Thermoelastic Property Of DNA Adsorption Film And Its Detection Signal Of Microbeam

Taking DNA-microbeam in label-free biological detection as the research object,by using the updated Parsegian's liquid crystal theory,thought experiment method,deformation equivalent method,and nonlinear elastic network model,we quantitatively characterize thermoelastic properties of DNA film,and establish the cross-scale models correlating microscopic interaction between DNA strands,thermoelastic properties of DNA film and microbeam detection signals,thereout the effects of temperature,packaging pattern,and different salt solutions on the elastic modulus,prestress,thermal expansion coefficient of DNA film and their influence on detection signals of microbeam were studied.The relevant methods,models and conclusions not only enrich the theoretical framework of laminated beams(biological-nonbiological layer),but also provide new technical references for the development of biological detection field.The main works are as follows:(1)Based on Parsegian's empirical potential,the macroscopic continuum elastic modulus and prestress of DNA adsorption film were characterized by the thought experiment method;thereout the equivalent laminated beam model of DNA filmsubstrate was established.Combined with the previous multi-scale model of DNA liquid crystal-substrate,a cross-scale analytical model for predicting the thermal expansion coefficient of DNA adsorption film was given by the deformation equivalent method.Meanwhile,the temperature change experiment of DNA-microbeam was conducted.The results reveal that the complex solution environment affects the microscopic interactions between DNA strands,and the monotonic or non-monotonic change in configuration entropy determines the thermoelastic properties of DNA adsorption film.Moreover,the experimental results are in good agreement with the model predictions in this chapter.(2)Breaking through the limitation of classical self-assembled pattern and considering the development of new nano-grafting technology,a model for predicting the thermoelastic properties of DNA film with concave-angle honeycomb packaging patterns was proposed;thereout,the dynamic frequency shift of microbeam caused by DNA adsorption,and the temperature fluctuation effect on the static deflection signals of microbeam were studied,respectively.The results reveal that the packaging pattern affects the fluctuation range of thermoelastic properties of DNA film;and the concaveangle honeycomb packaging pattern not only enhances the dynamic detection ability of microcantilever,but also weakens the temperature disturbance on the static detection signals of microcantilever.(3)Based on Parsegian's empirical potential and the attraction version in high salt solution,a new mesoscopic DNA liquid crystal potential has been developed to realize the unitization of the potential models for DNA liquid crystal under the conditions from low-valence to high-valence salt solutions,to a certain extent.By using the above models for predicting the thermoelastic properties of DNA film and the analytical models for the static and dynamic responses of DNA-microbeam,we studied the effect of packaging patterns in high-valent salt solutions on the static and dynamic signals of microbeam under the combined action of adsorption and temperature change.The results reveal that microscopic attraction incurs negative elastic modulus and positive prestress;and the complex DNA interchain interactions affect the responses of microbeam induced by adsorption and temperature effects;moreover,the specific boundary condition,packing pattern and its cell size can improve the abilities of microbeam in recognizing DNA molecules and resisting temperature noise.These insights provide some references and new ideas for the design of microbeam detection in high-valence salt solution.