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

Bubble-Propelled Micromotors for Enhanced Transport of Passive Tracers

Fluid convection and mixing induced by bubble-propelled tubular microengines are characterized using passive microsphere tracers. Enhanced transport of the passive tracers by bubble-propelled micromotors, indicated by their mean squared displacement (MSD), is dramatically larger than that observed in the presence of catalytic nanowires and Janus particle motors. Bubble generation is shown to play a dominant role in the effective fluid transport observed in the presence of tubular microengines. These findings further support the potential of using bubble-propelled microengines for mixing reagents and accelerating reaction rates. The study offers useful insights toward understanding the role of the motion of multiple micromotors, bubble generation, and additional factors (e.g., motor density and fuel concentration) upon the observed motor-induced fluid transport

Bubble-Propelled Micromotors for Enhanced Transport of Passive Tracers

Fluid convection and mixing induced by bubble-propelled tubular microengines are characterized using passive microsphere tracers. Enhanced transport of the passive tracers by bubble-propelled micromotors, indicated by their mean squared displacement (MSD), is dramatically larger than that observed in the presence of catalytic nanowires and Janus particle motors. Bubble generation is shown to play a dominant role in the effective fluid transport observed in the presence of tubular microengines. These findings further support the potential of using bubble-propelled microengines for mixing reagents and accelerating reaction rates. The study offers useful insights toward understanding the role of the motion of multiple micromotors, bubble generation, and additional factors (e.g., motor density and fuel concentration) upon the observed motor-induced fluid transport