Multifunctional Silver‐Exchanged Zeolite Micromotors for Catalytic Detoxification of Chemical and Biological Threats

Multifunctional reactive‐zeolite‐based micromotors have been developed and characterized toward effective and rapid elimination of chemical and biological threats. The incorporation of silver ions (Ag⁺) into aluminosilicate zeolite framework imparts several attractive functions, including strong binding to chemical warfare agents (CWA) followed by effective degradation, and enhanced antibacterial activity. The new zeolite‐micromotors protocol thus combines the remarkable adsorption capacity of zeolites and the efficient catalytic properties of the reactive Ag⁺ ions with the autonomous movement of the zeolite micromotors for an accelerated detoxification of CWA. Furthermore, the high antibacterial activity of Ag⁺ along with the rapid micromotor movement enhances the contact between bacteria and reactive Ag⁺, leading to a powerful “on‐the‐fly” bacteria killing capacity. These attractive adsorptive/catalytic features of the self‐propelled zeolite micromotors eliminate secondary environmental contamination compared to adsorptive micromotors. The distinct cubic geometry of the zeolite micromotors leads to enhanced bubble generation and faster movement, in unique movement trajectories, which increases the fluid convection and highly efficient detoxification of CWA and killing of bacteria. The attractive capabilities of these zeolite micromotors will pave the way for their diverse applications in defense, environmental and biomedical applications in more economical and sustainable manner.     

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.     

Cytotoxicity in the frog (Fejervarya limnocharis) after acute cadmium exposure in vivo

Chromosome aberrations (CA) in frogs (Fejervarya limnocharis) exposed to 5, 10 and 20 mg/L of cadmium chloride (CdCl₂) for 24, 48 and 72 h were invetegated. Treated frogs were compared to a control group. Cadmium (Cd) was not detected in the water or control frogs. The highest Cd concentrations in water and frog samples were found at 20 mg/L exposed for 72 h. The water samples indicated that exposure to 10 mg/L of Cd for 24 h was significantly different from the control (p < 0.05). Cd concentrations in frogs differed significantly between the control and experimental groups (p < 0.05). The cytotoxicity assessment revealed ten types of CA in the frogs, including single chromatid gap (SCG), isochromatid gap, single chromatid break, isochromatid break, iso-arm fragmentation, single chromatid decomposition, centric fragmentation, centromere gap, deletion and fragmentation. The most common CA in the study was SCG. The statistical analysis indicated significant differences in the percentage of cells with CA for exposures of 20 mg/L (24 h), 10 and 20 mg/L (48 h) and 5, 10 and 20 mg/L (72 h) compared to the control (p < 0.05). The results of this study show that high Cd concentrations and long duration exposure can cause CA in frogs.     

Differential protein expression between normal, early-stage, and late-stage myxomatous mitral valves from dogs

Valvular heart disease accounts for over 20 000 deaths and 90 000 hospitalizations yearly in the United States. Myxomatous valve disease (MVD) is the most common disease of the mitral valve in humans and dogs. MVD is pathologically identical in these species and its pathogenesis is poorly understood. The objectives of this study were to (i) develop proteomic methodology suitable for analysis of extracellular matrix‐rich heart valve tissues and (ii) survey over‐ and under‐expressed proteins that could provide mechanistic clues into the pathogenesis of MVD. Normal, early‐stage, and late‐stage myxomatous mitral valves from dogs were studied. A shotgun proteomic analysis was used to quantify differential protein expression. Proteins were classified by function and clustered according to differential expression patterns. More than 300 proteins, with 117 of those being differentially expressed, were identified. Hierarchical sample clustering of differential protein profiles showed that early‐ and late‐stage valves were closely related. This finding suggests that proteome changes occur in early degeneration stages and these persist in late stages, characterizing a diseased proteome that is distinct from normal. Shotgun proteome analysis of matrix‐rich canine heart valves is feasible, and should be applicable to human heart valves. This study provides a basis for future investigations into the pathogenesis of MVD.     

Alloy nanowires bar codes based on nondestructive X-ray fluorescence readout

We demonstrate here the ability to generate ternary Co-Ni-Cu alloy nanowires with distinct X-ray fluorescence (XRF) barcode patterns using a one-step template-guided electrodeposition. Such coupling of one-step templated synthesis with a nondestructive XRF readout of the composition patterns greatly simplifies practical applications of barcoded nanomaterials. The new protocol leads to alloy nanowires with broad composition range and hence to an extremely large number of distinguishable XRF signatures. The resulting fluorescence barcodes correlate well with the composition of the metal mixture plating solution, indicating a reproducible plating processes. Factors affecting the coding capacity and identification accuracy are examined, and potential tracking and authenticity applications involving embedding the nanowires within plastics or inks are demonstrated and discussed.     

Ultrasound‐Propelled Nanoporous Gold Wire for Efficient Drug Loading and Release

Ultrasound (US)‐powered nanowire motors based on nanoporous gold segment are developed for increasing the drug loading capacity. The new highly porous nanomotors are characterized with a tunable pore size, high surface area, and high capacity for the drug payload. These nanowire motors are prepared by template membrane deposition of a silver‐gold alloy segment followed by dealloying the silver component. The drug doxorubicin (DOX) is loaded within the nanopores via electrostatic interactions with an anionic polymeric coating. The nanoporous gold structure also facilitates the near‐infrared (NIR) light controlled release of the drug through photothermal effects. Ultrasound‐driven transport of the loaded drug toward cancer cells followed by NIR‐light triggered release is illustrated. The incorporation of the nanoporous gold segment leads to a nearly 20‐fold increase in the active surface area compared to common gold nanowire motors. It is envisioned that such US‐powered nanomotors could provide a new approach to rapidly and efficiently deliver large therapeutic payloads in a target‐specific manner.     

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 Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli 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.     

Isolation and characterization of a lipid-degrading bacterium and its application to lipid-containing wastewater treatment

To construct an efficient lipid-containing wastewater treatment system, microorganisms that degrade lipids efficiently were isolated from various environmental sources. Strain DW2-1 showed the highest rate of degradation of 1% (w/v) salad oil among the isolated strains. Strain DW2-1 was identified as Burkholderia sp. and designated Burkholderia sp. DW2-1. The rate of degradation of salad oil, olive oil, sesame oil, and beef tallow by strain DW2-1 were 96.7%, 92.3%, 90.1% and 77.4%, respectively, during a 48-h cultivation. Strain DW2-1 grew well in a synthetic wastewater medium (>1 x 10(10) colony forming unit [CFU]/ml) between 20 degrees C and 38 degrees C, and its rate of degradation of salad oil was above 90% after a 48-h cultivation. The lipase and biosurfactant (BSF) activities of strain DW2-1 after a 48-h cultivation were 1720 U/l and 480 U/ml, respectively. In continuous cultures for lipid-containing wastewater treatment, DW2-1 was stably maintained and degraded more than 90% of salad oil during a 7-d cultivation.     

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-Ag(flex)-Ni nanowire, with the Pt-Au and Au-Ag(flex)-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.