Implantable Biofuel Cells Research Articles

In-situ n-doped 3D-printed abiotic cathodes for implantable biofuel cells

In-situ n-doped 3D-printed abiotic cathodes for implantable biofuel cells

Highly Stretchable and Flexible Electrospinning‐Based Biofuel Cell for Implantable Electronic

AbstractWith the emerging demand of implantable microelectronics, it essentially requires the fully integrated and reliable power supplies. The study reports a stretchable and flexible electrospinning‐based glucose/O2 biofuel cell with glucose oxidase bioanode, Pt/C cathode and thermoplastic polyurethane substrate, which is capable for adapting to the various stresses and strains caused by individual movement. The rigid benzene rings and elastic chain segments of thermoplastic polyurethane ensure its superior tensile property. Furthermore, the stable covalent connections between the activated carbon nanotubes (CNTs‐COOH) and glucose oxidase inside 3D thermoplastic polyurethane network are established by amide reaction to ensure the rapid direct electron transfer of bioanode and stable power output of device in flexible environments. The biofuel cell exhibits an open circuit voltage of 0.575 V, and high‐power density of 57 µW cm−2 in 5 mM glucose. Moreover, the power‐generation properties of implantable biofuel cell keep steady, and its power density exhibits limited fluctuations on the dorsum of rat when bending, stretching, and twisting in 28 days. There is no obvious local inflammation or systemic abnormalities in rats. It satisfies the impressive biocompatible requirement, demonstrating the promising potential of electrospinning‐based biofuel cell as a robust self‐sustained power source for implantable electronics.

Chlorhexidine digluconate exerts bactericidal activity vs Gram positive Staphylococci with bioelectrocatalytic compatibility: High level disinfection for implantable biofuel cells

Implanted devices destined for contact with sterile body tissues, vasculature or fluids should be free of any microbial contamination that could lead to disease transmission. The disinfection and sterilisation of implantable biofuel cells is a challenging and largely overlooked subject due to the incompatibility of fragile biocatalytic components with classical treatments. Here we report the development of a convenient “soft” chemical treatment based on immersion of enzymatic bioelectrodes and biofuel cells in dilute aqueous chlorhexidine digluconate (CHx). We show that immersion treatment in a 0.5 % solution of CHx for 5 min is sufficient to remove 10-6 log colony forming units of Staphylococcus hominis after 26 h while shorter treatments are less effective. Treatments with 0.2 % CHx solutions were ineffective. Bioelectrocatalytic half-cell voltammetry revealed no loss in activity at the bioanode after the bactericidal treatment, while the cathode was less tolerant. A maximum power output loss of ca. 10 % for the glucose/O2 biofuel cell was observed following the 5 min CHx treatment, while the dialysis bag had a significant negative impact on the power output. Finally, we report a proof-of-concept in vivo operation for 4 days of a CHx-treated biofuel cell with a 3D printed holder and additional porous surgical tissue interface. Further assessments are necessary to rigorously validate sterilisation, biocompatibility and tissue response performance.

Microbial Biofuel Cells: Fundamental Principles, Development and Recent Obstacles.

This review focuses on the development of microbial biofuel cells to demonstrate how similar principles apply to the development of bioelectronic devices. The low specificity of microorganism-based amperometric biosensors can be exploited in designing microbial biofuel cells, enabling them to consume a broader range of chemical fuels. Charge transfer efficiency is among the most challenging and critical issues while developing biofuel cells. Nanomaterials and particular redox mediators are exploited to facilitate charge transfer between biomaterials and biofuel cell electrodes. The application of conductive polymers (CPs) can improve the efficiency of biofuel cells while CPs are well-suitable for the immobilization of enzymes, and in some specific circumstances, CPs can facilitate charge transfer. Moreover, biocompatibility is an important issue during the development of implantable biofuel cells. Therefore, biocompatibility-related aspects of conducting polymers with microorganisms are discussed in this review. Ways to modify cell-wall/membrane and to improve charge transfer efficiency and suitability for biofuel cell design are outlined.

