人間が動力を与えるデバイスに移植可能な新しいバッテリー？
外国メディアの報道によると、科学者たちは現在、ウェアラブルまたは埋め込み型デバイスを提供するために、圧電効果、熱エネルギー変換、静電効果、および化学反応を通じて、人体の機械的、熱的、および化学的エネルギーを電気エネルギーに変換することを研究しています。 。 搭載。
In ISing the Body Electric, poet Walt Whitman speaks fondly of the "action and power" of "beautiful, strange, breathing, laughing muscles." More than 150 years later, MIT materials scientist and engineer Canan Dagdeviren and her colleagues are using research to give new meaning to Whitman's poetry. They are working on a device that can generate electricity from the beating of people's hearts.
Today's electronics are so powerful that the computing power of smartphones far exceeds the processing power of NASA's associated crew equipment when the first astronauts were sent to the moon in 1969. Over time, the rapid development of technology has led to higher and higher expectations for wearable or implantable devices.
The main drawback of most wearable and implantable devices is still battery life, whose limited battery capacity can limit the long-term use of the device. When the pacemaker's power runs out, all you need to do is replace the battery for the patient's surgery. The fundamental solution to this problem may lie within the human body, which is rich in chemical, thermal, and mechanical energy. This has led scientists to repeatedly study how the device harvests energy from the human body.
For example, the movement a person makes while breathing can generate 0.83 watts of energy; the human body has about 4.8 watts of heat in a calm state; and a person's arms can generate up to 60 watts of energy when exercising. A pacemaker needs only five millionths of a watt to run for seven years, a hearing aid needs only one thousandth of a watt to run for five days, and a watt of power can power a smartphone for five Hour.
現在、Dagvirenらは、人体自体をデバイスのエネルギー源として使用する方法を調査しています。 研究者はすでに、動物と人間でウェアラブルまたは埋め込み型デバイスのテストを開始しています。
これらの環境発電戦略の1つには、振動、圧力、その他の機械的ストレスからのエネルギーを電気エネルギーに変換することが含まれます。 この方法では、スピーカーやマイクで一般的に使用される、いわゆる圧電性が生成されます。
A commonly used piezoelectric material is lead titanate zirconate, but its high lead content has raised concerns because lead is too toxic to humans. "But to break down the lead structurally, you need to heat it to more than 700 degrees Celsius," Dagvilen said. "You'll never get to that temperature in the human body."
To take advantage of the piezoelectric effect, Dagviren and her colleagues developed flat devices that can be attached to organs and muscles such as the heart, lungs and diaphragm. These devices are "mechanically invisible" because their mechanical properties are more similar to their environment, so they move without interfering with the normal functioning of these tissues.
So far, the devices have been tested on cows, sheep and pigs, because these animals have hearts about the same size as a human heart. "When these devices are mechanically distorted, they generate positive and negative charges, voltages and currents, so that energy can be harvested to charge the battery," Dagviren explained. "You can use them to run the heart biomedical devices such as pacemakers, rather than having to be surgically replaced every six or seven years after the battery is depleted."
科学者たちはまた、膝や肘に装着したり、靴、ズボン、下着に装着したりできるウェアラブル圧電エネルギーハーベスターを開発しています。 そうすれば、人は歩いたり、かがんだりしたときに、電子機器用の電気を生成することができます。
It may seem counterintuitive when designing piezoelectric components that you don't need the best materials for generating electricity. For example, instead of choosing a material that can convert 5 percent of mechanical energy into electrical energy, scientists may use materials that have a conversion efficiency of 2 percent or less. If it translates more, "it may do so by putting more load on the body, but the user certainly doesn't want to get tired from that," Dagvilen said.
Another energy harvesting method is to use thermoelectric conversion materials to convert bulk heat into electrical energy. "Your heart beats more than 40 million times a year," Dagviren points out. All of this energy is dissipated as body heat—a potential resource that can be captured.
Human thermal power generation does face some major problems. This type of energy conversion often relies on temperature differences, but the body's body temperature often remains fairly constant, so the temperature differences within the body are not high enough to generate a lot of electricity. However, if these devices could be exposed to a relatively cool external environment while collecting body temperature, the problem could be solved.
