Synthesis, characterization and bio-evaluation of core-shell QDs with ZnSe, CdS and CdSe combinations

Sreenu Bhanoth1, Anuraj Kshirsagar1, Pawan K Khanna1*, Aakriti Tyagi2, Ankita Leekha2,  Vijay Kumar2, Anita Verma2*

1Quantum Dots R & D Lab, Department of Applied Chemistry, Defence Institute of Advanced Technology (DIAT), Ministry of   Defence, Govt. of India, Girinagar, Pune 411021, India

2Nano Bio-Tech Lab, Department of Zoology, Kirorimal College, University of Delhi, Delhi

Adv. Mater. Lett., 2017, 8 (4), pp 352-361

DOI: 10.5185/amlett.2017.6495

Publication Date (Web): Mar 14, 2017

E-mail: pawankhanna2002@yahoo.co.in, akamra23@hotmail.com

Abstract


Present article describes one-pot, two-stage, in-situ controlled atmosphere method for synthesis of core-shell quantum dots (QDs) comprising of ZnSe, CdS and CdSe combinations e.g. CdS/CdSe, ZnSe/CdS and ZnSe/CdSe. The present method emphasizes on creating an effective surface passivation of core as well as formation of passivated shell via utilization of cyclo-octeno-1, 2, 3-selenadiazole as a precursor for selenium. Synthesis of ZnSe/CdS was compared by using two different selenium precursors viz cyclo-octeno-1, 2, 3-selenadiazole (C8-SDZ) and cyclo-hexeno-1, 2, 3-selenadiazole (C6-SDZ). Optical properties (UV-Visible and PL spectroscopy) indicate narrow peak width with band gap ranging in between 2.30 eV to 2.56 eV. The XRD analysis revealed the formation of respective core-shell QDs with zinc blende crystal structure. TEM analysis showed formation of spherical shaped core-shell QDs with lattice spacing of 0.35 nm due to presence of (111) crystal plane.  By virtue of the excellent optical properties of ZnSe/CdS core shell QDs, this was subjected to bio-evaluation in terms of cytotoxicity and therapeutic efficacy. Approximately, 65% bio-toxicity was observed in MCF-7 with negligible haemolysis by ZnSe/CdS QDs. About, 34% tumour regression was shown by ZnSe/CdS QDs, as against 93% observed by Mitomycin C (Positive control) with respect to placebo (PBS).

Keywords

Core-shell QDs, selenadiazole, cytotoxicity.

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