Diagnostic and sample preparation devices and methods
Contemplated methods and devices are drawn to preparation and analysis of analytes from biological samples. In a preferred embodiment the analytes are nucleic acids that are both released from biological compartment present in the sample and fragmented through the use of a voltage potential applied to a pair of electrodes. The nucleic acids thus prepared are subsequently characterized.
1. A method of analyzing a biological sample, the method comprising:
transferring the biological sample to an extraction zone, wherein the extraction zone comprises a pair of electrodes;
selecting a first electrical signal to apply to the pair of electrodes; and
applying the first electrical signal to the pair of electrodes, such that a plurality of nucleic acids are released from the biological sample and fragmented within the extraction zone to produce a plurality of fragmented nucleic acids,
wherein selecting the first electrical signal comprises selecting, based on a desired average length in bases of the plurality of fragmented nucleic acids, at least one of a magnitude of a voltage applied to the pair of electrodes, a duration of a voltage pulse applied to the pair of electrodes and a frequency at which a voltage pulse is applied to the pair of electrodes.
2. The method of claim 1 , wherein the average length in bases of the fragmented nucleic acids is equal to or less than 50% of the average length in bases of the plurality of nucleic acids prior to fragmentation.
3. The method of claim 1 , wherein the plurality of fragmented nucleic acids have an average length of equal to or less than 200 bases.
4. The method of claim 1 , wherein the first electrical signal is selected such that the average length of the plurality of fragmented nucleic acids is less than or equal to a predetermined average length.
5. The method of claim 4 , wherein selecting the first electrical signal further comprises selecting the overall treatment time.
6. The method of claim 4 , wherein selecting the first electrical signal is effective to produce the plurality of fragmented nucleic acids to be capable of hybridization to a solid-phase bound capture probe in a hybridization time that is at least 25% less than a corresponding hybridization time of the plurality of nucleic acids prior to fragmentation.
7. The method of claim 1 , further comprising contacting the biological sample in the extraction zone with an enhancing reagent.
8. The method of claim 7 , wherein the enhancing reagent is selected from the group consisting of a metal ion, a free radical promoting compound, a chaotropic salt, an ionic detergent, and a nonionic detergent.
9. The method of claim 1 , further comprising moving the biological sample containing the fragmented nucleic acids to an analysis zone and applying a second electrical signal to a sensing electrode and a reference electrode.
10. The method of claim 9 , further comprising measuring a charge or current flow between the sensing electrode and the reference electrode to quantify or ascertain the presence of a target nucleic acid in the biological sample.
11. The method of claim 10 , wherein the sensing electrode is a nanostructured microelectrode, and wherein the nanostructured microelectrode is spiky, rough or fractal.