Current Topics in Biomimetics Wrap-Up

Biomimetics is not an emerging field. However, its importance in medical biotechnology is increasing as people begin to realize that engineering cannot out-perform nature. Using nature as a model for the development of biotechnology provides scientists and engineers alike the blueprints to natural mechanisms, which have been refined through millions of years of natural selection. Though we may never achieve perfection in creating technologies that perform as well as natural systems, we can always try to come close. In attempting to achieve perfection we will continue to improve the health of the population and the efficiency of medical care. Biomimetics is the most practical and sustainable field of biotechnology, because nature has millions of natural mechanisms to offer, which have evolved into sustainable forms. Ultimately, through biomimetics, we can make technologies smaller, more efficient, easier to manufacture, and less wasteful. All of which will help reduce healthcare costs and solve additional healthcare problems.

As our most recent post on biomimetic robots points out, biomimetics as a field goes far beyond applications to medicine. It can be used in the military and the automotive industry, as well as in the development of common products like Velcro. However, medical bionics are some of the most useful and cost-effective applications. Biotechnology is an increasingly expensive field with excessive amounts of money spent researching specific solutions to very rare conditions. Nevertheless, biomimetics can help reduce the costs of these technologies by encouraging researchers to mimic the unique solutions nature has already developed, which are usually the most simple and efficient solutions available. For example, the artificial cornea and the new hearing aid technologies are fairly simple and cheap to manufacture and implant. They also work much better than existing technologies to address vision and hearing loss.

On another note, biomimetics can be used to come up with simpler and less expensive solutions to problems that affect a large proportion of the population. Two examples are the biomimetic glue based on worm glue that can repair bones without extensive surgery, along with the mussel adhesive proteins used as surgical adhesive. Another example is Delisea pulchra (red seaweed). The discovery of Delisea pulchra was very significant for the healthcare industry, because it can effectively avoid a wide range of bacterial infections without propagating any bacterial resistance. This can save healthcare costs on many fronts and improve the treatment of bacterial infections without fear of antibiotic resistance. Antibiotic resistance is an example of a human technology gone wrong. Antiobiotics were based on a natural model—pencillin—yet the human application of antibiotics has not been based on the understanding of natural systems. Delisea pulchra is a way to improve upon existing technologies through biomimetics.

Medical bionic technologies do not have to be technologies that are directly applied to the body. They can make hospitals and healthcare safer and more efficient. Examples of this are the anti-bacterial surface technology based on shark skin which could reduce the rates of infection in hospitals and the use of tiny robots that could perform surgery in small arteries in the body. Other robotic surgeries like those based on snakes can improve the safety of healthcare by replacing human error with more consistent technological solutions.

Biomimetic solutions are incredibly useful, but manufacturing these technologies can be extremely difficult. For example, the field of tissue bionics involves mimicking natural tissues. This entails both manipulating tissues and manufacturing synthetic analogues with similar properties. Because these tissues are so complex, it is difficult to reproduce them in the lab. Manipulating existing tissues is easier than manufacturing synthetic materials. One example of the usefulness of manipulated natural materials is the use of naked, natural heart scaffolds to grow new hearts for transplantation. Use of existing materials is a viable alternative to engineering completely new products.

Despite the promise of biomimetics, we need to make sure that we as a society do not become over-dependent on technology to improve health. In the US we have arguably already reached this point. Most of the deaths and loss of quality years of life in the US are a consequence of chronic disease. Often, these types of health problems can be most effectively and inexpensively addressed through preventative measures like healthy eating, routine check-ups, and basic healthcare. If we use nature as a model, not just for innovative technologies, but also for more general principles, we will see that simplicity and integration are key to the proper functioning of all things. We should not try to overcomplicate medicine and spend unnecessary resources looking for solutions to problems that are much more easily prevented than treated. We need to realize that technology will not solve all our problems and that solution-oriented thinking can be harmful when it leads to ignorance of underlying issues that could be more proactively addressed. When we do need to find solutions, we can save time and money that would be spent on research and development by mimicking simple and efficient solutions found in nature.

