近日，南方科技大学生物医学工程系肖凯课题组在学术期刊Nature Communications上发表了题为“A nanofluidic chemoelectrical generator with enhanced energy harvesting by ion-electron Coulomb drag”的文章。生物系统通常依靠离子或者分子进行信息传输以及能量的交换和存储，而当前的信息技术依赖于电子的传输。虽然后者响应速度快，传输效率高，但磁场、高温和高湿等极端工作环境严重限制了电子器件的使用环境；与此同时，集成电路正在接近基于冯·诺依曼计算架构的摩尔定律的极限。近年来，受到生物系统的启发，基于离子-电子的耦合器件表现出优异的适应性、机械柔韧性和类生物特性，使它们成为先进智能电子设备和生物智能之间沟通的潜在桥梁。

       离子-电子耦合通常发生在液体和固体界面之间。通常，耦合过程可以分为三种基本类型：双电层 （electric double layer，EDL） 电容过程；电化学氧化还原反应过程，以及赝电容过程。不同于上述被广泛研究和应用的离子-电子耦合过程，本文提出 “离子-电子”库伦拖拽效应，可实现离子电流和电子电流的直接交互和转换。库伦拖拽效应是指两个空间相近但彼此绝缘的导电层构成了电双层结构，在其中一层施加驱动电流会在另一层诱导产生开路电压，即产生层间拖拽效应。“离子-电子”库伦拖拽效应基于纳米流体内离子传输和半导体中电子传输的互相作用，进而实现离子-电子的耦合过程。具体来说，在纳米尺度下的离子移动行为可以诱导半导体中的自由电子移动，基于这一机制，本工作开发了一种纳米流体化学发电机。如图1所示，碳纳米管膜内的纳米离子流体由金属和氧气之间的自发氧化还原反应驱动。由于纳米离子流体中离子和空穴之间巨大的质量差距（10⁵ to 10⁶），基于动量守恒定律，大量的自由电子在碳纳米管膜中产生，进而实现了1.2 mA/cm²的放大电流。与此同时，单个纳米流体化学发电机单元可以产生~0.8 V的电压，并具有高达数十伏的线性可扩展性能。

图1. NCEG原理图及电输出特性：(a) NCEG的结构示意图：一个高度排列的多孔CNTM夹在一对金属电极之间，这对金属电极分别是金箔和含有铝衬底的导电碳带；(b) CNTM的形貌以及衬底AAO膜的XPS表征；(c)离子沿CNTM运动与CNTM中的自由电子被拖拽的离子库仑拖拽效应示意图；(d) NCEG在0.1 M NaCl电解液中产生的开路电压和短路电流密度。

 

       众所周知，智能生物是基于离子定向流动（细胞上蛋白质通道控制离子输运）形成的电势信号（动作电位）进行信号的传递和信息的交互；和智能生物不同，固态电子器件是基于电势驱动的电子流动尽心信号的传输，如何构筑离子-电子信号交互体系进而实现生物-器件（脑-机）无障碍交互是未来人机交互愿景中最基本的科学问题。本工作报道的基于库伦拖拽效应的离子-电子耦合过程可实现“离子电流-电子电流”直接交互，有望搭建起电子信息和生物信息交流的新型高速通道。

       南方科技大学为本论文第一单位，温州大学联合培养硕士生蒋义沙为论文第一作者，南科大生物医学工程系2022级博士生刘文超为论文共同第一作者，南科大王涛博士、云南大学王毓德教授、温州大学刘楠楠教授和南方科技大学副教授肖凯为论文通讯作者。本工作得到了国家重点研发计划、国家自然科学基金、广东省重点实验室项目和深圳市科技创新委员会的支持。

       原文链接：https://www.nature.com/articles/s41467-024-52892-4

 

       肖凯教授课题组（“神经仿生材料与器件”实验室）长期招聘博士后、科研助理和交流学生。课题组主要围绕“神经仿生材料、类脑计算器件、神经调控技术”开展化学、材料、电子、生物等多学科交叉研究，自2021年成立以来，课题组自主培养的学生以南科大为第一单位在Nat. Commun., Sci. Adv., Angew. Chem.,等杂志发表文章20余篇，课题组多位成员获批国自然面上项目（2项）、青年基金项目（3项）、博士后海外引才专项基金等。详细信息见课题组网站：http://www.xiaokai-group.cn/。

The biggest difference between electronic devices and brain information processing mechanisms is that the human brain is an intelligent system that uses ions as information carriers with ultra-low energy consumption and ultra-high performance. Voltage-gated ion channels, also known as life’s transistors (Figure 1), can precisely and selectively regulate ion transport and play important roles in maintaining important physiological activities and processing complex information in intelligent life.

Associate Professor Kai Xiao’s research group from the Department of Biomedical Engineering (BME) at the Southern University of Science and Technology (SUSTech) has published their research on ion transistors based on ions as information carriers. Inspired by the switching mechanism of voltage-gated ion channels (i.e., life’s transistors), they successfully prepared ionic transistors based on carbon nanotubes, which can achieve ultra-high switching ratios (10⁴) at ultra-low gate voltages. In addition, logic gates were constructed based on ionic transistors, demonstrating their application and development in ion circuits.