Metal-organic framework-erythrocytic hybrid surfaces with enhanced oxygen reduction performance for enzymatic biofuel cells–An updated strategy

Enzymatic biofuel cells (EBFCs), which can use oxygen in the body as a cathode fuel to generate electricity, have broad application prospects. For air cathode of EBFCs, the most important factors affecting the electrocatalytic performance are the inherent fragile nature, poor oxygen enrichment performance and low activity of enzyme catalysts. Herein, based on the natural oxygen enrichment performance of red blood cells (RBCs) and its electrocatalytic activity for oxygen reduction reaction, we fabricate the hybrid surfaces of metal–organic framework-nanocoated RBCs (RBC@ZIF-8) using an in situ synthesis method. Versus native RBCs, the electrocatalytic activity and stability of RBC@ZIF-8 are enhanced by 50% and 35%, respectively, when explored as a biocathode catalyst for implantable biofuel cells. And compared with enzyme catalysts, RBC@ZIF-8 has better stability and handleability. Mechanistic studies show that the coating surface increases the O2-enriched capacity of RBCs and then provides more reaction raw materials for the hemoglobin with catalytic active. Moreover, direct electron transfer capability of RBC@ZIF-8 is found on carbon cloth electrode without promoters and mediators. Our research expands the types of air cathode catalyst for EBFCs and suggests a promising strategy to enhance the electrocatalytic performance of gas-based biocatalysts, such as bioelectrocatalytic reduction of CO2 and N2.

Construction of a Cascade Catalyst of Nanocoupled Living Red Blood Cells for Implantable Biofuel Cell.

The broad applications of implantable glucose biofuel cells (GBFCs) have become very attractive in biomedical sciences. The key challenge of GBFCs is eliminating the inevitable product H2O2 generated from the oxidation of glucose when glucose oxidase (GOx) is used as a catalyst while improving the performance of GBFCs. In this work, the cascade electrocatalyst, RBCs@NPDA was obtained through the in situ polymerization of dopamine to form nanopolydopamine (NPDA) on the surface of red blood cells (RBCs). The RBCs@NPDA can catalyze both fuels of H2O2 and O2, so as to generate a high cathodic current (0.414 mA cm-2). Furthermore, when RBCs@NPDA was used as a cathodic catalyst in the membraneless GBFC, it exhibited the cascade catalytic activity in the reduction of O2-H2O2 and minimized the damage to RBCs caused by the high concentration of H2O2. The mechanism research indicates that RBCs@NPDA integrates the property of NPDA and RBCs. Specifically, NPDA plays a catalase-like role in catalyzing the decomposition of H2O2, while RBCs play a laccase-like role in electrocatalyzing the O2 reduction reaction. This work offers the cascade catalyst for improving the performance of implantable GBFC and presents a strategy for constructing catalysts using living cells and nanomaterials to replace deformable and unstable enzymes in other biofuel cells.

Substitution of Fe in hydroxyapatite as an efficient single-atom catalyst for oxygen reduction reaction in biofuel cells: A first-principles study

Single-atom biological catalysts have attracted enormous attentions for low cost, high stability and catalytic activity in therapeutics and biomedical devices. The properties of Fe atom substituted CaII in HAP surface (Fe@HAP) and Fe adsorbed over HAP surface (Fe/HAP), and the detailed kinetic and thermodynamic behaviors of the oxygen reduction reaction (ORR) processes have been investigated by using the first-principles study. It is found that Fe dopant by substituted CaII ion into HAP surface could be more stably anchored at HAP surface than Fe adsorbate, and the introduced Fe dopant can enormously increase the endogenous ORR catalytic activity of magnetic HAP catalysts. Furthermore, the ORR process on Fe@HAP prefers to the 4e- pathway with the small reaction barrier (0.73 eV) for the rate-limiting step, and the two OH species formed from the hydrogenation of the adsorbed O2 prefer to further hydrogenate into two H2O molecules and their self-dehydrogenation is not preferable according to the transition states simulation, which is also confirmed by the Gibbs free energy calculation. Consequently, our results revealed that the Fe@HAP could be an efficient catalyst as cathode material in the applications of the implantable biofuel cells and shed light on the design of biomaterials for various applications.

Two-Ply Carbon Nanotube Fiber-Typed Enzymatic Biofuel Cell Implanted in Mice.

Implantable devices have emerged as a promising industry. It is inevitable that these devices will require a power source to operate in vivo. Thus, to power implantable medical devices, biofuel cells (BFCs) that generate electricity using glucose without an external power supply have been considered. Although implantable BFCs have been developed for application in vivo, they are limited by their bulky electrodes and low power density. In the present study, we attempted to apply to living mice an implantable enzymatic BFC (EBFC) that was previously reported to be a high-power EBFC comprising carbon nanotube yarn electrodes. To improve their mechanical properties and for convenient implantation, the electrodes were coated with Nafion and twisted into a micro-sized, two-ply, one-body system. When the two-ply EBFC system was implanted in the abdominal cavity of mice, it provided a high-power density of 0.3 mW/cm2. The two-ply EBFC system was injected through a needle using a syringe without surgery and the inflammatory response in vivo initially induced by the injection of the EBFC system was attenuated after 7 days, indicating the biocompatibility of the system in vivo.

