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

Abstract

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.