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.

Signal Jamming in the Fight Against Bacteria

http://www.biomimicry.typepad.com/newsletter/files/bioinspired_v5.1.pdf

A fairly recent development in the field of biomimicry has been the discovery that the red seaweed, Delisea pulchra can effectively avoid a wide range of bacterial infections without propagating any bacterial resistance. This article, written by Norbert Hoeller and Peter Steinberg, is published in the first issue of the fifth volume of BioInspired! It reviews the new mechanism by which we understand bacterial growth and replication as well as introduces a fairly significant discovery regarding the use of Delisea pulchra that may help treat bacterial infection.

Hoeller and Steinberg explain that scientists previously believed bacteria to be simple, free-floating cells whose rapid rate of reproduction led to infection, which then caused illness. However, it’s now known that in their natural environments, bacteria organize themselves into communities called “biofilms”. These biofilms form complex multi-cellular structures of cells, carbohydrates, DNA and proteins, and sometimes develop specific channels that can be used to transport nutrients and waste. In addition to having the ability to organize into complex structures, these bacteria can also detect and release chemical signals and in effect, communicate with each other, as the cells of a multi-cellular organism would do.

This finding has proven to be incredibly important, as it has preceded the discovery that biofilms can become more resistant to antibiotics than just free-floating bacteria alone. So, though this isn’t really the main point of the article, the magnitude of this discovery is, nonetheless, nothing short of incredible. For years we have thought of bacteria as these simple organisms that are very similar to viruses in the way that they mutate rapidly and, in regard to drug resistance, dangerously. But now that we know we’re no longer fighting off just bacteria, but living systems, with antibiotics, more solutions to treating infections can be researched.

This article pinpoints one way that we can gain control over these living systems. One of the article’s authors, Peter Steinberg, was on a scuba diving expedition when he discovered that a certain species of seaweed, Delisea pulchra, was oddly free of any fouling on its surface. After doing a little more research, Steinberg discovered this red seaweed had a way of preventing the creation of biofilms when bacteria landed on its surface. Over the past several years, this discovery has been adapted to the manufacturing world, specifically in the reduction of bacteria bio-film build-up on contact lenses. Additionally, solutions are being developed to control bio-films that cause corrosion of oil and gas pipelines, thereby reducing the need for biocides and mechanical cleaning of pipes.

There is really no argument regarding the great value of this discovery. Not only can this organism control disease as well as reduce the need for toxic biocides, it can also control bacteria without killing them. Thus, if the bacteria aren’t dying, there is no occurrence of natural selection, thus less harmful mutations to deal with. Additionally, in regard to the ability of Delisea pulchra to control bacteria, less money would be spent on antibiotics as well as hospital visits for antibiotic-resistant strains of bacteria. So, in regard to healthcare, this biomimetic would be far more cost-effective than most all pharmaceuticals.

Synthetic bone glue based on marine worm secretions

Synthetic Sea Worm Glue May Mend Shattered Knee, Face Bones
ScienceDaily (Nov. 26, 2008)
http://www.sciencedaily.com/releases/2008/11/081125085620.htm

Glue bones
Aug 25th 2009
From Economist.com
http://www.economist.com/
displaystory.cfm?story_id=14299348

The discovery of a marine worm's shell-building mechanism has sparked the recent development of what might be the ideal bone fracture adhesive. The sandcastle worms lives in a mineral shell made from sand glued together by the worm's own adhesive secretion. The glue adheres to surfaces in aqueous solutions, does not dissolve, is relatively strong, and last year, Russel Stewart of the University of Utah figured out how it works. "The worm 'secretes two little dabs of glue onto the [sand, shell or other] particle,' says Stewart. 'And the building organ puts it onto the end of the tube and holds it there for about 25 seconds, wiggling it a little to see if the glue is set, and then it lets go. The glue is designed to set up and harden within 30 seconds after the worm secretes it.'" The molecular ingredients include a mixture of proteins and ions that create a specific charge,. In addition, the acidic gland that the glue is made in plays another vital role because when the substance is exposed to the alkaline water, it very quickly sets to form a very strong adhesive. And now Stewart has taken this magnificient biological adaptation and used the molecular knowledge to engineer a synthetic bone glue that not only functions like the sandcaste worm adhesive, but actually works better.

This glue is made out of two synthetic polymers with the same chemical groups and a similar electrical charge to that of the worm's glue-like secretion. "'We made polymers with side chains that mimicked the positive and negative charges in the worm glue,' Stewart says." The result is a synthetic bone glue that is twice as strong as the worm secretion and sets from liquid to solid based on temperature as well as acidity. In addition, though only early tests have been conducted, the glue appears to be non-toxic and biodegradable.

