Oral bacteria are microorganisms that live in the mouth and can cause various dental problems, such as cavities, gum disease, and bad breath. Some of the most common and harmful oral bacteria are Streptococcus mutans, which produces acid that erodes tooth enamel, and Porphyromonas gingivalis, which is associated with periodontitis, a serious inflammation of the gums and tissues that support the teeth.
To detect and treat oral bacteria, dentists usually rely on methods such as culturing, DNA testing, or visual inspection, but these can be time-consuming, costly, or inaccurate. Therefore, there is a need for a simpler, faster, and cheaper way to identify and eliminate oral bacteria.
A team of researchers from Shanghai Jiao Tong University has developed an innovative solution: an artificial tongue that can distinguish and deactivate different types of oral bacteria. The artificial tongue is based on a chemical sensor array that mimics the human gustatory system. It consists of several sensors that are coated with nanozymes, which are nanoscale particles that act like natural enzymes. The nanozymes are also coated with DNA strands that can bind to specific bacteria.
When the artificial tongue is exposed to a sample containing oral bacteria, the sensors produce different color changes depending on the type and amount of bacteria present. The color changes are caused by the interaction between the nanozymes, hydrogen peroxide, and a dye. The nanozymes catalyze the oxidation of the dye by hydrogen peroxide, turning the solution blue. However, when the bacteria attach to the DNA on the nanozymes, they block the catalytic activity, reducing the amount of blue color produced. By using different DNA sequences, the researchers can make each sensor respond differently to different bacteria, creating a unique color pattern for each bacterial species.
The artificial tongue can not only detect, but also inactivate oral bacteria. The researchers found that the nanozymes can damage the outer layers of the bacteria, causing them to lose their viability. The nanozymes can also release reactive oxygen species, which are molecules that can harm the bacteria’s DNA, proteins, and membranes. The researchers tested the artificial tongue on 11 types of oral bacteria and found that it could accurately identify and eliminate them. The artificial tongue also worked well in saliva samples and plaque samples from healthy and diseased subjects.
The artificial tongue is a promising tool for oral health care, as it can provide a rapid, simple, and low-cost way to diagnose and treat oral bacterial infections. The researchers hope to further improve the artificial tongue by increasing its sensitivity, specificity, and stability, and by exploring its potential applications in other fields, such as food safety, environmental monitoring, and biomedicine.
The following table summarizes the main features and advantages of the artificial tongue compared to conventional methods for oral bacteria detection and inactivation.
| Method | Features | Advantages |
|---|---|---|
| Culturing | Growing bacteria in a laboratory medium | Can identify and quantify bacteria, but requires time, equipment, and expertise |
| DNA testing | Looking for specific DNA markers of bacteria using molecular techniques | Can identify bacteria accurately, but requires expensive and sophisticated equipment and reagents |
| Visual inspection | Examining the mouth for signs of bacterial infection, such as cavities, plaque, or inflammation | Can provide a quick and easy assessment, but may not be reliable or precise |
| Artificial tongue | Using a chemical sensor array coated with nanozymes and DNA to produce color changes in response to bacteria | Can distinguish and deactivate bacteria rapidly, simply, and cheaply |
