Construction Of Nanomaterials Based Electrochemical Sensors And Applications In Detection Of Tumor Biomarkers

In recent years,with the increase in the number of tumor patients,public interest in early detection and diagnosis of tumors has been increasing.Traditional detection techniques,however,have several drawbacks,including high testing costs,large equipment sizes,the requirement for specialized employees to operate,lengthy examination cycles,and poor image quality.In addition,tumors at the sub-millimeter level are often difficult to detect in a timely manner due to difficulties in accurately locating the location of the patient’s lesion during biopsy,all of which adversely affect the timely diagnosis of early-stage lung cancer.To meet the practical demands of tumor marker detection in lung cancer patients,this thesis prepared and used nanocomposite electrochemical biosensors based on nanomaterials and aptamers.The research includes the following parts:Firstly,a nano-enhanced electrochemical sensor based on black phosphorus-gold nanoclusters and aptamers was designed for the simultaneous detection of two tumor biomarkers:Neuron Specific Enolase(NSE)and Epidermal Growth Factor Receptor(EGFR).The reference and counter electrodes of the sensor are screen printed on a flexible cotton fabric.The working electrode of the sensor is spherical and detachable and is modified with as a nano-matrix to complete the aptamer immobilization and electrode functionalization.Under optimal conditions,the sensor achieved good linearity for a concentration range of 0-400 ng/m L(NSE)and 0-600 ng/m L(EGFR),with detection limits of 0.1 ng/m L(NSE)and 0.6 ng/m L(EGFR),respectively,and linear correlation coefficients of R~2=0.9633(NSE)and R~2=0.9628(EGFR).Secondly,a nano-enhanced electrochemical sensor based on titanium carbide-graphene-gold nanocomposites and aptamers was constructed for the detection of the tumor biomarker NSE.The three-electrode system of the sensor was fabricated on PI film by laser printing,and the working electrode was modified by introducing titanium carbide-gold nanomaterials to complete the immobilization of the aptamer and improve the specificity and sensitivity of the detection.Under optimal conditions,the detection limit of the sensor for NSE was 0.01 ng/m L and the linear correlation coefficient was R~2=0.998 over the concentration range of 0.5～100 ng/m L.In summary,this thesis designs and fabricates high-performance electrochemical biosensors based on nanocomposites and particular aptamers.Material characterization and parameter adjustment have been completed,and it has demonstrated good sensitivity,specificity,stability,and accuracy in the detection of tumor biomarkers,providing a new platform for early diagnosis and screening of lung cancer.