A composition for selective interaction with a target nucleic acid molecule, wherein the target nucleic acid molecule comprises a sixth region and a seventh region, the composition comprising: a first concentration of a first nucleic acid strand comprising a first region, second region and third region; a second concentration of a second nucleic acid strand comprising a fourth region and fifth region; wherein the first and second concentrations are such that an interaction between the composition and the target nucleic acid molecule possesses a standard free energy as determined by Expression 1 [ΔG o rxn = ΔG o t-TC - ΔG o nh-PC + (ΔG o v-TC - ΔG o h-PC )] that is equal to the standard free energy as determined by Expression 2 [-R T ln(([P] 0 - [C] 0 )/[C] 0 ))], where the [P] 0 term of Expression 2 equals the second concentration and the [C] 0 term of Expression 2 equals the first concentration, and where the second concentration is greater than the first concentration; and wherein the composition possesses a standard free energy of hybridization with the target nucleic acid molecule from about -5 kcal/mol to about +5 kcal/mol as determined by Expression 1; and wherein the ΔG o t-TC term of Expression 1 represents the standard free energy of hybridization between the sixth region and the first region, wherein the ΔG o nh-PC term of Expression 1 represents the standard free energy of hybridization between the fifth region and the third region, wherein the ΔG o v-TC term of Expression 1 represents the standard free energy of hybridization between the seventh region and the second region, wherein the ΔG o h-PC term of Expression 1 represents the standard free energy of hybridization between the fourth region and the second region, and wherein the values for ΔG o t-TC and ΔG o nh-PC differ by more than 10%. a first concentration of a first nucleic acid strand comprising a first region, second region and third region; a second concentration of a second nucleic acid strand comprising a fourth region and fifth region; wherein the first and second concentrations are such that an interaction between the composition and the target nucleic acid molecule possesses a standard free energy as determined by Expression 1 [ΔG o rxn = ΔG o t-TC - ΔG o nh-PC + (ΔG o v-TC - ΔG o h-PC )] that is equal to the standard free energy as determined by Expression 2 [-R T ln(([P] 0 - [C] 0 )/[C] 0 ))], where the [P] 0 term of Expression 2 equals the second concentration and the [C] 0 term of Expression 2 equals the first concentration, and where the second concentration is greater than the first concentration; and wherein the composition possesses a standard free energy of hybridization with the target nucleic acid molecule from about -5 kcal/mol to about +5 kcal/mol as determined by Expression 1; and wherein the ΔG o t-TC term of Expression 1 represents the standard free energy of hybridization between the sixth region and the first region, wherein the ΔG o nh-PC term of Expression 1 represents the standard free energy of hybridization between the fifth region and the third region, wherein the ΔG o v-TC term of Expression 1 represents the standard free energy of hybridization between the seventh region and the second region, wherein the ΔG o h-PC term of Expression 1 represents the standard free energy of hybridization between the fourth region and the second region, and wherein the values for ΔG o t-TC and ΔG o nh-PC differ by more than 10%. <EOS>