1. Implantable Medical Devices Energy Supplying In Healthcare technology, during this decade, Scientific research has been focusing in the interaction between the Human Body and small medical devices. We are starting to create several Implantable Medical Devices (IMD’s) whose close interaction with the Human Body has brought new and better clinical diagnosis and treatment. However, these medical devices need an efficient energy production and distribution system. There are several devices that harvest energy for IMD’s, some already constructed and in use, like the Lithium-Ion battery, others in a development stage, like betavoltaics and Mechanical generators. Scientists are now also turning to Biofuel Cells, since they establish a perfect connection with the human body: the body provides the fuel for the cell, the cell provides energy for the IMD. Biofuel Cell that uses enzymes as biocatalysts for the Oxidation/ Reduction reactions in the Cell. Enzymatic Fuel Cells This type of Biofuel Cell takes advantage of the metabolic activity of microorganisms, specially bacterial species, to catalyze the reaction inside the cell. Microbial Fuel Cells Direct Glucose Fuel Cells use a metallic catalyst, like carbon or platinum, instead of biocatalysts. Direct Glucose Fuel Cells 1º AnoMestrado Integrado em Engenharia BiomédicaIntrodução à Engenharia Biomédica What is a Fuel Cell? A fuel cell (FC) is a device focused in the task of obtaining electrical energy from a chemical reaction, which is maintained by a continuous flux of fuel into the cell. Its components are the electrolyte, two Electrodes, the Anode and the Cathode, and a Selective Membrane between the electrodes. The best known example of a Fuel Cell is the Hydrogen Fuel Cell, which is gaining relevance in automobile industries. Main Types of Biofuel Cells : What is a Biofuel Cell? A Biofuel Cell (BFC) is a particular type of a Fuel Cell that utilizes molecules, mainly Glucose (C 6 H 12 O 6 ) and Oxygen (O 2 ), present in a fluid from a living organism, like blood, to generate electrical Energy. 3. Portable Hydrogen Fuel Cell Power Source Biofuel Cell Operational Concept 2. Hydrogen Fuel Cell operational concept 1. Implanted Medical Device: Pacemaker 4. Simple model of a Microbial BFC 6. 2x2 cm model of a Direct Glucose FC 5. A possible spot for implantation of a BFC, where the cell is continuously receiving the fuel from the blood flow Aknowledgments: Raul Martins, PhD Bibliography: Kerzenmacher, S. and Sumbharaju, R. and Ducrée, Jens and Zengerle, R. and von Stetten, F. (2007) A surface mountable glucose fuel cell for medical implants. In: TRANSDUCERS 2007 - International Solid-State Sensors, Actuators and Microsystems Conference, 10- 14 June 2007, Lyon, France. ISBN 1-4244-0842-3; CALABRESE BARTON, S.; GALLAWAY, J.; ATANASSOV, P.; Enzymatic Biofuel Cells for Implantable and Microscale Devices; Chem. Rev.; 2004; Images: 1. http://www.cosmosmagazine.com/files/imagecache/news/files/20080313_pacemaker.jpg; 2. http://www.fuelcells.org/fuelcells_files/how_diagram.jpg; 3. http://imagesme.net/igreenspot/g2-portable-fuel-cell.jpg http://imagesme.net/igreenspot/g2-portable-fuel-cell.jpg; 4. http://www.engr.psu.edu/ce/enve/logan/bioenergy/images/Julie_Paone_Biofuelcell.jpg; 5. http://www.faculty.iu-bremen.de/zakhartsev/bce/images/Biofuel%20cell%20adam%20heller%203.gif; 6,7. Kerzenmacher, S. and Sumbharaju, R. and Ducrée, Jens and Zengerle, R. and von Stetten, F. (2007) A surface mountable glucose fuel cell for medical implants. In: TRANSDUCERS 2007 - International Solid-State Sensors, Actuators and Microsystems Conference, 10-14 June 2007, Lyon, France. ISBN 1-4244-0842-3 The Importance of Biofuel Cells as power sources for Implantable Medical Devices Scientists have focused on this specific form of supplying energy to Implantable Medical Devices. The main reason for its relevance in the area of small implantable medical devices is the fact that Biofuel Cells requirements, Glucose and Oxygen, are present in the Human Body in several body fluids, so a BFC implanted in a patient has an unlimited source of Fuel and doesn’t need to be recharged, like Lithium-Ion batteries. Researchers have already developed several prototypes of BFC whose power output was capable of powering a large spectrum of Implantable Medical Devices. The current aspects of BFC’s that are being researched, besides improving the power output, are Dimensions and Packaging of Biofuel Cells: they need to be produced with small dimensions and materials strong enough to resist to natural body temperature and mechanical pressure (like muscle contractions ). Although currently there isn´t still any prototype of a BFC implanted on a patient, this could become the method of choice to power IMDs in the relatively near future. 7. Main Reactions in a Biofuel Cell with Glucose and Oxygen as Fuel