The patch consists of two main layers. In direct contact with the wound is the hydrogel layer, which is uniformly distributed spherical polymer particles with the antibiotic Cefazolin.
American engineers have created an active patch for chronic wounds, releasing the medicine, if necessary. To track the state of the wound band-aid is equipped with sensors of temperature and pH, as well as a microcontroller for data processing, tell the developers in the journal Small, inform news.enovosty.com.
Human skin has a strong ability to heal moderate damage, but it can be reduced in the case of severe damage such as extensive burns, wound healing can interfere with a variety of diseases — e.g., diabetes. Diabetes in the tissues worsens the blood circulation, which slows healing and reduces local immunity. Both of these factors increase the likelihood of developing infection at the site of injury.
A group of American engineers under the direction of Khademhosseini Ali (Ali Khademhosseini) from the University of California in Los Angeles developed an electronic patch that creates a barrier for pathogens from the environment and supplies the area of the wound with antibiotics if necessary. The engineers were chosen as a marker of infection of the wound pH value in it. During normal healing, the pH should be from 5.5 to 6.5, but in the case of infected non-healing wounds it would be higher.
The patch consists of two main layers. In direct contact with the wound is the hydrogel layer, which is uniformly distributed spherical polymer particles with the antibiotic Cefazolin. To ensure that the antibiotic is not released spontaneously, the researchers chose the polymer passes from a hydrophilic to a hydrophobic state when the temperature changes. Since the critical temperature of this transition is 32 degrees Celsius, the engineers modified the composition of the other monomers and brought the temperature up to 37 degrees.
The developers added to the layer of hydrogel particles-carriers of antibiotic-layer electronics controlling drug release. On a flexible polymer substrate are the sensors of pH and temperature, and a heater. When the critical pH, the heater increases the temperature of the hydrogel and causes the capsules to release the antibiotic, which then falls on the surface of the wound. The temperature sensor is used to monitor the heating. Data from sensors are read and processed using a small module with a microcontroller, which is connected to the electrodes of the patch and secured on the skin next to it.
Engineers have conducted several laboratory tests, including confirmed the ability of the patch to track changes in pH due to presence of Staphylococcus aureus. In addition, tests on human cells-keratinocytes showed that the patch is not toxic to these cells.
Last year, the United States conducted a clinical trial of the patch with microneedles containing virus antigen. After sticking needles painlessly penetrate the skin and inject the drug. In addition, there are several prototypes of electronic patches to measure the level of glucose in the blood and even enter antidiabetic drug, as well as to measure the speed of blood flow.