Wellcome Image of the Month: Microneedles
On 23 February 1954, a group of children in Pittsburgh, Pennsylvania were the first to receive Jonas Salk’s injected polio vaccine. Almost 59 years later, researchers at the Massachusetts Institute of Technology have developed pain-free “microneedles” that have the potential to deliver not only vaccines but other therapeutics also. This work was published last month in the journal Nature Materials.
Our Image of the Month is this optical micrograph of four microneedles each approximately 0.5 mm in height. They are made from multiple layers or films of biodegradable polymers, the composition of which can be used to control the rate at which embedded active molecules are released. At the base of the needle is a water soluble layer (green) which rapidly dissolves after application to the skin for approximately 5 minutes. This painlessly deposits the microneedle tips (blue and purple) into the epidermis, where their cargo can then be released more slowly over days or weeks as required. An array of microneedles forming a ‘patch’ approximately the size of a fingertip could be used to replace traditional hypodermic needles for some applications such as certain types of vaccination. These patches could be self-administered and thus remove the need for specific medical training. Other advantages include pain-free injections and dry storage at room temperature. This is particularly important in areas where the need for cold storage can hamper widespread distribution.
Polio (Poliomyelitis) is a highly contagious disease caused by three types of poliovirus infection. The virus can attack nerves in the central nervous system, which in some cases can lead to irreversible paralysis and even death. In 1988, the World Health Organization launched the Global Polio Eradication Initiative (GPEI) which has led to a 99 per cent decrease in the number of polio cases worldwide. National governments, health organisations, charities and private foundations are all working together to eradicate polio from the world. The only other disease for which this has been achieved to date is smallpox.
Image credit: Peter DeMuth, Wellcome Images (Microneedle vaccine patch, coloured)
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