Design And Application Of A Smartphone Based Real-time Detection System For Electrochemical Biosensing

With living standards become better and better,people concern more about health.But limited medical resources of per capita in hospital can not satisfy people’s daily nursing needs.Therefore,the emergence of point-of-care testing(POCT)made it possible to realize medical care in home.In addition,POCT has been further developed with the addition of electrochemical biosensing technology,which is famous for its high convenience,selectivity,and sensitivity,and smartphone platform with high popularity.In this paper,a portable real-time detection system for electrochemical biosensing was designed and developed based on the smartphone platform.The system consisted of three parts: a sensing unit as a three-electrode measurement system,a detection device and a smartphone with a special App.In the part of the detection device,the commercial Arduino Mega2560 was adopted as the core controller independent from other functional modules in the detection circuit.Various functional modules such as power module,D/A conversion module,potentiostat module,and micro-current detection circuit module,were designed and developed through integration.By compiling the control program code in Arduino IDE,followed by burning and downloading the code to the Arduino chip,the effective control of each functional module in the detection circuit was realized.In addition,through the hierarchical and modular design of various functional classes such as Activity class,communication service class(Bluetooth Service),database storage class(SQLite),custom interface for presenting the data curve(GUI),the data processing method class(Utilities),and related assisting class,the App dedicated to the detection device was successfully developed.Subsequently,the preasure biomarker,α-saliva amylase(s AA),was tested through combining the prepared disposable testing chip with the detection device.Under the optimized experimental conditions acquired through exploration in previous tests,such as the concentration of redox probe,p H of solution and reaction time,the linear quantitative detection of s AA in the concentration range of 50~1200 U/m L,was realized at room temperature of 20±1 ℃.Accordingly,the system could detect s AA in the standard solution sample as low as 1.6 U/m L.Besides,by combining with the trier social stress test(TSST),the concentrations of s AA in actual saliva samples were measured and analyzed,which verified the applicability of this detection system in psychological assessment test.Finally,the emotion biomarker,dopamine(DA),was tested through combining the modified screen-printed electrodes(SPEs)with the detection device.Two different electrochemical methods were utilized to characterize the modification process of the working electrode.Furthermore,the scan rate dependence of the DA peak current on modified SPEs was researched and analyzed.Eventually,the selective detection of DA with high sensitivity of 0.52±0.01 μA/μM and low limit of detection of 0.29 μM was realized.