Research On Nano-aptasensor For Detection Of Alpha-fetoprotein

Alpha fetoprotein?AFP?,a plasma protein produced by the yolk sac and secreted from the liver during fetal life,is an important clinical tumor marker for hepatocellular carcinoma?HCC?,and the concentration of AFP in human serum is closely related to the stage of HCC.Therefore,the rapid,sensitive and accurate analytical method for AFP detection is of great significance for the early clinical diagnosis and the long-term treatment.In this research,two types of nano-aptasensors for AFP detection have been proposed with AFP aptamer as recognition molecules.The main content was as follows:?1?The nano-aptasensor based on a real time LAPS system has successfully fabricated for AFP detection.The nano-aptasensor mainly consisted of four parts:LAPS substrate,light source driving circuit,signal detection circuit and Labview acquisition platform.The nano-aptasensor combined with LAPS system was constructed for AFP detection using layer-by-layer self-assembly technique,AFP aptamer as as recognition molecules to construct the biosensing membrane.The X-ray photoelectron spectrometer?XPS?and scanning electron microscope?SEM?were used to observe the elemental content and morphology of the surface of silicon wafers at different modification stages.The experimental results showed that the linearity of LAPS nano-aptasensor between the bias voltage??V?and the concentration of AFP was very well in the range of 0.1-100?g/m L.The linear regression equation was Y_?mV?=2.5892X_??g/mL?+103.42778?Y is the voltage offset,X is the AFP concentration?,with the correlation coefficient of 0.9959.The sensitivity was calculated to be 2.5892 mV per gland AFP concentration??g/mL?.All the results have shown that the LAPS nano-aptasensor has strong anti-interference ability and high sensitivity.?2?An AFP nano-aptasensor based on TH/RGO/Au NPs was designed with layer-by-layer self-assembly technique,using AFP aptamer as recognition molecules and thionin/reduced graphene oxide/gold nanoparticles?TH/RGO/Au NPs?as the sensor platform.With high electrocatalytic property and large specific surface area,RGO and Au NPs were used to load TH molecules on the screen-printed carbon electrod.The TH not only acted as a bridging to effectively capture AFP aptamer,but as the electron transfer mediator to provide the electrochemical signal.The quantitative detection of AFP was measured by the differential pulse voltammetry?DPV?.Under optimal conditions,the current of aptasensor depended linearly on the concentration of AFP in the range of0.1-100?g/m L with the linear regression equation was Y_??A?=0.3471X_??g/mL?+47.984and the regression correlation coefficient of 0.9987.The detection limit was estimated to be 0.050?g/m L at a signal-to-noise of 3.The recovery of real human surum was between101.52%and 107.95%which could meet the needs of the actual sample detection.