| Flexible biosensors have attracted the attention of researchers and the public because of their unique characteristics,such as light weight,low cost,high flexibility,good stretchability and strong adaptability.People have been made breakthrough in the manufacture and development of flexible electronic devices,new micro/nano-structured materials have shown great potential in many practical applications,including physiological monitoring,smart robots,smart displays,and energy harvesting and storage.In particular,wearable and flexible sensors have been proven to track physical signals over the past decade.These wearable devices can perform continuous physiology by measuring body movement,blood pressure,body and skin temperature,heart rate,and electrophysiological activities including EEG(electroencephalogram),ECG(electrocardiogram)and EMG(electromyography)in real time monitor.However,due to the lack of continuous monitoring technology that can identify the effects of biomarkers in time,many studies using biomarkers have failed to realize their full potential.Based on the enzymatic reaction and the gas-liquid coupling reaction,two new types of flexible batteryless biosensors were developed in this study,namely a lactic acid sensor and a glucose sensor.Ecoflex silica gel and multi-walled carbon nanotubes were used as the main materials to modify biological enzymes on the fabricated devices.When measuring,the measuring device is placed in physiological saline to simulate the physiological environment of the human body,and the concentration of sodium lactate or glucose in the solution is changed by dripping sodium lactate or glucose.The main purpose of the lactic acid sensor is to make biomimetic artificial muscle fibers,which can detect changes in the lactic acid concentration of the human body during exercise.When the concentration reaches a certain threshold,the electrical stimulation of the primary motor cortex of the human brain is performed,and the brain gives a tired human body a positive To stimulate the person’s athletic ability.The glucose sensor developed in order to detect changes in blood glucose concentration of the human body,monitors a person with diabetes in real time to prevent a series of effects caused by the increase in blood glucose.In this paper,the device voltage when modifying biological enzymes is about 0.15 V when stretched,and the current is 1 μA.Observing the different pull-up ratios and output voltages of the device,it can be clearly observed that the output voltage gradually increases with the increase of the stretching ratio.The output voltage is the maximum at a pull-up ratio of 60%,which is about 0.25 V.Test the pull-up frequency and observe that the frequency has little effect on the output voltage.Since the test was performed in physiological saline during this period,the relationship between the NaCl concentration and the output voltage was explored,and it was clearly observed that the output voltage increased as the NaCl concentration in the solution increased.A lactic acid concentration sensing test was performed.It was observed that when the lactic acid concentration was 3.35 mM/L,the voltage decreased from 0.1549V to 0.77 V,the current decreased from 1.67 μA to 0.36 μA,the output voltage decreased to half of the initial value,and the current decreased To about a third.The glucose concentration gradient gradually increased,and the voltage also gradually decreased,with 2.25 V dropping to 1.50 V,showing good sensing performance. |
PDF Full Text Request