Biomolecule-assisted Fabrication And Application Of Nano-architectured Conducting Polypyrrole

Conductive polymers(CPs)have conductivity reaching to semiconductor and possess good chemical stability biocompatibility.CPs are versatile candidates of biomaterials.Dopant plays an important role in study of CPs and could control the structure and the function of CPs.In this work,dopamine and biotin,as dopant,were incorporated into polypyrrole(PPy)to assist the fabrication of nanostructure.Finally,nanostructured PPy were applied in biomaterials.Firstly,dopamine was incorporated into PPy.A PPy/PDA nano-fibers coating was synthesized on the biomedical titanium.The different PPy/PDA nano-architectured coatings were fabricated on titanium when the pH of electrolyte,current density the concentration of dopamine was changed.The possible fabrication schematic of PPy/PDA nano-fibers was proposed based on the microtopography,crystalline texture and chemical composition.The DA monomers were electropolymerized to PDA chains that were attached to biomedical titanium after the potential was triggered.It is known that Py can form various oligomers and further orderly self-assemble or randomly aggregate.Thus,during the nucleation process,if the solution environment favors hydrogen bonding to form PPy and PDA complexes,PDA chains might promote nano-micelles to self-assemble,resulting in the formation of well-ordered nano-fibers approximately 180 nm in diameter.Because of(a)the higher specific surface area and(b)smoother electron flow in oriented nanostructured matrix,PPy nanowires could promote the electron transmission.Resistance of nanowires is 107 ?·cm2.Secondly,the PPy/PDA nano-fibers coatings possess outstanding bioactivity.Because of(a)the higher specific surface area and(b)abundant free catechols on PPy/PDA nanowires,the PPy/PDA nano-fibers could promote deposition of hydroxyapatite,accelerate the adhesion of protein and adhesion and spreading of cell.Finally,the PPy/biotin nano-cones were fabricated and applied to capture and release cancer cell.The nano-cones possess versatile reversible redox.Their oxidation potential is-0.167 V and reduction potential is-0.408 V.Based on the BSA technology,EpCAM was grafted onto the surface of nano-cones coatings.After being grafted EpCAM,the PPy/biotin nano-cones could capture EpCAM-positive cancer cell,but difficultly capture EpCAM-negative cancer cell.After electric simulation,the captured cancer cell could be released.In conclusion,biomolecular were incorporated into PPy to synthesize nanostructure.The nano-architectured PPy were applied to promote the osteointegration of titanium implant and capture/release of cancer cell.