Agile nucleic acid sensor and measuring a biomarker

An agile nucleic acid sensor for measuring a biomarker, the agile nucleic acid sensor comprising:

• a DNA switch that contacts and selectively duplexes with a chemical analyte comprising the biomarker;
• an analysis substrate in electrostatic communication with the DNA switch that is disposed on the analysis substrate, such that when the chemical analyte duplexes with the DNA switch, the analysis substrate produces a biomarker electrical signal;
• a transduction member in electrical communication with the analysis substrate and that receives the biomarker electrical signal and produces a transduction signal in response to receiving the biomarker electrical signal;
• a sensor counter electrode in electrical communication with and capacitively coupled to the analysis substrate and that receives a counter electrode voltage;
• a sensor reference electrode in electrical communication and capacitively coupled to the analysis substrate and that produces a feedback signal based on electrical interactions with a composition that is in fluid contact with the feedback signal and the analysis substrate;
• and a voltage follower in electrical communication with the sensor counter electrode and the sensor reference electrode and that receives the feedback signal from the sensor reference electrode and produces the counter electrode voltage for the sensor counter electrode based on the feedback signal.