They're Robots!? Those Beasts!

http://www.nytimes.com/2004/09/16/technology/circuits/16robo.html

Although all of the blog entries thus far have regarded biomimetics as related to medicine, however, it is important to understand that there are several other applications for biomimetics outside of the medical field. In order to shed light on this, and wrap up the Current Topics in Biomimetics blog, I’ve chosen to post an article from the September 16, 2004 edition of the New York Times. This article, written by Scott Kirsner, discusses the use of biomimetic robots, machines inspired by biology, that have the potential to go places that the robots of today’s generation wouldn’t even be able to come close to.

These new-age robots can be used to detect mines, divert the attention of enemies in wartime situations, understand the migratory patterns of certain animals, inspect underground fuel tanks, planetary exploration, as well as perform medical tests and surgeries. One particular biomimetic robot that was profiled in this article was the RoboLobster, designed by Joseph Ayers of Northeastern University. The RoboLobster is a seven-pound, boxy-shelled black lobster funded by the Office of Naval Research to hunt for mines buried beneath beaches, or floating in shallow waters. Dr. Ayers explained that animals are able to adapt to any niche that we would ever want to operate a robot in. The environments in which these mines are hidden are considered fairly harsh by any biological standards; however, live lobsters seem to have no trouble maintaining a sure footing. Thus it makes sense to approach the hazardous issue of these buried mines, by trying to design a robot based off of an incredibly well adapted organism to the area in which they are located.

Another area in which these biomimetic robots are being tailored to is the military. The military has shown an interest in “animal-like” robots since 1968 when General Electric designed an elephant-like walking machine. Another idea that is currently under investigation is a robotic mule that could be used to carry equipment for soldiers and enable them to march longer distances. Also, a company called Yobotics is developing a robotic dog that could potentially serve as a distraction to a sniper, giving soldiers a chance to defend themselves.

This brings up a very controversial issue in the way of these biomimetic robots. They’re incredibly expensive so there is a very valid public question as to whether they’re worth it. This is specifically in regard to the use of these robots for military purposes. There’s a high likelihood that in the face of weapons, machinery, and potentially heavy fire, these biomimetic robots will be destroyed, and reduced to nothing more than the biologically inspired parts that they were put together with. Thus, the thousands of dollars that were spent building this robot, in addition to the money necessary for research and development, may potentially be put to waste in the span of less than a year should the robot be used in the military.

However, as I mentioned earlier, these robots do have medical applications as well, which may make them more sensible in regard to their cost. Biomimetic robots have the potential to be used in robotic surgeries, should a biological model be deemed a better system than human hands. Thus, these biomimetic robots have the potential to be the future of medical surgeries.

Endothelial Inspired Polymeric Coating

Commentary on:

Preparation and characterization of polymeric coatings with combined nitric oxide release and immobilized active heparin

6 June 2005 - ScienceDirect database

Link to study here

In this study, a biomimetic approach was taken in order to improve the blood compatibility of polymeric materials used to construct or coat a variety of blood-contacting medical devices, such as vascular grafts. One of the major causes of graft failure remains lack of a functional endothelium on the luminal surface of a synthetic vascular graft, which leads to acute thrombosis and subsequent occlusion of the vessel. By mimicking the nonthrombogenic properties of the endothelial cell layer that lines the inner wall of healthy blood vessels, a new dual acting polymeric coating was produced. This biomimetic polymeric coating mimics the function of the endothelial layer by the anti-platelet component, nitric oxide, and anti-coagulant component, heparin.

