Application Research On QCM Immunosensor Technology In Cervical Precancer Detection

Quartz crystal microbalance（QCM） is a high sensitive mass sensor with detection limit at the nanogram level. Since the QCM has the advantage of low detection cost, simple structure, fast detection speed, it was widely used in the area of physics, chemistry, biology, medicine. QCM immunosensors which combines the high sensitive piezoelectric effect of quartz crystal and high specific recognition of immune reaction has aroused the extensive attention of researchers and was widely used in the area of food hygiene, environmental detection and medical diagnosis.Cervical cancer ranks the second leading cause of cancer deaths among women worldwide, however it is one of the most easily prevented cancers, and has a relatively good prognosis when diagnosed and treated early. But it has no apparent clinical symptoms during the pre-cancer piorode, if only rely on clinical symptoms to diagnose of cervical pre-cancer lesion cannot promptly early diagnosis, lead to illness delay. Therefore, it is important to develop a new method with high specificity and high sensitivity for the prevention of cervical cancer.Through exploration of the detection mechanism of QCM, a novel method based on piezoelectric immunosensors technique for cervical pre-cancer lesion detection was presented. The experiment system for cervical pre-cancer lesion detection was established by in-depth analysis of various factors affecting the mass sensitivity, and the experimental method which is most suitable to this experiment system was designed. the reasonability and validity of this experiment system for cervical pre-cancer detection was proved by clinical examination. The main works and innovation points in this paper are as follows:（1） The mass detection mechanism of QCM is in-depth studied. The reason why QCM has high mass sensitivity is revealed. The influence of different radius, thickness and shape of electrode on mass sensitivity of QCM is carefully studied through the perspective of the vibration amplitude of particle on the surface of quartz resonator, then, the methods to improve value and uniformity of mass sensitivity are proposed. The study on the mass detection mechanism provides a comprehensive theoretical support for the application of QCM.（2） The preparation method of the specific sensing membrane for the detection of cervical precancerous lesions is analyzed. The various methods for prepatating specific sensing membrane are in-depth studied. The effects of environmental temperature, incubation time and antibody concentration on the immobilization efficiency, stability and immune activity of the sensing membrane are studied. Finally, the most suitable preparation method and the preparation conditions of the specific membrane to cervical precancerous lesions detection are proposed.（3） A normal method for cervical pre-cancer detection based on QCM is proposed. A piezoelectric immunosensor was developed for the detection of p16^INK4a for different clinical samples that obtained form the West China Second University Hospital. The experimental data indicating that the content of p16INK4 A in liquid-based cervical cytology specimens is closely related to severity of cervical lesion, greater the severity of lesion grading is, the greater p16^INK4a becomes. it can be clearly observed that the range of p16^INK4a content for different lesion degrees showed significant difference（p<0.05） and have statistical significance. Therefore, by detecting the content of P16^INK4a protein in the clinical sample, the degree of cervical lesions can be determined. Futhermore, the level of p16INK4 A expression of cervical cytology specimens was distinctly correlated with the biopsy results. Finally, the method was tested for specificity, stability and detection limit, which provided the basis for the clinical research.