Silk in Medical Devices

In our last blog post, we examined the applications of the nanomaterials of liquorice. This post also deals with a well known material: silk. Silk is often recognized as a great textile, yet this material that has been around for centuries has very pertinent applications in the nanomaterials and medical implant industry. A recent Ted Talk by Fiorenzo Omenetto, a Professor of Biomedical Engineering at Tufts University, examines many of the attractive properties that silk has to offer, particularly its ability to be biocompatible and transmit light.



Omenetto envisions applications of silk that could revolutionize the medical industry. Silk fibers could carry light to places in the body for internal imaging, giving doctors the ability to perform diagnostic exams through very small openings in the body because the diameter of spider silk is a mere 5 microns think, 10 times thinner than human hair. Silk bandages equipped with electronics could be developed to monitor patients. Omenetto states that the best part about using silk is that "these materials are harmless so you can implant them." Couple this with scientists ability to use spider silk to fabricate electronic computer chips and you have an extremely powerful medical monitoring device.

Not only are device made out of silk biocompatible, but they are also programmable to decompose. Currently most medical implants need to be surgically removed after fulfilling their use. A team led by John Rogers at the University of Illinois Urbana-Champaign, created a special silk coating that would be able to dissolve in liquids. Because the material is non toxic, upon dissolving in a liquid environment like the human body, there would be no need for surgical removal and the risk of post-surgery infection would be reduced.

Although these applications of silk are sill not commercially feasible, Omenetto believes that in just a mere decade, silk will be the future of medical devices.


 

Liquorice in Nano-coating?

A recent study done by a team of researchers from Australia and Germany found a novel solution to a common problem in the medical field. The dilemma was that the biological components in medical implants are sensitive and can be damaged by harsh sterilization processes such as exposure to toxic gas or a blast of radiation. This would make the devices useless but sterilization cannot be avoided and is necessary to protect infection in patients when the devices are implanted. The research team discovered that a component in liquorice, glycrrhyzic acid, can be used to create a nano-coating on the surface of the medical device. The coating protects the bio-molecules from getting damaged by sterilization processes. It is unique in that it has no sugars, sugar-alcohol compounds or proteins that would hinder the biological activity of the device, unlike other stabilizing methods. The efficacy of this technique was tested by blasting a test device with radiation to completely sterilize it, resulting in no damage to the nano-coating and proteins and maintaining the function of the device. Now that the problem of medical devices containing biological components has been solved, the nano-coating can be used in the manufacturing of more effective biomedical devices.

So how exactly does the nano-coating protect proteins from radiation? Here is a diagram from the published article of what happens during the nano-coating process. (a) The “Y” shapes are proteins that are on the surface of a device. In (b), they are embedded with the nano-coating and dried. As seen in (c), the proteins are protected from radiation, which are represented by lightning bolt symbols. (d) The nano-coating is removed through rehydration. The gray oval shapes in (e) and (f) are the nano-coating that “stabilizes” the proteins by doing hydrogen bonding with the proteins and by replacing water. The coating ensures that radiation does not denature the proteins in the medical implant.

By: Soohee Lee and Olivia Park 

An illustration of the nano-coating process

Nanotechnology in Medicine

Here is an interesting article discussing the impact of nanotechnology on the medical field. Catharine Paddock, PhD defines nanotechnology in the following fashion:

“the manipulation of matter at the atomic and molecular scale to create materials with remarkably varied and new properties, is a rapidly expanding area of research with huge potential in many sectors, ranging from healthcare to construction and electronics.”

For the uninitiated, the nanoscale is incredibly small; one nanometer is approximately 3-5 atoms thick or about 40,000 times thinner than the human hair. Working at such microscopic levels gives scientists the ability to exploit interesting structures and properties of nanomaterials.  Such innovation technology is extremely promising for the medical industry; nanotechnology “promises to revolutionize drug delivery, gene therapy, diagnostics, and many areas of research, development and clinical application.”

Many of the applications of nanotechnology with regards to medical implants will be presented here as well as the concerns highlighted in the article about nanotechnology in general.

One use of nanotechnology is the fabrication of nanobots in the treatment of patients of various diseases. The primary benefit of nanobots is that it allows for the precise delivery of drugs. These nanobots bind to specific targeted molecules in the body and then release the drug they are carrying upon contact. Materials like gold have been researched and used for the fabrication of nanobots. An idea proposed by a MIT research team is to create nanomaterials that fabricate drugs at the site of the disease in the body. This solves the problem of drugs breaking down while being delivered to disease sites. 1

Like many other parts of science, fibers have recently been taken to the nanoscale as well. Fibers with “diameters of less than 1,000 nm” are referred to as nanofibers. Nanofibers have shown to have extremely important applications in “wound dressings, tissue engineering,” and medical implants as well. Until the past few years, synthesizing nanofibers has been a painstaking, time-consuming, and very expensive process. Researchers have, however, come up with a new method for developing nanofibers. The secret lies in the nickel nanoparticles - because of their structure, they can help grow nanofibers at high temperatures. Of course, in a modern-day lab setting, attaining these high temperatures is extremely cost-effective, and thus, making nanofibers is now a relatively cheap process.

Lead nanofibers have achieved a niche in the field of surgery, where surgeons are using lead nanofiber meshes to repair certain membranes found in the brain and spinal cord. For these situations, extremely small and not thick particles are needed. The applications can also be extended to fixing “hernias, fistulas, and other injuries.” Due to their versatility, nanofibers can be considered extremely important in the field of surgery and medical implants.

The future of nanotechnology in medical implants is not as rosy as it seems. There exist many concerns and obstacles regarding nanotechnology. The production costs of creating these unique nanomaterials are costly and cannot be adopted on a big manufacturing scale. The safety of nanomaterials has not been studied as extensively as other materials. Although the National Cancer Institute in the US states that most nanomaterials are less toxic than common household products, there still exists much ambiguity surrounding nanomaterials in general. There are concerns about what would happen to the human body if nanomaterials do not break down and dissolve as they were engineered to do.

Nanotechnology has the potential to revolutionize the medical industry despite some drawbacks and concerns about it. Stay tuned to our blog as we seek to document discoveries and innovations for nanotech medical implants.