Though it seems like science fiction, microscopic “factories” in which nanomachines produce tiny structures for miniaturized components or nanorobots that destroy tumor cells within the body and scrape blockages from our arteries may become reality in the foreseeable future. Nanomotors could transport drugs to specific target organs more rapidly or pilot analytes through the tiny channels on microchip diagnostic systems.
In the journal Angewandte Chemie, Ayusman Sen and his team from Pennsylvania State University (USA) describe a new type of micromotor that is powered by a polymerization reaction and deposits tiny threads along its trail like a microspider.The motors consist of spheres that are barely a micrometer in size, made half of gold, half of silicon dioxide. Certain catalyst molecules (a Grubbs catalyst) that catalyze polymerizations can be attached to the silicon dioxide surface. Sen and his team use norbornene as a monomer. The catalyst opens the rings and strings these monomers together into long chain molecules.
As soon as the reaction begins, the spheres start driving through the surrounding liquid. How is it that such a reaction can cause movement? The secret lies in the two different halves of the spheres. The monomer is only consumed on the side where the catalyst molecules are present. This causes the monomer concentration to decrease until it is lower than on the catalyst-free gold side. The resulting concentration gradient produces osmotic pressure, which causes a tiny current of solvent molecules toward areas with higher monomer concentration—toward the gold side. This miniature current drives the micromotor in the opposite direction.
Somatic cells—in processes such as embryogenesis—and certain single-celled organisms can follow concentration gradients of messenger substances or nutrients, a phenomenon known as chemotaxis. The new micromotors are also capable of such directed movement. The scientists used norbornene-filled gels that slowly leach out the monomer. The micromotors sense this and preferentially move towards the gel, following the nutrient gradient like a single-celled organism. The reason for this is that the polymerization goes faster when there is more monomer near the catalyst. This effect causes the local current driving the spheres to become stronger as well.
It is thus possible to direct the micromotors toward their target. In a solvent where the resulting polymer is insoluble, it could be deposited in the trail left behind; a microspider that moves around weaving a web. The micromotors can also be used to detect defects and fractures, moving towards them and sealing them with polymer.
Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University
Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering
23.05.2017 | Life Sciences