Study Of The Interaction Force Between Nucleic Acid Aptamer And Biological Molecular As Well As Its Detection Based On Microcantilever Array

In this dissertation, the interaction force between molecules was studied based on microcantilever array, thus achieve the purpose of detection. Detailed study a single binding protein (SSBP) and the interaction of single-stranded DNA (ssDNA); Research the oxytetracycline (OTC) specific Aptamer (OTC-Aptamer) interact with over-the-counter (OTC). The interaction between thrombin and thrombin specific aptamer was studied. The main content is as follows:1. The ssDNA modified microcantilever was developed by carbodiimide attachment of the5’-the HS-(CH2)6T70-3’ onto the surface of the cantilever. The interaction of ssDNA with SSBP was studied. The study found that the cantilever deflection level is associated with the concentration of SSBP, the degree of cantilever deflection changed more faster with the higher concentration of SSBP, and induced greater the degree of cantilever deflection; When ventilation with bovine serum albumin and dissolve the non-specific proteins such as enzymes, deflection of cantilever is not clearly. Experimental results show that the ssDNA modified cantilever of SSBP is wide response range, minimum concentration of response was0.008μg mL-1.2. The interaction of OTC specific aptamer (5’-GGA ATT CGC TAG CAC GTT GAC GCT GGT GCC CGG TTG TGG TGC GAG TGT TGT GTG GAT CCG AGC TCC ACG TG-(CH2)6-SH-3’) with OTC was studied by a microcantilever array in a flowing cell. Experimental results show that the concentrations of OTC cantilever deflection caused by the higher level. As we know the OTC structure is very similar to tetracycline, doxycycline, etc. But these material will not cause obvious deflection of cantilever. To verify the effective regeneration of cantilever array sensor, the cantilever array was treated with2M NaCl after OTC binding. Then OTC with the same concentration was injected again after each regeneration step. The microcantilever array is still showed a greater response and has good repeatability. The aptamer modified microcantilever array is a very good OTC sensor with high sensitivity and selectivity and detection limit of0.2nM. 3. The thrombin specific aptamer modified microcantilever was developed by carbodiimide attachment of the5’-SH-(CH2)6-GGT TGG TGT GGT TGG-3’ onto the surface of the cantilever. The interaction of thrombin specific aptamer with Thrombin was studied by a microcantilever array in a flowing cell. But different from the traditional detection method, microcantilever array detection technology is a label-free detection method, which can obtain real-time information about the interaction between thrombin and thrombin specific aptamer. The experimental results show that aptamer modified microcantilever array is a very good thrombin sensor with high specificity and sensitivity.It is demonstrated that the cantilever array sensors can be used as a powerful tool to detect drugs with high sensitivity and selectivity.