New progress has been made in the field of smart and Flexible Biomimetic biochemical sensors

In recent years, flexible electronics can realize wearable real-time continuous signal acquisition and processing on human skin surface It has become a revolutionary science and technology in sports health management, disease diagnosis and monitoring, environmental monitoring, human-computer intelligent interaction and other fields, as well as an important strategic emerging industry in various countries As one of the core components of flexible electronics, flexible sensors affect and determine the application and development of wearable intelligent devices At present, most of the flexible sensors have been widely used in the acquisition of physical signals (pressure / stretch, inertial force, bioelectricity, temperature, optics, etc.) However, there are still many challenges in the research of flexible sensors for biochemical signal detection Since ancient times, nature has been the source of all kinds of scientific discoveries, technological ideas and principles of invention After a long evolutionary process, organisms have a powerful system for receiving, transmitting and controlling the information of the external environment, and many functions are unmatched by any artificial manufacturing so far For example, as one of the frontier research fields of science and technology, the flexible sensor still has a huge gap compared with the biological flexible sensory system (smell, taste, touch, vision and hearing) Therefore, the concept and method of "bionics" will provide rich ideas and design principles for the research and development of flexible sensors and flexible electronics Recently, Zhang Yu, research team of Suzhou Institute of nanotechnology, Chinese Academy of Sciences, has made new progress in the field of Flexible Biomimetic biochemical sensors The paper was published in biosensors and bioelectronics (biosensors and Bioelectronics, 2019, 142, 111519) with the title of "rhinophore bio inspired stretchable and programmable electronic sensor" In the ocean, some mollusks, including Aplysia, Nautilus and nudibranchs, have an olfactory organ called rhinophore The olfactory angle is characterized by softness, extensibility, large number of olfactory cells on the surface, and multi fold morphology, as shown in figure (a) The olfactory horn is mainly responsible for the spatial scale tracking system of mollusks in the sea water medium, including foraging, courtship and resistance to enemies It was found that the olfactory angle was controlled by elongation / unfolding at a certain angle Inspired by this flexible biochemical sensor, the research team developed a programmable and adjustable stretchable flexible glucose electrochemical sensor by imitating the physiological and anatomical structure and function of the olfactory horn As shown in figure (b), the electrochemical sensor well imitates the fold / unfold morphology of olfactory angle, and realizes the programmed regulation of electrochemical active surface area (ECSA) in the process of stretching 150%, which is unique to the previous electrochemical sensors Based on this characteristic, the catalytic performance of the sensor for glucose can vary with the stretching state (Fig (d)) The programmed and adjustable electrochemical sensing performance is similar to that of olfactory angle, so it can be used to imitate the physiological function of animals For example, in the sea water, food chemical molecules diffuse in the water, and the concentration presents gradient distribution from near to far, as shown in figure (c) After the olfactory angle senses a certain threshold concentration of molecules far away from the source of food molecules (low concentration), it turns on the foraging state, and expands the sensing area by extending the olfactory angle to obtain high sensitive detection As shown in figure (E) experiment, at the initial 0% state, the sensor simulates the static state of the animal When 2 mM glucose is added to the solution, the sensor senses the glucose molecule and turns on the detection state (150%); when the sensor is extended to the high concentration direction (2 mM glucose is added), the response current rapidly increases to 4 times of the 0% state The results show that the sensor can improve the detection of food source direction by adjusting the stretching state A novel molecular detection mode based on olfactory angle bionic flexible electrochemical sensor is proposed, which has potential research significance and application prospect in intelligent flexible robot, bionic equipment and wearable electronics Flexible and malleable electrochemical glucose sensor based on olfactory angle bionics (A) The structure diagram of olfactory angle; (b) the surface SEM diagram of bionic sensor; (c) the foraging diagram of marine mollusks; (d) the programmed and adjustable glucose sensing performance of bionic sensor; (b) the bionic sensing diagram (source: biosensors and bioelectronics) the above work has been supported by the key R & D plan of the Ministry of science and technology, the National Natural Science Foundation, Jiangsu provincial fund for Distinguished Young Scholars, etc The first author of the above article is Dr Wang Shuqi, and Qu Chunyan, a postgraduate, has participated in the above work.