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Yi Xing, Qi Pan, Xin Du, Tailin Xu, Yan He, Xueji Zhang
Asymmetric dual-function of Janus micro/nanoparticles that have different surface modifications, structures or material properties, are extremely promising as building blocks in constructing micro-/nanomotors. However, current synthesis strategies are usually lack of controlling the coverages of Janus micro/nanoparticles, which hinders in-depth researches of their effects on the performance of Janus nanomotors. This study demonstrates a versatile approach for fabrication of Janus dendritic porous silica nanomotors with precisely modulated coverages from 0 to 100% by controlling the embedded depth of aminopropyl-modified dendritic porous silica nanoparticles (DPSNs-NH2) with positive charges and subsequently adsorbing the oppositely charged Pt nanoparticles...
February 20, 2019: ACS Applied Materials & Interfaces
Tania Patiño, Alessandro Porchetta, Anita Jannasch, Anna Llado, Tom Stumpp, Erik Schäffer, Francesco Ricci, Samuel Sanchez
Bio-catalytic micro- and nanomotors have emerged as a new class of active matter self-propelled through enzymatic reactions. The incorporation of functional nanotools could enable the rational design of multifunctional micromotors for simultaneous real-time monitoring of their environment and activity. Herein, we report the combination of DNA nanotechnology and urease-powered micromotors as multi-functional tools able to swim, simultaneously sense the pH of their surrounding environment and monitor their intrinsic activity...
February 1, 2019: Nano Letters
Yuxing Ji, Xiankun Lin, Hongyue Zhang, Yingjie Wu, Junbai Li, Qiang He
We report a thermoresponsive poly-N-isopropylacrylamide (PNIPAM) brush functionalized Janus Au-Pt bimetallic micromotor capable of modulating the direction of motion with the change of the ambient temperature. The PNIPAM@Au-Pt micromotor moved along the Au-Pt direction with a speed of 8.5 μm/s in 1.5% H2O2 at 25 oC (below the lower critical solution temperature (LCST) of PNIPAM), whereas it changed the direction of motion (i.e., along the Pt-Au direction) and the speed decreased to 2.3 μm/s at 35 oC (above LCST)...
January 30, 2019: Angewandte Chemie
Udit Choudhury, Dhruv P Singh, Tian Qiu, Peer Fischer
The rheological properties of a colloidal suspension are a function of the concentration of the colloids and their interactions. While suspensions of passive colloids are well studied and have been shown to form crystals, gels, and glasses, examples of energy-consuming "active" colloidal suspensions are still largely unexplored. Active suspensions of biological matter, such as motile bacteria or dense mixtures of active actin-motor-protein mixtures have, respectively, reveals superfluid-like and gel-like states...
January 30, 2019: Advanced Materials
Minfeng Zhou, Ting Hou, Jinxing Li, Shanshan Yu, Zijian Xu, Miao Yin, Joseph Wang, Xiaolei Wang
For many medical treatments, particularly cancer, it is necessary to develop a biocompatible microscale device that can carry a sufficient amount of a drug, deliver it to target sites. While chemically-powered micromotors have been applied in live animal therapy, many of them are difficult to biodegrade in vivo, which might cause toxicity and side effects. Here, we report on a microdevice that consists of a polyaspartic acid (PASP) microtube, a thin Fe intermediate layer, and a core of Zn. This device can be propelled using gastric acid as a fuel...
January 28, 2019: ACS Nano
Maria Michiko Alcanzare, Mikko Karttunen, Tapio Ala-Nissila
Externally controlled motion of micro and nanomotors in a fluid environment constitutes a promising tool in biosensing, targeted delivery and environmental remediation. In particular, recent experiments have demonstrated that fuel-free propulsion can be achieved through the application of external magnetic fields on magnetic helically shaped structures. The magnetic interaction between helices and the rotating field induces a torque that rotates and propels them via the coupled rotational-translational motion...
