Highly Efficient Catalytic Microengines: Template Electrosynthesis of Polyaniline/Platinum Microtubes

Highly efficient catalytic microtubular engines are synthesized rapidly and inexpensively using an electrochemical growth of bilayer polyaniline/platinum microtubes within the conically shaped pores of a polycarbonate template membrane. These mass-produced microtubular engines are only 8 μm long, are self-propelled at an ultrafast speed (of over 350 body lengths s^(–1)), and can operate in very low levels of the hydrogen peroxide fuel (down to 0.2%). The propulsion characteristics and optimization of these microtubular engines are described, along with their efficient operation in different biological environments which holds great promise for biomedical applications

Efficient bubble propulsion of polymer-based microengines in real-life environments

Template-electrodeposited polymer/Pt microtube engines display efficient propulsion in a wide range of real-life samples ranging from seawater to human serum. Remarkably high speeds are observed in fuel-enhanced raw serum, apple juice, seawater, lake and river water samples. Our results indicate that polymer-based microengines hold considerable promise for diverse practical applications and that real samples exert different effects upon propulsion of different bubble-propelled microtube engines

Hybrid Nanomotor: A Catalytically/Magnetically Powered Adaptive Nanowire Swimmer

A synthetic hybrid nanomotor, which combines chemically powered propulsion and magnetically driven locomotion, is described. The new catalytic–magnetic nanomotor consists of a flexible multisegment Pt-Au-Agflex-Ni nanowire, with the Pt-Au and Au-Agflex-Ni portions responsible for the catalytic and magnetic propulsion modes, respectively. The experimental data and theoretical considerations indicate that the hybrid design only minimally compromises the individual propulsion modes. Rapid and convenient switching from the catalytic to the magnetic mode is illustrated. The resulting catalytic–magnetic adaptive nanomotor can address the fuel depletion and salt limitation common to chemically powered motors by switching to magnetic propulsion. Reversal of the motion direction is also achieved upon applying the magnetic field. Such use of two sources to power a hybrid device offers a broader scope of operation and holds considerable promise for designing adaptive nanovehicles that reconfigure their operation in response to environmental changes or unexpected events

Highly Efficient Catalytic Microengines: Template Electrosynthesis of Polyaniline/Platinum Microtubes

Highly efficient catalytic microtubular engines are synthesized rapidly and inexpensively using an electrochemical growth of bilayer polyaniline/platinum microtubes within the conically shaped pores of a polycarbonate template membrane. These mass-produced microtubular engines are only 8 μm long, are self-propelled at an ultrafast speed (of over 350 body lengths s^(–1)), and can operate in very low levels of the hydrogen peroxide fuel (down to 0.2%). The propulsion characteristics and optimization of these microtubular engines are described, along with their efficient operation in different biological environments which holds great promise for biomedical applications

Examining Biased Assimilation of Brand-related Online Reviews

This paper examines the impact of pre-existing brand attitudes on consumer processing of electronic word-of-mouth (eWOM). This topic is particularly important for brands that simultaneously possess strongly pronounced proponents as well as opponents. Two experimental studies using univalent (study 1, N = 538) and mixed (study 2, N = 262) sets of online reviews find indications for biased assimilation effects of eWOM processing. Consumers perceive positive (negative) arguments in online reviews as more (less) persuasive when having a positive (negative) attitude towards the brand. Perceived persuasiveness in turn influences behavioral intentions and acts as a mediator on the relationship between attitude and behavioral intentions. We examine two moderators of this effect. When priming individuals to focus on other consumers (vs. a self-focus prime), the biased assimilation effect is weaker (study 3a, N = 131). In contrast, we show that biased assimilation becomes stronger under conditions of high (vs. low) cognitive impairment (study 3b, N = 124). Our findings contribute to the literature on the relationship between eWOM and brands and advance our understanding of potential outcomes of brand polarization

