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Katherine Villa, C Lorena Manzanares Palenzuela, Zdeněk Sofer, Stanislava Matějková, Martin Pumera
Photoactivated micromachines are at the forefront of the micro- and nanomotors field, as light is the main power source of many biological systems. Currently, this rapidly developing field is based on metal-containing segments, typically TiO2 and precious metals. Herein, we present metal-free tubular micromotors solely based on graphitic carbon nitride, as highly scalable and low-cost micromachines that can be actuated by turning on/off the light source. These micromotors are able to move by a photocatalytic-induced bubble-propelled mechanism under visible light irradiation, without any metal-containing part or biochemical molecule on their structure...
November 29, 2018: ACS Nano
Ye Yuan, Ghaneema N Abuhaimed, Qingkun Liu, Ivan I Smalyukh
Biological motors are marvels of nature that inspire creation of their synthetic counterparts with comparable nanoscale dimensions, high efficiency and diverse functions. Molecular motors have been synthesized, but obtaining nanomotors through self-assembly remains challenging. Here we describe a self-assembled colloidal motor with a repetitive light-driven rotation of transparent micro-particles immersed in a liquid crystal and powered by a continuous exposure to unstructured ~1 nW light. A monolayer of azobenzene molecules defines how the liquid crystal's optical axis mechanically couples to the particle's surface, as well as how they jointly rotate as the light's polarization changes...
November 28, 2018: Nature Communications
Brian G Gentry, Elke Bogner, John C Drach
A key step in the replication of human cytomegalovirus (HCMV) in the host cell is the generation and packaging of unit-length genomes into preformed capsids. Enzymes required for this process are so-called terminases, first described for double-stranded DNA bacteriophages. The HCMV terminase consists of the two subunits, the ATPase pUL56 and the nuclease pUL89, and a potential third component pUL51. The terminase subunits are essential for virus replication and are highly conserved throughout the Herpesviridae family...
November 22, 2018: Antiviral Research
Ming You, Chuanrui Chen, Leilei Xu, Fangzhi Mou, Jianguo Guan
Micro/nanomotors (MNMs) are micro/nanoscale devices that can convert energy from their surroundings into autonomous motion. With this unique ability, they may revolutionize application fields ranging from active drug delivery to biological surgeries, environmental remediation, and micro/nanoengineering. To complete these applications, MNMs are required to have a vital capability to reach their destinations. Employing external fields to guide MNMs to the targets is common and effective way. However, in application scenarios where targets are generally unknown or dynamically change, MNMs must possess the capability of self-navigation or self-targeting...
November 16, 2018: Accounts of Chemical Research
Zhen Wang, Qingjia Chi, Tao Bai, Qiang Wang, Lisheng Liu
In past decades, considerable advances have been achieved in micro and nanomotors. Particular attention has been given to self-propelled catalytic micromotors, which have been widely used in cell separation, drug delivery, microsurgery, lithography and environmental remediation. Fast moving, long life micromotors appear regularly, however it seems there are no solutions yet that thoroughly clarify the hydrodynamic behavior of catalytic micromotors moving in fluid. Dynamic behavior of this kind of micromotors is mainly determined by the driving force and drag force acting on the micromotors...
September 12, 2018: Micromachines
Yongjun Men, Yingfeng Tu, Wei Li, Fei Peng, Daniela A Wilson
A brush type nanomotor was fabricated via assembly assistant polymerization of poly(ionic liquid) and surface grafting polymerization. The method for large-scale fabrication of brush nanomotors with soft surfaces is described. These soft locomotive particles are based on core-shell brush nanoparticles assembled from poly(ionic liquid) as core and thermoresponsive PNIPAM as brush shells on which platinum nanoparticle (PtNP) were grown in situ. The particles show non-Brownian motion in H₂O₂ solution.
July 23, 2018: Micromachines
Pranay Mandal, Gouri Patil, Hreedish Kakoty, Ambarish Ghosh
Micro- and nanomotors are nonliving micro- and nanoparticles that are rendered motile by supplying energy from external sources, for example, through asymmetric chemical reactions or the application of electric, magnetic, optical, or acoustic fields. Their study is interesting for two reasons. First, nanomotors can impact future biomedical practices, where one envisions intelligent multifunctional nanomachines swarming toward a diseased site and delivering therapeutics with high accuracy. The second motivation stems from the prevalence of self-powered systems in nature, ranging from intracellular transport to human migration, which are nonequilibrium phenomena yet to be completely understood...
