title: Polymer-based tubular microbots: role of composition and preparation.
abstract: The influence of the composition and electropolymerization conditions upon the propulsion of new template-prepared polymer-based bilayer microtubular microbots is described. The effects of different electropolymerized outer layers, including polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), and of various inner catalytic metal surfaces (Ag, Pt, Au, Ni-Pt alloy), upon the movement of such bilayer microtubes are evaluated and compared. Electropolymerization conditions, such as the monomer concentration and medium (e.g. surfactant, electrolyte), have a profound effect upon the morphology and locomotion of the resulting microtubes. The most efficient propulsion is observed using PEDOT/Pt microbots that offer a record-breaking speed of over 1400 body lengths s(-1) at physiological temperature, which is the fastest relative speed reported to date for all artificial micro/nanomotors. An inner Pt-Ni alloy surface is shown useful for combining magnetic control and catalytic fuel decomposition within one layer, thus greatly simplifying the preparation of magnetically-guided microbots. Polymer-based microbots with an inner gold layer offer efficient biocatalytic propulsion in low peroxide level in connection to an immobilized catalase enzyme. Metallic Au/Pt bilayer microbots can also be prepared electrochemically to offer high speed propulsion towards potential biomedical applications through functionalization of the outer gold surface. Such rational template preparation and systematic optimization of highly efficient microbots hold considerable promise for diverse practical applications.
authors.affiliation: Department of Nanoengineering, University of California San Diego, San Diego, CA 92093, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Sirilak
authors.initials: S
authors.lastname: Sattayasamitsathit
authors.forename: Aysegul
authors.initials: A
authors.lastname: Uygun
authors.forename: Allen
authors.initials: A
authors.lastname: Pei
authors.forename: Adam
authors.initials: A
authors.lastname: Ponedal
authors.forename: Joseph
authors.initials: J
authors.lastname: Wang
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D055616:Microtechnology / Q000379:methods*; D008954:Models, Biological; D043942:Nanotubes / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry; D012371:Robotics / Q000295:instrumentation*; D013876:Thiophenes / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D011108:Polymers; D011758:Pyrroles; D013876:Thiophenes; C121383:poly(3,4-ethylene dioxythiophene); C416807:polyaniline; C066730:polythiophene; C067635:polypyrrole; D010984:Platinum; D006046:Gold