(Invited) Developing Universal Sensing Strategies-Combining Functional Nucleic Acids with Photoelectrochemical and Electrochemical Signal Transduction

Biosensors combine biorecognition with signal transduction for analyzing biologically-relevant analytes. Nucleic acids are powerful building blocks for biosensors and are used both for biorecognition and facilitating signal transduction. In this talk, we will show that functional nucleic acids can be specifically engineered for electrochemical signal transduction. We develop both aptamers and DNAzymes that are designed for electrochemical signal transduction. Electrochemical biosensors relying on functional nucleic acids are used herein to detect bacterial and viral infectious diseases in native clinical samples such as saliva and urine. In addition to electrochemical signal transduction, we show that nucleic acids serve as powerful tools in photoelectrochemical signal transduction. We use double stranded DNA for biorecognition and for serving as a nano-ruler for tuning the separation between a photoelectrochemical label and the electrode surface. This allows us to switch the signal transduction capability of the system between signal-on and signal-off. Additionally, engineering functional nucleic acids for photoelectrochemical signal transduction, enabled us to develop a new class of pathogen biosensors. These biosensors are used in direct analysis of bacteria in water.