Artificial Enzyme-Powered Microfish for Water-Quality Testing

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC₅₀ (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing

Artificial Enzyme-Powered Microfish for Water-Quality Testing

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC₅₀ (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing

Artificial Enzyme-Powered Microfish for Water-Quality Testing

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC₅₀ (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing

Artificial Enzyme-Powered Microfish for Water-Quality Testing

We present a novel micromotor-based strategy for water-quality testing based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants. The new micromotor toxicity testing concept mimics live-fish water testing and relies on the toxin-induced inhibition of the enzyme catalase, responsible for the biocatalytic bubble propulsion of tubular microengines. The locomotion and survival of the artificial microfish are thus impaired by exposure to a broad range of contaminants, that lead to distinct time-dependent irreversible losses in the catalase activity, and hence of the propulsion behavior. Such use of enzyme-powered biocompatible polymeric (PEDOT)/Au-catalase tubular microengine offers highly sensitive direct optical visualization of changes in the swimming behavior in the presence of common contaminants and hence to a direct real-time assessment of the water quality. Quantitative data on the adverse effects of the various toxins upon the swimming behavior of the enzyme-powered artificial swimmer are obtained by estimating common ecotoxicological parameters, including the EC₅₀ (exposure concentration causing 50% attenuation of the microfish locomotion) and the swimmer survival time (lifetime expectancy). Such novel use of artificial microfish addresses major standardization and reproducibility problems as well as ethical concerns associated with live-fish toxicity assays and hence offers an attractive alternative to the common use of aquatic organisms for water-quality testing

Molecularly Imprinted Polymer-Based Catalytic Micromotors for Selective Protein Transport

We demonstrate an attractive nanomachine “capture and transport” target isolation strategy based on molecularly imprinted polymers (MIPs). MIP-based catalytic microtubular engines are prepared by electropolymerization of the outer polymeric layer in the presence of the target analyte (template). Tailor-made selective artificial recognition sites are thus introduced into the tubular microtransporters through complementary nanocavities in the outer polymeric layer. The new microtransporter concept is illustrated using bilayer poly­(3,4-ethylenedioxythiophene) (PEDOT)/Pt–Ni microengines and fluorescein isothiocyanate (FITC)-labeled avidin (Av-FITC) as the template. The avidin-imprinted polymeric layer selectively concentrates the fluorescent-tagged protein target onto the moving microengine without the need for additional external functionalization, allowing “on-the-fly” extraction and isolation of Av-FITC from raw serum and saliva samples along with real-time visualization of the protein loading and transport. The new micromachine–MIP-based target isolation strategy can be extended to the capture and transport of other important target molecules, leading toward diverse biomedical and environmental applications

Molecularly Imprinted Polymer-Based Catalytic Micromotors for Selective Protein Transport

We demonstrate an attractive nanomachine “capture and transport” target isolation strategy based on molecularly imprinted polymers (MIPs). MIP-based catalytic microtubular engines are prepared by electropolymerization of the outer polymeric layer in the presence of the target analyte (template). Tailor-made selective artificial recognition sites are thus introduced into the tubular microtransporters through complementary nanocavities in the outer polymeric layer. The new microtransporter concept is illustrated using bilayer poly­(3,4-ethylenedioxythiophene) (PEDOT)/Pt–Ni microengines and fluorescein isothiocyanate (FITC)-labeled avidin (Av-FITC) as the template. The avidin-imprinted polymeric layer selectively concentrates the fluorescent-tagged protein target onto the moving microengine without the need for additional external functionalization, allowing “on-the-fly” extraction and isolation of Av-FITC from raw serum and saliva samples along with real-time visualization of the protein loading and transport. The new micromachine–MIP-based target isolation strategy can be extended to the capture and transport of other important target molecules, leading toward diverse biomedical and environmental applications

Molecularly Imprinted Polymer-Based Catalytic Micromotors for Selective Protein Transport

We demonstrate an attractive nanomachine “capture and transport” target isolation strategy based on molecularly imprinted polymers (MIPs). MIP-based catalytic microtubular engines are prepared by electropolymerization of the outer polymeric layer in the presence of the target analyte (template). Tailor-made selective artificial recognition sites are thus introduced into the tubular microtransporters through complementary nanocavities in the outer polymeric layer. The new microtransporter concept is illustrated using bilayer poly­(3,4-ethylenedioxythiophene) (PEDOT)/Pt–Ni microengines and fluorescein isothiocyanate (FITC)-labeled avidin (Av-FITC) as the template. The avidin-imprinted polymeric layer selectively concentrates the fluorescent-tagged protein target onto the moving microengine without the need for additional external functionalization, allowing “on-the-fly” extraction and isolation of Av-FITC from raw serum and saliva samples along with real-time visualization of the protein loading and transport. The new micromachine–MIP-based target isolation strategy can be extended to the capture and transport of other important target molecules, leading toward diverse biomedical and environmental applications

Molecularly Imprinted Polymer-Based Catalytic Micromotors for Selective Protein Transport

We demonstrate an attractive nanomachine “capture and transport” target isolation strategy based on molecularly imprinted polymers (MIPs). MIP-based catalytic microtubular engines are prepared by electropolymerization of the outer polymeric layer in the presence of the target analyte (template). Tailor-made selective artificial recognition sites are thus introduced into the tubular microtransporters through complementary nanocavities in the outer polymeric layer. The new microtransporter concept is illustrated using bilayer poly­(3,4-ethylenedioxythiophene) (PEDOT)/Pt–Ni microengines and fluorescein isothiocyanate (FITC)-labeled avidin (Av-FITC) as the template. The avidin-imprinted polymeric layer selectively concentrates the fluorescent-tagged protein target onto the moving microengine without the need for additional external functionalization, allowing “on-the-fly” extraction and isolation of Av-FITC from raw serum and saliva samples along with real-time visualization of the protein loading and transport. The new micromachine–MIP-based target isolation strategy can be extended to the capture and transport of other important target molecules, leading toward diverse biomedical and environmental applications

Superhydrophobic Alkanethiol-Coated Microsubmarines for Effective Removal of Oil

We demonstrate the use of artificial nanomachines for effective interaction, capture, transport, and removal of oil droplets. The simple nanomachine-enabled oil collection method is based on modifying microtube engines with a superhydrophobic layer able to adsorb oil by means of its strong adhesion to a long chain of self-assembled monolayers (SAMs) of alkanethiols created on the rough gold outer surface of the device. The resultant SAM-coated Au/Ni/PEDOT/Pt microsubmarine displays continuous interaction with large oil droplets and is capable of loading and transporting multiple small oil droplets. The influence of the alkanethiol chain length, polarity, and head functional group and hence of the surface hydrophobicity upon the oil–nanomotor interaction and the propulsion is examined. No such oil–motor interactions were observed in control experiments involving both unmodified microengines and microengines coated with SAM layers containing a polar terminal group. These results demonstrate that such SAM-Au/Ni/PEDOT/Pt micromachines can be useful for a facile, rapid, and efficient collection of oils in water samples, which can be potentially exploited for other water–oil separation systems. The integration of oil-sorption properties into self-propelled microengines holds great promise for the remediation of oil-contaminated water samples and for the isolation of other hydrophobic targets, such as drugs

Bacterial Isolation by Lectin-Modified Microengines

New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of <i>Escherichia coli</i> (<i>E. coli</i>) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of <i>E. coli</i> with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct, and label-free optical visualization of the captured bacteria and discrimination against nontarget cells