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Xiankun Lin, Tieyan Si, Zhiguang Wu, Qiang He
As artificial active colloids, micro-/nanomotors (MNMs) can convert energy from the environment into mechanical motion in different fluids, showing potential applications in diverse fields such as targeted drug delivery and photothermal therapy. However, chemical fuels for typical catalytic MNMs, e.g., hydrogen peroxide, are highly toxic to organisms, and thus fuel-free MNMs are required. Recently, we have developed near-infrared light (NIR) propelled MNMs through integrating plasmonic gold nanoshells into nanoparticles or layer-by-layer assemblies in an asymmetric manner...
May 22, 2017: Physical Chemistry Chemical Physics: PCCP
Fei Peng, Yingfeng Tu, Daniela A Wilson
Inspired by highly efficient natural motors, synthetic micro/nanomotors are self-propelled machines capable of converting the supplied fuel into mechanical motion. A significant advance has been made in the construction of diverse motors over the last decade. These synthetic motor systems, with rapid transporting and efficient cargo towing abilities, are expected to open up new horizons for various applications. Utilizing emergent motor platforms for in vivo applications is one important aspect receiving growing interest as conventional therapeutic methodology still remains limited for cancer, heart, or vasculature diseases...
May 19, 2017: Chemical Society Reviews
Yingfeng Tu, Fei Peng, Paul B White, Daniela A Wilson
The development of artificial nanomotor systems that are stimuli-responsive is still posing many challenges. Herein, we demonstrate the self-assembly of a redox-responsive stomatocyte nanomotor system, which can be used for triggered drug release under biological reducing conditions. The redox sensitivity was introduced by incorporating a disulfide bridge between the hydrophilic poly(ethylene glycol) block and the hydrophobic polystyrene block. When incubated with the endogenous reducing agent glutathione at a concentration comparable to that within cells, the external PEG shells of these stimuli-responsive nanomotors are cleaved...
May 10, 2017: Angewandte Chemie
Likui Yang, Kun Cai, Jiao Shi, Qing H Qin
Many factors can have a significant influence on the output power of a thermally driven rotary nanomotor made of carbon nanotubes (CNTs). Making use of a computational molecular dynamics approach, we evaluate for the first time the output power of a nanomotor, considering some of the main factors including temperature, the diameter of the rotor and the number of IRD atoms (N) on the stator. When applying extra-resistant torque to the rotor to let the stable value of the rotational frequency of the rotor fluctuate near zero, the value of the resistant torque can be considered as the output power of the rotor...
May 26, 2017: Nanotechnology
Berta Esteban-Fernández de Ávila, Doris E Ramírez-Herrera, Susana Campuzano, Pavimol Angsantikul, Liangfang Zhang, Joseph Wang
Direct and efficient intracellular delivery of enzymes to cytosol holds tremendous therapeutic potential while remaining an unmet technical challenge. Herein, an ultrasound (US)-propelled nanomotor approach and a high-pH-responsive delivery strategy are reported to overcome this challenge using caspase-3 (CASP-3) as a model enzyme. Consisting of a gold nanowire (AuNW) motor with a pH-responsive polymer coating, in which the CASP-3 is loaded, the resulting nanomotor protects the enzyme from release and deactivation prior to reaching an intracellular environment...
May 5, 2017: ACS Nano
Laurens Deprez, Pierre de Buyl
Chemotaxis is the response of a particle to a gradient in the chemical composition of the environment. While it was originally observed for biological organisms, it is of great interest in the context of synthetic active particles such as nanomotors. Experimental demonstration of chemotaxis for chemically-powered colloidal nanomotors was reported in the literature in the context of chemo-attraction in a still fluid or in a microfluidic channel where the gradient is sustained by a specific inlet geometry. In this work, we use mesoscopic particle-based simulations of the colloid and solvent to demonstrate chemotaxis in a microfluidic channel...
April 26, 2017: Soft Matter
Yingfeng Tu, Fei Peng, Xiaofeng Sui, Yongjun Men, Paul B White, Jan C M van Hest, Daniela A Wilson
Self-propelled catalytic micro- and nanomotors have been the subject of intense study over the past few years, but it remains a continuing challenge to build in an effective speed-regulation mechanism. Movement of these motors is generally fully dependent on the concentration of accessible fuel, with propulsive movement only ceasing when the fuel consumption is complete. Here we report a demonstration of control over the movement of self-assembled stomatocyte nanomotors via a molecularly built, stimulus-responsive regulatory mechanism...
