Graphene based multifunctional superbots (original) (raw)
Related papers
Advanced Functional Materials, 2010
The control over micro-and nanoobjects has attracted great attention in several areas of science, such as nanotechnology and drug delivery. One of the major challenges is to achieve autonomous movement of micro-and nanoscale machines in a fluid and employ them to perform complex tasks such as drug delivery, transport, and assembly of micro-/nano-objects. [1] Richard Feynman in his 1959 speech ''There's Plenty of Room at the Bottom'' envisioned microscopic factories with tiny machines that could perform sophisticated tasks. [2] The dream of manufacturing nanomachines is to mimic biological motors that can convert chemical into mechanical energy and hence develop diverse functions. [3] Some fascinating examples in nature are DNA and RNA polymerase; [4] rotary motors such as ATP synthase; [5] cilia and flagella motors; [6] dyneins, [7] kinesins, [8] and myosins. [9] Catalytic synthetic micro-and nanomotors [10-13] and engines [14,15] are of growing interest because of their high locomotive power and easy control. [16] Several approaches have been focused on the improvement of the catalytic conversion of chemicals (e.g., hydrogen peroxide) into kinetic energy [17-19] and the control over the movement of nanomotors by different sources has been reported. [20] The transport of spherical particles used as cargo [21,22] was recently achieved by either using electrostatic, chemical, or magnetic interactions to attach the cargo. [21,22] Extra functionality has also been given to the cargo (e.g., magnetic properties, chemical modification for electrostatic binding) for loading into the nanomotors. In addition, practical applications require higher towing forces and general mechanisms to bind and unbind different cargo in an easy and controllable way. Recently, rolled-up tubular structures that accumulate gas, which is generated by the catalytic decomposition of a fuel, have been developed. [14] These tubular microjets enhance the power of synthetic micromachines reaching a speed of up to 50 body lengths per second. [15] In this work, we describe the use of rolled-up thin Ti/Fe/Pt films as microbots developing tasks that require full control over their motion and high propulsion power. Maneuvers of self-propelled microbots were wirelessly coordinated by an external magnetic field, which allows the selective manipulation of different microobjects randomly suspended in solution. The physical characteristics of these tubular microbots led to a high propulsion power and allowed more than sixty polymeric cargo-particles to be attached and transferred to a desired location. Moreover, we achieved the selective loading of metallic nanoplates with a ''large'' surface area, their transport and directed assembly into different configurations. These illustrative examples form an attractive concept of
Chemistry (Weinheim an der Bergstrasse, Germany), 2014
A novel concept of an iridium-based bubble-propelled Janus-particle-type graphene micromotor with very high surface area and with very low catalyst loading is described. The low loading of Ir catalyst (0.54 at %) allows for fast motion of graphene microparticles with high surface area of 316.2 m(2) g(-1). The micromotor was prepared with a simple and scalable method by thermal exfoliation of iridium-doped graphite oxide precursor composite in hydrogen atmosphere. Oxygen bubbles generated from the decomposition of hydrogen peroxide at the iridium catalytic sites provide robust propulsion thrust for the graphene micromotor. The high surface area and low iridium catalyst loading of the bubble-propelled graphene motors offer great possibilities for dramatically enhanced cargo delivery.
ACS applied materials & interfaces, 2016
We describe the creation of polymeric microcapsules that can exhibit autonomous motion along defined trajectories. The capsules are made by cross-linking aqueous microdroplets of the biopolymer chitosan using glutaraldehyde. A coflow microfluidic tubing device is used to generate chitosan droplets containing nanoparticles (NPs) with an iron (Fe) core and a platinum (Pt) shell. The droplets are then incubated in a Petri dish with the cross-linking solution, and an external magnet is placed below the Petri dish to pull the NPs together as a collective "patch" on one end of each droplet. This results in cross-linked capsules (∼150 μm in diameter) with an anisotropic (patchy) structure. When these capsules are placed in a solution of H2O2, the Pt shell of the NPs catalyzes the decomposition of H2O2 into O2 gas, which is ejected from the patchy end in the form of bubbles. As a result, the capsules (which are termed micromotors) move in a direction opposite to the bubbles. Furth...
