Abstract: The solutions provided here use DNA aptamers and quantum dots for the detection of bacteria, viruses, proteins or other targets. An example of a method described here comprises: providing a complex of DNA complementary strands, one strand being an aptamer, having one strand covalently linked to a quantum dot, and having the other strand linked to a quencher; and contacting the complex of DNA complementary strands with a microorganism or components thereof, under conditions that permit binding of the aptamer with the microorganism or components thereof.

Abstract: The solutions provided here use DNA aptamers and quantum dots for the detection of bacteria, viruses, proteins or other targets. An example of a method described here comprises: providing a complex of DNA complementary strands, one strand being an aptamer, having one strand covalently linked to a quantum dot, and having the other strand linked to a quencher; and contacting said complex of DNA complementary strands with a microorganism or components thereof, under conditions that permit binding of said aptamer with said microorganism or components thereof. In some examples described here, the methods and systems are extremely simple to use and appear to have several advantages over the traditional ELISA. Since no blocking steps are required and the number of washing steps is reduced, the time required to conduct the test is greatly reduced. In some examples described here, a quantum dot aptamer complex comprises one strand of a duplex DNA molecule linked to the quantum dot by an amide bond.