Why jellyfish, porcupines and worms could save your life!
Nature has always been a rich source of inspiration when it comes to new medicines. It’s estimated nearly half the pharmaceutical drugs in use are derived from natural sources, mainly plants.
Now nature is helping science to combat major illnesses in other ways, too, with researchers designing medical devices and surgical instruments based on the unique features of certain animals or plants. the field even has its own name — ‘bioinspiration’.
Jeffrey Karp, an associate professor of medicine at Brigham and Women’s Hospital in the u.S., is seen as a world expert on bioinspiration and is involved in several major breakthroughs in the field. ‘the opportunities are enormous,’ says Professor Karp. ‘Nature is like an encyclopaedia of solutions for scientists because any species of plant or animal that survives has evolved to solve its problems.’
One well-known example is inspired by a dog’s powerful sense of smell. there are several anecdotal tales of dogs finding their owners’ undetected cancers, which scientists put down to the dogs’ ability to pick up traces of volatile organic compounds given off as gases by tumours.
Numerous electronic noses are now in development, including the Na-Nose, which sniffs out lung cancer by analysing these compounds in a patient’s breath.
Here we look at some of the other natureinspired new medical technologies set to benefit us all.
WASP PROBE FOR BRAIN SURGERY
ONE species of wasp has a unique feature which could transform brain surgery.
the female wood-boring wasp, native to europe, asia and north africa, has a hollow needle-like probe protruding from her rear which she uses to deposit eggs in the wood of dead or dying trees.
It’s made of three overlapping sections with interlocking teeth that can slide along each other. It uses this mechanism to bore through rotting wood, pushing one section into the soft wood until it encounters tougher material. It can then pull another section down along the teeth for added force.
the probe is also flexible enough to bend round hard bits in search of softer material.
Last year, neurosurgeons at Imperial College London began testing probes that mimic the wasp’s to deliver drugs deep into the brain. Currently, neurosurgeons have to insert rigid, plastic hollow devices — called cannulas — to deliver drugs into the brain or drain fluid from it.
But these can only be inserted in a straight path, potentially damaging tissue on the way.
Imperial College scientists developed a prototype robotic needle, inspired by the wasp, which is firm enough to push through brain tissue but also flexible enough to bend.
Like the wasp’s probe the needle has three interlocking segments, giving it the flexibility to travel along curved paths. So far, the wasp needle has been tested only on brain tissue in the lab, but human trials are planned by 2020.
PORCUPINE QUILLS FOR STITCHES
SCIENTISTS at Harvard Medical School’s Laboratory of accelerated Medical Innovation have been developing surgical staples based on the quills of the North american porcupine.
the quills serve as a superb defence mechanism — they’re very sharp and each has microscopic backward-facing arrow-like barbs on its tip.
this feature allows the quills to penetrate skin easily. But the barbs flare out if the quill is pulled, making it extremely hard to remove.
the Harvard team realised this natural design was ideal for the development of surgical staples. existing staples can cause large punctures, increasing the chances of bacteria getting in. the porcupine quills leave only tiny entry points.
In 2014, the Harvard team, led by Professor Karp reported they had developed a prototype staple based on porcupine quills which gripped tissue tightly but damaged skin less.
JELLYFISH TEST FOR LEUKAEMIA
PATIENTS with acute myeloid leukaemia, a type of blood cancer, are usually treated with chemotherapy. But even those who achieve remission still have low levels of cancerous cells circulating in their blood.
Doctors currently use a microfluidic device — not much larger than a phone SIM card — to check a sample of patients’ blood for cancerous cells: as the blood flows through tiny channels in the device, adhesive on the sides ‘capture’ cancer cells. If cancer cells are found, then more chemotherapy can be given.
But it works only if the cells make contact with the adhesive — and the devices often fail to spot cells in the early stages of cancer.
Now doctors at Brigham and Women’s Hospital are developing a device that could do a better job, inspired by the way jellyfish capture their food.
Jellyfish have dozens of tentacles with thousands of stinging cells on the surface to stun prey. the tentacles stretch out into the water to catch any passing food, mainly plankton.
the new microfluidic device has dozens of ‘tentacles’, or strands made from the patient’s own DNA harvested from bone marrow. these float around inside the device and bind to a protein on the leukaemia cells.
