METHODS FOR SEPARATING SHORT SINGLE-STRANDED NUCLEIC ACID FROM LONG SINGLE- AND DOUBLE-STRANDED NUCLEIC ACID, AND ASSOCIATED BIOMOLECULAR ASSAYS

摘要

Methods and kits are provided for detecting the presence or absence of target nucleic acid sequences in a sample. The methods and kits involve the use of negatively charged nanoparticles and the electrostatic interactions between the metal nanoparticles and nucleic acid molecules. The methods rely upon the differential interaction of ss-nucleic acids and ds-nucleic acids with the negatively charged nanoparticles that differentiate between tagged oligonucleotide probes that hybridize with a target and those that do not. Improvements in sensitivity for a fluorescent variation of the method have been obtained by including a step of separating the ds-nucleic acids in solution from the negatively charged nanoparticles to which ss-nucleic acids have been bound, and then detecting for the presence of the ds-target nucleic acids in the solution. The same separation protocols can be used to make the detection approach viable with electrochemical or radioactive tags.