Three engineering design students in the United States have developed a fast and efficient method for numbing a patient’s skin prior to an injection.

A 3D-Printed Alternative to the Traditional Syringe

The fear of needles and injections, known under the medical term trypanophobia, is a fairly widespread problem that now affects one American in five but very little is being done about it. This is a worrying state of affairs from a public health viewpoint. The fact is that at least 20% of those affected balk at seeking medical treatment as they are terrified of having the injections they will need. Now three students at Rice University in Texas have come up with a solution which should make having a jab a less traumatic experience. Andy Zhang, Mike Hua and Greg Allison used 3D printing techniques to manufacture a small device which is able to anaesthetise a patient’s skin quickly and efficiently before s/he receives an injection. “Our device is 3D-printed and consists of two sealed chambers containing chemical ammonium nitrate and water,” explained Mike Hua in a university communiqué. A simple twisting motion moves the chambers into alignment, allowing the chemicals to flow through the chamber to produce a rapid endothermic reaction. The metal plate at the bottom of the device becomes cold very quickly. The device’s metal surface is then placed on the patient’s skin, which numbs it, and a hypodermic needle incorporated into the device is used to inject him/her in the usual way.

The device includes a metal plate, which rapidly becomes cold as a result of a chemical reaction. The plate is then used to anaesthetise the patient’s skin

A boon for pain-sensitive people

The whole venture began with a course module where students were tasked to work on a practical design project. The trio were invited to put their skills to good use by a Texan surgeon who had to deliver injections on a daily basis to the face and the groin, two areas where injections can be very painful. He asked the students to look for a solution to numb the skin prior to an injection. Lots of cobbling together, some advice gleaned from professionals, and a 3D printout later, the Comfortably Numb team was born. Explained Greg Allison: “We’re targeting anyone who has to get an injection, which is nearly everyone. But the device is especially applicable to people who are more susceptible to pain.” This includes children and elderly people as well as patients needing shots in more sensitive areas of the body.

                                        The numbing process takes effect in less than a minute


Fast and efficient but costly   

The Comfortably Numb device recently won an award at Rice's engineering and design showcase and the team are now deciding whether to set up a company to produce and market the device on a large scale. Although still at the prototype stage, its creators believe it could well have great potential in the medical sector given that current solutions are either ineffective or simply take too long. The team point out that one of the most widespread methods takes an hour to work, while Comfortably Numb takes less than a minute. Another advantage is that as no chemical substances come into contact with the skin, the device will not encounter the thicket of legal obstacles and health standards which inventions in this field usually have to overcome. The only drawback is the cost, estimated at $2 per unit – a considerable price tag for a disposable device. By way of comparison, a traditional syringe costs just 35 cents. They also need to discover what it is that really frightens trypanophobes – the pain or the needle itself. Needle phobia sufferers should also take a look at Tasso Inc., a Madison, Wisconsin-based company which is currently perfecting a device that can take a blood sample completely painlessly.

By Guillaume Renouard