October 22, 2018: Accounts of Chemical Research
Martin Pumera
Self-propelled micro/nanomotors are synthetic machines that can convert different sources of energy into motion; at the same time, they are able to serve innovative environmental applications, e.g., water purification. The self-propelled autonomous micro and nanomachines can rapidly zoom through the solution, carrying catalytic surface or chemical to remove or degrade pollutants in much faster fashion than static systems which depend on diffusion and fluxes. This review highlights the recent progress of MNMs in water pollutant detection and removal applications...
October 11, 2018: Chemistry: a European Journal
Francisco Mendoza-Hoffmann, Mariel Zarco-Zavala, Raquel Ortega, José J García-Trejo
The ATP synthase is a ubiquitous nanomotor that fuels life by the synthesis of the chemical energy of ATP. In order to synthesize ATP, this enzyme is capable of rotating its central rotor in a reversible manner. In the clockwise (CW) direction, it functions as ATP synthase, while in counter clockwise (CCW) sense it functions as an proton pumping ATPase. In bacteria and mitochondria, there are two known canonical natural inhibitor proteins, namely the ε and IF1 subunits. These proteins regulate the CCW F1 FO -ATPase activity by blocking γ subunit rotation at the αDP /βDP /γ subunit interface in the F1 domain...
October 2018: Journal of Bioenergetics and Biomembranes
Chunyan Liang, Chen Zhan, Fanyu Zeng, Dandan Xu, Yong Wang, Weiwei Zhao, Jiaheng Zhang, Jinhong Guo, Huanhuan Feng, Xing Ma
There are two main aspects of environmental governance including monitoring and remediation, both of which are essential for environmental protection. Self-propelled micro/nanomotors (MNM) have shown promising potential for achieving on-demand tasks in environmental field, including environmental sensing and pollutant removal or degradation. However, most of the current MNM used in environmental protection can hardly accomplish the two major tasks of both monitoring and pollutant degradation. Hereby, we present a bubble-propelled mesoporous silica-coated titania (TiO2@mSiO2) bilayer tubular micro-motor with platinum (Pt) and magnetic Fe3O4 nanoparticles modified on their inner walls...
September 24, 2018: ACS Applied Materials & Interfaces
Wenjuan Liu, Hongbin Ge, Zhongwei Gu, Xiaolong Lu, Jinxing Li, Joseph Wang
Artificial micro/nanomotors that could perform diverse tasks autonomously at the micro/nanoscale have been emerging as promising tools in many practical applications. Electrochemical synthesis is one of the dominating methods to fabricate these micro/nanodevices with diverse geometries and material components. By changing the conditions of electrochemical deposition, the surface morphology, crystal structure, and hence the resultant performance of deposited material could be tailored. In the current work, a feasible fabrication strategy is presented in terms of three unique electrodeposition types (i...
November 2018: Small
Lilia Colina-Tenorio, Alain Dautant, Héctor Miranda-Astudillo, Marie-France Giraud, Diego González-Halphen
Rotary ATPases are a family of enzymes that are thought of as molecular nanomotors and are classified in three types: F, A, and V-type ATPases. Two members (F and A-type) can synthesize and hydrolyze ATP, depending on the energetic needs of the cell, while the V-type enzyme exhibits only a hydrolytic activity. The overall architecture of all these enzymes is conserved and three main sectors are distinguished: a catalytic core, a rotor and a stator or peripheral stalk. The peripheral stalks of the A and V-types are highly conserved in both structure and function, however, the F-type peripheral stalks have divergent structures...
2018: Frontiers in Physiology
Daolin Wang, Changyong Gao, Wei Wang, Mengmeng Sun, Bin Guo, Hui Xie, Qiang He
The T-1000 liquid metal terminator, which can transform and self-repair, represents a dream for decades that robots can fundamentally change our daily life. Until now, some large-scale liquid metal machines have been developed. However, there is no report on nanoscaled liquid metal machines and their biomedical applications. We describe here a shape-transformable and fusible rodlike swimming liquid metal nanomachine, based on the biocompatible and transformable liquid metal gallium. These nanomachines were prepared by a pressure-filter-template technology, and the diameter and length could be controlled by adjusting the nanoporous templates, filter time, and pressure...