Their work, entitled “Bioinspired carbon nanotubes-based nanofluidic ionic transistor with ultrahigh switching capabilities for logic circuits”, has been published in the journal Science Advances.

Figure 1. Life’s transistors and how to construct ionic transistors through nanofluidic systems

The research group reported a nanofluidic ionic transistor based on carbon nanotubes, which exhibits an on/off ratio of 10⁴ at an operational gate voltage as low as 1 V (Figure 2). By controlling the morphology of carbon nanotubes, both unipolar and ambipolar ionic transistors are realized, and their on/off ratio can be further improved by introducing an Al₂O₃ dielectric layer. Meanwhile, this ionic transistor enables polarity switching between p-type and n-type by controlled surface properties of carbon nanotubes. The implementation of constructing ionic circuits based on ionic transistors is demonstrated, which enables the creation of NOT, NAND, and NOR logic gates.

Figure 2. Bioinspired design and switching state of nanofluidic ion transistor

The researchers provide a comprehensive overview of the first generation of bioinspired ionic transistors, including their operating mechanisms, device architecture development, and property characterizations. Despite its infancy, significant progress has been made in the applications of ionic transistors in fields such as DNA detection, drug delivery, and ionic circuits. Challenges and prospects of full exploitation of ionic transistors for a broad spectrum of practical applications are also discussed (Figure 3).

Nature has chosen ions as the information carrier for the human brain, and the close coordination of various ion channels on nerve cells has formed the advantage of fast computing and low energy consumption in the human brain. Inspired by nature, ion information devices, compared to electronic devices, are still in their early stages and have shown enormous application prospects. They expect ion transistors to play important roles in the near future in the concentration or separation of ions and molecules in seawater and physiological disease detection in clinical medicine. Additionally, nanofluidic systems can aim to mimic the energy-efficient information processing of the human brain (such as various pulse signals based on action potentials, biological oscillations, long-term and short-term memory, etc.). This provides significant advantages for implantable nanofluidic devices and barrier-free brain-computer interfaces.

Figure 3. Application and outlook diagram of ionic transistor

Exploring artificial devices that precisely control ion transport will promote the development of ultra-low-energy information technology based on ion systems, and have broad application prospects for ion sensing, low-energy neuromorphic computing, and brain-machine interfacing.

The research group has also made a series of progress in the construction of ion information devices, which have been published in top journals, including Angewandte Chemie International Edition, Device, and ACS Nano.

 

Wenchao Liu, a doctoral student from the Department of BME at SUSTech, is the first author of the paper. Research Assistant Tingting Mei from the Department of BME at SUSTech and Zhouwen Cao from the National Center for Nanoscience and Technology (NCNST) at the University of Chinese Academy of Sciences (UCAS) are the co-first authors. Associate Professor Kai Xiao is the corresponding author, while Associate Researcher Ruotian Chen from the Dalian Institute of Chemical Physics at UCAS and Associate Researcher Bin Tu from NCNST, UCAS are the co-corresponding authors.

SUSTech is the first affiliated unit of the paper, with collaborative units including the Technical Institute of Physics and Chemistry at UCAS, along with the Department of Mechanics & Aerospace Engineering and the Department of Materials Science & Engineering at SUSTech.

This work was supported by the National Key Technologies R&D Program of China, National Natural Science Foundation of China (NSFC), Shenzhen Science and Technology Innovation Committee, Shenzhen Science and Technology Program, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Starting Grant from SUSTech, and the Strategic Priority Research Program of the Chinese Academy of Sciences.

 

Paper link published in Science Advance: https://www.science.org/doi/10.1126/sciadv.adj7867

 

Related links:

Angewandte Chemie International Edition: https://doi.org/10.1002/anie.202401477

Device: https://www.sciencedirect.com/science/article/pii/S2666998624000565‍

ACS Nano: https://pubs.acs.org/doi/10.1021/acsnano.3c06190

The National Key R&D Program “Synthetic Biology”, which is being led by the Southern University of Science and Technology (SUSTech), held a meeting on its project’s commencement and implementation plan at the University.

In attendance at the meeting were Jinqiang TIAN, Deputy Director of Life Sciences and Frontier Technology at the China National Center for Biotechnology Development, Bo YUAN, Deputy Director of the Frontier Technology Working Group of the Shenzhen Science and Technology Innovation Commission (SZSTI), and Xueming YANG, Vice President of SUSTech.

Accompanying them were Mingzhou GUO, a project expert, and Hanmei XU, a consulting expert, alongside other experts and researchers in this field.

Jinqiang TIAN provided an analysis of the “Synthetic Biology” project, highlighting its goals, vision, and strategic task deployment. He outlined specific requirements and suggestions for various research institutions involved.

Bo YUAN emphasized SZSTI’s commitment to project development and planning, encouraging the lead unit and responsible individuals to oversee the project’s smooth execution as planned.

Xueming YANG briefed the expert team on SUSTech’s scientific research landscape and expressed high expectations for the innovative results and technologies that would emerge from the project.

Lu ZHANG, Associate Professor of the Department of Biomedical Engineering at SUSTech and project leader, presented a comprehensive report detailing the project’s core research objectives, technical indicators, and implementation strategy.

Following in-depth discussions among the experts, it is believed that this project will solve the inherent challenges of in vivo cell engineering and facilitate breakthroughs in the field of synthetic biomedicine.