The Preparation, Characterization And Application Of Thermo-responsive Polymer Brushes

The so-called polymer brushes refers to polymer chain with a certain density, ofwhich one of the chain end is chemically or non-chemically anchored to the substratesurface to form a structure with special polymer structure. There is an increasinginterest of preparing polymer brushpatterns on solid substrates, especially in anano-scale, to tailortheir surface properties such as adsorption behavior, wetability,friction, and thermal stability.With advances in medical technology, Tissue engineering is thought to be a verypromising therapies for patients suffer from seriousdiseases. however, for theconventional biological tissue engineering, which use biodegradablescaffolds as cellsupport,has meet its end by the disadvantage of the polymer scaffolds itself. By usingENVIROMENTAL-responseculture dishes, Newly cell sheet engineering can avoidsunnecessary troubles caused by the biodegradable stents.By changing the culturetemperature, cultured cells can be harvested as intact sheetswithout the use of enzymes,which maintain the activityand the structure of cells at the same time. Since noadditional material was introduced, the complications caused by those implantedpolymer materials in former tissue engineering technique could be eliminated.It’s asignificant advantage for cell sheet engineering.In this article, By using self-assembled monolayer technique, weon gold-platedsilicon surface mount technology monolayer lead agent; in situ grafting the PNIPAAMbrushes from the initiator monolayer on gold-plated silicon surface;by cell adhesionexperiment, Hela PNIPAAM brushes the surface of cells in the prolifertion, migrationand other acts; nondestructive get Hela cell sheet, the main work consists of thefollowing four parts:Preparation of monolayer: By micro-contact printing method, the wafer platingsurface of the microarray successful assembly DTBU initiator monolayer binding XPS,optical microscope observation characterization methods, micro-contact printing proofthe reliability of preparing the DTBU monolayer.Synthesis of polymer brush: The premise of successful grafting initiatormonolayer, in conjunction with surface-initiated polymerization, success in situ graftthe PNIPAAM brushes on the surface of gold. Characterized by a variety of means suchas XPS, AFM, EDS, optical microscopy and SEM, demonstrate that the combination ofself-assembled monolayer technology and surface-initiated polymerization is a veryeffective way forsynthesizing polymer brushes microarrays. the molecular weight ofpolymer brush is linearly with the polymerization time and prove that thepolymerization reaction is a controllable polymerization.Cell behavior on polymer brush: On the basis of grafting polymer brushesPNIPAAM microarrays,By culturingHela cell on the substrate, Using microscopy and other testing method, we find that Hela can absorb, spread and proliferate on PNIPAAMbrush. And by changing the culture temperature, the Hela cells can isolatefrom thesubstrate surface spontaneously, intact sheets cell sheets can be harvestedand lay afoundation for the cell sheet engineering.The PNIPAAM polymer brush prepared this article will have a promisingapplication in the field of cell sheet engineering, micro-electronics and biomedicalmaterials in future.