Rapid Detection of Methicillin Resistant Staphylococcus Aureus (MRSA) Using Electric-Double-Layer (EDL) Field-Effect Transistor (FET) Biosensors

According to the latest statistics and analysis by American researchers based on the data from 195 countries worldwide, it has been found that one person in every five people died due to sepsis. The annual death caused by sepsis reaches up to eleven million people, and the number of deaths from sepsis is even higher than those from cancer. We believe that the detection of MRSA is necessary. Staphylococcus aureus is the most common pathogen of sepsis. Methicillin-resistant Staphylococcus aureus (MRSA) or Multiple-resistant Staphylococcus aureus is a distinct strain of Staphylococcus aureus. It has mecA gene which codes for penicillin binding protein 2a (PBP 2A) that will remain active under beta lactams antibiotics. This gives bacterial the ability to grow under concentrations of beta-lactam antibiotics which leads to MRSA's resistance to almost all the different penicillin-type antibiotics including methicillin and other beta-lactamase-resistant penicillins. To detect MRSA in the shortest possible time, we adopt field-effect transistor (FET) biosensor for the real-time detection of binding reactions between DNA probe and cDNA. We select DNA probe sequence of mecA to be the aptamer and immobilize probe DNA which are complementary to the target cDNA on the sensor. This process allows DNA strands to attach to the gold surface. After that, we detect the binding reaction of DNA probe and cDNA by analyzing electrical response of field-effect transistor (FET). We can observe that the Id current changes after cDNA hybridizes with DNA probe. In conclusion, in our research results, Field-effect transistor (FET) biosensor can detect concentration ranging from 1fM to 1pM. In addition, we can achieve other advantages such as more portable, higher sensitivity, real-time monitoring capability, and lower detection limits. With this rapid detection procedure, we can do early diagnosis and treatment, thus improving the quality of human life.