The benefit of this biomimetic technology for the healthcare industry would be tremendous. Fractures are common injuries and though simple, linear types can heal on their own and large fractures can be set with pins and screws, more complex fractures that are too small to set with pins are very hard to repair properly. This glue would be inexpensive and would require simplified procedures than current broken bone repair. In addition, the glue sets very quickly allowing the patient to regain function and mobility without the aid of inserted metal screws or pins. The glue also biodegrades, theoretically leaving the healed, native bone in its place, even for the most complex fractures. The development of a safe and effective adhesive that can be used in aqueous solutions has been a long time coming. Current glue alternatives are too toxic to be used in deep tissues and are used only in superficial skin wounds or in elderly people in which toxicity over the long term is not as much of an issue, such as in hip replacements. The glue might also be used to adhere tissue scaffolds to bone in cancer patients and to deliver drugs to sites that bone fragments are glued. Stewart expects the synthetic worm glue will be tested on animals within a year or two, and will be tested and used on humans in five to 10 years.

Mussel Adhesive Proteins

Role of L-3,4-Dihydroxyphenylalanine in Mussel Adhesive Proteins, by Miaoer Yu, Jungyeon Hwang, and Timothy J. Deming, published in June 1999 by the Journal of the American Chemical Society, available at http://pubs.acs.org/doi/full/10.1021/ja990469y?&


The blue mussel, Mytilus edulis, anchors itself to rocks and other surfaces using structures called byssal threads. The threads produce an adhesive that is waterproof and incredibly strong. Isolating the compounds responsible for this adhesive property would allow it to be synthetically reproduced and used in numerous medical procedures where a strong adhesive is necessary.

Miaoer Yu, Jungyeon Hwang, and Timothy J. Deming worked with these mussel adhesive proteins, or MAPs. The biggest challenge in replicating the adhesive was isolating the particular protein responsible for its strength. They thought that a protein called L-3,4-dihydroxyphenylalanine, or DOPA, was responsible, but also suspected that other proteins might be involved, complicating the mechanism of adhesion. They isolated a variety of adhesive proteins and found that, while many different amino acids were present, DOPA levels were consistently high among all samples.

Yu, Hwang, and Deming developed a series of experiments to determine which proteins were responsible for the adhesive properties of MAPs. Preliminary research suggested DOPA was the protein common to all MAPs, so they tested DOPA copolymers containing different amino acids, looking for differences in adhesive strength. All copolymers tested formed strong, waterproof adhesive bonds. They concluded that DOPA was responsible for the adhesive properties of MAPs.

The article describing the results of this study was published ten years ago, but new applications of MAPs have been discovered more recently. Researchers at Northwestern University developed a coating for medical devices susceptible to clogs and build up of cells and proteins. The coating is two-sided: one side, a strong adhesive based on MAPs, sticks to the device, and the other side, a repellant, prevents unwanted build up. This could mean fewer clots and increased efficacy of implants ranging from stents to catheters. MAPs are also being studied as a possible gene delivery material to be used in gene therapy. This technology has the potential to reach across many different areas of medicine. A strong, nontoxic adhesive that can be used in biomedical procedures and devices with reliable results is invaluable to engineers as they develop new technologies.

Tissue Bionics

Tissue bionics: examples in biomimetic tissue engineering, by David W Green, published August 15, 2008 by IOP Publishing, available at http://www.iop.org/EJ/abstract/1748-605X/3/3/034010

Tissue bionics, a subfield of the diverse field of biomimetics, involves the use of naturally occurring substances to assist in replacing and regenerating damaged human tissue. There are two main areas of tissue bionics. The first modifies natural structures to make them compatible with the human body. The second uses these natural structures as inspiration and makes synthetic copies with similar properties. This article explains the advantages of biomimicry in the development of tissues and gives some examples of natural sources adapted for medical uses.

The use of naturally occurring materials as replacement tissue is generally the simpler approach to tissue bionics. An example of a material used is collagenous marine sponge tissue. The tissue is treated to remove all original proteins, leaving behind a scaffolding of collagen. Cells adhere to the porous surface provided by the many collagen fibers better than they adhere to synthetic materials. The sponge skeleton can also be coated with proteins which promote differentiation of pro-myoblast cells into bone cells. Studies done on rats at the University of Otago demonstrated that after a few weeks the sponge skeleton was accepted into the body more successfully than synthetic collagen scaffolding.

