How squid could help people get over their needle phobia

Needles, THOugh GLPessential for delivering a great many vital medications, are not universally popular among patients. This has serious consequences: an aversion to needles leads one in six American adults to skip vaccinations, and is an important reason why people who rely on injectable drugs such as insulin fail to keep up with their dosage. Now new work led by Giovanni Traverso at the Massachusetts Institute of Technology is revealing a way to get medication into patients without having to jab them at all, by copying the jet-propulsion techniques used by squid and their kin.This is not Dr Traverso’s first foray into the field of alternative drug delivery. Most of his previous inventions, however, have involved tiny automated syringes packaged inside capsules that can be swallowed. Once in the digestive tract, the capsules dissolve, leaving the syringes free to inject a drug payload through the mucosal surface layer of the stomach or the intestines and into the subsurface tissues below. As the walls of the digestive system are extremely rich in blood vessels, it is an excellent location for deploying drugs. Patients treated in such a way need never feel or even see the needle.Such techniques, though usable, are far from reliable. For a syringe to properly deliver a drug, it must be nearly perpendicular to the target tissue. This is as true for shots going into arms as it is for those jabbed into the lining of the gut. When it comes to penetrating the skin, a medical professional can set the alignment manually. In the depths of the digestive tract, such alignment is extremely challenging.Keen to find a better way forward, Dr Traverso considered the cephalopod. Just as cephalopods are able to propel ink and water at high pressure in all directions, Dr Traverso theorised a similar system might be able to propel drugs with sufficient force to penetrate the soft tissues lining the digestive tract without needing the perfect angle required by needles. To build such a device he worked with a team of colleagues at Novo Nordisk, a pharmaceutical company, as well as researchers at Brigham and Women’s Hospital in Boston and the Royal Institute of Technology in Stockholm. The collaboration resulted in tiny spring-loaded devices capable of releasing high-velocity jets when triggered.To test the efficacy of the system, the team loaded the devices with green dye and tested them out on digestive tissues taken from pigs and dogs. Microscopic analysis revealed that the green dye was frequently able to cross the mucosal layer. Crucially, the team found that the devices were still able to propel most of their dye into tissues even when the angle between the spring-loaded device and the tissue layer dropped below 70°.Eager to try the devices inside living animals, the researchers designed two versions of their drug-propulsion technology. One, bearing a resemblance to a miniature lunar lander, is designed to navigate the cavern of the stomach and squirt its contents downwards as soon as it makes contact with a surface. The second, designed to deliver its cargo in long narrow spaces such as the oesophagus, looks like a cylinder that can launch drugs out of its sides.The team armed both sets of devices with a range of drugs including insulin and an analogue for (a hormone that helps the body regulate blood sugar) and inserted them into the digestive tracts of pigs (which are very similar to those found in humans) for testing. In results published this week in the researchers reveal the jets were, once more, able to consistently deliver their drug payloads to a range of locations including the oesophagus, the stomach and the intestines.Though tests in humans have yet to be carried out, Dr Traverso and his colleagues hope that individuals with diabetes will be able to make use of this technology soon. Given that proper management of the condition involves multiple insulin jabs a day, a more convenient delivery mechanism could be transformative. But the technology will hardly be limited to this group. The researchers expect that similar devices could one day be used to administer vaccines. If all goes well, needle anxiety may be a thing of the past.