With this extra ‘fishing net’, blood can be pumped through more quickly and test results produced in a tenth of the time.
the technology could be in routine use among leukaemia patients within three to five years.
LOTUS LEAVES TO STOP BLOOD CLOTS
THE leaves of the lotus flower plant have a remarkable way of keeping themselves clean and healthy, with a highly waterproof coating.
rain forms into ‘beads’, which roll off the leaf, carrying away dirt and deposits that might interfere with the plant’s exposure to sunlight.
So when Harvard scientists wanted to develop a coating for medical implants that would repel blood and fluid, they based it on the lotus leaf.
all medical devices used internally increase the risk of a potentially fatal blood clot because blood cells tend to ‘stick’ to the surface of foreign materials.
But by coating such implants and devices with a synthetic form of the lotus leaf’s waterproof chemical, scientists hope to significantly reduce the risks.
they coated a range of different devices with two chemicals similar to those found on lotus leaves. In each case, the coating reduced the build-up of blood cells four-fold, slashing the likelihood of a clot forming.
GECKO FEET LINK TO SURGICAL GLUE
SURGICAL glues have transformed treatment of minor cuts and abrasions.
But the problem with most glues is that they are hydrophilic — they dissolve easily in water or fluid such as blood so can’t be used deep inside the body.
One solution may come from gecko feet. geckos have millions of tiny hairs under their five toes which allow them to stick to smooth surfaces. the end of each hair splits into tinier fragments, each shaped like a spatula.
their sheer number and proximity to the surface means the gecko feet can conform to any shape or surface, wet or dry, and this has been the basis for the development of a new adhesive tape for surgery.
a company, gecko Biomedical, has been set up to commercialise the tape, which will be used to cover large internal wounds in a trial which began this year.
another option for the future has taken its inspiration from the tiny sandcastle worm, found mainly on the coast of California.
It builds hive-like shelters on the sea bed by secreting a glue that bonds grains of sand together — the glue sets in seconds despite being submersed.
Last year, a team of scientists at the university of California Santa Barbara published a paper in Nature Materials showing they had successfully produced a synthetic glue based on worm glue — it could stick materials such as glass, wood and biological tissue even when wet. and it worked without applying pressure.
It could mean surgeons will soon be able to glue tissue together rather than injure it further by piercing it with needles and sutures. glueing broken bones could also be a possibility.
WORMS INSPIRE NEW SKIN GRAFT
TREATMENTS for burns and scars could soon be using a key feature of a tiny creature called the spiny-headed worm.
Called Pomphorhynchus laevis, it sets up home in the intestines of fish by plunging head-first into the host’s intestinal wall. the worm then swells its head for a secure hold, allowing it to feed on nutrients in fish blood.
the strength and simplicity of the technique inspired scientists at Harvard Medical School to produce an adhesive patch to hold delicate skin grafts in place, without damaging surrounding tissue further.
the patch features hundreds of tiny cone-shaped needles with tips that swell when exposed to water in the surface of the skin.
the needles pierce tissue with minimal force and once the tips have swollen, are ‘locked’ in place so the graft cannot move. It can be easily removed as the needles don’t rip skin.
Current techniques with stitches or staples can damage skin and tear the graft’s edges.
In a 2013 report, the scientists said the worm-inspired patch was three times stronger than sutures or staples, increasing the chances of grafts staying in place and bonding with skin.
SPIDER SILK FOR KNEE IMPLANTS
SPIDER silk is 25 times tougher than high-tensile steel, weight for weight. It’s also very flexible and biocompatible (it doesn’t get rejected by the immune system).
that’s why Oxford university set up the Oxford Silk group to explore how spiders’ web-building prowess could benefit medicine. the result is an implant called FibroFix, which is about to undergo clinical trials in Britain to treat damaged joint cartilage.
the implant is made from fibroin, the major protein found in silk from spiders and silk worms. Scientists developed a manufacturing process where fibroin molecules can be aligned in the same way as spider silk.
It meant they could produce a soft material spongy enough to work like cartilage — absorbing impact during running, say — but tough enough to withstand the body’s weight on the joint.
the developer, Orthox Ltd, is in the process of recruiting patients with severe knee osteoarthritis for a trial.