Tag Archives: electrospinning

Magnetospinning with an inexpensive magnet

The fridge magnet mentioned in the headline for a May 11, 2015  Nanowerk spotlight aricle by Michael Berger isn’t followed up until the penultimate paragraph but it is worth the wait,

“Our method for spinning of continuous micro- and nanofibers uses a permanent revolving magnet,” Alexander Tokarev, Ph.D., a Research Associate in the Nanostructured Materials Laboratory at the University of Georgia, tells Nanowerk. “This fabrication technique utilizes magnetic forces and hydrodynamic features of stretched threads to produce fine nanofibers.”

“The new method provides excellent control over the fiber diameter and is compatible with a range of polymeric materials and polymer composite materials including biopolymers,” notes Tokarev. “Our research showcases this new technique and demonstrates its advantages to the scientific community.”

Electrospinning is the most popular method to produce nanofibers in labs now. Owing to its simplicity and low costs, a magnetospinning set-up could be installed in any non-specialized laboratory for broader use of magnetospun nanofibers in different methods and technologies. The total cost of a laboratory electrospinning system is above $10,000. In contrast, no special equipment is needed for magnetospinning. It is possible to build a magnetospinning set-up, such as the University of Georgia team utilizes, by just using a $30 rotating motor and a $5 permanent magnet. [emphasis mine]

Berger’s article references a recent paper published by the team,

Magnetospinning of Nano- and Microfibers by Alexander Tokarev, Oleksandr Trotsenko, Ian M. Griffiths, Howard A. Stone, and Sergiy Minko. Advanced Materials First published: 8 May 2015Full publication history DOI: 10.1002/adma.201500374View/save citation

This paper is behind a paywall.

* The headline originally stated that a ‘fridge’ magnet was used. Researcher Alexander Tokarev kindly dropped by correct this misunderstanding on my part and the headline has been changed to read  ‘inexpensive magnet’ on May 14, 2015 at approximately 1400 hundred hours PDT.

Honey nanofibres tested as scaffolding for wound dressing in an Iran-Netherlands collaboration

It’s taken me a while to get to this one but I can’t resist this honey-enabled technology any longer. According to a Sept. 19, 2013 news item on Nanowerk, honey, a well known antibiotic, has been used in a new technique for wound dressings (Note: A link has been removed),

Researchers applied electrospinning process and produced a drug-carrying nanofibrous web to be used in wound dressing by using an artificial and biodegradable polymer and honey as a natural polymer (“A novel honey-based nanofibrous scaffold for wound dressing application”).

A wide range of biological and biodegradable materials have been electrospun in recent years to produce nanofibers. In this research, a drug carrying nanofibrous web was produced to be used in wound dressing by using an artificial and biodegradable polymer and a natural polymer through electrospinning method.

The Sept. 19, 2013 Iran National Nanotechnology Initiative Council (INIC) news release, which originated the news item, mentions honey’s antibiotic properties and explains how its application in this new technique for wound dressing,

Honey has antibacterial and anti-inflammation properties. Many studies have been published on the effects of honey in the treatment of infections and in prevention of the wound from being infected. Therefore, the combination of the unique properties of nanofibers and the natural properties of honey in the production of wound dressing is the most important characteristic of this research.

SEM [scanning electron microscope] and AFM [atomic force microscope] results showed that the fibers were completely homogenous with relatively smooth surface. However, spindle-like beads were observed in nanofibers containing 60% honey. As the concentration of honey increased in the mixture, a decrease was observed in the diameter of nanofibers. Drug-loaded nanofibers, too, had relatively smooth and homogenous surface, and as the amount of drug increases, the diameter of the nanofibers decreased. Drug release behavior studies demonstrated a sudden initial release. Statistical analyses showed that the presence of honey did not have significant effect on the process or on the behavior of drug release. Therefore, electrospun nanofibers that contain honey are appropriate option to be used in wound dressing.

Wounds can be dressed faster by using the achievements of this research. Honey is considered as a well-known drug in traditional medical sciences, which has been loaded with drugs in this research.

The research paper’s (a link and citation will be provided further down) abstract provides a bit more detail,

In this study, nanofiber meshes were produced from aqueous mixtures of poly(vinyl alcohol) (PVA) and honey via electrospinning. The Electrospinning process was performed at different PVAs to honey ratios (100/0, 90/10, 80/20, 70/30, and 60/40). Dexamethasone sodium phosphate was selected as an anti-inflammatory drug and incorporated in the electrospinning solutions. Its release behavior was determined. Uniform and smooth nanofibers were formed, independent of the honey content. In case honey content increased up to 40%, some spindle-like beads on the fibers were observed. The diameter of electrospun fibers decreased as the ratio of honey increased. The release characteristics of the model drug from both the PVA and PVA/honey (80/20) nanofibrous mats were studied and statistical analysis was performed. All electrospun fibers exhibited a large initial burst release at a short time after incubation. The release profile was similar for both PVA and PVA/honey (80/20) drug-loaded nanofibers. This study shows that an anti-inflammatory drug can be released during the initial stages and honey can be used as a natural antibiotic to improve the wound dressing efficiency and increase the healing rate.

