Crosslinked, glassy styrenic surfactants stabilize quantum dots against environmental extremes

Abstract

Semiconductor, quantum dot (QD) nanoparticles (including CdSe/ZnS, CdTe/ZnS, and CdSe) were encapsulated within cross-linked shells of amphiphilic polystyrene-block-poly(acrylic acid) block copolymer. Transmission electron microscopy revealed that each particle was surrounded by a uniform, layer of copolymer, and that the average diameter of the resulting QD-core micelles was between 25 and 50 nm, depending on the conditions of particle assembly. Overall, we found that aqueous suspensions of these QDs were substantially more stable to heat and pH than particles with other surface preparations; we argue that the enhanced stability is due to the uniform, hydrophobic coating of polystyrene around each particle and the reinforcement of this layer by shell-cross-linking. The biocompatibility of these particles was investigated by microinjection of particle suspension into live zebrafish embryos. The particles permanently stained the fish vasculature, but did not interfere with the normal development of the fish. We propose that QDs encapsulated in cross-linked block-copolymer shells allow QDs to be used in biological or biotechnological protocols requiring harsh reaction conditions.

Stability studies of CdSe nanocrystals in an aqueous environment

“…High quality CdSe nanodots, nanorods, tetrapods, and nanowires can be produced with these methods [8][9][10]. Although extensive work has been carried out to study the growth and application of CdSe nanocrystals, little has been done on the stability or the dissolution of CdSe nanocrystals [11][12][13]. For effective application of such quantum dots, understanding of their stability under specific environments is critical.…”

Ultralong cylindrical micelles precisely located with semiconductor nanorods by solvent evaporation-driven self-assembly

“…Cylindrical micelles as nano-carriers can provide high loading capacity of hydrophobic objects per micelle and long in vivo circulation times, 14 which show particular potential in drug delivery and offer additional opportunities to control biodistribution and release proles of therapeutic agents. 15,16 The traditional "solution phase self-assembly" approach, which is a practical way to incorporate NPs into micelles, [3][4][5][6][7] does not easily allow the growth of extended wormlike micelles with NPs encapsulated in the core. Herein, the formation of NR-loaded cylindrical micelles was investigated using PS 356 -b-PEO 148 and PS-tethered CdS NRs in emulsions.…”

“…2 In solution, NP-BCP hybrid micelles have been prepared by incorporating one or multiple hydrophobic NPs into the hydrophobic domains of amphiphilic BCP micelles. [3][4][5][6][7][8][9] In particular, nanorod (NR) based nanocomposites have attracted tremendous interest primarily because of the unique inherent physical properties originated from the one-dimensional shape of NPs. 10,11 For example, the plasmonic properties of Au NRs can be tuned by simply varying the aspect ratio of the NRs.…”

Luminous block copolymer–quantum dots hybrids formed by cooperative assembly in a selective solvent

“…[28][29][30][31] The coassembly behaviors of semiconductor NPs and amphiphilic BCPs were seldom reported. [32][33][34][35][36] There are still many scientic problems that need to be solved, including the QDs loading and location control, the ergodicity of the hybrid micelle morphologies and the mechanisms for the morphological transition. Moreover, the properties and applications of semiconductor NPs/BCP hybrid assemblies are urgent to be investigated.…”