Scientists are exploring heat-generating devices for wearable devices, such as powering watches. The heat produced by the human body could, in principle, generate enough electricity to power wireless health monitors, artificial hearing aids and cerebral cortical stimulators for Parkinson's disease.
さらに、科学者は一般的な静電効果を介してデバイスに電力を供給しようとしています。 2つの異なる材料が繰り返し衝突または摩擦すると、一方の表面が他方の表面から電子をつかみ、電荷を蓄積する可能性があります。これは、摩擦電気帯電として知られる現象です。 摩擦電気帯電の主な利点は、自然と合成の両方のほぼすべての材料が静電気を生成できることです。これにより、研究者はさまざまなガジェットを設計するための多くの可能性が開かれます。
"The more I study triboelectricity, the more exciting it is, and the more applications it may have," said Georgia Tech nanotechnology expert ZhongLin Wang, co-author of the paper. "I can Seeing myself committing to this research for the next 20 years."
The amount of electricity produced by different materials through triboelectricity varies widely, so scientists are experimenting with a variety of materials. The researchers made grids of cubes that resemble microscopic city blocks, nanowires that resemble bamboo forests, and pyramid arrays of the kind that resemble the Great Pyramid of Giza. Not only do these materials "look beautiful," Wang said, but covering the surface with an array of pyramids can increase power generation by a factor of five compared to flat panels.
Researchers have conducted experiments in mice, rabbits and pigs, where they have tested pacemakers, heart monitors and other implantable devices powered by breathing and the rapid heartbeat. "We're also investigating whether we can use triboelectricity to stimulate cell growth and accelerate wound healing," Wang said. "Also, we've started triboelectric experiments on neural stimulation to see if we can do it for neuroscience. any contribution."
Wang and his colleagues also designed wearable devices that are triboelectrically charged. For example, they made triboelectric cloths that can charge flexible wristbands with lithium-ion batteries. The gadget powers a Bluetooth-enabled wearable heart rate monitor, which transmits its data wirelessly to a smartphone. "The mechanical energy generated by human movement every day can be converted into electricity through our cloth," Wang said.
別の戦略は、バイオ燃料電池と呼ばれるデバイスに依存しています。バイオ燃料電池は、酵素と体内のエネルギー-貯蔵分子（血液中のブドウ糖や汗で分泌される乳酸塩など）との化学反応によって電気を生成します。 たとえば、真菌から抽出されたセロビオースデヒドロゲナーゼは、グルコースを分解し、ナノメートル（10億分の1メートル）の炭素管に電流を生成する可能性があります。
酵素の選択には注意が必要です。 たとえば、数人の科学者は、グルコースオキシダーゼが実験用マウスに埋め込まれたバイオ燃料電池で電気を生成できることを発見しましたが、酵素は過酸化水素（一般的な漂白剤成分）も生成し、デバイスの性能を低下させ、身体に害を及ぼす可能性があります。
別の研究では、走査型電子顕微鏡写真は、実験的なバイオ燃料電池で使用されたカーボンナノチューブが体から電気を生成することができたことを示しました。 チューブは、汗中の乳酸や血液中のブドウ糖などの自然エネルギー分子を処理する酵素でコーティングされています。 このツールは電気活性であり、酵素がエネルギーと反応するための大きな表面積を提供し、特定の体積に対してより多くの電気を生成できるようにします。
フランスの科学者はまた、酵素-でコーティングされたカーボンナノチューブをベースにしたバイオ燃料電池を作成しました。これは小さじ半分のサイズで、マウスに移植すると、血糖値と反応してLEDまたはデジタル温度計に電力を供給するのに十分な電力を生成できます。 。 実験では、ヘッドバンドとリストバンドに織り込まれた布製バイオ燃料電池が、牛乳や汗に含まれる乳酸と酵素との化学反応により、時計に電力を供給するのに十分な電力を生成できることも示されています。
Dagvilenが知る限り、これらのデバイスは現在市場に出ていません。 しかし、彼女はこの技術が10年以内に市場に出ると予測しています。 将来的には、環境発電装置が人体により適したものになる可能性があります。 Dagvilenと彼女の同僚は、分解可能な電力-生成ガジェットにも取り組んでいます。
"Imagine," she said, "putting a device in your body, and after a while it degrades into molecules that dissolve into body fluids, and you can take it out without opening your chest: we can use biodegradable Materials such as silk and zinc oxide that decompose over time."
