Stabilization of Metal Nanoparticles in Aqueous Medium by Polyethyleneoxide–Polyethyleneimine Block Copolymers

Sidorov, Stas N.; Bronstein, Lyudmila M.; Valetsky, Pyotr M.; Hartmann, Jürgen; Cölfen, Helmut; Schnablegger, Heimo; Antonietti, Markus

doi:10.1006/jcis.1998.6035

Cited by 142 publications

(123 citation statements)

References 42 publications

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“…8,9 Later, biocompatible dendrimers and diblock/triblock copolymers were included in the composition. 13,14 Dextran and PEG make the nanoparticles hydrophilic and increase their half-life in the circulation. However, in some cases, the dextran can induce an acute immune response as anaphylaxis.…”

Section: Introductionmentioning

confidence: 99%

Chemical nature and structure of organic coating of quantum dots is crucial for their application in imaging diagnostics

Bakalova¹,

Zhelev²,

Kokuryo³

et al. 2011

IJN

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Background: One of the most attractive properties of quantum dots is their potential to extend the opportunities for fluorescent and multimodal imaging in vivo. The aim of the present study was to clarify whether the composition and structure of organic coating of nanoparticles are crucial for their application in vivo. Methods: We compared quantum dots coated with non-crosslinked amino-functionalized polyamidoamine (PAMAM) dendrimers, quantum dots encapsulated in crosslinked carboxyl-functionalized PAMAM dendrimers, and silica-shelled amino-functionalized quantum dots. A multimodal fluorescent and paramagnetic quantum dot probe was also developed and analyzed. The probes were applied intravenously in anesthetized animals for visualization of brain vasculature using two-photon excited fluorescent microscopy and visualization of tumors using fluorescent IVIS ® imaging (Caliper Life Sciences, Hopkinton, MA) and magnetic resonance imaging. Results: Quantum dots coated with non-crosslinked dendrimers were cytotoxic. They induced side effects in vivo, including vasodilatation with a decrease in mean arterial blood pressure and heart rate. The quantum dots penetrated the vessels, which caused the quality of fluorescent imaging to deteriorate. Quantum dots encapsulated in crosslinked dendrimers had low cytotoxicity and were biocompatible. In concentrations <0.3 nmol quantum dots/kg bodyweight, these nanoparticles did not affect blood pressure and heart rate, and did not induce vasodilatation or vasoconstriction. PEGylation (PEG [polyethylene glycol]) was an indispensable step in development of a quantum dot probe for in vivo imaging, based on silica-shelled quantum dots. The non-PEGylated silica-shelled quantum dots possessed low colloidal stability in high-salt physiological fluids, accompanied by rapid aggregation in vivo. The conjugation of silica-shelled quantum dots with PEG1100 increased their stability and half-life in the circulation without significant enhancement of their size. In concentrations <2.5 nmol/kg bodyweight, these quantum dots did not affect the main physiological variables. It was possible to visualize capillaries, which makes this quantum dot probe appropriate for investigation of mediators of vasoconstriction, vasodilatation, and brain circulation in intact animals in vivo. The multimodal silica-shelled quantum dots allowed visualization of tumor tissue in an early stage of its development, using magnetic resonance imaging. Conclusion: The present study shows that the type and structure of organic/bioorganic shells of quantum dots determine their biocompatibility and are crucial for their application in imaging in vivo, due to the effects of the shell on the following properties: colloidal stability, solubility in physiological fluids, influence of the basic physiological parameters, and cytotoxicity.

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Section: Introductionmentioning

confidence: 99%

Chemical nature and structure of organic coating of quantum dots is crucial for their application in imaging diagnostics

Bakalova¹,

Zhelev²,

Kokuryo³

et al. 2011

IJN

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“…In a similar way, micellization via complexation in an aqueous medium was carried out using PEO-b-PEI (polyethyeleneimine) [50,51], since PEI, being a polydentate ligand, easily interacts with any metal compounds yielding metal complexes [52]. Complexation results in aggregation of the PEI blocks and micelle core formation, while PEO blocks form coronas and ensure colloidal solubility.…”

Section: Micelle Formation Via Complexationmentioning

confidence: 99%

Nanostructured Polymeric Nanoreactors for Metal Nanoparticle Formation

Bronstein

2004

Metal–Polymer Nanocomposites

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“…25,26 This property may be applied for the immobilization of proteins and enzymes, [27][28][29] anchoring metal nanoparticles, 30 or drug delivery. 31,32 Different authors have reported ionomer complex micelles of PEI grafted with methoxypolyethylene glycol (mPEG) and anionic surfactants, 9,33 metal ions (AuCl 3 or PtCl 6 2-), 26,34 oligonucleotides, 35 or plasmid DNA. 36 The covalent attachment of mPEG is commonly used to improve aqueous solubility and to reduce immunogenicity and cytotoxicity of polymeric systems.…”

Section: +mentioning

confidence: 99%

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

Abolmaali¹,

Tamaddon²,

Yousefi³

et al. 2014

IJN

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A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG) and Zn 2+ were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn 2+ , and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman’s assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX), approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 μM. The enhanced antitumor activity in vitro might be attributed to endocytic entry of MTX-loaded nano-networks that was found in the epifluorescence microscopy experiment for the fluorophore-labeled nano-networks.

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Stabilization of Metal Nanoparticles in Aqueous Medium by Polyethyleneoxide–Polyethyleneimine Block Copolymers

Cited by 142 publications

References 42 publications

Chemical nature and structure of organic coating of quantum dots is crucial for their application in imaging diagnostics

Chemical nature and structure of organic coating of quantum dots is crucial for their application in imaging diagnostics

Nanostructured Polymeric Nanoreactors for Metal Nanoparticle Formation

Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

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