Hybrid Nanomotor: A Catalytically/Magnetically Powered Adaptive Nanowire Swimmer

A synthetic hybrid nanomotor, which combines chemically powered propulsion and magnetically driven locomotion, is described. The new catalytic–magnetic nanomotor consists of a flexible multisegment Pt-Au-Agflex-Ni nanowire, with the Pt-Au and Au-Agflex-Ni portions responsible for the catalytic and magnetic propulsion modes, respectively. The experimental data and theoretical considerations indicate that the hybrid design only minimally compromises the individual propulsion modes. Rapid and convenient switching from the catalytic to the magnetic mode is illustrated. The resulting catalytic–magnetic adaptive nanomotor can address the fuel depletion and salt limitation common to chemically powered motors by switching to magnetic propulsion. Reversal of the motion direction is also achieved upon applying the magnetic field. Such use of two sources to power a hybrid device offers a broader scope of operation and holds considerable promise for designing adaptive nanovehicles that reconfigure their operation in response to environmental changes or unexpected events

Magnetically Powered Flexible Metal Nanowire Motors

Fuel-free magnetically driven propulsion of flexible Au/Ag/Ni nanowires, with a gold ‘head’ and nickel ‘tail’, linked by a partially dissolved and weakened silver bridge, is described. The flexible bridge facilitates the cyclic mechanical deformations under an external rotating magnetic field. Under such a field the nickel segment starts to rotate, facilitating the rotation of the gold segment at a different amplitude, hence breaking the system symmetry and inducing the movement. Forward (‘pushing’) and backward (‘pulling’) magnetically powered locomotion and a precise On/Off motion control are achieved by tailoring the length of the nickel and gold segments and modulating the magnetic field, respectively. Efficient locomotion in urine samples and in high-salt media is illustrated. The new magnetic nanowire swimmers can be prepared in large scale using a simple template electrodeposition protocol and offer considerable promise for diverse practical applications

Magnetically Powered Flexible Metal Nanowire Motors

Fuel-free magnetically driven propulsion of flexible Au/Ag/Ni nanowires, with a gold ‘head’ and nickel ‘tail’, linked by a partially dissolved and weakened silver bridge, is described. The flexible bridge facilitates the cyclic mechanical deformations under an external rotating magnetic field. Under such a field the nickel segment starts to rotate, facilitating the rotation of the gold segment at a different amplitude, hence breaking the system symmetry and inducing the movement. Forward (‘pushing’) and backward (‘pulling’) magnetically powered locomotion and a precise On/Off motion control are achieved by tailoring the length of the nickel and gold segments and modulating the magnetic field, respectively. Efficient locomotion in urine samples and in high-salt media is illustrated. The new magnetic nanowire swimmers can be prepared in large scale using a simple template electrodeposition protocol and offer considerable promise for diverse practical applications

Self-Propelled Carbohydrate-Sensitive Microtransporters with Built-In Boronic Acid Recognition for Isolating Sugars and Cells

A new nanomotor-based target isolation strategy, based on a “built-in” recognition capability, is presented. The concept relies on a poly(3-aminophenylboronic acid) (PAPBA)/Ni/Pt microtube engine coupling the selective monosaccharide recognition of the boronic acid-based outer polymeric layer with the catalytic function of the inner platinum layer. The PAPBA-based microrocket is prepared by membrane-templated electropolymerization of 3-aminophenylboronic acid monomer. The resulting boronic acid-based microengine itself provides the target recognition without the need for additional external functionalization. “On-the-fly” binding and transport of yeast cells (containing sugar residues on their wall) and glucose are illustrated. The use of the recognition polymeric layer does not hinder the efficient propulsion of the microengine in aqueous and physiological media. Release of the captured yeast cells is triggered via a competitive sugar binding involving addition of fructose. No such capture and transport are observed in control experiments involving other cells or microengines. Selective isolation of monosaccharides is illustrated using polystyrene particles loaded with different sugars. Such self-propelled nanomachines with a built-in recognition capability hold considerable promise for diverse applications