The blood compatible coating is a fine example of the promise of biomimetics in the field of artificial vascular graft development of the biomedical industry. The surface composition of a biomaterial can have an important influence on biologic responses. Changing the surface chemistry of a synthetic graft by coating it with endothelial cell components is a great way to enhance thromboresistivity and further improve the vascular graft’s patency rate. In particular, this biomimetic coating may prove to be more of a solution for small-diameter grafts, since large-diameter vascular grafts remain excellent for more than ten years after implantation, while small-diameter vascular grafts typically occlude rapidly upon implantation.

Even though this particular biomimetic coating is one of many ways that biomedical engineers have developed in order to improve current polymer materials used to construct a variety of blood-contacting medical devices, it is a risk-averse method. By understanding the biology of the endothelial layer and its ability to control thrombosis, it makes sense to apply an endothelial inspired biomimetic approach. Biomimetic models, such as this coating, are used because they already have the biological proven research to ensure their feasibility. It’s just a matter of being able to properly replicate them.

Preventing Bacterial Growth in Hospitals: The Sharklet Hygienic Surface™

http://www.sharklet.com/market.html

We think of hospitals as places we go to get better when we are sick. Ideally, you enter the hospital with a problem, and you leave with a cure. Unfortunately, sometimes the opposite is true. Each year thousands of people die from healthcare-associated infections, or HAIs. Patients are admitted to the hospital to be treated for one thing and in the process sometimes pick up an infection such as methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE). According to the Center for Disease control, approximately 1.7 million people contract HAIs in American hospitals every year.
Many of these infections can be prevented by following proper protocol. One of the most basic things doctors and nurses can do to protect their patients is wash their hands before and after contact with patients. However, while this seems like a simple solution, many doctors find it difficult to adhere strictly to the rules. In his book, Better: A Surgeon’s Notes on Performance (Metropolitan Books), Dr. Atul Gawande explains why doctors are so reluctant to follow proper hand washing procedure: “On morning rounds, our residents check in on twenty patients an hour….Even if you get the whole process down to a minute per patient, that’s still a third of staff time spent just washing hands. Such frequent hand washing can also irritate the skin, which can produce a dermatitis, which itself increases bacterial counts.” The introduction of alcohol-based sanitizing gels has helped the problem considerably, but infection rates are still staggeringly high.
Another common method of HAI transmission is through contact with infected surfaces. Bacteria can live for hours on surfaces, turning hospital rooms into bacterial breeding grounds. Sharklet Technologies, Inc, a Florida-based life sciences company, has developed a solution to this problem: the Sharklet Hygienic Surface™. Used to cover surfaces that are often touched by doctors and patients, this product resists bacterial growth without using chemicals or toxins. The anti-bacterial properties come from the texture of the material. Inspired by the pattern of shark skin (which naturally resists growth of bacteria), the Sharklet Hygienic Surface is etched with microscopic diamond shapes. The surface has been shown to drastically reduce bacterial growth compared to smooth surfaces without contributing to antibiotic resistance.
The potential applications of this technology go far beyond the hospital room. Sharklet plans to design a catheter using the same pattern, hoping it will reduce the incidence of infections caused by catheters. It could also be used on surfaces in public restrooms, schools, restaurants, and anywhere else where bacterial growth could pose a health risk.
If this technology works and is implemented in hospitals around the country, it could have serious effects on our healthcare system. Each year billions of dollars are spent treating HAIs in millions of patients. Reducing the number of HAIs will save insurance companies money and allow hospitals to reallocate resources that were once used to treat these infections. Part of the solution to this problem must come from hospital personnel following procedures like hand washing, but making hospital surfaces resistant to bacterial growth would help considerably in the fight against healthcare-associated infections.

An Artificial Cornea is in Sight, Thanks to Biomimetic Hydrogels

http://news-service.stanford.edu/news/2006/september13/cornea-091306.html?

