Polyelectrolyte Complexation of Oligonucleotides by Charged Hydrophobic – Neutral Hydrophilic Block Polymers

Polyelectrolyte complex micelles (PCMs, core-shell nanoparticles formed by complexation of a polyelectrolyte with a polyelectrolyte-hydrophilic neutral block polymer) offer an attractive solution to the critical problem of delivering therapeutic nucleic acids, but few structure-property studies have been carried out to date. We present data comparing oligonucleotide PCMs formed with poly(vinylbenzyl trimethylammonium) as the cationic block to those using poly(lysine), which is more commonly used. Despite its higher charge density, increased hydrophobicity, and permanent charge, pVBTMA appears to complex DNA more weakly than does poly(lysine). Using small angle X-ray scattering and electron microscopy, we find that, at physiological ionic strength, PCMs formed from both cationic blocks exhibit very similar structure-property relationships, with PCM radius determined by the cationic block size and shape controlled by the hybridization state of the oligonucleotides. These observations narrow the design space for optimizing therapeutic PCMs and provide new insights into the rich polymer physics of polyelectrolyte self-assembly. <br>

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Polyelectrolyte Complexation of Oligonucleotides by Charged Hydrophobic—Neutral Hydrophilic Block Copolymers

Polymers ◽

10.3390/polym11010083 ◽

2019 ◽

Vol 11 (1) ◽

pp. 83 ◽

Cited By ~ 12

Author(s):

Alexander E. Marras ◽

Jeffrey R. Vieregg ◽

Jeffrey M. Ting ◽

Jack D. Rubien ◽

Matthew V. Tirrell

Keyword(s):

Charge Density ◽

Self Assembly ◽

Block Size ◽

Structure Property ◽

Shell Nanoparticles ◽

Polyelectrolyte Complexes ◽

Structure Property Relationships ◽

Polyelectrolyte Complexation ◽

The Rich ◽

Core Shell Nanoparticles

Polyelectrolyte complex micelles (PCMs, core-shell nanoparticles formed by complexation of a polyelectrolyte with a polyelectrolyte-hydrophilic neutral block copolymer) offer a solution to the critical problem of delivering therapeutic nucleic acids, Despite this, few systematic studies have been conducted on how parameters such as polycation charge density, hydrophobicity, and choice of charged group influence PCM properties, despite evidence that these strongly influence the complexation behavior of polyelectrolyte homopolymers. In this article, we report a comparison of oligonucleotide PCMs and polyelectrolyte complexes formed by poly(lysine) and poly((vinylbenzyl) trimethylammonium) (PVBTMA), a styrenic polycation with comparatively higher charge density, increased hydrophobicity, and a permanent positive charge. All of these differences have been individually suggested to provide increased complex stability, but we find that PVBTMA in fact complexes oligonucleotides more weakly than does poly(lysine), as measured by stability versus added salt. Using small angle X-ray scattering and electron microscopy, we find that PCMs formed from both cationic blocks exhibit very similar structure-property relationships, with PCM radius determined by the cationic block size and shape controlled by the hybridization state of the oligonucleotides. These observations narrow the design space for optimizing therapeutic PCMs and provide new insights into the rich polymer physics of polyelectrolyte self-assembly.

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Synthesis and Advanced Characterization of Polymer-Protein Core-Shell Nanoparticles

Catalysts ◽

10.3390/catal11060730 ◽

2021 ◽

Vol 11 (6) ◽

pp. 730

Author(s):

Erik Sarnello ◽

Tao Li

Keyword(s):

Particle Size ◽

Small Angle ◽

Core Shell ◽

Assembly Process ◽

Shell Nanoparticles ◽

X Ray ◽

X Ray Scattering ◽

Wide Range ◽

Core Shell Nanoparticles ◽

Ray Scattering

Enzyme immobilization techniques are widely researched due to their wide range of applications. Polymer–protein core–shell nanoparticles (CSNPs) have emerged as a promising technique for enzyme/protein immobilization via a self-assembly process. Based on the desired application, different sizes and distribution of the polymer–protein CSNPs may be required. This work systematically studies the assembly process of poly(4-vinyl pyridine) and bovine serum albumin CSNPs. Average particle size was controlled by varying the concentrations of each reagent. Particle size and size distributions were monitored by dynamic light scattering, ultra-small-angle X-ray scattering, small-angle X-ray scattering and transmission electron microscopy. Results showed a wide range of CSNPs could be assembled ranging from an average radius as small as 52.3 nm, to particles above 1 µm by adjusting reagent concentrations. In situ X-ray scattering techniques monitored particle assembly as a function of time showing the initial particle growth followed by a decrease in particle size as they reach equilibrium. The results outline a general strategy that can be applied to other CSNP systems to better control particle size and distribution for various applications.

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Magnetic-field-induced self-assembly of FeCo/CoFe2O4 core/shell nanoparticles with tunable collective magnetic properties

Nanoscale ◽

10.1039/d1nr00136a ◽

2021 ◽

Vol 13 (8) ◽

pp. 4519-4529

Author(s):

J. Mohapatra ◽

J. Elkins ◽

M. Xing ◽

D. Guragain ◽

Sanjay R. Mishra ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Physical Properties ◽

Self Assembly ◽

Core Shell ◽

Shell Nanoparticles ◽

Novel Approach ◽

Core Shell Nanoparticles

Self-assembly of nanoparticles into ordered patterns is a novel approach to build up new consolidated materials with desired collective physical properties.

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Identification of aggregates of magnetic nanoparticles in ferrofluids at low concentrations

Journal of Applied Crystallography ◽

10.1107/s002188980301104x ◽

2003 ◽

Vol 36 (4) ◽

pp. 1069-1074 ◽

Cited By ~ 2

Author(s):

D. Eberbeck ◽

A. Lange ◽

M. Hentschel

Keyword(s):

Magnetic Nanoparticles ◽

Radial Distance ◽

Core Shell ◽

Shell Nanoparticles ◽

Core Diameter ◽

X Ray Scattering ◽

Low Concentrations ◽

Dilute Suspensions ◽

Shell Particles ◽

Core Shell Nanoparticles

Different very dilute suspensions of magnetic nanoparticles (magnetite surrounded by an organic shell) in water (ferrofluids) were investigated using small-angle X-ray scattering. It is shown that the scattering originates not only from noncorrelated core–shell nanoparticles, but also from larger structures. By modelling, these structures can be identified as close-packed clusters consisting of core–shell particles (core diameter ∼10 nm). The analysis of the radial distance distribution function, obtained by Fourier transformation of the scattered intensity, reveals a lower bound of the mean cluster size of about 40 nm. The formation of clusters is persistent, even in very dilute suspensions.

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