Nanotechnology techniques can improve cardiovascular implant devices


Electronics-research-001(Nanowerk News) Jeong-Yeol Yoon, associate professor of agricultural and biosystems engineering, and Dr. Marvin Slepian, professor of cardiology and biomedical engineering, collaborated to test how nanotechnology-based techniques can be used to better facilitate adhesion between tissue and implanted devices.
“When we created the nanotexture surface, we thought it could be used as a sticky surface for the implants,” Yoon says.
Cell-substrate adhesion involves the interplay of mechanical properties, surface topographic features, electrostatic charge and biochemical mechanisms. By working at the nanoscale level, Yoon was able to maximize the physical properties of the underlying substrate in promoting adhesion.
But beyond simply creating a sticky surface, the researchers’ goal was to create a selectively sticky surface, favoring endothelial cell attachment, without favoring platelet attachment, Slepian says.
The connection between Yoon, a specialist in biosensors and nanotechnology from the College of Agriculture and Life Sciences, and Slepian, co-founder and chief scientific officer of artificial-heart manufacturer SynCardia, came about by chance. A graduate student in Yoon’s lab met Slepian through their shared interest in bicycling.
“It’s very rare for the agriculture people to work with the cardiovascular people in the medical school,” Yoon says.
But their research specialties clicked.
One particular challenge to overcome in cardiovascular implants is the potential for devices – such as stents placed inside coronary arteries – to become detached as a result of blood flow, Yoon says.
“We’re particularly focused on the cardiovascular applications because there’s a blood flow involved and our system is very good when there’s a flow situation,” Yoon says.
The results of the study, published in the journal Advanced Healthcare Materials (“Nanowell-Trapped Charged Ligand-Bearing Nanoparticle Surfaces: A Novel Method of Enhancing Flow-Resistant Cell Adhesion”), reveal that the researchers’ strategy leads to enhanced endothelial cell adhesion under both static and flow conditions.
The adhesive properties derive from optimized surface texturing, electrostatic charge and cell adhesive ligands (molecular binding substances) that are uniquely assembled on the substrata surface as an ensemble of nanoparticles trapped in nanowells.
“There are lot of other people out there who use nanotechnology for improving the implants, but this is stronger than other adhesive methods using nanotechnology,” Yoon says.
“Obviously it can be used for everything else – lungs, digestive track and other systems. There are lots of other opportunities we haven’t explored,” he says.
The research is a perfect fit for Advanced Healthcare Materials, a new journal that spun off from the longstanding Advanced Materials journal.
“The use of the materials for the health care applications is probably the hottest area in materials science and engineering,” Yoon says. “We believe the journal will become even stronger than the mother journal.”
Just as the new journal marks an exciting intersection of disciplines, Yoon says the environment at the UA encourages such interdisciplinary approaches.
“I joined the University of Arizona because there are so many interdisciplinary activities going on. I see a lot of collaboration between departments in the same college at other universities, but at the University of Arizona, the environment is more open and you see collaboration across colleges,” Yoon says.
Slepian agreed, saying the pair has already filed grant applications for future work together.
“It has been fun and exciting to have an interdisciplinary collaborator,” he says.
Source: University of Arizona

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Nano-particles Release Insulin into Diabetics’ Bloodstream


QDOTS imagesCAKXSY1K 8Diabetics could cut their need for injections to less than once a week thanks  to new insulin-releasing “smart” particles.

Researchers in the US have developed a type of nanoparticle that  automatically releases insulin into the blood when glucose levels get too high,  and have demonstrated that its effects last for 10 days in mice.

Regular injections of the particles could mean type 1 diabetics  wouldn’t have to check their blood sugar levels several times a day, or inject  the exact right amount of insulin when needed, which can result in too high or  low doses being administered, with further health problems following.

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‘We’ve created a ‘smart’ system that is injected into the body and  responds to changes in blood sugar by releasing insulin, effectively controlling  blood-sugar levels,’ said Dr Zhen Gu, an assistant professor in the joint  biomedical engineering program at North Carolina State University and the  University of North Carolina.

‘This technology effectively creates a ‘closed-loop’ system that mimics  the activity of the pancreas in a healthy person, releasing insulin in response  to glucose level changes. This has the potential to improve the health and  quality of life of diabetes patients.’

The nanoparticles have a solid core of insulin surrounded by a layer of  a modified glucose-based material known as dextran and another of glucose  oxidase enzymes.

When the enzymes are exposed to high glucose levels they effectively  convert the sugar into gluconic acid, which breaks down the modified dextran and  releases the insulin.

The insulin then brings the glucose levels under control. The gluconic  acid and dextran are biocompatible and dissolve in the body.

The nanoparticle cores are given a biocompatible coating that makes  them positively or negatively charged, causing them to form a network that  prevents them from dispersing throughout the body.

The positively charged coatings are made of chitosan (a material  normally found in shrimp shells), abnd the negatively charged coatings are made  of alginate (a material normally found in seaweed).

When the solution of coated nanoparticles is mixed together, the  positively and negatively charged coatings are attracted to each other to form a “nano-network.”

Once injected into the subcutaneous layer of the skin, the nano-network  holds the nanoparticles together. Both the nano-network and the coatings are  porous, allowing blood – and blood sugar – to reach the nanoparticle cores.

Gu’s research team is now in discussions to move the technology into  clinical trials for use in humans.

A paper on the research has been published in the scientific journal  ACS Nano.

Read more:  http://www.theengineer.co.uk/medical-and-healthcare/news/smart-particles-release-insulin-into-diabetics-bloodstream/1016213.article#ixzz2ScNHSXmx