Here’s a link to and a citation for paper,

A novel honey-based nanofibrous scaffold for wound dressing application by  H. Maleki, A. A. Gharehaghaji, and P. J. Dijkstra.
Journal of Applied Polymer Science, Volume 127, Issue 5, pages 4086–4092, 5 March 2013 (Article first published online: 29 MAY 2012) DOI: 10.1002/app.37601

Copyright © 2012 Wiley Periodicals, Inc.

This article is behind a paywall.

One final note, the researchers are from (Maleki and Gharehaghaji) Amirkabir University of Technology, Tehran, Iran and (Dijkstra) the University of Twente, Enschede, The Netherlands

Contraception and HIV protection in cloth*

Researchers at the University of Washington have published a study in the peer-reviewed, open access journal, Public Library of Science ONE (PLoS ONE), concerning their work to produce fibres that can deliver both contraceptives and anti-HIV drugs, according to a Nov. 30, 2012 news item on Nanowerk,

The only way to protect against HIV and unintended pregnancy today is the condom. It’s an effective technology, but not appropriate or popular in all situations.

A University of Washington team has developed a versatile platform to simultaneously offer contraception and prevent HIV. Electrically spun cloth with nanometer-sized fibers can dissolve to release drugs, providing a platform for cheap, discrete and reversible protection.

Hannah Hickey’s  Nov. 30, 2012 University of Washington news release, which originated the news item, provides details,

“Our dream is to create a product women can use to protect themselves from HIV infection and unintended pregnancy,” said corresponding author Kim Woodrow, a UW assistant professor of bioengineering. “We have the drugs to do that. It’s really about delivering them in a way that makes them more potent, and allows a woman to want to use it.”

Electrospinning uses an electric field to catapult a charged fluid jet through air to create very fine, nanometer-scale fibers. The fibers can be manipulated to control the material’s solubility, strength and even geometry. Because of this versatility, fibers may be better at delivering medicine than existing technologies such as gels, tablets or pills. No high temperatures are involved, so the method is suitable for heat-sensitive molecules. The fabric can also incorporate large molecules, such as proteins and antibodies, that are hard to deliver through other methods.

They first dissolved polymers approved by the Food and Drug Administration and antiretroviral drugs used to treat HIV to create a gooey solution that passes through a syringe. As the stream encounters the electric field it stretches to create thin fibers measuring 100 to several thousand nanometers that whip through the air and eventually stick to a collecting plate (one nanometer is about one 25-millionth of an inch). The final material is a stretchy fabric that can physically block sperm or release chemical contraceptives and antivirals.

“This method allows controlled release of multiple compounds,” Ball said. “We were able to tune the fibers to have different release properties.”

One of the fabrics they made dissolves within minutes, potentially offering users immediate, discrete protection against unwanted pregnancy and sexually transmitted diseases.

Another dissolves gradually over a few days, providing an option for sustained delivery, more like the birth-control pill,  to provide contraception and guard against HIV.

The fabric could incorporate many fibers to guard against many different sexually transmitted infections, or include more than one anti-HIV drug to protect against drug-resistant strains (and discourage drug-resistant strains from emerging). Mixed fibers could be designed to release drugs at different times to increase their potency, like the prime-boost method used in vaccines.

The electrospun cloth could be inserted directly in the body or be used as a coating on vaginal rings or other products.

Electrospinning has existed for decades, but it’s only recently been automated to make it practical for applications such as filtration and tissue engineering. This is the first study to use nanofibers for vaginal drug delivery.

While this technology is more discrete than a condom, and potentially more versatile than pills or plastic or rubber devices, researchers say there is no single right answer.

The citation and link to the article,

Drug-Eluting Fibers for HIV-1 Inhibition and Contraception by Cameron Ball, Emily Krogstad, Thanyanan Chaowanachan, Kim A. Woodrow (2012) PLoS ONE 7(11): e49792. doi:10.1371/journal.pone.0049792

Last month, the Bill and Melinda Gates Foundation awarded these researchers a $1M grant to pursue this work.

*ETA Dec.2.12: I erroneously used the word clothing in the headline. It’s now been corrected to ‘cloth’.

Printing new knee cartilage

I was reminded of the 1992 Olympics in Barcelona while reading the Nov. 22, 2012 news item on Nanowerk about printing cartilage for knees. Some years ago I knew a Canadian wrestler who’d participated in those games and he had a story about knee cartilage that featured amputation.

Apparently, wrestlers in earlier generations had knee surgeries that involved removal of cartilage for therapeutic purposes. Unfortunately, decades later, these retired wrestlers found that whatever cartilage had remained was now worn through and bones were grinding on bones causing such pain that more than one wrestler agreed to amputation. I never did check out the story but it rang true largely because I’d come across a similar story from a physiotherapist regarding  a shoulder joint and the consequences of losing cartilage in there (very, very painful).

