Rapid and Highly Efficient Preparation of Water-Soluble Luminescent Quantum Dots via Encapsulation by Thermo- and Redox-Responsive Hydrogels

Abstract

A water solubilization method for hydrophobic CdSe-ZnS quantum dots (QDs) is exhibited in this paper. The thermo-sensitive and photo-cross-linkable poly(N-isopropylacrylamide) (PNiPAm) copolymer is used for extraction of the hydrophobic QDs in dichloromethane and transferring them to water. This was accomplished via a solvent-induced phase separation process based on the amphiphilic nature of PNiPAm and their interactions with the different solvents. In addition, the functional ferrocene-containing PNiPAm is also used for the water solubilization of the hydrophobic QDs and the hydrogel/QDs particles demonstrate the chemical redox-controlled switch on−off property.

CdS and ZnS quantum dots embedded in hyaluronic acid films

“…Success in the application of QDs in biological studies have frequently been associated with their conjugation with proteins [26][27][28][29][30], peptides [31] and amino acids [32]. Therefore, studies on polysaccharides as components of composites with QDs have focused on aminopolysaccharides such as chitosan [3,[33][34][35][36][37][38], cellulose [39], and other saccharides [40][41][42][43][44][45].…”

Nanoscale Architectures for Smart Bio-Interfaces: Advances and Challenges

“…The ability to easily modulate the chemical nature of Qdot surfaces by employing one or more of the recently developed Qdot coatings, together with their exceptional photophysics have been key elements for Qdots to acquire a status of revolutionary fluorescent bio-probes. Indeed, the unique properties of Qdots not only give biologists the opportunity to explore advanced imaging techniques such as single molecule or lifetime imaging but also to revisit traditional fluorescence imaging methodologies, or based on shifting the diffraction peak, and extract yet unobserved or inaccessible information in vitro or in vivo (Alivisatos, 2004;Asher et al 2002;Cameron, Zhong & Knoll;Cheng et al 2008;Feng et al, 2007Feng et al, , 2008Medintz, Mattoussi & Clapp, 2008;Tomczak, et al, 2009). The improved Qdots semiconductor nanocrystals display longer quenching time compared to conventional fluorescence dyes and size-tunable optical properties, which recommend them for optoelectronic, photonic or bio-labeling uses.…”

Rheological and fluorescent properties of riboflavin–poly(N-isopropylacrylamide) hybrid hydrogel with a potentiality of forming Ag nanoparticle

“…4,5 Utilizing this property, PNIPAAM has been extensively used for the fabrication of optoelectronic devices [6][7][8] and bio-medical appliances. [9][10][11][12][13][14][15][16] Because of this coil-to-globule transition, PNIPAAM hydrogel also serves to be an effective candidate for designing temperature sensors. [17][18][19][20] Yamashita and co-workers have reported an interpenetrating gel network of PNIPAAM and poly(sodium acrylate), which has been successfully used as an adsorbent of heavy metal ions.…”