Some people can roll up their sleeves at the doctor's office and get a shot without even flinching. Others fall to pieces at the sight of a needle.
For the latter group, there is new hope. Researchers at MIT have engineered a device that delivers a tiny, high-pressure jet of medicine through the skin without the use of a hypodermic needle. The device can be programmed to deliver a range of doses to various depths — an improvement over similar jet-injection systems that are now commercially available.
And this new invention may do more than spare the needle-phobics. It may also prevent accidents in the healthcare industry. The Centers for Disease Control and Prevention estimates that hospital-based health care workers accidentally prick themselves with needles 385,000 times each year.
Then, there are patients who must self-inject themselves with a drug every days, such as diabetics who must take daily insulin. A pain-free injection device might make them more likely to follow doctors' orders.
“If you are afraid of needles and have to frequently self-inject, compliance can be an issue,” said Catherine Hogan, a research scientist in MIT’s Department of Mechanical Engineering and a member of the research team. “We think this kind of technology … gets around some of the phobias that people may have about needles.”
Search for alternatives
This isn't the first attempt to make the needle obsolete, as scientists have been searching for years for alternatives to the hypodermic needle. For example, nicotine patches slowly release drugs through the skin. But these patches can only release drug molecules small enough to pass through the skin’s pores, limiting the type of medicine that can be delivered.
Researchers have been developing new technologies capable of delivering them, including jet injectors which produce a high-velocity jet of drugs that penetrate the skin. While there are several jet-based devices on the market today, Hogan notes that there are drawbacks to these commercially available devices. The mechanisms they use, particularly in spring-loaded designs, are essentially “bang or nothing,” releasing a coil that ejects the same amount of drug to the same depth every time.
The MIT prototype is a jet-injection system that delivers a range of doses to variable depths in a highly controlled manner. It ejects the drug at very high pressure and velocity, almost the speed of sound in air, out through the ampoule’s nozzle — an opening as wide as a mosquito’s proboscis. The person giving the injection can control the force.