Recent Advances in Nano‐ and Micromotors
Advanced Functional Materials, 2020
Nano-and micromotors are fascinating objects that can navigate in complex fluidic environments. Their active motion can be triggered by external power sources or they can exhibit self-propulsion using fuel extracted from their surroundings. The research field is rapidly evolving and has produced nano/micromotors of different geometrical designs, exploiting a variety of mechanisms of locomotion, being capable of achieving remarkable speeds in diverse environments ranging from simple aqueous solutions to complex media including cell cultures or animal tissue. This review aims to provide an overview of the recent developments with focus on predominantly experimental demonstrations of the various motor designs developed in the past 24 months. First, externally driven motors are discussed followed by considering fuel-driven approaches. Finally, a short future perspective is provided.
ACS Nano, 2018
We report a controllable and precision approach in manipulating catalytic nanomotors by strategically applied electric (E-) fields in three dimensions (3-D). With the high controllability, the catalytic nanomotors have demonstrated new versatility in capturing, delivering, and releasing of cargos to designated locations as well as in-situ integration with nanomechanical devices (NEMS) to chemically power the actuation. With combined AC and DC E-fields, catalytic nanomotors can be accurately aligned by the AC E-fields and instantly change their speeds by the DC E-fields. Within the 3-D orthogonal microelectrode sets, the in-plane transport of catalytic nanomotors can be swiftly turned on and off, and these catalytic nanomotors can also move in the vertical direction. The interplaying nanoforces that govern the propulsion and alignment are investigated. The modeling of catalytic nanomotors proposed in previous works has been confirmed quantitatively here. Finally, the prowess of the precision manipulation of catalytic nanomotors by E-fields is demonstrated in two applications: the capture, transport, and release of cargos to pre-patterned microdocks, and the assembly of catalytic nanomotors on NEMS to power the continuous rotation. The innovative concepts and approaches reported in this work could further advance ideal applications of catalytic nanomotors, e.g. for assembling and powering nanomachines, nanorobots, and complex NEMS devices.
Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water
Nano letters, 2016
Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavy metal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots' structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 pp...
Chemically Powered Micro- and Nanomotors
Angewandte Chemie International Edition, 2014
Jaideep Katuri received his BSc (Hons) in Physics from Sri Sathya Sai Institute of Higher Learning, Bangalore. He then joined the University of Stuttgart to pursue his Masters in Physics. Currently he is a student assistant at the research group of Samuel Sanchez at the MPI for Intelligent Systems in Stuttgart. His research focuses on studying the behavior and interactions of micromotors at different interfaces.
Nanorobots Constructed from Nanoclay: Using Nature to Create Self-Propelled Autonomous Nanomachines
Advanced Functional Materials, 2018
Self-propelled, autonomous micro and nanomachines are at the forefront of current nanotechnology. These micro and nanodevices move actively to perform desired tasks, usually using chemical energy from their surrounding environment. Typically, these structures are fabricated via clean room or template-based electrodeposition methodologies, which yield relatively low numbers of these devices. To utilize these machines in industrial-scale operations, one would need an inexpensive fabrication route for mass production of nanomachines. The use of naturally occurring nanotubes, Halloysite nanoclay, to fabricate functional nanomotors in great quantities is demonstrated. These nanotubes can be mined in ton quantities and used as base for the fabrication of nanomachines. In addition, it is well known that the surface groups of Halloysite nanoclay bind strongly with heavy metals, which makes it potentially useful in environmental remediation.
Colloidal Micromotors: Controlled Directed Motion
2008
Here we demonstrate a synthetic micro-engine, based on long-range controlled movement of colloidal particles, which is induced by a local catalytic reaction. The directed motion at long timescales was achieved by placing specially designed magnetic capped colloids in a hydrogen peroxide solution at weak magnetic fields. The control of the motion of the particles was provided by changes of the concentration of the solution and by varying the strength of the applied magnetic field. Such synthetic objects can then be used not only to understand the fundamental driving processes but also be employed as small motors in biological environments, for example, for the transportation of molecules in a controllable way.
ACS Nano, 2012
We describe nanoscale tools in the form of autonomous and remotely guided catalytically self-propelled InGaAs/ GaAs/(Cr)Pt tubes. These rolled-up tubes with diameters in the range of 280À600 nm move in hydrogen peroxide solutions with speeds as high as 180 μm s À1. The effective transfer of chemical energy to translational motion has allowed these tubes to perform useful tasks such as transport of cargo. Furthermore, we observed that, while cylindrically rolled-up tubes move in a straight line, asymmetrically rolled-up tubes move in a corkscrew-like trajectory, allowing these tubes to drill and embed themselves into biomaterials. Our observations suggest that shape and asymmetry can be utilized to direct the motion of catalytic nanotubes and enable mechanized functions at the nanoscale.