However, these devices, often created with nondegradable elastic polymers, bear an inherent risk of intestinal obstruction as a result of accidental fracture or migration.
Now, researchers at MITS Koch Institute for Integrative Cancer Research and Massachusetts General Hospital (MGH) have created a polymer gel that overcomes this safety concern
Image courtesy of the researchers) This polymer is ph-responsive: It is stable in the acidic stomach environment
and folding of devices into easily ingestible capsules meaning this polymer can be used to create safe devices designed for extremely prolonged residence in the stomach.
-responsive supramolecular polymer gel as an enteric elastomer for use in gastric devices")that describes the application of this new polymer gel for creating gastric devices.
the researchers were interested in developing a polymer with elastic properties. An elastic device can be folded into something small
But the size and shape of existing devices with elastic polymers have been limited by safety concerns,
Because of this, the researchers wanted their polymer to also be enteric or have a mechanism that would enable it to pass through the stomach unaltered before disintegrating in the intestines.
The proposed supramolecular polymer gel network. Structures in yellow are synthesized polymer; structures in purple are linear polymer;
and the red structures are inter-polymer hydrogen bonds. Image courtesy of the researchers) To lower any possible risk of obstruction,
we wanted a material that could dissolve in the intestines, thereby dissociating the device, and safely pass out of the body,
Zhang says. To create this new material, the researchers synthesized an elastic polymer and combined it in solution with a clinically utilized enteric polymer.
Adding hydrochloric acid and centrifuging the solution resulted in a flexible, yet resilient, polymer gel that exhibits both elastic and enteric properties.
The researchers used the gel polycaprolactone (PCL), a nontoxic, degradable polyester, to construct several device prototypes.
They first created ring-shaped devices by using the gel to link arcs of PCL in a circular mold.
These elastic devices had a diameter of 3 centimeters wider than the pylorus before they were folded into orally ingestible capsules.
the polymer gel dissolved, allowing for the safe passage of the small PCL pieces without obstruction.
Improving adherence The combined enteric and elastic properties of this polymer gel could significantly improve the design and adoption of gastric-resident devices.
With further work in adjusting the polymer composition or the design of the system they say that they could tailor devices to release drugs over a specific timeframe of up to weeks or months at a time.
They also scattered polystyrene beads 10 micrometres wide into a Petri dish filled with macrophages a type of white blood cell that ingests foreign material.
"That clinical use involves the carbon spheres being coated with polymer-a polymer that can gradually release drugs into the system to fight cancer and other diseases.
and vibrational spectroscopic techniques were used to monitor how the polymers gradually released their payload. The researchers ran a series of different experiments to check the temperatures required for the drugs to disperse,
Different polymer coatings were tested too as the team works towards getting these'homemade'carbon nanoparticles ready for clinical use."
"You can coat it with different polymers to give it a different optical response. You can load it with two drugs,
And a new development set to open in New jersey later this year is transforming an old steel factory into the world largest vertical farm.
They are characterized by a high thermal conductivity and mechanical robustness with a low pressure loss during alternating operation modes.
because with the lower surface tension we expect less risk of head flattening and less risk for pressure ulcers."
However the lifetime of this kind of component is reduced greatly due to the fact that the thermal expansion coefficients of these elements are significantly different from that of silicon.
The shortcoming of conventional honeycombs is that they lose their full protective properties after only one impact due to plastic buckling of the material.
Compared to other polymers like plastics, the wood nanomaterial is biocompatible and has relatively low thermal expansion coefficient,
which means the material won't change shape as the temperature changes. All these superior properties make cellulose nanofibril an outstanding candidate for making portable green electronics.
Ma's team employed silicon nanomembranes as the active material in the transistor--pieces of ultra-thin films (thinner than a human hair) peeled from the bulk crystal
#Producing biodegradable plastic just got cheaper, greener Biodegradable drinking cups or vegetable wrapping foil: the bioplastic known as polylactic acid (PLA) is already a part of our everyday lives.
And yet, PLA is considered not yet a full alternative to traditional petroleum-based plastics, as it is costly to produce.
Researchers from the KU Leuven Centre for Surface Chemistry and Catalysis now present a way to make the PLA production process more simple and waste-free.
which in turn is a building block for polylactic acid. PLA degrades after a number of years in certain environments.
PLA is also one of the few plastics that are suitable for 3d printing. However, PLA is not yet a full alternative for petroleum-based plastics due to its cost.
The production process for PLA is expensive because of the intermediary steps.""First, lactic acid is fed into a reactor and converted into a type of pre-plastic under high temperature and in a vacuum,
"Professor Bert Sels explains.""This is an expensive process. The pre-plastic--a low-quality plastic--is broken then down into building blocks for PLA.
In other words, you are first producing an inferior plastic before you end up with a high-quality plastic.
And even though PLA is considered a green plastic, the various intermediary steps in the production process still require metals and produce waste."
"The KU Leuven researchers developed a new technique.""We have applied a petrochemical concept to biomass,
"says postdoctoral researcher Michiel Dusselier.""We speed up and guide the chemical process in the reactor with a zeolite as a catalyst.
and without using metals. In addition, the production process is cheaper, because we can skip a step."