The cornea of the eye is positioned as the outermost lens, serving as a shield for the eye from dust and germs as well as contributing to up to seventy-five percent of the eye’s focusing power. A damaged or diseased cornea is the cause of blindness for at least ten million people worldwide, and a misshapen cornea is the source of nearsighted or farsightedness in many millions more worldwide. However, thanks to a new advancement in the field of biomimetics, there may, for the first time, be a solution. This article appeared in the Stanford University News on September 13, 2006. In it, author Dawn Levy details the potential that his novel biomiemetic material could have in the field of artificial corneas.

This innovative new technology is nothing more than a

polymer that is capable of holding a large amount of water. The material, invented by a team of ophthalmologists, bioengineers and chemical engineers, is called Duoptix and can swell to a water content of about eighty percent – the same capacity of that of a biological tissue. A very important aspect of this biocompatible hydrogel is that it is transparent as well as permeable to nutrients, including glucose, the cornea’s favorite energy source. In order to make the artificial cornea, the hydrogel has been shaped into a disc with a clear center and very small pores that populate the periphery, allowing cells to permeate the artificial lens and integrate it into the surrounding tissue.

Artificial corneas have been developed in the past, but none have been well tolerated by patients. Currently the only other option in the way of artificial corneas is corneal transplant from cadavers. However, this donor tissue has about a twenty percent rejection rate, and a visual recovery of about six months. This new hydrogel, has the potential to make these problems of the past with a simple, fast, and incredibly effective artificial lens.

Personally, I see this is an incredible breakthrough in biomimetics. This polymer may be artificial in the way that it’s produced, however, it receives inspiration from real molecules, synthesized by human tissue cells. Basically, although it’s technically artificial, this material is being modeled after the best subject that we have: the human body itself. In my mind there is no better way to create a solution, than to model it after the system that is creating the problem. Although human cadaveric tissue has appeal in that it is truly a human solution the Duoptix lens is able to create the same effect as real tissue, yet bypass the problem that comes up in all types of organ transplant – rejection of a different human body’s tissue. Additionally, this artificial cornea is not out of financial reach of many people who may need it. It is not a very pricey procedure and thus, in regard to the current issues with healthcare it is the most sensible option. It’s reliable, durable, and within a reasonable price range.

Bee Inspired Robot

Nissan Press Release, September 26, 2008

Nissan Exhibits for CEATEC Japan

"Crash Avoidance Robotic Car inspired by Flight of the Bumblebee"

http://www.nissan-global.com/EN/NEWS/2008/_STORY/080926-01-e.html

Nissan has partnered with the University of Tokyo’s Research Center for Advanced Science and Technology to build a biomimetic accident-avoiding robot, the BR23C. This joint research studied a bee’s ability to avoid collisions. They found out that bees are capable of seeing more than 300-degrees, due to bee’s compound eyes, which allows them to steer clear of collisions and fly uninterrupted. In order to replicate the function of a bee’s compound eye, Nissan engineers thought to use a Laser Range Finder (LRF). “The LRF detects obstacles up to two meters away within a 180-degree radius in front of the BR23C, calculates the distance to them, and sends a signal to an on-board microprocessor, which is instantly translated into collision avoidance.” A bee will change direction if an obstacle enters its “safety zone”, likewise, the BR23C will react by turning its wheels at a 90-degree angle or greater to avoid the object. Nissan hopes that the BR23C will promote the progress of future collision-avoidance technologies.

The application of this safety feature in cars could drastically decrease automobile accident rates. With 4,563,000 automobile accidents per year requiring emergency department visits (CDC, 2000), there is a need for added safety amongst drivers. I particularly like the idea that Nissan is undergoing research to prevent automobile collisions altogether, rather than developing accident resilient vehicles. This novel technology is unique in the way that its avoidance maneuvering is completely instinctive. Thus, allowing it to respond fast enough to avoid accidents. However, I find the technology far removed from applying to cars that are on a highway going 80 mph. With the LRF only able to detect objects up to 2 meters away, it would be impossible to steer clear of an obstacle while on a highway. Also, a car’s maneuverability or handling would have to be remarkable in order to keep the car from flipping or skidding out of control. Though the BR23C is far from applying to real world applications, it is a great start to potentially collision free streets. It’s amazing to think that a simple bee could provide the basis for technology that could revolutionize the automobile industry.

