title: Bubble-Free Propulsion of Ultrasmall Tubular Nanojets Powered by Biocatalytic Reactions.
abstract: The motion of self-propelled tubular micro- and nanojets has so far been achieved by bubble propulsion, e.g., O2bubbles formed by catalytic decomposition of H2O2, which renders future biomedical applications inviable. An alternative self-propulsion mechanism for tubular engines on the nanometer scale is still missing. Here, we report the fabrication and characterization of bubble-free propelled tubular nanojets (as small as 220 nm diameter), powered by an enzyme-triggered biocatalytic reaction using urea as fuel. We studied the translational and rotational dynamics of the nanojets as functions of the length and location of the enzymes. Introducing tracer nanoparticles into the system, we demonstrated the presence of an internal flow that extends into the external fluid via the cavity opening, leading to the self-propulsion. One-dimensional nanosize, longitudinal self-propulsion, and biocompatibility make the tubular nanojets promising for future biomedical applications.
authors.affiliation: Max-Planck Institute for Intelligent Systems Institution , Heisenbergstraße 3, 70569 Stuttgart, Germany.|School of Materials Science and Engineering, Harbin Institute of Technology Shenzhen Graduate School , 518055 Shenzhen, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Ma
authors.affiliation: Max-Planck Institute for Intelligent Systems Institution , Heisenbergstraße 3, 70569 Stuttgart, Germany.|Institut de Bioenginyeria de Catalunya (IBEC) , Baldiri i Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Hortelao
authors.affiliation: Institut de Bioenginyeria de Catalunya (IBEC) , Baldiri i Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Miguel-López
authors.affiliation: Max-Planck Institute for Intelligent Systems Institution , Heisenbergstraße 3, 70569 Stuttgart, Germany.|Institut de Bioenginyeria de Catalunya (IBEC) , Baldiri i Reixac 10-12, 08028 Barcelona, Spain.|Institució Catalana de Recerca i Estudis Avancats (ICREA) , Pg. Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: Samuel
authors.initials: S
authors.lastname: Sánchez