Nanomotor-based biocatalytic patterning of helical metal microstructures

Abstract

A new nanomotor-based surface-patterning technique based on the movement of a magnetically powered enzyme-functionalized flexible nanowire swimmer offers the ability to create complex helical metal microstructures.There has been a considerable recent interest in synthetic nanomotors, based on different propulsion mechanisms, owing to their great promise for a wide range of future technological applications. 1-10 Self-propelled nano/microscale machines have demonstrated considerable potential for performing diverse operations and important tasks, ranging from isolation of biomaterials, 11 nanotool-based drilling, 12 delivery of therapeutic payloads, 13 to environmental remediation. 14 This communication reports on the use of exible magnetic nanowire swimmers for biocatalytic patterning of complex surface microstructures. The preparation of well-dened surface micro/ nanostructures represents an important goal of microfabrication. Tip-based scanning-probe (SP) techniques have been extremely useful for depositing chemical or biological materials onto at substrates. 15 Such tip-based SP fabrication methods commonly rely on the controlled movement of a functionalized tip along predetermined paths for a localized surface modication. Willner et al. [16][17][18][19] have demonstrated the successful combination of Dip-PenNanolithography (DPN) and biocatalytic inks for generating Au or Ag nanowires in connection with the deposition of glucose oxidase (GOx) or alkaline-phosphatase lines, respectively. However, patterning of three-dimensional structures with high topological complexity of a helix represents a major fabrication challenge even with advanced lithographic techniques such as DPN. [16][17][18][19] Recent advances in nanomotors have facilitated the realization of the new nanomotor-based direct biocatalytic patterning method.These include the ability to navigate the motors along predetermined complex paths, to control and regulate their speed, to functionalize them with different biological or chemical entities, and to move them rapidly over large areas. 20,21 Previous studies reported that HRP-functionalized catalytic nanowire motors can be used for writing localized polymeric lines. 22 However, the limited propulsion of these catalytic nanomotors in high-ionic strength environments and the peroxide-fuel requirement hinder the applications of these nanomotors. 23 Similar to different tip-based SP fabrication techniques, 15 nanomotors based on different propulsion and guidance mechanisms could be employed for creating a variety of surface microstructures. Various microstructures, made of different materials (polymers, metals, etc.), can thus be fabricated on conducting and insulating substrates based on a judicious choice of the reactants and the specic reaction involved. In view of the 'large' (submicrometer) size of catalytic nanomotors, compared to common SP tips, the new nanomotor 'writing' method is currently limited to the creation of microscale surface features.This study illustrates for the rst time th...

Fabrication of Micro/Nanoscale Motors

“…Given the strong interaction of sulfur atoms with gold, gold is often used as a surface for the formation of SAM. 231 The interaction of biotin and streptavidin has been widely exploited in biotechnology. On the basis of strong noncovalent interactions, a self-assembled monolayer of biotin-terminated disulfide at the Au end was used to bind streptavidin-coated cargo via the specific biotin−streptavidin interaction.…”

Polymersome magneto-valves for reversible capture and release of nanoparticles

“…Some of the most promising applications are the use of magnetic fields as external stimuli in drug delivery (magnetically triggered drug release system)67891011, magnetic steering and/or propulsion121314151617181920 or in imaging applications through magnetic resonance imaging16212223. Magnetic fields affect all matter and its effect depends not only on the magnetic properties of the material (ferromagnetic, paramagnetic or diamagnetic) but also on the type of the magnetic field applied (homogeneous, inhomogeneous or rotating field)19.…”

Selecting for Function: Solution Synthesis of Magnetic Nanopropellers

“…29 Other potential applications include fluid mixing at low Reynolds numbers and local rheological probes. 10 Production of our nanopropellers is simple, cheap, and scalable and thus of particular interest to large-scale applications, such as micropatterning of large surfaces 30 and environmental remediation. 31 …”