One-step Aqueous Synthesis of Zn-based Quantum Dots as Potential Generators of Reactive Oxygen Species
- PDF / 1,121,140 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 70 Downloads / 181 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.27
One-step Aqueous Synthesis of Zn-based Quantum Dots as Potential Generators of Reactive Oxygen Species Julio A. Rivera1, Sonia J. Bailón-Ruiz2, Oscar J. Perales-Perez3
1
Department of Chemical Engineering, University of Puerto Rico at Mayagüez, Mayagüez PR 00680, USA
2
Department of Chemistry and Physics, University of Puerto Rico at Ponce, Ponce PR 00732, USA
3
Department of Engineering Science and Materials, University of Puerto Rico at Mayagüez, Mayagüez PR 00680, USA
Abstract
The actual incorporation of dopant species into the ZnS Quantum Dots (QDs) host lattice will induce structural defects evidenced by a red shift in the corresponding exciton. The doping should create new intermediate energetic levels between the valence and conduction bands of the ZnS and affect the electron-hole recombination. These trap states would favour the energy transfer processes involved with the generation of cytotoxic radicals, so-called Reactive Oxygen Species, opening the possibility to apply these nanomaterials in cancer research. Any synthesis approach should consider the direct formation of the QDs in biocompatible medium. Accordingly, the present work addresses the microwave-assisted aqueous synthesis of pure and doped ZnS QDs. As-synthesized quantum dots were fully characterized on a structural, morphological and optical viewpoint. UV-Vis analyzes evidenced the excitonic peaks at approximately 310 nm, 314 nm and 315 nm for ZnS, Cu-ZnS and Mn-ZnS, respectively, Cu/Zn and Mn/Zn molar ratio was 0.05%. This indicates the actual incorporation of the dopant species into the host lattice. In addition, the Photoluminescence spectrum of non-doped ZnS nanoparticles showed a high emission peak that was red shifted when Mn2+ or Cu2+ were added during the synthesis process. The main emission peak of nondoped ZnS, Cu-doped ZnS and Mn-doped ZnS were observed at 438 nm, 487 nm and 521 nm,
Downloaded from https://www.cambridge.org/core. Iowa State University Library, on 20 Jan 2019 at 19:54:27, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.27
respectively. Forthcoming work will address the capacity of pure and Cu-, Mn-ZnS quantum dots to generate cytotoxic Reactive Oxygen Species for cancer treatment applications.
INTRODUCTION: Semiconductors quantum dot (QDs) are fluorescent nanocrystals with a ranging diameter of 2 nm - 10 nm [1]. The optical properties of these nanoparticles rely upon the band gap energy values; if an energy equal or greater to the band gap energy is applied to a valence electron, it will be transferred to the conduction band and thus the electron hole pair is generated. The recombination of this electron will lead to a release of energy as fluorescence [2]. Due to intrinsic optical properties of QDs, which are dependent of their size, these nanoparticles have found many technological and bio-medical applications including production of LED’s (light emitti
Data Loading...
