OICC Press International Nano Letters 2228-5326 9 1 (March 2019) 2019 01 01 Synthesis, characterization and cytotoxicity of polyethylene glycol-encapsulated CdTe quantum dots 10.1007/s40089-018-0262-2 EN Magdy Ali Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, Alexandria, EG European Egyptian Pharmaceutical Industries (EEPI), Alexandria, EG Dina Zayed Department of Industrial Pharmacy, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, EG W. Ramadan Physics Department, Faculty of Science, Alexandria University, Alexandria, EG Ola A. Kamel Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy and Drug Manufacturing, Pharos University, Alexandria, EG Mona Shehab Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, Alexandria, EG General Bureau of Beheira Governorate, Damanhour, Beheira, 22111, EG Shaker Ebrahim Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, Alexandria, EG Journal Article 2019 01 01 Abstract Semiconductor quantum dots (QDs) offer tremendous scope to be used in the field of energy, imaging, sensors and optoelectronic devices. However, several issues regarding their hydrophilicity, stability and cytotoxicity remain unresolved. One of the methods to render CdTe QDs water-soluble is to functionalize the surface with carboxylate groups by the use of heterobifunctional ligands such as 3-mercaptopropionic acid (MPA). Following this motif, we report the synthesis of CdTe QDs using the non-aqueous organometallic route, ligand exchange with MPA was performed to replace the initial surface passivation ligands trioctylphosphine oxide (TOPO) and hexadecylamine, and finally, the prepared MPA-CdTe QDs were encapsulated into the biocompatible polyethylene glycol. Our results show that pegylation of CdTe QDs provided minimal cytotoxicity against baby hamster kidney (BHK 21) cells even at high levels. The IC 50 values of pegylated CdTe QDs were higher than the non-pegylated ones with a % viability ranges from 89:90% at a concentration range of 0.01:0.03 nM. Currently, available ligand exchange procedures lead to significant loss of quantum yields. In our study, the photoluminescence (PL) emission of the MPA capped CdTe QDs decreased gradually as the pH increased from 4 to 10 while after pegylation the prepared QDs exhibited significantly enhanced PL efficiency and storage stability.