Improving the Efficacy of Riboswitch Based Sensor for Visual Detection of Fluoride in Water
Fluoride, in appropriate quantities, has been recognized as beneficial for protecting tooth enamel from decay. However, a significant problem arises when excess amounts of fluoride infiltrate drinking water. High fluoride concentrations can result in dental fluorosis, which is characterized in children by hypomineralization of the enamel. To address this challenge by efficiently detecting fluoride in water, we aim to develop a fluoride biosensor using previously characterized fluoride riboswitches. Last year, we have developed an operon that, when fluoride binds, activates the riboswitch resulting in transcription of the chloramphenicol acetyltransferase gene. Thus, when fluoride is present, bacterial growth can be observed in the presence of chloramphenicol. However, this system was only able to detect high fluoride concentrations. To improve the efficacy and reduce the detection threshold, we used restriction enzymes to test various promoters and riboswitch sequences. We found that two of the new sequences promoted higher bacterial growth.