It seems that scientists are now working on a solution for those of us unlucky enough to have damaged or worn through cartilage in our joints, from the Nov. 22, 2012 IOP science news release, (Institute of Physics) which originated the news item,

The printing of 3D tissue has taken a major step forward with the creation of a novel hybrid printer that simplifies the process of creating implantable cartilage.

The printer is a combination of two low-cost fabrication techniques: a traditional ink jet printer and an electrospinning machine. Combining these systems allowed the scientists to build a structure made from natural and synthetic materials. …

In this study, the hybrid system produced cartilage constructs with increased mechanical stability compared to those created by an ink jet printer using gel material alone. The constructs were also shown to maintain their functional characteristics in the laboratory and a real-life system.

The key to this was the use of the electrospinning machine, which uses an electrical current to generate very fine fibres from a polymer solution. Electrospinning allows the composition of polymers to be easily controlled and therefore produces porous structures that encourage cells to integrate into surrounding tissue.

In this study, flexible mats of electrospun synthetic polymer were combined, layer-by-layer, with a solution of cartilage cells from a rabbit ear that were deposited using the traditional ink jet printer. The constructs were square with a 10cm diagonal and a 0.4mm thickness.

The researchers tested their strength by loading them with variable weights and, after one week, tested to see if the cartilage cells were still alive.

The constructs were also inserted into mice for two, four and eight weeks to see how they performed in a real life system. After eight weeks of implantation, the constructs appeared to have developed the structures and properties that are typical of elastic cartilage, demonstrating their potential for insertion into a patient.

The researchers state that in a future scenario, cartilage constructs could be clinically applied by using an MRI scan of a body part, such as the knee, as a blueprint for creating a matching construct. A careful selection of scaffold material for each patient’s construct would allow the implant to withstand mechanical forces while encouraging new cartilage to organise and fill the defect.

The researchers’ article in the IOP science jouBiofrarnal, Biofabrication, is freely available for 30 days after its date of publication, Nov. 21, 2012. You do need to register with IOP science to gain access. Here’s the citation and a link,

Hybrid printing of mechanically and biologically improved constructs for cartilage tissue engineering applications by Tao Xu, Kyle W Binder, Mohammad Z Albanna, Dennis Dice, Weixin Zhao, James J Yoo and Anthony Atala in 2013 Biofabrication 5 015001 doi:10.1088/1758-5082/5/1/015001

I believe all of the scientists involved in this bioprinting project are with the Wake Forest Institute for Regenerative Medicine.

A breath-based and handheld diagnostic device

Researcher Perena Gouma and her team at Stony Brook University (New York, US) are hoping that eventually their device will be available over the counter so anyone will be able to perform a preliminary diagnostic test as casually as you take a breath. From the May 7, 2012 news item on Nanowerk,

You blow into a small valve attached to a box that is about half the size of your typical shoebox and weighs less than one pound. Once you blow into it, the lights on top of the box will give you an instant readout. A green light means you pass (and your bad breath is not indicative of an underlying disease; perhaps it’s just a result of the raw onions you ingested recently); however, a red light means you might need to take a trip to the doctor’s office to check if something more serious is an issue.

Here’s a bit more about the device and the researchers’ hopes in a video from the US National Science Foundation (NSF) featuring the NSF’s Miles O’Brien as the reporter,

O’Brien in his May 7, 2012 article for the NSF’s Science Nation online magazine describes the technology,

With support from the National Science Foundation (NSF), Professor Perena Gouma and her team at Stony Brook University in New York developed a sensor chip that you might say is the “brain” of the breathalyzer. It’s coated with tiny nanowires that look like microscopic spaghetti and are able to detect minute amounts of chemical compounds in the breath. “These nanowires enable the sensor to detect just a few molecules of the disease marker gas in a ‘sea’ of billions of molecules of other compounds that the breath consists of,” Gouma explains. This is what nanotechnology is all about.

The manufacturing process that creates the single crystal nanowires is called “electrospinning.” It starts with a liquid compound being shot from a syringe into an electrical field. The electric field crystallizes the inserted liquid into a tiny thread or “wire” that collects onto an aluminum backing. Gouma says enough nanowire can be produced in one syringe to stretch from her lab in Stony Brook, N.Y. to the moon and still be a single grain (monocrystal).

“There can be different types of nanowires, each with a tailored arrangement of metal and oxygen atoms along their configuration, so as to capture a particular compound,” explains Gouma. “For example, some nanowires might be able to capture ammonia molecules, while others capture just acetone and others just the nitric oxide. Each of these biomarkers signal a specific disease or metabolic malfunction so a distinct diagnostic breathalyzer can be designed.”

Gouma also says the nanowires can be rigged to detect infectious viruses and microbes like Salmonella, E. coli or even anthrax. “There will be so many other applications we haven’t envisioned. It’s very exciting; it’s a whole new world,” she says.

I think most (if not all) of the handheld diagnostic projects I’ve covered have been fluids-based, i.e., they need a sample of saliva, blood, urine, etc. to perform their diagnostic function. I believe this is the first breath-based project I’ve seen.