Development Of Micro Sensors For Cancer Biomarker Detection

Cancer is a disease with high mortality in the world,and prostate cancer is one of the most common male cancers,with a high cure rate of early cancer.So it is very important to find a method for early prostate cancer diagnosis.Because of its portability and ease of operation,electrochemical technology can be used to detect cancer markers.Compared with traditional electrochemical sensors,microelectrodes have better detection limits,higher sensitivity,faster detection efficiency and lower detection cost,which can be widely used in the early diagnosis of cancer and related efficacy evaluation.The key to developing microelectrodes for detection of cancer markers is to find the proper electrode material and an easy way to make the electrodes.The purpose of this article is to develop an electrochemical sensor made by low-cost printing technology and to test the detection performance of this electrode using sarcosine,a prostate cancer marker.This thesis used the dispensing machine to print the electrode,a new electrochemical sensor was developed,which can fabricate the electrode with low cost and high efficiency.By changing the production process,an electrochemical sensor with excellent electrochemical properties was obtained.Combining with microfluidic technology,a microfluidic chip was integrated for electrochemical detection,with high accuracy detection of sarcosine.This thesis mainly tried to use carbon and gold as electrode materials to make electrochemical sensor by printing with dispensing machine.By trying to change the forming conditions or simple surface modification methods,we wanted to improve the detection accuracy.Cyclic voltammetry of the working electrode and the auxiliary electrode(the counter electrode)were scanned in 0.5 M sulfuric acid(H2SO4)and a mixture of 1.0×10-4 M potassium chloride(KCl)and 0.05 M potassium ferricyanide(K3[Fe(CN)6]),respectively,and compared with the test curves of the purchased standard electrode;Silver/silver chloride(Ag/Ag Cl)ink was applied on the surface of the silver electrode,and the cyclic voltammetry curve was scanned in phosphate buffer solution(PBS),which was compared with the standard reference electrode.Then electrochemical experiments were conducted to detect sarcosine at different concentrations in the solution by cyclic voltammetry(CV)and constant potential(IT).The final detection limit was 0.1 ?M(S/N=3),while the sarcosine concentration in the blood of prostate cancer patients was 5 ?M on average.The results showed that the electrode made by dispensing mechanism had good electrochemical properties and could be used for the determination of sarcosine.In addition,the electrode was integrated into a complete microfluidic chip to realize the rapid detection of sarcosine under flow conditions.This study provided a new idea for the detection of cancer markers using low-cost electrochemical electrodes.