Anode-Driven Controlled Release of Cathodic Fuel via pH Response for Smart Enzymatic Biofuel Cell.

SummaryEnzymatic biofuel cells (EBFCs) with or without a membrane to separate the anodic and cathodic compartments generally suffered from high internal resistance or interactive interference, both of which restricted the improvement of their performance. Herein, a smart membrane-less EBFC was engineered based on anode-driven controlled release of cathodic acceptor via pH-responsive metal-organic framework ([Fe(CN)6]3-@ZIF-8) nanocarriers. The glucose anodic oxidation would produce gluconic acid accompanied by the change in pH value from neutral to the acidic case, which could drive the degradation of [Fe(CN)6]3-@ZIF-8 nanocarriers and further realize the controlled release of cathodic acceptor [Fe(CN)6]3-. More importantly, compared with controlled EBFC with or without membrane, the power output of the as-proposed EBFC enhanced at least 700 times due to the seamless electronic communication. Therefore, the ingenious strategy not only realized the successful engineering of the membrane-less EBFC but also provided an appealing idea for constructing smart devices.

Extracting Power from Biological Sources for Activating Sensors/Biosensors

Implantable devices harvesting energy from biological sources and based on electrochemical transducers are currently receiving high attention. The energy collected from a biological environment can be utilized to activate various microelectronic and biosensor devices. This lecture is an overview of the recent research activity in the area of enzyme-based biofuel cells implanted in biological tissue and operating in vivo. The electrical power extracted from the biological sources presents use for activating microelectronic devices for biomedical and biosensor applications. While some microelectronic devices can work within a fairly broad range of electrical operating conditions, others, such as pacemakers, require precise voltage levels and voltage regulation for correct operation. Thus, certain classes of electronic devices powered by implantable energy sources will require careful attention not only to energy and power considerations, but also to voltage scaling and regulation. This requires appropriate interfacing between the energy harvesting device and the energy consuming microelectronic and biosensor devices. The lecture focuses on the problems in the present technology as well as offers their potential solutions. Lastly, perspectives and future applications of the implanted biofuel cells, particularly for powering biosensors are also discussed. The considered examples include a microelectronic sensor and a wireless signal-transfer system powered by implantable biofuel cell extracting electrical energy from biological sources.

A Microelectronic Sensor Device Powered By a Small Implantable Biofuel Cell

Biocatalytic buckypaper electrodes modified with pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase and bilirubin oxidase for glucose oxidation and oxygen reduction, respectively, were prepared for their use in a biofuel cell [1]. A small (millimeter-scale; 2×3×2 mm3) enzyme-based biofuel cell was tested in a model glucose-containing aqueous solution, in human serum, and as an implanted device in a living gray garden slug (Deroceras reticulatum), producing electrical power in the range of 2–10 μW (depending on the glucose source) [2]. A microelectronic temperature-sensing device equipped with a rechargeable supercapacitor, internal data memory and wireless data downloading capability was specifically designed for activation by the biofuel cell. The power management circuit in the device allowed the optimized use of the power provided by the biofuel cell dependent on the sensor operation activity. The whole system (power-producing biofuel cell and power-consuming sensor) operated autonomously by extracting electrical energy from the available environmental source, as exemplified by extracting power from the glucose-containing hemolymph (blood substituting biofluid) in the slug to power the complete temperature sensor system and read out data wirelessly. Other sensor systems operating autonomously in remote locations based on the concept illustrated here are envisaged for monitoring different environmental conditions or can be specially designed for homeland security applications, particularly in detecting bioterrorism threats. References Gamella, M., Lee, I., Guz, N., Blaauw, D., Katz, E. (2018). International Journal of Unconventional Computing, 14(1), 27-41.Bollella, P., Lee, I., Blaauw, D., Katz, E., ChemPhysChem (2019), in press. DOI:10.1002/cphc.201900700

A Lactate/Oxygen Biofuel Cell: The Coupled Lactate Oxidase Anode and PGM-Free Fe-N-C Cathode.