September 21, 2018: ACS Nano
Zexi Liang, Donglei Fan
Highly efficient and widely applicable working mechanisms that allow nanomaterials and devices to respond to external stimuli with controlled mechanical motions could make far-reaching impact to reconfigurable, adaptive, and robotic nanodevices. We report an innovative mechanism that allows multifold reconfiguration of mechanical rotation of semiconductor nanoentities in electric ( E ) fields by visible light stimulation. When illuminated by light in the visible-to-infrared regime, the rotation speed of semiconductor Si nanowires in E -fields can instantly increase, decrease, and even reverse the orientation, depending on the intensity of the applied light and the AC E -field frequency...
September 2018: Science Advances
Maria Jose Esplandiu, Kuan Zhang, Jordi Fraxedas, Borja Sepulveda, David Reguera
The development of effective autonomous micro- and nanomotors relies on controlling fluid motion at interfaces. One of the main challenges in the engineering of such artificial machines is the quest for efficient mechanisms to power them without using external driving forces. In the past decade, there has been an important increase of man-made micro- and nanomotors fueled by self-generated physicochemical gradients. Impressive proofs of concept of multitasking machines have been reported demonstrating their capabilities for a plethora of applications...
September 18, 2018: Accounts of Chemical Research
Jizhuang Wang, Ze Xiong, Jing Zheng, Xiaojun Zhan, Jinyao Tang
A micro/nanomotor (MNM), as miniaturized machinery, can potentially bridge the application gap between the traditional macroscale motor and the molecular motor to manipulate materials at the cellular scale. The fascinating biomedical potential application for these tiny robots has been long envisioned by science fiction, such as "Fantastic Voyage", where complicated surgery can be performed at single cell precision without any surgical incision. However, to enter the highly conservative biomedical and healthcare industry in practice, the MNM must provide unique advantages over existing technology without introducing additional health risk, which has not been fully materialized...
September 18, 2018: Accounts of Chemical Research
Isamar Ortiz-Rivera, Motilal Mathesh, Daniela A Wilson
Autonomous micro- and nanoscale systems have revolutionized the way scientists look into the future, opening up new frontiers to approach and solve problems via a more bioinspired route. However, to achieve systems with higher complexity, superior output control, and multifunctionality, an in-depth study of the different factors that affect micro- and nanomotor behavior is crucial. From a fundamental perspective, the mechanical response of micro- and nanomotors still requires further study in order to have a better understanding of how exactly these systems operate and the different mechanisms of motion that can be combined into one system to achieve an optimal response...
September 18, 2018: Accounts of Chemical Research
Yingjie Wu, Tieyan Si, Changyong Gao, Mingcheng Yang, Qiang He
We report a hollow dumbbell-shaped manganese dioxide (MnO2 ) colloidal kayaker capable of converting a pair of breathing oxygen bubbles into self-propelled movement. The bubble pair generated by catalytic decomposition of hydrogen peroxide fuel grew either synchronously or asynchronously, driving the colloidal kayaker to move along a fluctuating circle. The synchronous or asynchronous breathing mode of bubble pair is governed by the asymmetric catalytic sites of the colloidal kayakers. This imbalanced distribution of bubble propulsion force generates the driving force and the centripetal force on the colloidal kayaker...
September 26, 2018: Journal of the American Chemical Society
Jan-Philipp Günther, Michael Börsch, Peer Fischer
Self-propelled chemical motors are chemically powered micro- or nanosized swimmers. The energy required for these motors' active motion derives from catalytic chemical reactions and the transformation of a fuel dissolved in the solution. While self-propulsion is now well established for larger particles, it is still unclear if enzymes, nature's nanometer-sized catalysts, are potentially also self-powered nanomotors. Because of its small size, any increase in an enzyme's diffusion due to active self-propulsion must be observed on top of the enzyme's passive Brownian motion, which dominates at this scale...
September 18, 2018: Accounts of Chemical Research
Renfeng Dong, Yuepeng Cai, Yiran Yang, Wei Gao, Biye Ren
Synthetic micro/nanomotors (MNMs) are a particular class of micrometer or nanometer scale devices with controllable motion behavior in solutions by transferring various energies (chemical, optical, acoustic, magnetic, electric, etc.) into mechanical energy. These tiny devices can be functionalized either chemically or physically to accomplish complex tasks in a microcosm. Up to now, MNMs have exhibited great potential in various fields, ranging from environmental remediation, nanofabrication, to biomedical applications...
September 18, 2018: Accounts of Chemical Research
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