Detection of chemical and biological agents using oligonucleotide aptamers

A sensor array for detecting a plurality of chemical and biological agents, comprising:

• a plurality of detection sensors, each of said plurality of detection sensors comprising:
• a detection complex comprising:
• (i) an aptamer having a binding domain for said chemical or biological agent, and (ii) a first oligonucleotide having a sequence complementary to a region of said aptamer, wherein in the absence of said target the aptamer and said complementary region of said first oligonucleotide form an intermediate combination, and wherein in the presence of said target the intermediate combination dissociates;
• a second oligonucleotide comprising a metal nanoparticle and having a sequence that interacts with a region of said first oligonucleotide to form a duplex structure only when said first oligonucleotide is dissociated from said intermediate combination;
• and
• a reporter molecule having a region that interacts with said duplex structure to form a reporter complex, wherein said reporter complex initiates a reporter signal.

A method of detecting a target, the method comprising the steps of:

• contacting a sample with a sensor comprising a detection complex, said detection complex comprising:
• (i) an aptamer having a binding domain for said target, and (ii) a first oligonucleotide having a sequence complementary to a region of said aptamer, wherein in the absence of said target the aptamer and said complementary region of said first oligonucleotide form an intermediate combination, and wherein in the presence of said target the intermediate combination dissociates;
• forming a duplex structure between the dissociated first oligonucleotide and a second oligonucleotide, said second oligonucleotide comprising a metal nanoparticle, a redox reporter, an electrically-conducting or -insulating group, a chelating group, or an electroconductive fluorophone and having a sequence that interacts with a region of said first oligonucleotide only when said first oligonucleotide is dissociated from said intermediate combination;
• forming a reporter complex between said duplex structure and a reporter molecule;
• and
• generating a reporter signal by said reporter complex.