The rapid development of both wearable and implantable biofuel cells has triggered more and more attention on the lactate biofuel cell. The novel lactate/oxygen biofuel cell (L/O-BFC) with the direct electron transfer (DET)-type lactate oxidase (LOx) anode and the platinum group metal (PGM)-free Fe-N-C cathode is designed and constructed in this paper. In such a reasonable design, the surface-controlled direct two-electron electrochemical reaction of the lactate oxidase was determined by cyclic voltammetry (CV) on the carbon nanotube (CNT) modified electrode with favorable high electrochemical active surface area and electronic conductivity. Additionally, the biosensor based on DET-type LOx modified electrode impressively presented linear response to lactate with different concentrations from 0.000 mM to 12.300 mM. In particular, the apparent Michealis-constant (KMapp) calculated as 0.140 mM clearly indicates that LOx on CNT has strong affinity to the substrate lactate. Meanwhile, 4e- transfer oxygen reduction reaction (ORR) was proven to take place on the Fe-N-C catalysts inthe 0.1 M PBS system, indicating the advantage by using the Fe-N-C catalysts at the cathode of L/O-BFC. Last but not least, the L/O-BFC with the direct electron transfer (DET)-type lactate oxidase(LOx) anode and the Fe-N-C cathode produced an superior open circuit potential (OCP) of 0.264 V and a maximum output power density (OPD) of 24.430 μW cm-2 in O2 saturated 95.020 mM lactate solution. The above results will not only bring about significant interest in developing a DET-type biofuel cell, but also offer guiding direction to explore novel catalyst materials for the biofuel cell. This work enriches the research content and may push developments of the implantable and wearable biofuel cell forward.

High-performance enzymatic biofuel cell based on three-dimensional graphene

Enzymatic biofuel cells are a subclass of biofuel cells, which employ enzymes to generate energy from renewable sources. In this study, 3-dimensional graphene (3DG)/glucose oxidase (GOx) bio-nanocomposite was fabricated in order to improve enzyme immobilisation and enzyme lifetime with an enhanced electron transfer rate. These enhancements are due to the unique physical properties of 3DG, e.g. high porosity, large surface area, and excellent electrical conductivity. A power density of 164 μW cm−2 at 0.4 V was achieved from this enzymatic biofuel cell (EBFC) with an acceptable performance compared to that of the other glucose biofuel cells (GBFCs). The 3DG enhances the enzyme lifetime, decreases enzyme leaking and, due to its good conductivity, facilitates the electron harvest and transfer from the enzyme active site to the electrode. This suggests that 3DG could be used as effective support for enzyme immobilisation on the surface of the electrode in EBFC applications and related areas such as biosensors, bioreactors and implantable biofuel cells.

A Microelectronic Sensor Device Powered by a Small Implantable Biofuel Cell.

Biocatalytic buckypaper electrodes modified with pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase and bilirubin oxidase for glucose oxidation and oxygen reduction, respectively, were prepared for their use in a biofuel cell. A small (millimeter-scale; 2×3×2 mm3 ) enzyme-based biofuel cell was tested in a model glucose-containing aqueous solution, in human serum, and as an implanted device in a living gray garden slug (Deroceras reticulatum), producing electrical power in the range of 2-10 μW (depending on the glucose source). A microelectronic temperature-sensing device equipped with a rechargeable supercapacitor, internal data memory and wireless data downloading capability was specifically designed for activation by the biofuel cell. The power management circuit in the device allowed the optimized use of the power provided by the biofuel cell dependent on the sensor operation activity. The whole system (power-producing biofuel cell and power-consuming sensor) operated autonomously by extracting electrical energy from the available environmental source, as exemplified by extracting power from the glucose-containing hemolymph (blood substituting biofluid) in the slug to power the complete temperature sensor system and read out data wirelessly. Other sensor systems operating autonomously in remote locations based on the concept illustrated here are envisaged for monitoring different environmental conditions or can be specially designed for homeland security applications, particularly in detecting bioterrorism threats.

In Situ Engineering of Intracellular Hemoglobin for Implantable High-Performance Biofuel Cells.

The key challenge for the broad application of implantable biofuel cells (BFCs) is to achieve inorganic-organic composite biocompatibility while improving the activity and selectivity of the catalysts. We have fabricated nanoengineered red blood cells (NERBCs) by an environmentally friendly method by using red blood cells as the raw material and hemoglobin (Hb) embedded with ultrasmall hydroxyapatite (HAP, Ca10 (PO4 )6 (OH)2 ) as the functional BFC cathode material. The NERBCs showed greatly enhanced cell performance with high electrocatalytic activity, stability, and selectivity. The NERBCs maintained the original biological properties of the natural cell, while enhancing the catalytic oxygen reduction reaction (ORR) through the interaction between -OH groups in HAP and the Hb in RBCs. They also enabled direct electron transportation, eliminating the need for an electron-transfer mediator, and showed catalytic inactivity for glucose oxidation, thus potentially enabling the development of separator-free BFCs.

