Most vaccines need to be refrigerated, which makes it difficult and expensive to get them to remote areas where they’re often needed most. Now, researchers at ETH Zurich have developed a new method for encapsulating vaccines in hydrogels so they can be transported and stored at much higher temperatures.
In order to produce an immune response, vaccines contain proteins or live viruses, which are vulnerable to heat. As such, they need to be refrigerated at under 8 °C (46.4 °F) for the entire journey from manufacturing plant to patient, which requires a complex infrastructure of facilities and transport vehicles with adequate cooling. That can be costly or downright unachievable in remote or developing areas, resulting in wasted doses and people going without much needed medication.
So scientists at ETH Zurich and a startup called Nanoly Bioscience have developed a new hydrogel that can keep vaccines stable at much higher temperatures, removing the need for refrigeration. The key ingredient is a synthetic polymer called polyethylene glycol (PEG), and the resulting hydrogel encapsulates the vaccine’s proteins and keeps them separated. This allows the medicine to remain viable at room temperature and indeed, much higher – up to 65 °C (149 °F).
When the vaccines need to be used, a sugar solution can be added to dissolve the hydrogel and release the proteins. Toxicology data indicate that the components in the hydrogel itself are safe for use in the body.
Other scientists have found some success stabilizing vaccines by freeze-drying them, which can then make for dissolvable oral films or microneedle skin patches. Unfortunately, this process can reduce the effectiveness of the drugs – the hydrogel, on the other hand, doesn’t interfere with its cargo.
The team says there’s still more study to be done before the new hydrogel can be used to distribute vaccines, but before then it could find use transporting other temperature-sensitive ingredients, like proteins and enzymes for medical research.
The study was published in the journal Science Advances.
Source: ETH Zurich
