Luca Turin's company,
Flexitral, is working with MIT in response to DARPA's (Defence Advanced Research Projects Agency) RealNose project. The RealNose project aims to mimic dogs ability to detect and interpret scent. There have been several more viable e-nose innovations and chemo sensors over the last 5 years or so, but still all with limitations on the number and specificity of the substances they can identify and so there is still a critical military need for innovation here. Now however MIT researchers have had a breakthrough that allows them to produce the receptors humans use to smell, a critical step in advancing scent detection technology. The project challenge laid down is to, build a nose using the canine nose as inspiration to simulate the mammalian olfactory system - from air intake to pattern recognition.
The mammalian olfactory system is pretty sophisticated, us humans have 5-6 million olfactory receptors and are capable of detecting substances in dilutions of less than one part in a billion parts of air. Dogs win on the scent top trumps though with 220 million olfactory receptors, while our olfactory cones are about the size of a corn kernal, dogs have a veritable cob wedged in their brains. The downside for dogs is that their ability to detect butyric acid is 100,000,000 x better than humans - this is the chemical responsible for smelly feet.
As with many military projects this could have huge benefits for medicine. Dogs can sense when we're ill, infections and various cancers release chemicals into the bloodstream and breath, creating distinctive odour patterns which dogs are able to detect.
Professor Julian Gardner who heads up the Sensors Research Lab at Warwick University, has been trialling an electronic sniffer to help detect the MRSA virus. In testing hospital patients or workers for MRSA, samples are sent off to be cultured which then take two or three days to complete. Time that patients with serious infections or hospitals needing to identify and control outbreaks just don't have. (Interesting article here on various methods being worked on to either identify or combat superbugs in hospital setting).
Gardner's e-nose recognises a unique cocktail of volatile compounds that s.aureus excretes, within 15 minutes. The gas is identified through pattern recognition as it's passed over reactive electrodes. In dogs a wet nose is a good sign of health and also it turns out important for detection of chemicals, as they dissolve in the mucus and separate into different odour molecules, in an orderly fashion, so that they can be interpreted individually. Gardner set about developing artificial snot - a project sure to re-engage any teenager with science - consisting of a 10 micron polymer sliver, increasing the performance of the e-nose and its ability to differentiate between different smells. Warwick University and many others have been working on e-noses for some 20 years now, improvements in technology and the cost of the technology are starting to make it more viable. Gardner thinks that an e-nose to detect s.aureus could cost as little as £5.00 each.
Perhaps the DARPA project will produce a gadget that is capable of identifying a wider range of pathogenic bacteria that could have applications in wound care and post operative monitoring both in a home and hospital setting, a kind of singing detective that translates the bacterial by products into a signature tune based on their vibrational frequency picture.
These innovations would be well combined with some other exciting developments in biomimicry. A UK firm, First Water Gel Technology, has developed a range of wound care applications based on the way our own cells initiate and manage wound healing.
Highly Sulphated Glycosaminoglycans (HSGs or GAGs) are long polysaccaride chains found in both the extra cellular matrix and on the outer surface of cell membranes. The HSGs act as binding sites involved in the normal wound healing process. In chronic wounds however the HSGs are dysfunctional. First Water has developed polymers that mimic HSGs and integrated them into a number of dressings for both the clinical and home market. The polymers are pro-ionic and have, weight for weight, the same absorbancy as aliginate - key for highly exuding wounds esp. those in the yellow and black phases. The polymers make the dressings somewhat adaptogenic as they are able to cope with high and low levels of exudate, absorbing and locking away moisture and allowing wound to breathe, but as the polymer gel is also 30% water, it is able to moisturize wounds such as burns giving a specific high heat capacity, controlling scarring, pain and epidermal breakdown, the moist environment allows cell movement, division and growth. Rather neatly they've seen a (much needed) role here in helping nursing mothers with breastfeeding - in helping to heal cracked nipples and absorb moisture both from exudate and leaked milk, current breastpads have been ripe for innovation for some time.
Usefully the gel is also naturally antibacterial against; c.albicans, p.aeruginosa, s.aureus and e.coli. The dressings are transparent (unlike traditional hydrocolloids) for better monitoring and reduce both cost and wound disturbance with unnecessary dressing changes. The polymer technology has also been integrated into their contact dressings. The exudate passes through pores of a primary layer (not unlike the pores which pass fluid through to the pedicels in the kidney's filtration membrane) into a secondary application that can be changed frequently as it doesn't disturb the wound - particular as the adhering gel only sticks to the surrounding skin and not the wound.
Things get really exciting when we can start to integrate complimentary innovations. These contact dressings are interesting and I wonder if some R&D could integrate them with the diagnostic technology in the e-noses where the removed secondary polymer layer is used as a form of mucus with an e-nose to analyse and monitor the presence of key bacteria within the wound. The polymer is also interesting in that another biomimicry innovation is based around using polymers - seaweed mimicing antibacterial compounds. Australian firm BioSignal have researched and developed a compound based on the seaweed Delisea Pulchra.
This seaweed produces compounds - fumerones - that inhibit bacteria's ability to colonise and form virulent biofilms. Over 80% of bacterial infections in people are estimated to involve biofilms. If you want to see a biofilm in action don't clean your teeth for a day, that gunky plaque is a biofilm - an appetising blend of bacteria, sugars, proteins and bacterial DNA. A wound is perfect for them as the fluid in the wound acts a medium to deliver nutrients and get rid of wastes. A vital aspect of colony formation is communication the bacteria signal to one another and that controls the virulence of the colony. Biofilms can't form on the Delisea Pulchra as the fumerones interfere with bacterial signalling and communication, crucially as they don't actually kill the bacteria the bacteria don't then develop resistance. Antibiotic resistant bacteria are a huge and dangerous challenge for the healthcare system and so other methods of effective bacterial control are vital. BioSignal's mission is to 'Provide effective defense against bacteria without generating bacterial resistance.' The industries that they're looking at are water and air conditioning systems, pipes and corrosion, industrial surfaces, foods, management of chronic lung infections, catheters and contact lenses - where they can be bound to polymers. Clearly it also has potential applications in healthcare, and in particular wound care, preventing and controlling infections in wounds and post-operative healing. Hushing the bacterial chatter- the quiet wound.
All of these are linked not only by potential applications but also by advances in polymer technology. Could they all work together to form an integrated solution?
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