May 2017: Nature Chemistry
K E Dunn, M C Leake, A J M Wollman, M A Trefzer, S Johnson, A M Tyrrell
DNA has been used to construct a wide variety of nanoscale molecular devices. Inspiration for such synthetic molecular machines is frequently drawn from protein motors, which are naturally occurring and ubiquitous. However, despite the fact that rotary motors such as ATP synthase and the bacterial flagellar motor play extremely important roles in nature, very few rotary devices have been constructed using DNA. This paper describes an experimental study of the putative mechanism of a rotary DNA nanomotor, which is based on strand displacement, the phenomenon that powers many synthetic linear DNA motors...
March 2017: Royal Society Open Science
Kun Cai, Jingzhou Yu, Jiao Shi, Qing-Hua Qin
In the fabrication of a thermally driven rotary nanomotor with the dimension of a few nanometers, fabrication and control precision may have great influence on rotor's stability of rotational frequency (SRF). To investigate effects of uncertainty of some major factors including temperature, tube length, axial distance between tubes, diameter of tubes and the inward radial deviation (IRD) of atoms in stators on the frequency's stability, theoretical analysis integrating with numerical experiments are carried out...
April 10, 2017: Scientific Reports
Md Mushfiqur Rahman, Mokter Mahmud Chowdhury, Md Kawsar Alam
Using molecular dynamics simulations, it is shown that a carbon nanotube (CNT) suspended in water and subjected to a rotating electric field of proper magnitude and angular speed can be rotated with the aid of water dipole orientations. Based on this principle, a rotational nanomotor structure is designed and the system is simulated in water. Use of the fast responsiveness of electric-field-induced CNT orientation in water is employed and its operation at ultrahigh-speed (over 10(11) r.p.m.) is shown. To explain the basic mechanism, the behavior of the rotational actuation, originated from the water dipole orientation, is also analyzed ...
May 2017: Small
Jacek Czub, Miłosz Wieczór, Bartosz Prokopowicz, Helmut Grubmüller
F1-ATPase is a highly efficient molecular motor that can synthesize ATP driven by a mechanical torque. Its ability to function reversibly in either direction requires tight mechanochemical coupling between the catalytic domain and the rotating central shaft, as well as temporal control of substrate binding and product release. Despite great efforts and significant progress, the molecular details of this synchronized and fine-tuned energy conversion mechanism are not fully understood. Here, we use extensive molecular dynamics simulations to reconcile recent single-molecule experiments with structural data and provide a consistent thermodynamic, kinetic and mechanistic description of the main rotary substep in the synthetic cycle of mammalian ATP synthase...
March 9, 2017: Journal of the American Chemical Society
Carla Schmidt, Jamie A Macpherson, Andy M Lau, Ken Wei Tan, Franca Fraternali, Argyris Politis
Mass spectrometry (MS) has become an indispensable tool for investigating the architectures and dynamics of macromolecular assemblies. Here we show that covalent labeling of solvent accessible residues followed by their MS-based identification yields modeling restraints that allow mapping the location and orientation of subunits within protein assemblies. Together with complementary restraints derived from cross-linking and native MS, we built native-like models of four heterocomplexes with known subunit structures and compared them with available X-ray crystal structures...
February 7, 2017: Analytical Chemistry
Yingfeng Tu, Fei Peng, Alain A M André, Yongjun Men, Mangala Srinivas, Daniela A Wilson
We report the self-assembly of a biodegradable platinum nanoparticle-loaded stomatocyte nanomotor containing both PEG-b-PCL and PEG-b-PS as a potential candidate for anticancer drug delivery. Well-defined stomatocyte structures could be formed even after incorporation of 50% PEG-b-PCL polymer. Demixing of the two polymers was expected at high percentage of semicrystalline poly(ε-caprolactone) (PCL), resulting in PCL domain formation onto the membrane due to different properties of two polymers. The biodegradable motor system was further shown to move directionally with speeds up to 39 μm/s by converting chemical fuel, hydrogen peroxide, into mechanical motion as well as rapidly delivering the drug to the targeted cancer cell...
