Research On Artificial Cell Intercellular Signaling And Sensing Systems

There are complex stimulus and responding communication mechanisms between cells and cells,which lead to many life processes and phenomena.Therefore,the establishment of biomimetic system to simulate the transfer of small molecules between cells and signal transmission process will help to promote the understanding of life phenomena.Traditionally,the researches of biomimetic signal transduction were mainly focused on the surface of liposome vesicle to build a signal reception,transfer or conversion on the molecular level.In this paper,the artificial biomimetic cell A,which is a nano-reactor with thermo-sensitive on/off characteristics,is used to realize the reaction and transmission of small molecules controlled by the hot-channel,and then a novel biomimetic transmission and conduction system of artificial bionic cells was constructed by controlling the on/off of the fluorescent signal by artificial cell B with the sensing property of 4-AP.In this study,we designed a cell membrane with thermo-sensitive,magnetic and reactive nucleus as the core,Au nanoparticles as the catalyst.On kind of artificial cell B with a biosensor as the acceptor cells.Thus,a biomimetic system of mass transfer and signal transduction can be monitored by the the high sensitivity of fluorescence.The main work of this thesis is as follows:(1)Fe3O4 magnetic nanoparticles with excellent dispersibility was prepared by solvothermal method as the cell nucleus of nano-reactors(artificial cell A).Amino groups were introduced on the surface of Fe3O4 microspheres by silane coupling agent(APTES).AuNPs were prepared by reduction of chloroauric acid with sodium citrate and immobilized on the surface of Fe3O4 microspheres.Therefore,the magnetic catalytic structure unit Fe3O4/Au was prepared.Then,a layer of SiO2 was loaded on the surface of the hybrid microspheres by Stober method,and the double bond is introduced by 3-methacryloxypropyltrimethoxysilane(MPS).Then,NIPAM was used as monomer to introduce a layer of thermo-sensitive porous membrane.After etching the middle SiO2 layer with HF,the artificial cell A with Fe3O4 magnetic nanospheres as the nucleus,AuNPs as the reaction center and thermo-sensitive PNIPAM as the cell membrane was obtained.(2)One kind of 4-AP sensor was designed,and constructed a high sensitivity detection method to 4-AP.SiO2 nanospheres were prepared by Stober method,After the surface double bond was introduced by silane coupling agent MPS,the(4-VP)as the monomer and divinylbenzene(DVB)as the crosslinking agent.The polymerization was initiated on the surface of SiO2 microspheres,and the core-shell microspheres were prepared with(4-vinylpyridine)(P4-VP)was packaged SiO2 microspheres surface.After the SiO2 core was etched with HF,the mercaptopropionic acid MPA-stabilized CdTe quantum dots were assembled on the surface of the hollow microcapsules to obtain fluorescent artificial cell B.(3)The process of mass transfer and signal transduction of small molecule 4-AP in different artificial cells was investigated.The closure of the artificial A cell porous switch was controlled by adjusting the temperature to control the transfer of the product 4-AP between cells.And the presence of 4-AP was detected by the combination of 4-AP and artificial cell B according to the change of fluorescence intensity.