January 25, 2019: Soft Matter
Qinglong Wang, Renfeng Dong, Chun Wang, Shuyu Xu, Decheng Chen, Yuying Liang, Biye Ren, Wei Gao, Yue-Peng Cai
Synthetic micro/nanomotors powered by the green energy and operated in completely biocompatible conditions are strongly desired for numerous practical applications. Glucose is one of the most attractive fuels for driven micro/nanomotors due to its outstanding biocompatible properties. However, currently, all of the glucose-fuelled micro/nanomotors based on enzyme-catalytic driven mechanisms and usually suffer from strict operated conditions and weak propulsions which greatly limit their applications. Here, we report the fastest glucose-fuelled cuprous oxide@N doped carbon nanotube (Cu2O@N-CNT) photocatalytic micromotor, which can be operated in fully green environment...
January 23, 2019: ACS Applied Materials & Interfaces
Lucie Reinišová, Soňa Hermanová, Martin Pumera
Conventional drug delivery systems face several issues in medical applications, such as cyto/genotoxicity and off-targeting. These issues are particularly significant for cancer therapeutics because many of the currently used systems are toxic in their free form. Self-propelled autonomous micro/nanomachines offer promising alternative drug delivery systems based on high cargo loading, fast autonomous movement, precise targeting and the on-demand release of therapeutics in vivo. With this unique set of properties, it is not surprising that they are receiving considerable research attention...
January 11, 2019: Nanoscale
Ana C Hortelao, Rafael Carrascosa, Nerea Murillo-Cremaes, Tania Patiño, Samuel Sanchez
Cancer is one of the main causes of death around the world, lacking from efficient clinical treatments that generally present severe side-effects. In recent years, various nanosystems have been explored to specifically target tumor tissues, enhancing the efficacy of cancer treatment and minimizing the side-effects. In particular, bladder cancer is the 9th most common cancer worldwide, which presents high survival rate but serious recurrence levels, demanding for an improvement in the existent therapies. Here we present urease-powered nanomotors based on mesoporous silica nanoparticles, that contain both PEG and anti-FGFR3 antibody on their outer surface to target bladder cancer cells in the form of 3D spheroids...
December 27, 2018: ACS Nano
Shauni Keller, B Jelle Toebes, Daniela A Wilson
Nature's motors are complex and efficient systems, which are able to respond to many different stimuli present in the cell. Nanomotors for biomedical applications are designed to mimic nature's complexity, however, they usually lack biocompatibility and the ability to adapt to their environment. Polymeric vesicles can overcome these problems due to the soft and flexible nature of polymers. Herein we will highlight the recent progress and the crucial steps needed to fabricate active and adaptive motor systems for their use in biomedical applications and our approach to reach this goal...
December 21, 2018: Biomacromolecules
Yuxing Ji, Xiankun Lin, Daolin Wang, Chang Zhou, Yingjie Wu, Qiang He
Engineering self-propelled micro-/nanomotors (MNMs) with continuously variable speeds, like macroscopic automobiles equipped a continuously variable transmission, is still a huge challenge. In this study, through grafting with salt-responsive poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC) brushes, bubble-propelled Janus microcapsule motors with polyelectrolyte multilayers exhibit adjustable motion speeds upon changing the type and concentration of counterions. The reversible switching between low-speed and high-speed states has been realized through modulating PMETAC brushes between hydrophobic and hydrophilic configurations by exchanging anions between ClO4- and polyphosphate...
December 17, 2018: Chemistry, An Asian Journal
Benjamin M Tansi, Matthew L Peris, Oleg E Shklyaev, Anna C Balazs, Ayusman Sen
The field of active matter holds promise for applications in particle assembly, cargo and drug delivery, and sensing. In pursuit of these capabilities, researchers have produced a suite of nanomotors, fluid pumps, and particle assembly strategies. Although promising, there are many challenges, especially for mechanisms that rely on chemical propulsion. One way to circumvent these issues is by the use of external energy sources. Herein, we propose a method of using freely suspended nanoparticles to generate fluid pumping towards desired point sources...
December 13, 2018: Angewandte Chemie
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
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