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Biomedical Engineering

The Biomedical Engineering blog is the place for conversation and discussion about topics related to engineering principles of the medical field. Here, you'll find everything from discussions about emerging medical technologies to advances in medical research. The blog's owner, Chelsey H, is a graduate of Rensselaer Polytechnic Institute (RPI) with a degree in Biomedical Engineering.

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Gold Nanowires to Treat Heart Attack Patients

Posted September 29, 2011 2:09 PM by Chelsey H

Heart attacks are a devastating occurrence. Each year, approximately 1.5 million heart attacks occur in the United States and cause 500,000 deaths. A new technology, developed by researchers at MIT and Children's Hospital Boston, could someday help these millions of sufferers.

A heart attack occurs when blood flow to part of the heart is blocked long enough to cause part of the heart muscle to become damaged or die.

Heart Attack. Image Credit: MedicineNet.com

The new nano-technology is a cardiac patch studded with tiny gold nanowires. The patch is used to help create pieces of tissue where the cells all beat in time, mimicking the dynamics of natural heart muscle. This product could also be used to help other types of tissues - such as muscles, vascular tissues and neurons - to heal and grow.

Current cardiac patches have difficulty achieving enough conductivity to ensure a smooth, continuous "beat" throughout the whole piece of tissue. Duke University has created a stem-cell-based heart patch which has successfully grown and seeded heart cells (cardiomyocytes), but it blocks the electrical signals shared by calcium ions that dictate when the cells contract. Without a uniform beat, the tissue won't grow or function properly.

Daniel Kohane, a professor in the Harvard-MIT Division of Health Sciences and Technology (HST) and senior author of the paper published in the journal Nature Nanotechnology, describes the heart as a sophisticated piece of electrical machinery.

Click here to watch a video: New cardiac patch uses gold nanowires to enhance electrical signaling

The Discovery

New tissue is regenerated using a miniature scaffold made of a porous material so that the cells can grow into a specific shape. The scaffold materials being used in research now are materials like polylactic acid or alginate. These materials are insulators, which prevent cardiomyocytes from receiving the needed electrical signals to coordinate their movement. This patch is made of a new scaffold material that allows electrical signals to pass through.

The material is made of a base alginate, an organic gum-like substance often used for tissue scaffolds, and a solution containing gold nanowires, which are 1mm long (diameter 30nm). The solution creates a composite scaffold with billions of tiny metal structures running through it. The nanowires are able to bridge the pores of the alginate and improve electrical communication between adjacent cardiomyocytes. "In healthy, native heart tissue, you're talking about conduction over centimeters," Timko says. Previously, tissue grown on pure alginate showed conduction over only a few hundred micrometers, or thousandths of a millimeter. But the combination of alginate and gold nanowires achieved signal conduction over a scale of "many millimeters," Timko says.

A wider SEM image of the nanowire-alginate composite scaffolds.
Image courtesy of the Disease Biophysics Group, Harvard University

A Heart of Gold

Scientists had to first grow the nanowires and then the heart cells to test the new machine. Heart cells are hard to grow in a lab because they must develop the proper beating motion. So researchers collected cardiomyocytes from rat embryos and seeded them on to the alginate. The calcium levels were labeled so their electrical conductivity could be monitored. Scientists looked at the amount of calcium present in different areas of the tissue to determine if there was an electrical signal. Compared to a typical scaffold system, the gold nanowire cells' conductivity improved by three orders of magnitude. Kohane said it was "night and day." Over time, the scaffold degrades and the nanowires are left embedded within the new tissue.

The next step is for researchers to do in vivo studies to observe the composite - grown tissue function when implanted into live hearts. Future research will look at applying the technology into other cellular systems.

Resources

http://www.allheartattack.com/statistics.php

http://www.rsc.org/chemistryworld/News/2011/September/27091101.asp

http://web.mit.edu/newsoffice/2011/gold-nanowire-heart-0926.html

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001246/

http://www.innovationnewsdaily.com/nanowire-heart-of-gold-cardiac-victims-2280/

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Guru

Join Date: Jan 2008
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#1

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 1:01 AM

A quite respectable idea. Rebuilding, based on preexisting scaffolding, yes. Absolutely.If I am off the track, let me know.

On the other hand, I am of the mind, of PREVENTING problems, if possible. Hearth problems are electrical and preventable.

If you care, the two approaches may be supportive.

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#2
In reply to #1

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 11:41 AM

I agree regarding prevention. I was going to post about that. Probably a number of people thought it. I would add, though, that heart/circulatory problems are not only electrical in nature. The food one eats plays a huge role in heart disease.

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Guru

Join Date: Jan 2008
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#3

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 12:20 PM

I am interested in the Original Poster's ideas. Anonymous Posters need not apply.

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Participant

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#4

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 1:24 PM

Very interesting concept.......

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Power-User

Join Date: Aug 2011
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#5

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 1:25 PM

I agree that prevention is always the best approach. Living a healthy lifestyle and teaching others how to live a healthy lifestyle is beneficial for the patient's health and the economy. Not all heart problems are electrical, some are caused by diet and lifestyle. Heart attacks are caused by a buildup of plaque that hardens and disrupts blood flow in the arteries. Plaque is made of fat, cholesterol, calcium and other blood materials. The buildup occurs over a long time.

The new patch is designed to aid in regrowing damaged heart tissue. The damaged is generally caused by heart attacks but I'm sure there there are genetic or trauma related conditions where this device would be helpful.

The electrical component of the new patch is because a current keeps the cardiomyocytes beating together, and the gold conducts the current across the tissue. The new device can also be applied to other cells in the body because of the scaffolding implemented.

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Guru

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#6

Re: Gold Nanowires to Treat Heart Attack Patients

09/30/2011 8:59 PM

The idea you presented is startling, and flat out unexpected. The repair of the tissue, as a doable way, was demonstrated to me by a german doctor some 2 years ago, using adult stemcells to repair a wall of the hearth. 2 ambulant applications, 6 months regrowth, practically full reversal. As far as I could see, it was a "proof of concept", but worthy of a Nobel consideration.

This one may be in the same class, time will tell.

If and when I try to express myself in your profession, cut me some slack. I am an electronic engineer, with biochemistry as a second.

And here my thoughts fork onto two different paths. The first is the controlled DNA expressions of the enzyme components (like CoQ10 for example).

The other one, which bothered me for a long time, is the timing of the pulses traveling around the hearth. I understand the description, and agree. BUT, being an engineer first and foremost, I know, that things do stop, and need to be restarted. From outside, or from inside. The restart from inside is the quite interesting problem. Electronic feedback in a loop similar to it starts from environmental noise. That starter is not available - as far as I can tell - for the hearth's round robin electrical pulsing. Taking this model seriously, the hearth ought to stop, with no restart, frequently enough. But, it ticks reliably. Why? Any pointer would be appreciated.

And please forgive me for the present digression.

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