Abstract
Quantum dots (QDs) have applications and promising myriad applications in photovoltaic cells, biomedical imaging, targeted drug delivery, and quantum information processing. These have led to much research on their interactions with other systems. For biological systems, research has focused on the biocompatibility and cytoxicity of QDs in the context of imaging/therapy. However, there is a paucity of work on how biological systems and bioactive molecules might be used to alter the opto-electronic properties of QDs.|Here, we show that these properties can be altered by bioactive molecules and biological macromolecules following controlled changes in cellular activities. Using CdSe/ZnS core/shell QDs, spectroscopic analysis of optically excited colloidal QDs with HL60, K562, and T98G cell lines are performed. Our results show statistically significant (p < 0.001 and p < 0.0001) quenching of the emission spectra of the colloidal dispersions due to bioactive molecules in common chemotherapeutic drugs and due to reactive oxygen species (ROS) produced by these cells (HL60, K562) following chemotherapy and radiotherapy. This optical modulation constitutes what we describe as opto-electronic modulation. This type of tuning will possibly enhance applications of QDs in green energy and biomedical imaging.