February 28, 2017: ACS Nano
Fabiana Arduini, Stefano Cinti, Viviana Scognamiglio, Danila Moscone, Giuseppe Palleschi
Through the years, scientists have developed cutting-edge technologies to make (bio)sensors more convenient for environmental analytical purposes. Technological advancements in the fields of material science, rational design, microfluidics, and sensor printing, have radically shaped biosensor technology, which is even more evident in the continuous development of sensing systems for the monitoring of hazardous chemicals. These efforts will be crucial in solving some of the problems constraining biosensors to reach real environmental applications, such as continuous analyses in field by means of multi-analyte portable devices...
March 22, 2017: Analytica Chimica Acta
Hong Wang, Martin Pumera
Self-propelled autonomous nano and micromotors are devices which in many aspects mimic living organisms: they take chemical energy from the environment and convert it to motion; they are capable of phototaxis, chemotaxis and magnetotaxis, following the gradient of fuel, a magnetic field or light. There is an immense spectrum of possible applications of these devices, ranging from environmental remediation to the biomedical field. All of these developments depend on the materials used and there has been intensive development of materials allowing more efficient propulsion, phototaxis, chemotaxis and enhanced applications of these devices...
February 1, 2017: Nanoscale
Ilya L Sokolov, Vladimir R Cherkasov, Andrey A Tregubov, Sveatoslav R Buiucli, Maxim P Nikitin
BACKGROUND: Theranostics, a fusion of two key parts of modern medicine - diagnostics and therapy of the organism's disorders, promises to bring the efficacy of medical treatment to a fundamentally new level and to become the basis of personalized medicine. Extrapolating today's progress in the field of smart materials to the long-run prospect, we can imagine future intelligent agents capable of performing complex analysis of different physiological factors inside the living organism and implementing a built-in program thereby triggering a series of therapeutic actions...
January 24, 2017: Biochimica et Biophysica Acta
Renfeng Dong, Yan Hu, Yefei Wu, Wei Gao, Biye Ren, Qinglong Wang, Yuepeng Cai
Light-driven synthetic micro-/nanomotors have attracted considerable attention due to their potential applications and unique performances such as remote motion control and adjustable velocity. Utilizing harmless and renewable visible light to supply energy for micro-/nanomotors in water represents a great challenge. In view of the outstanding photocatalytic performance of bismuth oxyiodide (BiOI), visible-light-driven BiOI-based Janus micromotors have been developed, which can be activated by a broad spectrum of light, including blue and green light...
January 30, 2017: Journal of the American Chemical Society
Fei Peng, Yingfeng Tu, Ashish Adhikari, Jordi C J Hintzen, Dennis W P M Löwik, Daniela A Wilson
A nanomotor based strategy for fast cellular entry and cargo delivery is presented. The concept focuses on integrating tat peptide, a basic domain of HIV-1 tat protein, with state of the art nanomotors which possess attractive autonomous properties, facilitating cellular penetration and uptake. The rapid cellular internalization process leads to higher delivery efficiency.
January 3, 2017: Chemical Communications: Chem Comm
Tailin Xu, Wei Gao, Li-Ping Xu, Xueji Zhang, Shutao Wang
Inspired by the swimming of natural microorganisms, synthetic micro-/nanomachines, which convert energy into movement, are able to mimic the function of these amazing natural systems and help humanity by completing environmental and biological tasks. While offering autonomous propulsion, conventional micro-/nanomachines usually rely on the decomposition of external chemical fuels (e.g., H2 O2 ), which greatly hinders their applications in biologically relevant media. Recent developments have resulted in various micro-/nanomotors that can be powered by biocompatible fuels...
December 27, 2016: Advanced Materials
Muhammad Safdar, Tam Do Minh, Niko Kinnunen, Janne Jänis
Manganese oxide (MnO2) has recently emerged as a promising alternate material for the fabrication of self-propelled micromotors. Platinum (Pt) has been traditionally used as a catalytic material for this purpose. However, the high cost associated with Pt restricts its widespread use toward practical applications where large amounts of material are required. MnO2 exists in different crystalline forms (polymorphs), which govern its catalytic behavior. In spite of this, the recent reports on MnO2 based micromotors have seldom reported on the polymorphic form involved...
November 30, 2016: ACS Applied Materials & Interfaces
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