In Situ Engineering of Intracellular Hemoglobin for Implantable High‐Performance Biofuel Cells

AbstractThe key challenge for the broad application of implantable biofuel cells (BFCs) is to achieve inorganic–organic composite biocompatibility while improving the activity and selectivity of the catalysts. We have fabricated nanoengineered red blood cells (NERBCs) by an environmentally friendly method by using red blood cells as the raw material and hemoglobin (Hb) embedded with ultrasmall hydroxyapatite (HAP, Ca10(PO4)6(OH)2) as the functional BFC cathode material. The NERBCs showed greatly enhanced cell performance with high electrocatalytic activity, stability, and selectivity. The NERBCs maintained the original biological properties of the natural cell, while enhancing the catalytic oxygen reduction reaction (ORR) through the interaction between −OH groups in HAP and the Hb in RBCs. They also enabled direct electron transportation, eliminating the need for an electron‐transfer mediator, and showed catalytic inactivity for glucose oxidation, thus potentially enabling the development of separator‐free BFCs.

Remote wireless control of an enzymatic biofuel cell implanted in a rabbit for 2 months

A bioelectronic device comprising an enzymatic biofuel cell (GBFC) connected to a wireless tele-transmission system was implanted in a rabbit and its function was monitored and controlled in vivo for a period of 2 months. After the 18th day of implantation, the tele-transmission system was used to wirelessly charge and discharge the operational GBFC in vivo through a 100 kΩ load for 30 min each day. For a further 16 days of operation, the GBFC delivered 16 μW mL−1 continuously during each 30 min discharge each day for 16 days. At the end of the 2 month period of implantation the power output had diminished, which was most likely due to an inflammatory process. Our results also indicate that the duration of operational activity is increased by optimizing the interface between the GBFC and the body to minimize inflammatory processes and biofouling. These data provide a significant advance in the achievable output from a GBFC that is implanted in a mammal, and importantly provide a basis upon which to further develop stable implantable biofuel cells. Improving the in vivo performance of an implanted GBFC includes the development of biocompatible diffusing polymers to act as buffering diffusion barriers.

A High-Efficiency Energy Harvesting Interface for Implanted Biofuel Cell and Thermal Harvesters

A dual-source energy harvesting interface that combines energy from implanted glucose biofuel cell and thermoelectric generator is presented. A single-inductor dual-input dual-output boost converter topology is employed to efficiently transfer the extracted power to the output. A dual-input feature enables the simultaneous maximum power extraction from two harvesters, whereas a dual output allows a control circuit to perform complex digital functions at nW power levels. The control circuit reconfigures the converter to improve the efficiency and achieve zero-current and zero-voltage switching. The measurement results of the proposed boost converter, implemented in a 0.18 ${\mu }$ m CMOS process, show a peak efficiency of 89.5% when both sources provide a combined input power of 66 ${\mu }$ W. In the single-source mode, the converter achieves a peak efficiency of 85.2% at 23 ${\mu }$ W for the thermoelectric source and 90.4% at 29 ${\mu }$ W for the glucose biofuel cell. The converter can operate from minimum input voltages of 10 mV for the thermoelectric source and 30 mV for the glucose biofuel cell.

Implantable biofuel cells operating in vivo: Potential power sources for bioelectronics devices from basic research to practical applications

Implantable biofuel cells operating in vivo: Potential power sources for bioelectronics devices from basic research to practical applications

Shades of grays for implanting an enzymatic biofuel cell

An implanted biofuel cell (IBFC) is a novel device that provides the means to create electricity from glucose and oxygen, using an original architecture for the IBFC that provides efficient work inside a living organism. In the future these IBFCs will be required to power implanted devices to assist failing physiological functions in humans. The active ingredients of such IBFCs are glucose oxidase at the anode and laccase at the cathode. These enzymes are entrapped in a 3D network of conductive and insulated materials. This publication solves the issue of the sterilization of such a complex device, using gamma irradiation. A 12kGy dose was sufficient to show absence of implant infection in all the implantations performed. We also prove in vitro functioning of both bioelectrodes with a high dose of 42kGy.