Organic Electrochemical Sensors For Biological Sensing Application

Cancer is one of the biggest factors threatening people’s quality of life and life safety.Early detection and prevention of cancer is the most effective way to change the situation.Unfortunately,relying solely on hospitals to achieve early diagnosis cannot meet people’s needs,especially in remote rural areas.Low living standards and weak awareness of early diagnosis play a big role in the increasing incidence and mortality of cancer in China.Therefore,the development of small portable devices for the detection of major diseases such as tumor markers,for self-test and family use,on-time tracking is very urgent.The portable sensing devices based on organic electrochemical transistors(OECTs)have the advantages of high sensitivity,low cost and easy fabrication,which have broad application prospects.The main research content of this thesis focuses on how to build a biosensor based on OECT for low-cost real-time rapid detection of tumor markers.The detection of tumor markers such as CEA is used as an implementation case to explore the construction of tumor marker detection OECT system by optimizing detection sensitivity and selectivity.The main works are as follows:1.Based on the basic theory and technology of biochemical sensing application,optimizing OECT detection electrode by inkjet printing and spin coating.Comparing the results of the two methods by testing the uniformity after high production and large-area fabrication,after the test of electrochemical properties and sensitivity to the detection of target compounds,we found that the two processing methods can meet the detection requirement.Spin coating process is more artificially controlled,and the thickness of the film is not that uniform,but the cost is lower compared to inkjet printing,which is more automatic with high repeatability.2.CEA aptamer was selected as the target for specific recognition of CEA,and the OECT prepared by inkjet printing and spin coating,the detection limit could reach 0.2 pg/m L.Based on fluorescence quenching theory,the N,P-Cdots fluorescent probe coated with CEA antibody probe was proposed,and the detection limit was 0.1 n M.The experimental procedure is complicated and test process relies on fluorescence equipment.3.A new portable integrated system combined of bluetooth module and mobile application is designed,of which feasibility is verified.It paves a new way of detection of human serum and multi-indicator detection in the future.In general,this paper focuses on inkjet printing based OECTs to realize the detection of biological tumor markers.This technology has advantages such as low cost,high repeatability,easy large-area fabrication,which provides technical support for the development of portable and wearable medical detection devices.