Study On Construction Of Biological Ion Channel-liked Nano-architectured Conducting Polymers And Its Intelligent Switch-behaviors

Life through millions of years of evolution is almost completed all the process ofintelligent control. The biological ion channels, embedded within plasma membrane, aretuned to take on open or closed states (i.e., switch action), controlling permeation of specificsignal ions to the extracellular environment, in response to ambient stimuli. Control of thesechannels is of great importance to the implementation of basic physiological functions such asnutrient transportation and immune response. Bio-spired by biological ion channel, inconjunction with the studies on biomimetic responsive nanochannels and intelligentapplications of conducting polymers, biological ion channel-liked nano-architecturedpolypyrrole (NAPPy, one typical type of conducting polymers) was constructed to study theintelligent switch-behaviors in response to weak potential signal/stimuli, compassing theswitches in wettability, nanotubular structure, ion transport, protein adsorption and cellularactivities.1. Fine-tunability and of functional biomolecule decoration of biological ion channel-liked NAPPy. Based on the PBS as electrolyte and prenucleation film, a template-freeelectrochemical approach was developed and EC-AFM was utilized to realize or study thelarge-area and fine construction of NAPPy on biomedical titanium: the appropriate spreadingbehavior of Py micelles on prenucleation film promoted the formation of sufficient activenucleation sites, which was the premise of large-area construction of NAPPy arrays; fine-tunable self-assembly construction could be completed through the manipulation on theequilibrium between Py micelles and free-Py. Functional biomolecule decoration of biologicalion channel-liked NAPPy: biomolecule played roles not only on decorating NAPPy as dopant,but also on participating in the self-assembly construction of NAPPy through the restrictedspace created by molecular chains or hydrogen bonding; functional biomolecule made NAPPymore bioactive and delivered a more biomimetic surface in terms of chemical compositionand biological function.2. Biological ion channel-liked NAPPy with switch-behaviors of wettability andnanotubular structure. Switch-behaviors of wettability: NAPPy arrays on biomedical titaniumexhibited largest extremes of switch-behavior of wettability compared with other two nano-architectures of NAPPy; switching potentials could reversibly change the concentration ofNSA on NAPPy surface by redox reactions, leading to switch-behaviors of water andunderwater-oil wettability. Switch-behaviors of nanotubular structure: both of NAPPy/NSAand NAPPy/Tau obtained by ion-exchange, showed switch-behavior of nanotubular structure responsive to potential signal, which was due to the switching potential guiding periodicalchanges on nanochannel inner space of by repulsive forces from dopant on inner surface, aswell as the volume variation.3. Biological ion channel-liked NAPPy with switch-behaviors of ion transport. Bio-spiredby volume-regulated anion channel (VRAC), NAPPy was electrochemically constructed oninner channel surface of AAO membrane with aim to more easily analyze the performance ofion transport. Inner diameter of NAPPy, which could be tuned by polymerization time andAAO size, was linearly correlated with the conductance of ion transport; the changes on thearrangement of NAPPy polymeric chain were dependent on the switching potential, whichleaded to the expansion or contraction of NAPPy in AAO (i.e., compression or enlargement ofchannel space of NAPPy), and thus intelligently manipulating the ion transport through theNAPPy and achieving a switch-behavior.4. Biological ion channel-liked NAPPy with switch-behaviors of protein adsorption andcellular activities. On biomedical titanium, template-free electrochemical approach was usedto construct NAPPy doped with a biomolecule, that was, TCA who acted as surfactant-likerole in self-assembly construction of NAPPy/TCA; switching potentials decided the switchingof the orientation between hydrophobic face and hydrophilic face of TCA on the NAPPysurface, and thus showing a switch-behavior of wettability on NAPPy/TCA; the faceorientation of TCA induced the repulsion or attraction of different proteins, which achievedthe preferential adsorption and switch-behaviors; switch-behaviors of MC3T3-E1osteoblastsadhesion and spreading were realized, which was based on switch-behaviors of proteinadsorption; in response to switching potentials, NAPPy/TCA was characterized by excellentswitching stability and biocompatibility.Biological ion channel-liked platform, NAPPy, constructed on biomedical titanium bytemplate-free electrochemical approach, provides an intelligent interface for implant, whichenables us to manipulate the biological response (or switch-behaviors of biological activities)on the implant surface in real time as needed at different implantation stages. This workprovides material platform and scientific reference for the development of intelligentswitching areas, as well as a new choice for intelligent biomimetic decoration of biomedicalmaterials and intelligent application of conducting polymers.