This artificial kidney could be implanted directly into the patient.
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Category: materials
By narrowing the bandgap of titania and graphene quantum dots.
Researchers have found a method of harvesting light.
Griffith University researchers have discovered significant new potentials for light harvesting through narrowing the bandgap of titania and graphene quantum dots.
The researchers for the first time have found a quantum-confined bandgap narrowing mechanism where UV absorption of the grapheme quantum dots and TiO2 nanoparticles can easily be extended into the visible light range.
Such a mechanism may allow the design of a new class of composite materials for light harvesting and optoelectronics.
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A new study of the early universe reveals how it could have been formed from an older collapsing universe, rather than being brand new. The universe is currently expanding and it is a common theory that this is the result of the ‘Big Bang’ – the universe bursting into existence from a point of infinitely dense and hot material.
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Very cool; another example where nature inspires others. Einstein was inspired often by nature and its environment.
Titanium is used medically in applications such as artificial joints and dental implants. While it is strong and is not harmful to tissues, the metal lacks some of the beneficial biological properties of natural tissues such as bones and natural teeth. Now, based on insights from mussels—which are able to attach themselves very tightly to even metallic surfaces due to special proteins found in their byssal threads—scientists from RIKEN have successfully attached a biologically active molecule to a titanium surface, paving the way for implants that can be more biologically beneficial.
The work began from earlier discoveries that mussels can attach to smooth surfaces so effectively thanks to a protein, L-DOPA, which is known to be able to bind very strongly to smooth surfaces such as rocks, ceramics, or metals. Interestingly, the same protein functions in humans as a precursor to dopamine, and is used as a treatment for Parkinson’s disease.
Using a combination of recombinant DNA technology and treatment with tyrosinase, they were able to create a hybrid protein that contained active parts of both the growth factor and L-DOPA. Tests showed that the proteins were able to fold normally, and further experiments in cell cultures demonstrated that the IGF-1 was still functioning normally. Thanks to the incorporation of the L-DOPA, the team was able to confirm that the proteins bound strongly to the titanium surface, and remained attached even when the metal was washed with phosphate-buffered saline, a water-based solution. Zhang says, “This is similar to the powerful properties of mussel adhesive, which can remain fixed to metallic materials even underwater.”
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Nice.
“Our study suggests for the first time that the doping-induced modulation of the charge carrier density in graphene influences its wettability and adhesion,” explained SungWoo Nam, an assistant professor in the Department of Mechanical Science and Engineering at Illinois. “This work investigates this new doping-induced tunable wetting phenomena which is unique to graphene and potentially other 2D materials in complementary theoretical and experimental investigations.”
Graphene, being optically transparent and possessing superior electrical and mechanical properties, can revolutionize the fields of surface coatings and electrowetting displays, according to the researchers. A material’s wettability (i.e. interaction with water) is typically constant in the absence of external influence and are classified as either water-loving (hydrophilic) or water-repelling (hydrophobic; water beads up on the surface). Depending on the specific application, a choice between either hydrophobic or hydrophilic material is required. For electrowetting displays, for example, the hydrophilic characteristics of display material is enhanced with the help of a constant externally impressed electric current.
“What makes graphene special is that, unlike conventional bulk materials, it displays tunable surface wetting characteristics due to a change in its electron density, or by doping,” said Ali Ashraf, a graduate student researcher and first author of the paper, “Doping-Induced Tunable Wettability and Adhesion of Graphene,” appearing in Nano Letters. “Our collaborative research teams have discovered that while graphene behaves typically as a hydrophobic material (due to presence of strongly held air-borne contamination on its surface), its hydrophobicity can be readily changed by changing electron density.
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Way cool.
Ideally, injectable or implantable medical devices should not only be small and electrically functional, they should be soft, like the body tissues with which they interact. Scientists from two UChicago labs set out to see if they could design a material with all three of those properties.
The material they came up with, published online June 27, 2016, in Nature Materials, forms the basis of an ingenious light-activated injectable device that could eventually be used to stimulate nerve cells and manipulate the behavior of muscles and organs.
“Most traditional materials for implants are very rigid and bulky, especially if you want to do electrical stimulation,” said Bozhi Tian, an assistant professor in chemistry whose lab collaborated with that of neuroscientist Francisco Bezanilla on the research.
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