Where Is My Hypospray?

Welcome to Ask a Biogeek, a column where you ask UC Berkeley researcher Terry Johnson any question you want — no matter how weird.
Reader Mairi proxies the following question: My mom wants to know when we're going to get needle-less, painless injections.
While I personally covet the medical tricorder, I would almost prefer that my doctor have a hypospray - Starfleet's painless, needle-free injection system. The concept of a high-pressure alternative to a syringe dates back to The Shadow's radio show, and medical devices that function accordingly exist today. These, however, are not the only potential alternatives to a painful jab.

The syringe has been around since the 9th century, thanks to the Iraqi/Egyptian physician Ammar ibn 'Ali al-Mawsili', though he used it exclusively to remove cataracts from the eyes of his patients. Intravenous injection using syringes didn't come into vogue until the mid 1700s. Likewise, the first high-pressure jet injectors were not intended to deliver drugs - they were grease guns or components of diesel engines, and their accidental application to human bodies was anything but painless.

Where Is My Hypospray?S

The Ped-O-Jet, a foot-powered jet injection vaccinator.

In 1960 the medical jet-injector, the Ped-O-Jet, was developed for vaccination against smallpox - predating Star Trek's hypospray by several years. Not exactly painless, but invaluable for quick, mass-injections or vaccinations. The "Ped" referred to the power supply - a foot-powered pump. Its reusable tip made is less expensive, but led to concerns that infections could be passed from one patient to subsequent patients. More compact improvements like the Jtip, Biojector, or PenJet make it possible to self-administer flu vaccines and migraine medication.

Needle or no, shooting liquids into your flesh at high speed is not guaranteed to be painless, and some users complain of bruising and soreness. The MicroJet uses a piezoelectric actuator to repeatedly deliver more precisely controlled volumes of liquid. The very thin streams of liquid produced by the MicroJet reduce the area of skin affected by the injection and (with a little luck and the right settings) reduce pain.

A MicroJet in action.

When a drug can penetrate the skin or mucous membranes on its lonesome, an inhaler or topical application of the drug in a cream or a transdermal patch will do. Topical applications are painless, but not every pharmaceutical can penetrate the skin without help. The SonoPrep uses ultrasound to permeabilize an area of skin, making it temporarily possible for drugs to seep through skin that would typically block it from entry.

Microelectricalmechanical systems (MEMS) devices are another alternative. Instead of one big injection, why not lots of tiny ones? Microneedle devices look and feel like a patch, but they actually consist of hundreds of microneedles that can be programmed to deliver drugs steadily and painlessly.

Where Is My Hypospray?S

Lilliputian microneedle jabs.

NanoPumps deliver insulin slowly enough that large-scale injections are unnecessary, regulating blood insulin levels with steady, constant flow.

Where Is My Hypospray?S

An insulin NanoPump.

While many of these drug delivery methods are far less painful than a needle stick, I love a challenge - how about a pleasurable drug delivery method? Look no further than edible vaccines produced by genetically modified food. No matter how picky an eater you are, it's preferable to an injection.

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