Concentration Cell-based Electrochmeical Biosensors For Point-of-care Testing

With the continuous development of medical personalization,POCT(point-of-care testing)has become a heated topic in medical field.POCT,as a rising research field,is now widely used in detection of physiological signal for its unique advantages including miniaturization,portability,low energy consumption and reduced time cost.However,POCT devices developed in laboratory used to cost expensive reagents with complex operation.Therefore,it has been an urgency to develop a low-cost detection system with great repeatability to use in daily life for untrained personnel.In this paper,a stable POCT detection system was accomplished and applied on prothrombin time test.When testing,the blood sample is directly added into the electrochemical sensing chip and the results would be displayed on a smartphone within one minute.During the testing process,the sensitivity of this method is not satisfactory.While the traditional three-electrode system presents high sensitivity,the system is difficult to operate,and the resulting curve is complicated to analyze.To conclude,it is not fit for POCT.Therefore the concentration cell principle is developed to improve conventional electrochemical method.Concentration cell is based on electrochemical cell.Two half cells in the system is preloaded with reagents that are different in concentration.Due to the difference in concentration,the progress of the redox reaction in two half cells will be different,thus a change of potential can be produced and measured between the two half cells.In this way,a relationship between the unmeasured concentration and the measured voltage can be established.Based on the concentration cell,a electrochemical biosensor is designed to test the physiological signal—salivary α-amylase.Similarly,the testing results could be read on the smartphone.The POCT device reported in this paper is composed of three parts: a sensing chip,a sensing device and an APP on smartphone.The structure of sensing chip contains three layers: the top and bottom layers are transparent PET paper and the middle layer is patterned hydrophobic double-side adhesive tape.As a new methodology,concentration cell can eliminate the background noise to maintain high detection accuracy.At the same time,it is a universal method to detect various biomolecules.Compared with traditional electrochemical method,concentration cell have prominent advantages.First of all,it has simpler electrodes system without complex electrode preparation or expensive electrode materials.Second,it has straightforward working principle,which makes the biosensors based on concentration cell smaller and less in cost.And the last,it has simplified operation steps.“Sample-to-result” mode benefits users significantly,it’s simple operation steps and easy-to-understand detection result can meet the demand of POCT.Compared with traditional POCT devices,the two electrochemical biosensors reported in this paper lowered the cost,simplified operation procedure,shortened the measurement time,thus can complete meet the marketing requirements and the public expectancy.It’s sure that this work can fill the blank in the related fields.