Patent ID: 8450103

Claim:
A sensor for detection of a derivatized analyte, comprising a detection compartment comprising: a) a first nucleic acid capable of specifically recognizing and binding said derivatized analyte, said first nucleic acid comprising: an activatable enzyme domain, said enzyme domain, in an active state, having a site specific cleavage activity on nucleic acids, an analyte binding domain capable of specifically recognizing and binding said derivatized analyte, a communication domain linking said activatable enzyme domain and said analyte binding domain, wherein said activatable enzyme domain is activated from an inactive to an active state upon binding of said analyte to said analyte binding domain; b) a set of at least a first and second electrode attachable to a power supply; and c) a second nucleic acid having a partially double stranded structure and comprising an intercalating, redox-active compound capable of binding to said second nucleic acid, which compound either is electrochemically detectable in its unbound form and is electrochemically not detectable in its bound form, or said compound is electrochemically detectable in its bound form and is electrochemically not detectable in its unbound form, wherein said second nucleic acid further comprises a cleavage site recognized by said enzyme domain of said first nucleic acid in its active state, and wherein, upon cleavage of said cleavage site, said intercalating, redox-active compound, when bound to said second nucleic acid, becomes released from said second nucleic acid, wherein said sensor specifically recognizes said derivatized analyte by the first nucleic acid a) specifically recognizing and binding said derivatized analyte; the sensor further comprising a separation compartment located upstream of said detection compartment and separated from said detection compartment by a polymeric semipermeable membrane that excludes RNAse and other molecules having a molecular weight >10,000 Da and responsible for the rapid breakdown of RNA and/or DNA and which permits the passage of molecules of the derivatized analyte to pass from said separation compartment to said detection compartment, wherein said first nucleic acid binds to a derivatised analyte that is produced by reacting a starting analyte and a derivatisation agent to form said derivatised analyte, wherein: said starting analyte comprises a first functional group; said derivatisation agent comprises a second functional group; said first functional group and said second functional group are capable of reacting with each other to form a bond between said starting analyte and said derivatisation agent; and said derivatisation agent further comprises a substituent allowing for base stacking or hydrogen bonding between said derivatisation agent and a nucleic acid, and wherein said starting analyte is a molecule having a molecular weight in the range of from 50 to 250 Da and wherein said derivatised analyte has a molecular weight in the range from 250 to 2,000 Da.