Of course, PLA will never fully replace petroleum-based plastics. For one thing, some objects, such as toilet drain pipes, are meant not to be biodegradable.
And it is not our intention to promote disposable plastic. But products made of PLA can now become cheaper and greener.
said study co-author Michael Mcgehee, a professor of materials science and engineering at Stanford. ight now, silicon solar cells dominate the world market,
so Bailie did it manually. e used a sheet of plastic with silver nanowires on it, he said. hen we built a tool that uses pressure to transfer the nanowires onto the perovskite cell, kind of like a temporary tattoo.
surface smoothness and thermal expansion. ou don want it to expand or shrink too much. Wood is a natural hydroscopic material
Gong and her students also have been based studying bio polymers for more than a decade. CNF offers many benefits over current chip substrates, she says. he advantage of CNF over other polymers is that it a bio-based material and most other polymers are based petroleum polymers.
Bio-based materials are sustainable biocompatible and biodegradable, Gong says. nd, compared to other polymers,
CNF actually has a relatively low thermal expansion coefficient. The group work also demonstrates a more environmentally friendly process that showed performance similar to existing chips.
The majority of today wireless devices use gallium arsenide-based microwave chips due to their superior high-frequency operation and power handling capabilities.
have the right boiling point distribution and lubricity, and a very low pour point, meaning the fuel can become gelatinous in the cold temperatures of the stratosphere,
these particles are coated with polymers, which fine-tune their optical properties and their rate of degradation in the body.
These polymers can be loaded with drugs that are released gradually. Finally, carbon nanoparticles are rather small, less than eight nanometres in diameter (in comparison,
Scientists also found that they can alter the infusion of the particles into melanoma cells by adjusting the polymer coatings.
Scientists say that they can be coated with different polymers to give them different optical properties to make them even easier to detect in the organism,
When pressure is increased in the pores of the polymer, the structure swells and expands in a preferred direction.
The walls of the cells are made of a non-swellable polymer; a swellable polymer fills the interior of the chambers.
If the pressure inside the cells increases, for example, because the swellable polymer absorbs liquids, the structure expands in one direction.
Advanced Materials Interfaces/MPI of Colloids and Interfacesif you enjoy walking in the woods, you may well be familiar with the phenomenon.
To this end, they developed a computer simulation as well as tissue-like materials from a porous polymer in
Moveable parts of such robots, the actuators, might consist of a porous polymer with precisely defined pore properties. he actual motion could then be controlled by compressed air or an expandable fluid in the pores
The researchers were delighted also that the theoretical predictions from the computer simulation almost perfectly matched the results of their tests on synthesized porous polymer materials.
says Dunlop. Synthetic polymer honeycomb structures from a 3d printerthe composition of the cell walls plays a key role in the expansion process in the relevant cells of pinecones
The researchers simulated this structure for their practical experiments by bonding two different swellable polymer layers together.
The scientists envisage using porous polymer materials whose pores are filled with a hygroscopic fluid, for example a superabsorbing hydrogel, in future practical applications.
as well as semiconductive and conductive polymers to tailor the behavior of natural cotton fibers. he layers were so thin that the flexibility of the cotton fibers is preserved always,
which are coated with a charged polymer layer that helps them adhere to the target microbes,
and Staphylococcus epidermis, a bacterium that can cause harmful biofilms on plastics like catheters in the human body.
However, these devices, often created with nondegradable elastic polymers, bear an inherent risk of intestinal obstruction as a result of accidental fracture or migration.
Now, researchers at MIT Koch Institute for Integrative Cancer Research and Massachusetts General Hospital (MGH) have created a polymer gel that overcomes this safety concern
This polymer is ph-responsive: It is stable in the acidic stomach environment but dissolves in the small intestine near-neutral ph,
and folding of devices into easily ingestible capsules meaning this polymer can be used to create safe devices designed for extremely prolonged residence in the stomach. ne of the issues with any device in the GI TRACT is that there the potential for an obstruction,
polymer gel for creating gastric devices. Shiyi Zhang, a postdoc at the Koch Institute, is the paper lead author.
the researchers were interested in developing a polymer with elastic properties. n elastic device can be folded into something small,
But the size and shape of existing devices with elastic polymers have been limited by safety concerns,
Because of this, the researchers wanted their polymer to also be enteric or have a mechanism that would enable it to pass through the stomach unaltered before disintegrating in the intestines. o lower any possible risk of obstruction,
the researchers synthesized an elastic polymer and combined it in solution with a clinically utilized enteric polymer.
Adding hydrochloric acid and centrifuging the solution resulted in a flexible, yet resilient, polymer gel that exhibits both elastic and enteric properties.
The researchers used the gel polycaprolactone (PCL), a nontoxic, degradable polyester, to construct several device prototypes.
They first created ring-shaped devices by using the gel to link arcs of PCL in a circular mold.
the polymer gel dissolved, allowing for the safe passage of the small PCL pieces without obstruction.
Improving adherence The combined enteric and elastic properties of this polymer gel could significantly improve the design and adoption of gastric-resident devices.
With further work in adjusting the polymer composition or the design of the system they say that they could tailor devices to release drugs over a specific timeframe of up to weeks or months at a time.
The researchers have been studying bio-based polymers for more than a decade. While they showed some promise,
< Back - Next >
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011