In Situ Preparation of Amphibious ZnO Quantum Dots with Blue Fluorescence Based on Hyperbranched Polymers and their Application in Bio-Imaging

Abstract

A new strategy for preparing amphibious ZnO quantum dots (QDs) with blue fluorescence within hyper-branched poly(ethylenimine)s (HPEI) was proposed in this paper. By changing [Zn2+]/[OH−] molar ratio and heating time, ZnO QDs with a quantum yields (QY) of 30% in ethanol were obtained. Benefiting from the amphibious property of HPEI, the ZnO/HPEI nanocomposites in ethanol could be dissolved in chloroform and water, acquiring a QY of 53%, chloroform and 11% in water. By this strategy, the ZnO/HPEI nano-composites could be applied in not only in optoelectronics, but also biomedical fields (such as bio-imaging and gene transfection). The bio-imaging application of water-soluble ZnO/HPEI nanocomposites was investigated and it was found that they could easily be endocytosed by the COS-7 cells, without transfection reagent, and they exhibited excellent biological imaging behavior.

Enhanced Emission of Zinc Nitride Colloidal Nanoparticles with Organic Dyes for Optical Sensors and Imaging Application

“…Jiao et al 71 synthesized silver indium sulfide quantum dots, using glutathione and polyethyleneimine and glutathione, behave as a ligand-based luminescence enhancement with the quantum yield of 37.2%. Lei et al 72 work on zinc oxide/hyper branched poly ethylenimine nanocomposites (ZnO/HPEI) in different solvents gives a quantum yield of 30% in ethanol and 53% in chloroform and 11% in water, and (ZnO/HPEI) shows the blue fluorescence. However, in the present work, our Zn 3 N 2 colloidal nanoparticle has a quantum efficiency of 59% without any further functionalization and any external solvent dispersion.…”

Journey of ZnO quantum dots from undoped to rare-earth and transition metal-doped and their applications

“…Impurity element detection is one of these applications, which is not applicable using nanoparticles. Apart from impurity detection, energy storage, 117 gas and chemical sensing, 118 optoelectronics, 20,119 anti-bacterial, 120 cancer treatment, 121,122 cellular imaging, 123,124 electronics, 125 and photocatalytic activity 126 are the other major application elds of QDs. However, these QDs will denitely augment the performance of these devices, which have based on nanoparticles to date.…”

“…ZnO is emerging as a potential candidate for bio-imaging because of its excellent photoluminescence efficiency. Lei and his group 124 prepared the ZnO QD-HPEI composite using the reflux method. The ethanolic solution of ZnO/HPEI nanocomposite, on characterizing with fluorescence microscopy, gives blue emission (shown in Fig.…”

“…Fig.23 (a-d) Illustration of the ZnO/HPEI nanocomposite and the fluorescent cell imaging, UV-Vis and PL spectra of ZnO QDs at [Zn 2+ /OH À ] molar ratio of (e and f) 1 : 2, (g and h) 1 : 1, and (i and j) 1 : 4 124. Adapted with permission from ref 124…”

Research progress in the synthesis and biological application of quantum dots

“…Due to the transfection characteristics of HPEI, ZnO/HPEI nanocomposites are easily endocytosed by cells, and only COS-7 cells without fluorescence show blue fluorescence under a fluorescence microscope, showing excellent biological imaging behavior. 162 Liu et al first synthesized ZnO QDs (5 nm) with yellow fluorescence, and then added them to peroxalate and hydrogen peroxide solution to modify them with a silane coupling agent. Bright blue photoluminescence (PL) was observed and the quantum yield was greatly improved (Fig.…”