energy-harvesting-by-implantable.pdf

Energy harvesting by implantable abiotically catalyzed glucose fuel cells

In experiments performed using graphite electrodes poised by a potentiostat (+200 mV versus Ag/AgCl) or in a microbial fuel cell (with oxygen as the electron acceptor), the Fe(III)-reducing organism Geothrix fermentans conserved energy to support growth by coupling the complete oxidation of acetate to reduction of a graphite electrode. Other organic compounds, such as lactate, malate, propionate, and succinate as well as components of peptone and yeast extract, were utilized for electricity production. However, electrical characteristics and the results of shuttling assays indicated that unlike previously described electrode-reducing microorganisms, G. fermentans produced a compound that promoted electrode reduction. This is the first report of complete oxidation of organic compounds linked to electrode reduction by an isolate outside of the Proteobacteria.

/pdf/evidence-for-involvement-of-an-electron-shuttle-in-5fva2jrrvp.pdf

Evidence for involvement of an electron shuttle in electricity generation by Geothrix fermentans.

Over the past two decades, there has been an increasing trend towards miniaturization of both biological and chemical sensors and their integration with miniaturized sample pre-processing and analysis systems. These miniaturized lab-on-chip devices have several functional advantages including low cost, their ability to analyze smaller samples, faster analysis time, suitability for automation, and increased reliability and repeatability. Electrical based sensing methods that transduce biological or chemical signals into the electrical domain are a dominant part of the lab-on-chip devices. A vital part of any electrochemical sensing system is the reference electrode, which is a probe that is capable of measuring the potential on the solution side of an electrochemical interface. Research on miniaturization of this crucial component and analysis of the parameters that affect its performance, stability and lifetime, is sparse. In this paper, we present the basic electrochemistry and thermodynamics of these reference electrodes and illustrate the uses of reference electrodes in electrochemical and biological measurements. Different electrochemical systems that are used as reference electrodes will be presented, and an overview of some contemporary advances in electrode miniaturization and their performance will be provided.

https://www.mdpi.com/1424-8220/10/3/1679/pdf

Microfabricated Reference Electrodes and their Biosensing Applications

Rapid growth of smart electronics and implantable medical devices markets has driven the development of next-generation sustainable, flexible, or implantable batteries. Conducting polymers with uni...

/pdf/tunable-conducting-polymers-toward-sustainable-and-versatile-4392s4vnbk.pdf

Tunable Conducting Polymers: Toward Sustainable and Versatile Batteries

A biomaterial is any material that comprises whole or part of a living structure or biomedi‐ cal device which performs, augments, or replaces a natural function to improve the quality of life of the patients [1]. Over the past fifty years biomaterials has been developed as a sci‐ ence with various forms of implants/medical devices, and have been widely used to replace and/or restore the function of traumatized or degenerated tissues or organs. As a life-saving and life-improving option for countless patients, biomaterials have been paid more and more attention during the last decade. Only in the United States, more than 13 million im‐ plant/medical devices implanted annually. As a result, the impact factor of the journal of “Biomaterials” has boomed from 2.489 to 7.404 from the year 2001 to 2012.

/pdf/overview-on-biocompatibilities-of-implantable-biomaterials-1cp4p2rnjg.pdf

Overview on Biocompatibilities of Implantable Biomaterials

A biological fuel cell such as an oxygen/glucose cell has been considered to be an ideal power source for implantable cardiac pacemakers and similar devices. This study is mainly concerned with the development of a single oxygen/glucose cell, which can be implanted inside the body fluids with the simultaneous presence of oxidant and fuel(s). Present results ofin vitro experiments with a single oxygen/glucose cell consisting of a platinum black on platinum-mesh electrode (cathode) and a platinum black on porous-graphite electrode (anode) have shown that cell performance was markedly increased after glucose addition. Half-cell testings by means of a potentiostat coupled to a linear sweep generator also demonstrated that the anode current of a platinised graphite electrode after glucose was over 3 mA/cm2. It was also found that a steady and continuous power output of 20 μW/cm2 could be generated from the above oxygen/glucose cell. When the cell was testedin vivo in the rat. the continuous power output was steady at 3·3 μW/cm2. The present study also investigated the possibility of generating electricity from an oxygen concentration cell and an oxygen/hydrogen cell. It was concluded that a platinum black on porous graphite electrode offers promise as a specific electrode for glucose oxidation. An oxygen/hydrogen cell could also provide a long termin vivo power supply provided the Pd-H electrode is properly encapsulated. The significance of the present study in relation to the development of biological power sources is discussed, and the importance of fundamental investigation for the development of a specific electrode is emphasised.

Some studies related to electricity generation from biological fuel cells and galvanic cells, in vitro and in vivo.

This study describes the structure and performance of an encapsulated, implantable aluminium/platinum black electrochemical cell. It is covered with a silicone rubber membrane, and the anode and cathode compartments are separated by an anionic ion exchange membrane.In vitro studies and intermittentin vivo tests with rats demonstrate that a cell of 5·5 cm2 area gave a continuous power output of more than 70–100 μW at 0·9 V over 12 months. Although the results of long term implantation experiments now in progress remain to be assessed, preliminary data show that there was no leakage of waste products, and that tissue-cell reactions should not be serious enough to affect cell performance. It is considered that this cell can overcome the disadvantages of unencapsulated biogalvanic cells, and that it offers great promise as a long-termin vivo power source.

An encapsulated, implantable metal-oxygen cell as a long-term power source for medical and biological applications.

The diffusion of H2 in the α-and β-phase of palladium hydride was measured electrochemically and found to agree very well with results reported in the literature. The α-β phase transition on continuous electrolysis of Pd wire and Pd foil electrodes was found to be strongly dependent on both charging current and charging time. An internally-charged Pd wire electrode on continuous charging gave a stable open circuit voltage of+53·5±4 mV against r.h.e. over a test period of 330 h in N2 saturated 0·5M H2SO4 solution. The pH response and reproducibility of such an electrode was superior to conventional palladium hydride electrodes. The potential of this electrode can still be maintained in air saturated solutions, provided higher charging currents are used. It was also shown that β-phase palladium hybride gave an irreproducible pH response.

Internally charged palladium hydride reference electrode--Part 1: The effect of charging current density on long-term stability.

A novel design for the internally charged palladium hydride α—β electrode is proposed, based on the Wheatstone-bridge principle. The construction of the electrode and electronic control circuit require little specialist skills. Both long- and short-term tests have shown that the proposed reference electrode system possesses remarkable stability and response time in changing conditions. The design permits a number of improvements to be made in the construction and optimisation of the performance.

Internally charged palladium hydride reference electrode: II. Automatically controlled palladium hydride electrode.

The electrochemical principles governing the application ofin vivo reference electrodes are discussed. It is shown that the currently usedin vivo reference electrodes are not very satisfactory and that the use of an internally charged palladium hydride electrode may provide a far more stable reference electrode which has a lower impedance and is less susceptible to poisoning by protein adsorption and metal/tissue reaction

A. C. C. Tseung

Papers

Some studies related to electricity generation from biological fuel cells and galvanic cells, in vitro and in vivo.

An encapsulated, implantable metal-oxygen cell as a long-term power source for medical and biological applications.

Internally charged palladium hydride reference electrode--Part 1: The effect of charging current density on long-term stability.

Internally charged palladium hydride reference electrode: II. Automatically controlled palladium hydride electrode.

In vivo reference electrodes