A novel fluorescent aptasensor for selective and sensitive detection of digoxin based on silica nanoparticles

Digoxin is a useful drug in the treatment of heart failure. The therapeutic index of digoxin is very narrow. Thus, its detection in serum is of remarkable interest. In this study we designed a sensitive and selective fluorescent aptasensor for detection of digoxin based on silica nanoparticles (SNPs) coated with streptavidin. In the absence of digoxin, the fluorescence of the SNP-double stranded DNA (dsDNA) complex is strong. Upon addition of digoxin, the aptamer binds to its target, leading to release of the labeled-complementary strand from dsDNA and SNPs and decrease of the fluorescence intensity. This aptasensor showed a high selectivity toward digoxin and a limit of detection as low as 566 pM was obtained. This sensing platform is expected to be used successfully for detection of other drugs and biomolecules. Digoxin is a useful drug in the treatment of heart failure.