Multifunctional Wound Monitoring Sensor Based On Laser-induced Graphene

In recent years,with the wide application of various sensors in wearable devices,higher requirements have been placed on miniaturization,flexibility,and stability of sensing materials and devices.In addition,people also want wearable sensors to have as many functions as possible to meet the needs of different fields.In daily production and life,it is inevitable that wounds appear on the skin due to trauma of various reasons.Wounds can be roughly divided into chronic wounds and acute wounds.Chronic wounds are not only difficult to treat and have a long recovery period,but severe chronic wounds can also cause amputations and even endanger patients' lives.Therefore,it is of great scientific significance and social value to develop and develop wearable flexible sensors that can effectively monitor the status of chronic wounds.At present,the wound monitoring sensors developed by scholars at home and abroad often have a single function.They can only monitor a single information of the wound,and cannot accurately measure the true state of the wound.In addition,the current wound monitoring sensors developed by scholars at home and abroad have not effectively monitored and warned of the wound tear,and the secondary tear of the wound is also one of the important reasons for the difficult healing of the wound.Therefore,this paper proposes a new type of wound monitoring sensor based on laser-induced graphene.The sensor not only has the characteristics of flexibility and stretchability,but also can monitor a variety of wound information(pH,temperature,strain).The main research of this article includes the following four aspects:(1)design,manufacture and test of flexible strain sensor.A layer of porous graphene was prepared on the surface of polyimide film by laser induced graphene method.The porous graphene is then transferred to the surface of the polydimethylsiloxane by the viscosity of the polydimethylsiloxane when it is not solidified.Under the stretching deformation,porous graphene will form a large number of gap cracks on the surface,resulting in the change of resistance,which can be used to monitor whether the wound is stretched,so as to give the wound a stretch warning.(2)Preparation and performance monitoring of flexible temperature sensors.An electrochemical workstation was used to electroplate a layer of metallic copper on the surface of the laser-induced graphene,and the resistance-temperature characteristics of metallic copper were used to determine the temperature change of the wound.Through the structural design of soft and hard combination,the interference of strain on the temperature sensor is isolated,making the temperature sensor measurement more accurate.(3)Preparation and performance monitoring of flexible pH sensors.Electrochemical polymerization of polyaniline on the surface of laser-induced graphene using an electrochemical workstation.The pH of the wound was monitored based on the electrochemical properties of polyaniline,and the effect of different electropolymerization conditions on the performance of the pH sensor was studied.A snake-like structure is designed through theoretical derivation and finite element simulation,so that the sensor can still work normally under large deformation conditions.(4)Analysis of monitoring performance of wound monitoring sensors.Laser-induced graphene-based strain sensors,temperature sensors,and pH sensors are integrated into multifunctional wound monitoring sensors.By using polydimethylsiloxane to simulate human skin wounds,experiments show that the use of multifunctional wound sensors can effectively monitor the physical and chemical parameters such as pH,temperature,and strain state of the simulated wounds,and then can judge the wound status.In this study,through the reasonable structural design,finite element analysis,and experimental research,a flexible multi-functional sensor for pH,temperature,and strain was prepared for real-time monitoring of wound status.The sensor can not only monitor wound healing information,provide guidance for doctors' treatment,but also monitor the strain at the wound in time to remind patients to avoid secondary laceration injuries.