It is a common fear, known as trypanophobia. For around 20 per cent of the population, the thought of going to the doctors for an injection invokes a deep-rooted sense of dread. Many avoid the doctor's surgery altogether, leaving themselves open to the risk of various illnesses and infections. But for those terrified of needles, a team of scientists at Rice University in Houston, may have the answer. They have developed a new device, Comfortably Numb, to ease the pain of an injection. Their invention numbs the skin prior to the jab by producing a rapid chemical reaction to cool the patient's skin. Scroll down for video . Comfortably Numb is a new, single-use device that eases the pain of an injection by producing a rapid chemical reaction to cool the patient's skin within 60 seconds . Three first year students, (from L-R) mechanical engineer Mike Hua, bioengineer Andy Zhang and computer scientist Greg Allison, came up with the invention, they describe as 'simple and elegant' The trio, made up of computer scientist Greg Allison, bioengineer Andy Zhang and mechanical engineer Mike Hua, currently has a functioning prototype, that has produced a numbing effect in just 60 seconds. 'Our device is 3D printed and consists of two sealed chambers containing the chemical ammonium nitrate and water, ' Mr Hua said. 'A simple twisting motion moves the chambers into alignment to allow the chemicals to flow through the chamber to produce a rapid endothermic reaction. 'We then numb the skin by contacting the device's metal surface to the patient's skin.' Current solutions are either ineffective because they fail to numb the skin adequately, or take too long, the researchers said. They noted that a commonly used medicated topical patch takes about an hour to work, whereas their new device 'works on the order of seconds and minutes', Mr Zhang said. 'We are targeting anyone who has to get an injection, which is nearly everyone,' Mr Allison said. 'But the device is especially applicable to people who are more susceptible to pain.' As such, he said, it is particularly useful for children and the elderly. And, it is intended for use during procedures 'where you have to get shots in more sensitive areas of the body, such as the face or the groin', he added. The team designed the device to be single-use, rather than reusable to avoid the difficulties of cleaning it and resetting the device. It costs around $2 (£1.34) to produce, they said . The trio said the device could also be used to ease the pain of ear piercings and tattooing, and help reduce swelling. 'We looked into all sorts of methods for numbing, both quick and long-term, chemicals, using ice packs - which is similar to what we're using now,' Mr Hua said. The device is 3D printed and consists of two sealed chambers containing the chemical ammonium nitrate and water. A simple twisting motion moves the chambers into alignment to allow the chemicals to flow through the chamber to produce a rapid endothermic reaction. The skin can then be numbed by contacting the device's metal surface to the patient's skin. Within 60 seconds the patient's skin is numb and they can have an injection without experiencing pain. 'We explored everything that surrounded the problem before we even began brainstorming.' 'At the end of the day, what we're creating is a self-contained device with a very cold contact surface, and there are many applications for that,' Mr Allison added. Some of the solutions the trio researched were highly technical and required a materials science degree, or skills the first-year students had not yet learned. 'That's the kind of amazing thing about our project,' Mr Allison said. 'Because we don't have these incredibly refined skills in certain areas, that meant we had to think of very simple solutions. 'Being limited in that way led to something that is very novel and innovative, but at the same time, simple and elegant.' The team designed the device to be single-use, rather than reusable to avoid the difficulties of cleaning it and resetting the device. Mr Zhang, said: 'The materials that we use are relatively inexpensive and found in abundance: plastic, rubber and metal. The team from Rice University in Houston said the device could be used in future for those having tattoos, or people wanting to get their ears pierced without suffering the pain . 'The materials for one of these cost about a quarter, and then we just had to do estimates based on how much manufacturing would cost. 'We compared our device to similar things already in production, and we've estimated the cost at about $2 (£1.34).' The team is currently in the process of applying for a provisional patent for the device, and the students hope to continue their work together in their spare time when they return to Rice in their second year. 'As a team, we just want to follow the project, because we think it has a lot of potential. I think that's what drew us to this specific project,' Mr Allison said. 'We haven't really discussed yet whether we're going dedicate to making this a company, but it's something we're open to.'
Comfortably Numb is a single-use 3D printed device that numbs the skin .
Produces a rapid chemical reaction to cool the patient's skin in 60 seconds .
Invention costs around $2 to make and could help millions terrified of pain .
Three first-year students behind invention say it could work for tattoos too .