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Monolayer-protected gold nanoparticles by the self-assembly of micellar poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymer.
Langmuir 2007; 23(4):2126-32L

Abstract

A study is presented of the preparation of gold nanoparticles incorporated into biodegradable micelles. Poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) copolymer was synthesized by ring-opening polymerization, and the hydroxyl end group of the PCL block was modified with thioctic acid using dicyclohexyl carbodiimide as the coupling reagent. The PEO-b-PCL-thioctate ester (TE) thus obtained was used in a later step to form monolayer protected gold nanoparticles via the thioctate spacer. Gold nanoparticles stabilized with the PEO-b-PCL block (named Au/Block (x/y), where x/y is the mole feed ratio between HAuCl4 and PEO-b-PCL-TE) were prepared and analyzed. Au/Block (1/1), Au/Block (2/1), and Au/Block (3/1) nanoparticles were found to form stable dispersions in the organic solvents commonly used to dissolve the unlabeled block copolymer. The average diameter of the nanoparticles was determined by transmission electron microscopy (TEM) and found to be 6+/-2 nm. Au/Block (4/1) nanoparticle dispersions in organic solvents, on the other hand, were not stable and produced large gold clusters (50-100 nm). Cluster formation was attributed to the low grafting density of the block copolymer, which facilitates agglomeration. For Au/Block (12/1), along the same trend, only an insoluble product was isolated. Micelles in water were prepared by the slow addition of the dilute Au/Block solution in dimethylformamide into a large excess of water with vigorous stirring. Au/Block (1/1) and Au/Block (2/1) formed nanosized structures of 5-7 nm. TEM images of stained Au/Block (1/1) micelles, made in water, clearly showed the formation of core-shell structures. Au/Block (3/1) micelles, on the other hand, were not stable and large agglomerates a few microns in size were observed. The study focuses on the synthesis, characterization, and aggregation behavior of gold-loaded PEO-b-PCL block copolymer micelles, a potential system for drug delivery in conjunction with tissue and subcellular localization studies.

Authors+Show Affiliations

Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, H3A2K6, Quebec, Canada.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17279704

Citation

Azzam, Tony, and Adi Eisenberg. "Monolayer-protected Gold Nanoparticles By the Self-assembly of Micellar Poly(ethylene Oxide)-b-poly(epsilon-caprolactone) Block Copolymer." Langmuir : the ACS Journal of Surfaces and Colloids, vol. 23, no. 4, 2007, pp. 2126-32.
Azzam T, Eisenberg A. Monolayer-protected gold nanoparticles by the self-assembly of micellar poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymer. Langmuir. 2007;23(4):2126-32.
Azzam, T., & Eisenberg, A. (2007). Monolayer-protected gold nanoparticles by the self-assembly of micellar poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymer. Langmuir : the ACS Journal of Surfaces and Colloids, 23(4), pp. 2126-32.
Azzam T, Eisenberg A. Monolayer-protected Gold Nanoparticles By the Self-assembly of Micellar Poly(ethylene Oxide)-b-poly(epsilon-caprolactone) Block Copolymer. Langmuir. 2007 Feb 13;23(4):2126-32. PubMed PMID: 17279704.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Monolayer-protected gold nanoparticles by the self-assembly of micellar poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymer. AU - Azzam,Tony, AU - Eisenberg,Adi, PY - 2007/2/7/pubmed PY - 2007/5/3/medline PY - 2007/2/7/entrez SP - 2126 EP - 32 JF - Langmuir : the ACS journal of surfaces and colloids JO - Langmuir VL - 23 IS - 4 N2 - A study is presented of the preparation of gold nanoparticles incorporated into biodegradable micelles. Poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) copolymer was synthesized by ring-opening polymerization, and the hydroxyl end group of the PCL block was modified with thioctic acid using dicyclohexyl carbodiimide as the coupling reagent. The PEO-b-PCL-thioctate ester (TE) thus obtained was used in a later step to form monolayer protected gold nanoparticles via the thioctate spacer. Gold nanoparticles stabilized with the PEO-b-PCL block (named Au/Block (x/y), where x/y is the mole feed ratio between HAuCl4 and PEO-b-PCL-TE) were prepared and analyzed. Au/Block (1/1), Au/Block (2/1), and Au/Block (3/1) nanoparticles were found to form stable dispersions in the organic solvents commonly used to dissolve the unlabeled block copolymer. The average diameter of the nanoparticles was determined by transmission electron microscopy (TEM) and found to be 6+/-2 nm. Au/Block (4/1) nanoparticle dispersions in organic solvents, on the other hand, were not stable and produced large gold clusters (50-100 nm). Cluster formation was attributed to the low grafting density of the block copolymer, which facilitates agglomeration. For Au/Block (12/1), along the same trend, only an insoluble product was isolated. Micelles in water were prepared by the slow addition of the dilute Au/Block solution in dimethylformamide into a large excess of water with vigorous stirring. Au/Block (1/1) and Au/Block (2/1) formed nanosized structures of 5-7 nm. TEM images of stained Au/Block (1/1) micelles, made in water, clearly showed the formation of core-shell structures. Au/Block (3/1) micelles, on the other hand, were not stable and large agglomerates a few microns in size were observed. The study focuses on the synthesis, characterization, and aggregation behavior of gold-loaded PEO-b-PCL block copolymer micelles, a potential system for drug delivery in conjunction with tissue and subcellular localization studies. SN - 0743-7463 UR - https://www.unboundmedicine.com/medline/citation/17279704/Monolayer_protected_gold_nanoparticles_by_the_self_assembly_of_micellar_poly_ethylene_oxide__b_poly_epsilon_caprolactone__block_copolymer_ L2 - https://dx.doi.org/10.1021/la0627563 DB - PRIME DP - Unbound Medicine ER -