According to foreign media reports, everyone should have heard of the so-called “microneedle patch”, which is used for painless, continuous drug release through the skin. In general, the microneedle patch consists of a small polymer block, and its bottom is covered with a set of small needles filled with drugs made of water-soluble and biocompatible materials. < / P > < p > when the patch is applied to the patient, the needles painlessly penetrate the surface of the skin, and then they dissolve and release the drug into the blood through the tissue fluid around the skin cells. A team led by Benedetto Marelli and Professor A. John Hart at MIT have developed the new patch, which is made of silk fibroin (an edible protein extracted from moth cocoons) and two “bio ink” polymers. One is sensitive to one molecule in E. coli, and the other is very sensitive to pH, which is usually associated with food spoilage. In both cases, the polymer changes color if the target molecule or pH value is present. < / P > < p > when the patch is attached to the surface of a fresh product, its needles (each about 1.6 mm long and 600 μ m wide) will extract liquid from the product. According to reports, this method is more accurate than those that only test food surfaces, because these surfaces may have hidden corners and gaps in which pathogens can be hidden without being detected by sensors. < / P > < p > in laboratory tests, scientists injected Sashimi with solutions containing E.coli, Salmonella or no contaminants at all. The patch is then applied to all samples. The E. coli active bio ink on each patch is displayed with the letter E, and the pH active bio ink is displayed as type C. < / P > < p > when placed at room temperature for about 16 hours, e changes from blue to red, but only on samples with E.coli present. However, after a few hours, the E and C on all the samples turned red, indicating that they had gone bad for too long without refrigeration. < / P > < p > scientists are now working to speed up the reaction time and make the patch sensitive to a wider range of pollutants. Eventually, the technology is expected to be used by workers to monitor products during transportation, and for consumers to inspect food in stores and at home. Global Tech