{"id":115404,"date":"2013-04-24T17:55:11","date_gmt":"2013-04-24T20:55:11","guid":{"rendered":"http:\/\/revistapesquisa.fapesp.br\/?p=115404"},"modified":"2017-03-07T18:19:57","modified_gmt":"2017-03-07T21:19:57","slug":"glucose-battery","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/glucose-battery\/","title":{"rendered":"Glucose battery"},"content":{"rendered":"

\"074_075_Biocelula_205\"<\/a>Every five to eight years, pacemaker users must undergo minor surgery to replace the battery on their lifesaving implant. To create a pacemaker that can stay in place without ever needing a new power source, a number of research groups worldwide are working to develop tiny biobatteries that can convert chemical energy into electricity inside the blood vessels, using biocatalysts (enzymes or microorganisms) to speed up the chemical reactions and generate an electrical current. One of the most promising projects is being developed by the team headed by Professor Frank Crespilho, coordinator of the Bioelectrochemistry and Interfaces Group at the S\u00e3o Carlos Institute of Chemistry (IQ-SC) of the University of S\u00e3o Paulo (USP). The group also includes researchers from the Federal University of the ABC (UFABC) in the city of Santo Andr\u00e9, S\u00e3o Paulo State. They are researching a biofuel cell (BFC) that produces energy from blood glucose in rats. To test the device, the researchers implanted it in the jugular vein of a rodent.<\/p>\n

Crespilho first started his work on these cells in 2008 and began developing implantable microcells in late 2010. \u201cThe main objective was to develop a biofuel cell and use it as an alternative power source for pacemakers, insulin pumps, neural implants, electric biostimulators, and devices for controlled release of medications,\u201d he explains. \u201cImplantable BFCs powered by glucose and oxygen, like the one we are developing, are desirable because they can generate a potential difference of more than 1.0 volt [an AA battery generates 1.5 volts, for example]. Also, both glucose and molecular oxygen are readily available in many regions of the human body.\u201d<\/p>\n

The innovations in the BFC developed by Crespilho’s group include the scale and size of its components. \u201cOur biofuel cell is called a \u2018microcell\u2019 because it operates with microvolumes. And the size of the electrodes makes it possible to implant the device in the vein of a rat,\u201d he explains. The electrodes are 20 micrometers in diameter (six times thinner than a strand of hair), inserted in a catheter 0.5 millimeter in thickness by 0.6 millimeter in length. Like common batteries, the BFC created in S\u00e3o Carlos has two electrodes \u2013 one positive (cathode) and one negative (anode). The cathode is made of platinum nanoparticles and the anode is based on the enzyme glucose oxidase. Both are coated in a polymer and affixed to the electrode’s flexible carbon fiber frame. \u201cBlood cells, such as the red or white cells, may adhere to the electrodes’ surface and block the diffusion of glucose,\u201d Crespilho explains. \u201cSo our strategy was to use a special polymer called a dendrimer, which prevents adhesion and blockage of the electrodes.\u201d<\/p>\n

The microcell’s flexible carbon fibers are an additional innovation created by the group. According to Crespilho, when the team decided to develop biofuel cells for medical applications, their first insight was that they needed to create flexible electrodes that were compatible with biological systems. \u201cFrom there, we began using flexible carbon fibers,\u201d he says. The researchers were already well acquainted with carbon fibers and electrodes. But in the scientific literature, there was no reported use of these flexible fibers in biological implants. Using new techniques in micromanipulation, they extracted different types of fibers from commercially available carbon fabrics used for manufacturing highly resistant, lightweight materials including F1 race cars, surfboards, and bicycle frames.<\/p>\n

Devising a flexible carbon fiber with the right properties for use in BFCs was one of the most complicated parts of the project. They could not simply use any commercially available material. \u201cIt took us at least two years to find the ideal fabric, as the electrodes strongly depend on how the carbon atoms are aligned, as well as the quality of the materials used to produce the fibers,\u201d Crespilho clarifies. \u201cWe had to develop a technique to obtain these fibers. Once selected, they undergo a chemical treatment that makes them suitable for use in a biofuel cell.\u201d When the BFC is ready, it is implanted in a rat’s jugular vein. \u201cThe blood goes through it and brings glucose, which is the fuel for the anode, and the oxygen in the blood reacts with the cathode,\u201d the professor explains. \u201cThe glucose \u2018donates\u2019 electrons to the BFC by reacting with the anode’s surface which contains the glucose oxidase enzyme, in a process known as oxidation. The cathode reduces an oxidizing agent, which in this case is the oxygen dissolved in the animal’s blood. In this reaction, the oxygen receives electrons.\u201d<\/p>\n

The two electrodes enable electrons to pass from one extremity of the BFC to the other. The combined reactions of oxidation and reduction (or simply \u201credox\u201d) create an electric current that can be used to power an external circuit \u2014 such as a pacemaker. For this to happen, the generated electricity is transported from the BFC to the device through wires that cross the vein’s walls. This means that the biofuel cell is constantly \u201cfed\u201d by the blood’s oxygen and glucose, which are continuously replenished as an animal breathes and eats.<\/p>\n

Greater density<\/b>
\nIn their paper published in the journal Lab on a Chip<\/i>, the researchers also mention that further studies are still needed in order to discover alternatives for preventing inflammation and the formation of fibrous tissue around the electrodes implanted in blood vessels, which would reduce the devices’ useful life. In addition to the group from USP S\u00e3o Carlos and UFABC, biofuel cells are also being developed by two research teams in the United States and one in France. The pioneer of this field was Professor Serge Cosnier of Joseph Fourier University in France, who implanted a BFC in a rat’s abdomen in 2010. In 2012, Daniel Scherson from Case Western Reserve University in the U.S. did the same to a cockroach. That same year, the group led by Evgeny Katz from Clarkson University, also in the U.S., implanted a BFC in a snail. \u201cIn all this work, our group developed the implantable biobatteries with the highest power density reported until now, roughly 100 microwatts per square centimeter,\u201d Crespilho assures. To implement their project, the researchers in S\u00e3o Carlos and Santo Andr\u00e9 received funding from FAPESP, the National Institute for Organic Electronics (Ineo), the Nanobiomedicine Network (Nanobiomed), and the Coordinating Agency for the Improvement of Higher Education Personnel (Capes).<\/p>\n

Project<\/strong>
\nBiomolecules and cellular system interaction with nanostructures 0D, 1D and 2D by using electrochemical methods (n\u00ba 2009\/15558-1<\/a>); Grant mechanism<\/strong>\u00a0Regular Line of Research Project Award; Coordinator <\/strong>Frank Crespilho\/USP; Investment<\/strong>\u00a0R$ 92,262.80 and R$ 50,821.57 (FAPESP).<\/p>\n

Scientific article<\/em>
\nSALES, F. C. \u00a0et al<\/em>. An intravenous implantable glucose\/dioxygen biofuel cell with modified flexible carbon fiber electrodes<\/a>. Lab on a Chip<\/strong>. v. 13, p. 468-74, 2013.<\/p>\n","protected":false},"excerpt":{"rendered":"Pacemakers will run on electricity obtained from the blood","protected":false},"author":20,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[169],"tags":[259],"coauthors":[112],"class_list":["post-115404","post","type-post","status-publish","format-standard","hentry","category-technology","tag-chemistry"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/115404","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=115404"}],"version-history":[{"count":0,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/115404\/revisions"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=115404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=115404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=115404"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=115404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}