Researchers have fabricated a biosensor that can detect minute traces of chloramphenical, an antibiotic used in clinical and pharmaceutical samples1 . They developed the sensor by coating edge-plane pyrolytic graphite with a polymer and a peptide.
Chloramphenical can inhibit the growth of a wide variety of disease-causing bacteria. It is the drug of choice for treating bacterial infections that have grown resistant to antibiotics (such as vancomycin and tetracycline) and for treating patients who are allergic to other antibiotics (such as penicillin and cephalosporin). However, chloramphenical reduces the numbers of certain types of white blood cells and gives rise to other harmful side effects, such as pale skin, elevated heart rate, bleeding and sore throat. Consequently, a simple, sensitive and fast method for monitoring the levels of this antibiotic in biological samples is needed.
The researchers fabricated the biosensor by coating edge-plane pyrolytic graphite with a polymer and a peptide. They then used the biosensor in electrochemical studies to detect levels of chloramphenical in laboratory-based solutions and clinical samples.
The researchers found that an uncoated graphite-based electrode showed a substantially lower current signal than the biosensor. The higher current signal of the biosensor was the result of the peptide capturing chloramphenicol. Furthermore, the biosensor detected the antibiotic in pharmaceutical and human urine samples. Current peaks due to other foreign chemicals were not observed for these samples, indicating that the presence of other chemicals and biomolecules did not interfere with chloramphenicol detection.
Besides detecting chloramphenicol, the biosensor could screen chloramphenicol-sensitive and chloramphenicol-resistant infectious bacteria such as Haemophilus influenza. "This screening potential of the biosensor will be very useful for selecting drugs to treat bacterial infections," says Rajendra N. Goyal, a co-author of the study.
