Abstract: An agile nucleic acid sensor includes: a DNA switch; an analysis substrate in electrostatic communication with the DNA switch and that produces a biomarker electrical signal; a transduction member that receives the biomarker electrical signal and produces a transduction 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.

Abstract: Embodiments of the present invention relate to a system and method for determining quantity of target nucleic acid sequence in a sample. During a PCR-based amplification reaction, fluorescence intensity signals are acquired that form an amplification profile from which an exponential amplification region is desirably identified. In determining the exponential region, embodiments of the present invention determine a fluorescence threshold by background subtraction, test the feasibility of matching a signal to a reference curve and, in the event the feasibility test is successful, determine the matching parameters that quantify the initial amplicon number, and signal detection that reduces systematic errors in the measurements and increase the sensitivity of the measurement by decreasing the apparent noise-floor.