| Colon cancer is the third most common cancer in the world.The incidence rate of colon cancer have been increasing because of the improvement of living standard and the change of dietary habit,along with the reduce of physical activity.Although the level of modern medical treatment has been improved in recent years,the mortality rate of colon cancer is still rising,second only to the world's two biggest cancer(lung cancer,liver cancer),which caused serious harm to human health.Early prevention and detection are the major method for reducing morbidity and mortality of human cancer.At present,the traditional surgical therapies clinically have shown poor efficacy with serious side effects,convenient transfer.Thus,It is important to build a simple and low cost method for detecting colon cancer cells.Phospholipase is an enzyme that controls the level of free fatty acids through the hydrolysis of phospholipids,which plays an important role in the cell membrane system.phospholipase C(PLC)specifically catalyzes the hydrolysis of Phosphodiester bond to the second messengers diacylglycerol(DAG),in order to regulate' diverse biological processes.The degradation of phospholipid by phospholipase C is related to some important biological processes,such as digestion,inflammation and signal transduction between the cells.The hydrolysis reaction has been involved in abnormal choline metabolism in cancer cells.Therefore,low cost,simple and effective method was developed for detecting enzyme activity,which is of critical importance for point-of-care diagnostics and drug screening in biomedical applications.The aim of this paper is to study the electrochemical detection of Pb2+ and human colon cancer cell line HCT116 cells based on a printed copper electrode,and construct a convenient and low-cost method using glucose meter as a detector and glucose-encapsulated liposome as a probe for the detection of PLC.This thesis consists of three parts.The first chapter consists of four parts.The first part is an overview of colon cancer cells,phospholipase and its detection methods.The second part is an overview of the properties of quantum dots and the use of amphiphilic molecular.The third part is an overview of electrochemical biosensor.The fourth part mainly illustrates the research background,research purpose and research content of this paper.Chapter 2,we studied the electrochemical detection of Pbrv and human colon cancer cell line HCT116 cells based on a printed copper electrode.Firstly,the polymer micelles modified by folic acid-encapsulated PbS QDs were synthesized by dialysis.Secondly,polymer micelles were targeted to uptake by HCT116 cells by folate receptor-mediated endocytosis,followed by centrifugation,nitric acid dissolution.Finally,the detection of HCT116 cells by detecting Pb2+were achieved by square wave anodic stripping voltammetry.The experiment results showed that the response current has a good linear relationship with the concentration of HCT116 cells in the range of 102?104 cells/mL.the detection limit is 33 cells/mL.This shows that the method has good sensitivity for detecting Pb2+.The copper-based electrochemical sensor is expected to detect HCT116 cells effectively.Chapter 3,we developed a simple and low cost method using a glucose meter as a detector and glucose-encapsulated liposome as a probe for the detection of PLC.Firstly,glucose-encapsulated liposome were synthesized by a reversed-phase evaporation method.Then,after PLC is added to the liposome,PLC hydrolyzes the liposomes immediately,leading to the release of the encapsulated glucose from the nanoliposomes,which can be quantitatively determined via a personal glucometer.The experiment results showed that glucometer readout was in good linearity with the concentration of PLC in the range of 10?100 U/L with the detection limit of 2.3 U/L.The detection limit of this method is lower than the detection limit of the method of detecting PLC activity previously reported,this approach was used to detect PLC with good sensitivity. |
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