Artificial bacteria flagella that act as surgical micro robots

Commentary on:
Medical Micro-Robots Made As Small As Bacteria
in ScienceDaily (Apr. 19, 2009)
http://www.sciencedaily.com/releases/2009/04/090418085333.htm

Medical 'microbot' to swim human arteries
in Cosmos Magazine. By Agence France-Presse (Jan. 21, 2009)
http://www.cosmosmagazine.com/news/2484/medical-microbot-swim-human-arteries?page=0%2C0


This new biomimetic technology seems like something out of the Magic School Bus kids' book series. Imagine tiny self-propelling microbots that can enter the bloodstream and deliver drugs, remove plaque from clots, do micro-scale surgeries, etc. all under the control of a physician. This science-fiction-esque future of medicine is becoming increasingly feasible with the recent invention of the “Artificial Bacterial Flagella” (ABFs). They were invented, manufactured and enabled to swim in a controllable way by researchers in the group led by Bradley Nelson, Professor at the Institute of Robotics and Intelligent Systems at ETH Zurich. There are many other pioneers working in this field of medical microbots, as well.

What is unique about these microscopic microbots is how remarkably they resemble flagella bacteria. They range in size from 25-65 micrometers in length while bacteria are only slightly smaller at 5-25 micrometers and they move just as bacteria do--via propulsion from the spiral whip-like tail based precisely on that of the bacteria. These artificial bacteria are made of ultra-thin layers of the elements indium, gallium, arsenic and chromium vapor-deposited onto a substrate in a particular sequence which forms super-thin, very long narrow ribbons that curl themselves into a spiral shape as soon as they are detached from the substrate. There is also a tiny "head" attached to one end made out of chromium-nickel-gold tri-layer film which is slightly-magnetic. This magnetism is what allows the bacteria to propel itself and be controlled by scientists without using any energy or moving parts. "The ABF can be steered to a specific target by tuning the strength and direction of the rotating magnetic field which is generated by several coils. The ABFs can move forwards and backwards, upwards and downwards, and can also rotate in all directions." As of now these ABFs can swim at about the same speed as bacteria but scientists predict that they will be able to create ABFs that can swim at least 3 times as fast.

ABFs are still undergoing basic research and its healthcare applications are far in the future, however, with the invention of these ABFs the use of microbots in medicine is becoming increasingly feasible. One of the earliest applications of this technology will probably be for observation such as through transmitting images. Nelson believes that ABFs could eventually be used on the cellular level to repair cell damage, remove plaque, among other surgical applications, which will greatly expand the ability of today's healthcare to treat a wide variety of diseases and disorders. In theory, the ABFs could be injected into the bloodstream and then controlled via an external remote control and then once done traveling where needed and performing the necessary tasks, they would be removed via syringe at the point of entry.

With further development the technology will likely become much more accurate than physician surgery and will go far beyond what any physician today can do. This may revolutionize surgery, however, it has potential applications beyond surgery including drug-delivery. If ABFs can carry medicines to the exact target cells and areas that need them, the side effects that develop from today's systemic drugs will be a thing of the past. The impact of this technology on the cost of healthcare will depend on the application. Drug-delivery will be more expensive if ABFs are used than the standard pill-form, however some surgeries may be less expensive with the use of microbots. Many diseases like atherosclerosis that are very common in the U.S. are prime candidates for this technology and because of this, microbots have the potential to have a tremendous impact on the healthcare industry in the future.

The ability of Nelson's team to create an artificial bacteria that so accurately resembles the structure and function of a flagella bacteria opens up endless possibilities for biomedical applications and proves that the use of microbots in medicine may not be too far off in the future.