A change in color indicates when the medicine is too hot, The researchers used color coding, rather than color, for their visualization process.
Some foods and medicines, such as many vaccines against COVID-19, need to be kept cold. As a step toward a robust and stable system that can indicate when these products have exceeded safety limits, ACS Nano researchers report a class of microcrystals that glow in colorless materials high temperature and response time. As a proof of concept, the team assembled color changing vial caps and QR codes.
Refrigerators in refrigerators and refrigerated trucks maintain their maximum temperature, but accidents can happen. Air sensors can monitor the temperature of individual products, but these devices generate a lot of electronic waste. Recently, researchers have suggested the use of materials that act as indicators to provide this information with less waste.
However, some current options use color reactions or dyes to create tints that can be fatal. But they only adhere to temperatures higher than freezing, which is not helpful for some COVID-19 vaccines that can start to break down below freezing – above -4 or -94 degrees Fahrenheit. So Yadong Yin, Xuemin Du and their colleagues wanted to create better color-changing materials and melts to match different temperatures.
The researchers used color coding, rather than color, for their visualization process. The team made silicon dioxide nanoparticles coated with glycerol, which appear green or red when they aggregate into microcrystals in water. Then they produce liquids with different melting points by mixing different proportions of polyethylene glycol or ethylene glycol with water. When these two parts are combined, they can create an incredible loss of color as the solution of heat melts and the microcrystals explode.
Equipment can be programmed to withstand exposure to temperatures of -94 to +99 degrees Fahrenheit lasting from minutes to days. In other experiments, a two-dimensional display system was incorporated into a flexible circular vial label with a QR code.
These systems are very sensitive and perform well when things get really hot. Researchers say the color-changing technology holds promise for a variety of conditions found in pharmaceutical refrigeration supply chains.
Source: American Chemical Society.