Green’s article also provides examples of successful synthetic technologies inspired by biological processes, such as polysaccharide capsules. These micro capsules are used to help facilitate tissue regeneration. They can be designed to include different materials depending on the components needed to regenerate a certain type of tissue. Components can even be separated within a capsule and released at different times. These polysaccharide capsules are made using a process which imitates biomineralization, the process living things use to make minerals.

Though the technology in the emerging field of tissue bionics is promising, it is still in the early stages of development. One concern with the replication of biomaterials is that their complexity makes them difficult to reproduce synthetically. This is not an issue when using manipulated natural materials, but it hinders the development of synthetic analogues. Another question is whether the implanted tissues will be as strong as the rest of the body’s tissue. Despite these concerns, developments in tissue bionics are exciting alternatives to older synthetic materials used to repair human tissue. By using and taking inspiration from natural materials, researchers are taking advantage of the successful designs developed by years of trial and error in nature.

Database of Biological Patents

Commentary on June 9, 2005 Economist article, "Technology that imitates nature."
http://www.economist.com/search/displaystory.cfm?story_id=E1_QDPTDRP&source=login_payBarrier

In this article, Julian Vincent, the director of the Centre for Biomimetic and Natural Technologies at the University of Bath in England, and his colleagues are working on a database of "biological patents" to promote and enable the use of natural solutions to technological problems. The database in 2005 contained 2,500 patents. The term "biological patent" means that nature is the patent holder and it represents natural systems or mechanisms. The article addresses nature's superiority in designing effective solutions, "Over billions of years of trial and error, nature has devised effective solutions to all sorts of complicated real-world problems." Therefore, it is wise to take advantage of evolution by matching natural mechanisms with technological problems. Some examples of biomimetics were discussed, such as, Velcro, robotic fish, biomimtetic lens arrays from Brittlestars, gecko tape, planetary exploration vehicles with legs, shark coating for submarines, advanced plastic film from moth eyes, shape-shifting airplane wings, and humidity controlled smart fabric.

Dr. Vincent discusses the problems with the former process of biomimetics, "Engineers depend on biologists to discover interesting mechanisms for them to exploit." Engineers and biologists speak very different languages and work in different ways, which makes it harder for engineers to find natural solutions to their design problems. With this biological database available, engineers can now bypass the biologists altogether and more easily find out what natural mechanisms apply to their design problems. There are a few ways to use the database system. First, the simplest way is to search the database with keywords. Another way is to use the TRIZ (theory of inventive problem solving) technique, which is commonly used in engineering, and substitute the biological database with the normally used database of engineering patents. Also, one could use the system by characterizing an engineering problem in the form of a list of desirable and undesirable features, and then searching the database for any biological patents that meet those criteria.

I found this article and biological database very exciting to the future and progress of biomimetics. Dr. Vincent estimates that there is only a 10% overlap between biological and technological mechanisms used to solve particular problems, which helps prove how little natural mechanisms have been used to solve technological problems. This biological database, with ongoing additions of new mechanisms, could provide a multitude of solutions for engineers. Knowing that these biological mechanisms have been refined from millions of years of evolution, it makes sense to study and replicate them. I think that with the continual increase in biomimetic inventions, like the ones talked about in this article, there will be an increasing amount of biological mechanisms that could be applied. The potential for this database to grow exponentially is high, especially with the help of the online community. In conclusion, why try to slave over new designs when we could use nature as a guide?

Hearing aid technology based on a fly's ear

Commentary on the original 2003 New York Times article by Anne Eisenberg, "For Hearing Aids, a Lesson From a Fly on the Wall."
http://www.nytimes.com/2003/12/11/technology/circuits/11next.html?8cir

Hearing aids and cochlear implants are being redesigned based on the minuscule, yet tremendously sensitive ear of the Ormia fly. Hearing loss affects at least 28 million Americans yet only 10% of these people use and are satisfied with the modern hearing aid. One of the major issues with today's hearing aids is their poor sound localization, especially in loud situations when a particular sound or voice is to be distinguished from the background noise. We have long believed the human ear to be the most remarkable hearing systems in nature in terms of sound localization. This superior functionality is largely the result of the distance between our ears which helps us detect the direction of a noise based on the distance in time that it takes the noise to hit one ear relative to the other. However the directional hearing of the Ormia fly easily matches our own ability. When Ron R. Roy discovered that Ormia flies had ears he was surprised but was even more astonished to realize how effective they were. These flies have even better directional hearing capabilities than the human ear yet they are located just millimeters from each other. This means that they can detect directional differences in noise reaching the ears on the timescale of nanoseconds (1000 times smaller time discrepancies than the human ear can detect). The functional unit of the ear that is of greatest interest to engineers looking to mimic the Ormia's ear is the tiny ear drum. The fact that these ears are so tiny means that they could be indiscreetly put or implanted in people's ears and could potentially be inexpensive to manufacture. But how exactly have engineers taken Roy's research on fly ears and transferred this to hearing aids and cochlear implants?






