A high sensitivity in the analysis of biological components and drugs is essential to be able to plainly determine the behavior of these and their different actions in the human body. For this reason, it is been developed a potential and sensitive detection method based on the fluorescence resonance energy transfer (FRET) system between mercaptopropionic acid (MPA)-capped CdTe quantum dots (QDs) and cysteamine (CS)-capped Au nanoparticles. Acting as energy donors, CdTe QDs and Au nanoparticles as energy acceptors, in our system is produced the modulation in FRET efficiency between QDs and AuNPs in the presence of a target analytes like captopril, L- cysteine, glutathione, etc, which inhibits the interaction of the QD-AuNP assembly. Depending of the target analyte, the interaction could be either with MPA-capped CdTe QDs or CS-capped Au nanoparticles, enabling the measurement of the magnitude of this interaction and how it affects the FRET system.\r\nAs a result, rapid, simple and novel methods of analysis based on that fluorescence resonance energy transfer (FRET) in combination with quantum dots (QDs) and their unique properties is being designing, providing new and improved sensors for the determination of relevant analytes.\r\n