创新背景

人们通过皮肤来感知外界，从感知温度和压力，到快乐或痛苦，皮肤上的许多神经末梢可传递许多信息。

皮肤也可以告诉外界很多关于人体的信息，如用手触摸额头看是否发烧，约会中的脸颊泛红，健身后皮肤渗出汗珠等。

创新过程

加州理工学院的研究人员开发了一种电子皮肤，或称e-skin，可以直接应用在真实皮肤上。这种电子皮肤由柔软、有弹性的橡胶制成，可以嵌入传感器，监测心率、体温、血糖水平和代谢副产物等信息，这些都是健康指标，甚至还可以监测控制肌肉的神经信号。它不需要电池，因为它完全依靠生物燃料电池运行，生物燃料电池由人体自身的一种废物提供动力。

人体汗液中含有非常高水平的化学乳酸盐，这是一种化合物，是正常代谢过程的副产物，特别是在运动时肌肉产生的。电子皮肤内的燃料电池吸收乳酸盐，并将其与大气中的氧气结合，生成水和代谢的另一副产物丙酮酸。当生物燃料电池工作时，它们产生足够的电力为传感器和蓝牙设备供电，这种蓝牙设备类似于连接手机和汽车音响的蓝牙设备，使电子皮肤能够无线传输传感器的读数。

虽然近场通信是许多无电池电子皮肤系统的常用方法，但它只能用于非常短的距离内的电力传输和数据读取。蓝牙通信消耗更高的功率，但在实际医疗和机器人应用中，它是一种更有吸引力的扩展连接方式。

设计一种生物燃料电池，由浸渍了铂/钴催化剂的碳纳米管和含有分解乳酸酶的复合网制成。它们可以在人的汗液中连续、稳定地输出电力（最高可达几毫瓦/平方厘米），持续数天。

创新关键点

新型电子皮肤不需要电池，它完全依靠生物燃料电池运行，生物燃料电池由人体自身产生的废物提供动力。

创新价值

除了可穿戴生物传感器，该技术还可以人机界面形式展示。利用该平台收集的生命体征和分子信息可用于设计和优化下一代假肢。

Innovative development of "electronic skin" to monitor human health

Researchers at the California Institute of Technology have developed an electronic skin, or e-skin, that can be applied directly to real skin. Made of soft, elastic rubber, the electronic skin can be embedded with sensors to monitor information such as heart rate, body temperature, blood sugar levels and metabolic by-products, all indicators of health, and even the nerve signals that control muscles. It requires no batteries because it runs entirely on biofuel cells, which are powered by a form of the body's own waste.

Human sweat contains very high levels of the chemical lactate, a compound that is a byproduct of normal metabolic processes, especially produced by muscles during exercise. Fuel cells inside the e-skin take lactate and combine it with oxygen in the atmosphere to produce water and pyruvate, another by-product of metabolism. When the biofuel cells work, they generate enough electricity to power sensors and Bluetooth devices, similar to those connected to cell phones and car stereos, allowing the electronic skin to transmit sensor readings wirelessly.

Although NFC is a common method for many battery-free electronic skin systems, it can only be used for power transmission and data reading over very short distances. Bluetooth communication consumes more power, but it is a more attractive way to extend connectivity in practical medical and robotics applications.

To design a biofuel cell made of carbon nanotubes impregnated with a platinum/cobalt catalyst and a composite mesh containing lactate enzymes. They can produce a continuous, steady output of electricity (up to a few milliwatts per square centimeter) in human sweat for several days.