Engineers are using the drum of the Ormia ear as a framework for developing a microphone that can be used in hearing aids and cochlear implants. The use of highly sensitive silicon and new innovations in laser technology combined with the guidance of the Ormia's tympranal structure make this technology feasible on a nanoscale. The mike membrane works by rocking like a seesaw that is hinged on a central pivot and "when acoustic waves come past, the sound pressure drives both sides of the teeter-totter. If sound comes on both sides at exactly the same time and with the same amplitude the mechanism doesn't move. But if the sound comes to one side before the other, it moves because the two pressures are unequal." This replaces the old mike technology which looked more like a drum head and left much to be desired in terms of sound localization.

This innovation is important for the healthcare industry which deals with a large demand for hearing aids, especially if those who have hearing loss but don't currently wear hearing aids are interested in this new technology. Currently medicare and private insurance companies cover hearing aids on more of a case-to-case basis while cochlear implants are universally covered. Therefore the healthcare industry would benefit from a less expensive and more effective hearing aid technology. And if the devices were less expensive consumers may additionally benefit if insurance companies are willing to cover the new price. In addition, there is a large market for hearing aid manufacturers which increases incentives to develop better technologies. This technology would not revolutionize the way that hearing loss is medically addressed, however, it would greatly improve existing biotechnologies for hearing problems.

Engineers Ask Nature for Design Advice

http://www.nytimes.com/2001/12/11/science/engineers-ask-nature-for-design-advice.html

For my first blog entry I’ve decided to start out with an article from the New York Times, entitled Engineers Ask Nature for Design Advice. I found this article on their website, written in the Science section for the December 11, 2001 issue of the newspaper. In the article, writer Jim Robbins provides a really straightforward, and unbiased introduction to emerging discoveries and future designs in the field of biomimetics. In the article he gives several examples of organisms in nature that have served as inspiration for scientists and engineers in the pursuit of solutions to common problems in manufacturing as well as medical science.

To be honest, before I found this article the most I knew about biomimetics was what is written in the introduction to this blog. Yes, I understood that this field of science is basically the mimicking of natural biological systems to be put to use in an engineering field, but the amount of that that relies on the ingenuity and creativity of the engineers was completely unknown to me. Although the biologists can supply the engineers with the way the system functions down to the very last chemical compound, the engineers have to figure out a way to apply this information to a product or technique that can then be used in the human world.

According to Robbins, biomimicry is not a new concept, but rather has been inspiring engineers for years. Hypodermic needles are shaped life the fangs of rattlesnakes, and Velcro is based off of the same principle as those annoying cockleburs that get stuck in your socks when you walk through a dry field. And you know those house paints that claim they don’t need to be cleaned earlier than five years after application? They’re not just making that up. It’s based off of the self-cleaning system of the sacred white lotus. The lotus has tiny points on its leaves that create a surface for debris to attach to, and an easy surface for water to run across to wash away any debris that has already settled. This concept was applied to paints, and truly is self-cleaning as promised.

It’s hard to find any opposition to this article, as there are no real harmful or disadvantageous aspects of biomimetics as a scientific field. It does require some trial and error that may cause the ineffective and inefficient use of an organism until better means of utilizing their desirable trait is determined. In the article Robbins exemplified this in his description of the muscles that were being targeted for their adhesive abilities. Ten thousand muscles were shucked and ground-up just to extract one gram of the protein that was necessary to make the adhesive. However, through research and development, a better method was obtained and scientists were able to become more efficient in the production of the adhesive.

Another notable part of the article was the quote by Janine M. Benyus, a science writer, saying “[Businesses] should find a way to create conditions conducive to life, not toxic to life”. Such a simple statement evokes a very powerful idea. When I think of factories and manufacture, I think of tall smokestacks, billows of black smog, and animals being forced to leave their already well-established environments in search of new areas to live. This is probably largely due to the presence of Dr. Seuss in my life as a child, and the fact that Fern Gully was undoubtedly my favorite movie from the ages of five to twelve. But to think that this is not the way that large-scale manufacture and production has to be is a revolutionary idea. Factories that work off of nature, not destroy it, is an incredible concept. This is the way it should have been all along. Humans and nature working hand in hand to grow and evolve, without destroying ourselves in the process.