Turning Erythrocytes into Functional Micromotors

Attempts to apply artificial nano/micromotors for diverse biomedical applications have inspired a variety of strategies for designing motors with diverse propulsion mechanisms and functions. However, existing artificial motors are made exclusively of synthetic materials, which are subject to serious immune attack and clearance upon entering the bloodstream. Herein we report an elegant approach that turns natural red blood cells (RBCs) into functional micromotors with the aid of ultrasound propulsion and magnetic guidance. Iron oxide nanoparticles are loaded into the RBCs, where their asymmetric distribution within the cells results in a net magnetization, thus enabling magnetic alignment and guidance under acoustic propulsion. The RBC motors display efficient guided and prolonged propulsion in various biological fluids, including undiluted whole blood. The stability and functionality of the RBC motors, as well as the tolerability of regular RBCs to the ultrasound operation, are carefully examined. Since the RBC motors preserve the biological and structural features of regular RBCs, these motors possess a wide range of antigenic, transport, and mechanical properties that common synthetic motors cannot achieve and thus hold considerable promise for a number of practical biomedical uses

Self-Propelled Activated Carbon Janus Micromotors for Efficient Water Purification

Self-propelled activated carbon-based Janus particle micromotors that display efficient locomotion in environmental matrices and offer effective ‘on-the-fly’ removal of wide range of organic and inorganic pollutants are described. The new bubble-propelled activated carbon Janus micromotors rely on the asymmetric deposition of a catalytic Pt patch on the surface of activated carbon microspheres. The rough surface of the activated carbon microsphere substrate results in a microporous Pt structure to provide a highly catalytic layer, which leads to an effective bubble evolution and propulsion at remarkable speeds of over 500 μm/s. Such coupling of the high adsorption capacity of carbon nanoadsorbents with the rapid movement of these catalytic Janus micromotors, along with the corresponding fluid dynamics and mixing, results in a highly efficient moving adsorption platform and a greatly accelerated water purification. The adsorption kinetics and adsorption isotherms have been investigated. The remarkable decontamination efficiency of self-propelled activated carbon-based Janus micromotors is illustrated towards the rapid removal of heavy metals, nitroaromatic explosives, organophosphorous nerve agents and azo-dye compounds, indicating considerable promise for diverse environmental, defense, and public health applications

Self-Propelled Activated Carbon Janus Micromotors for Efficient Water Purification

Self-propelled activated carbon-based Janus particle micromotors that display efficient locomotion in environmental matrices and offer effective ‘on-the-fly’ removal of wide range of organic and inorganic pollutants are described. The new bubble-propelled activated carbon Janus micromotors rely on the asymmetric deposition of a catalytic Pt patch on the surface of activated carbon microspheres. The rough surface of the activated carbon microsphere substrate results in a microporous Pt structure to provide a highly catalytic layer, which leads to an effective bubble evolution and propulsion at remarkable speeds of over 500 μm/s. Such coupling of the high adsorption capacity of carbon nanoadsorbents with the rapid movement of these catalytic Janus micromotors, along with the corresponding fluid dynamics and mixing, results in a highly efficient moving adsorption platform and a greatly accelerated water purification. The adsorption kinetics and adsorption isotherms have been investigated. The remarkable decontamination efficiency of self-propelled activated carbon-based Janus micromotors is illustrated towards the rapid removal of heavy metals, nitroaromatic explosives, organophosphorous nerve agents and azo-dye compounds, indicating considerable promise for diverse environmental, defense, and public health applications

Turning Erythrocytes into Functional Micromotors

Attempts to apply artificial nano/micromotors for diverse biomedical applications have inspired a variety of strategies for designing motors with diverse propulsion mechanisms and functions. However, existing artificial motors are made exclusively of synthetic materials, which are subject to serious immune attack and clearance upon entering the bloodstream. Herein we report an elegant approach that turns natural red blood cells (RBCs) into functional micromotors with the aid of ultrasound propulsion and magnetic guidance. Iron oxide nanoparticles are loaded into the RBCs, where their asymmetric distribution within the cells results in a net magnetization, thus enabling magnetic alignment and guidance under acoustic propulsion. The RBC motors display efficient guided and prolonged propulsion in various biological fluids, including undiluted whole blood. The stability and functionality of the RBC motors, as well as the tolerability of regular RBCs to the ultrasound operation, are carefully examined. Since the RBC motors preserve the biological and structural features of regular RBCs, these motors possess a wide range of antigenic, transport, and mechanical properties that common synthetic motors cannot achieve and thus hold considerable promise for a number of practical biomedical uses

Inter- and intraindividual variability in daily resting heart rate and its associations with age, sex, sleep, BMI, and time of year: Retrospective, longitudinal cohort study of 92,457 adults.

BackgroundHeart rate is routinely measured as part of the clinical examination but is rarely acted upon unless it is well outside a population-based normal range. With wearable sensor technologies, heart rate can now be continuously measured, making it possible to accurately identify an individual's "normal" heart rate and potentially important variations in it over time. Our objective is to describe inter- and intra-individual variability in resting heart rate (RHR) collected over the course of two years using a wearable device, studying the variations of resting heart rate as a function of time of year, as well as individuals characteristics like age, sex, average sleep duration, and body mass index (BMI).Methods and findingsOur retrospective, longitudinal cohort study includes 92,457 de-identified individuals from the United States (all 50 states), who consistently-over at least 35 weeks in the period from March 2016 to February 2018, for at least 2 days per week, and at least 20 hours per day-wore a heart rate wrist-worn tracker. In this study, we report daily RHR and its association with age, BMI, sex, and sleep duration, and its variation over time. Individual daily RHR was available for a median of 320 days, providing nearly 33 million daily RHR values. We also explored the range in daily RHR variability between individuals, and the long- and short-term changes in the trajectory of an individual's daily RHR. Mean daily RHR was 65 beats per minute (bpm), with a range of 40 to 109 bpm among all individuals. The mean RHR differed significantly by age, sex, BMI, and average sleep duration. Time of year variations were also noted, with a minimum in July and maximum in January. For most subjects, RHR remained relatively stable over the short term, but 20% experienced at least 1 week in which their RHR fluctuated by 10 bpm or more.ConclusionsIndividuals have a daily RHR that is normal for them but can differ from another individual's normal by as much as 70 bpm. Within individuals, RHR was much more consistent over time, with a small but significant seasonal trend, and detectable discrete and infrequent episodes outside their norms

Turning Erythrocytes into Functional Micromotors

Attempts to apply artificial nano/micromotors for diverse biomedical applications have inspired a variety of strategies for designing motors with diverse propulsion mechanisms and functions. However, existing artificial motors are made exclusively of synthetic materials, which are subject to serious immune attack and clearance upon entering the bloodstream. Herein we report an elegant approach that turns natural red blood cells (RBCs) into functional micromotors with the aid of ultrasound propulsion and magnetic guidance. Iron oxide nanoparticles are loaded into the RBCs, where their asymmetric distribution within the cells results in a net magnetization, thus enabling magnetic alignment and guidance under acoustic propulsion. The RBC motors display efficient guided and prolonged propulsion in various biological fluids, including undiluted whole blood. The stability and functionality of the RBC motors, as well as the tolerability of regular RBCs to the ultrasound operation, are carefully examined. Since the RBC motors preserve the biological and structural features of regular RBCs, these motors possess a wide range of antigenic, transport, and mechanical properties that common synthetic motors cannot achieve and thus hold considerable promise for a number of practical biomedical uses

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