Hydrophobic Modification of Copper Nanospheres for Incorporation into Poloxamer Micelles, Aggregated Micellar Nanocages and Supramolecular Assemblies

Yunlong Xu,Kaspars Melkis,Chinn T Sia,Dipak K Sarker

doi:10.2174/2405461503666180628155014

Abstract

Background: Polymer nanogels are increasingly used for the encapsulation of nano-solids and quantum dots such as in advanced forms of drug and therapeutic isotope delivery. Objective: Unlike ex vivo application of systems in vivo application and internalization are likely to suffer from aspects of failure to ensure safety and biocompatibility. Biocompatible hydrophilic poloxamer (Pluronic F108 and F68) micelles were studied by light scattering and tensiometry. Methods: The micelles of nano-gels are synthetic heteropolymer aggregates, which are used to encapsulate drugs but in this study chemically-modified (hydrophobized) copper nano-spheres, for the purposes of demonstration for further application and medical use. Copper benzoate nano-particles (CuBzNPs) were produced by maceration and subsequently stabilized in Pluronic F108 solution was added at different concentrations. Results: The resulting particle size increase was studied by dynamic light scattering. Moderate size increase was observed at low Pluronic F108 concentrations, which indicated successful coating, but at higher F108 concentrations large size agglomerates formed. Coated copper benzoate nano-particles (CuBzNPs) were fabricated as a proof-of-principle and as a substitute for bare metal nano-particles (MNs), which were not successfully entrained in the poloxamer nano-gel. As part of the synthesis copper benzoate (CuBz) beads and their characterization through contact angle measurements were performed. Conclusion: Micelles sizes of 4 nm for F68 Pluronic at equilibrium surface tensions of 36 mNm-1 were captured in weak, 1.25 to 2.0 Pas pseudoplastic gels fabricated from hydroxypropylmethylcellulose (HPMC).

Highlights

Colloidal dispersions are used ubiquitously in applications as diverse as pharmacy and electronic engineering [1, 2]
The distinction in surface tension between two types of surfactant is indicative of interfacial packing efficiency [35], which is much better for small low molecular weight surfactants
A simple way of grinding solid to make CuBzNPs from a synthesized copper benzoate powder was used along with uniformly-sized purchased copper oxide nanospheres

Summary

Introduction

Colloidal dispersions are used ubiquitously in applications as diverse as pharmacy and electronic engineering [1, 2]. Disguising of the NP surface by a coating can be achieved by chemical conjugation or physisorption coating of poly (ethyleneglycol) (PEG), which neutralizes the metal surface and makes it hydrophilic, prolonging NP circulation time. Many of these issues can be overcome by appropriately dispersing metal and metal oxide NPs into synthetic and naturally occurring polymers or self-assemblies [3, 24]. Liposomes are a common encapsulation vehicle [12, 19] and several examples of already licensed anti-cancer drugs or chemical agents encapsulated by liposomes include the Visudyne®, Ambisome® and Doxil® vesicular therapeutic formulations Among those Visudyne® used for treatment of macular degeneration of the eye by photodynamic therapy (PDT) and emission of light contains the optically-active organic molecule, verteporfin. Polymer nanogels are increasingly used for the encapsulation of nano-solids and quantum dots such as in advanced forms of drug and therapeutic isotope delivery

Methods

Results

Conclusion