scholarly journals Temperature Driven Transformation in Dextran-Graft-PNIPAM/Embedded Silver Nanoparticle Hybrid System

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
V. Chumachenko ◽  
N. Kutsevol ◽  
Iu Harahuts ◽  
D. Soloviov ◽  
L. Bulavin ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Silver Nanoparticles ◽  
Conformational Transition ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Thermally Induced ◽  
X Ray ◽  
X Ray Scattering ◽  
The Comparative Study ◽  
Novel Drug

During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix.

Studies on Interaction Parameters of Poly(N-isopropylacrylamide) in 1-Propanol–Water Mixtures by Small-Angle X-ray Scattering

1997 ◽  
Vol 30 (5) ◽  
pp. 712-716 ◽  
Author(s):  
S. Shimizu ◽  
M. Kimura ◽  
T. Maruyama ◽  
K. Kurita
Keyword(s):  
Small Angle ◽  
Interaction Parameters ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
X Ray ◽  
X Ray Scattering ◽  
Cluster Integrals ◽  
Semidilute Solutions ◽  
Poor Solvent ◽  
Ray Scattering

Small-angle X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in 1-propanol–water mixtures has been measured in a poor-solvent regime. The binary and ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical-solution temperature. The contributions of the segment–segment interactions to the entropy S int and enthalpy H int have been calculated from the temperature dependence of interaction parameters (binary and ternary cluster integrals) and it has been found that both values are positive. The dependence of S int on the concentration of propanol does not show a simple linear relationship.

scholarly journals Modulating the Thermoresponse of Polymer-Protein Conjugates with Hydrogels for Controlled Release

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2772
Author(s):  
Vincent Huynh ◽  
Natalie Ifraimov ◽  
Ryan G. Wylie
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Ethylene Glycol ◽  
Solution Temperature ◽  
Residence Times ◽  
Release Rates ◽  
Critical Solution Temperature ◽  
Protein Conjugates ◽  
Particle Encapsulation ◽  
Glycol Methyl Ether

Sustained release is being explored to increase plasma and tissue residence times of polymer-protein therapeutics for improved efficacy. Recently, poly(oligo(ethylene glycol) methyl ether methacrylate) (PEGMA) polymers have been established as potential PEG alternatives to further decrease immunogenicity and introduce responsive or sieving properties. We developed a drug delivery system that locally depresses the lower critical solution temperature (LCST) of PEGMA-protein conjugates within zwitterionic hydrogels for controlled release. Inside the hydrogel the conjugates partially aggregate through PEGMA-PEGMA chain interactions to limit their release rates, whereas conjugates outside of the hydrogel are completely solubilized. Release can therefore be tuned by altering hydrogel components and the PEGMA’s temperature sensitivity without the need for traditional controlled release mechanisms such as particle encapsulation or affinity interactions. Combining local LCST depression technology and degradable zwitterionic hydrogels, complete release of the conjugate was achieved over 13 days.

Microstructural Characterization of Polyanhydride Blends for Controlled Drug Delivery

2000 ◽  
Vol 662 ◽  
Author(s):  
Elizabeth E. Shen ◽  
Hsin-Lung Chen ◽  
Balaji Narasimhan
Keyword(s):  
Drug Delivery ◽  
Microstructural Characterization ◽  
Peak Shift ◽  
Crystalline Morphology ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Drug Delivery Devices

AbstractThis research examines the microstructure of polyanhydride blends for use in drug delivery devices. Atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) studies were performed on the homopolymers and blends of the polyanhydrides poly(1,6-carboxyphenoxy hexane) (CPH) and poly(sebacic anhydride) (SA). AFM of the CPH/SA blends 20:80, 50:50, and 80:20 showed distinct patterns indicating spinodal decomposition and phase separation on the micron-scale. Because it has been shown that incorporated drugs will thermodynamically partition into phase-separated domains depending on their hydrophobicity, polyanhydride blends will be able to encapsulate larger bioactive compounds including nucleotides, proteins, and vaccines. Preliminary SAXS studies of the CPH/SA blend systems provide information on the crystalline morphology of the polymer. A peak shift to a lower q from poly(SA) to the blends indicates that the poly(CPH) is incorporated into and causes swelling of the interlamellar amorphous regions of poly(SA).

Formation and Thermally-Induced Disruption of Nanowhiskers in Poly(3-hexylthiophene)/Xylene Gel Studied by Small-Angle X-ray Scattering

2010 ◽  
Vol 43 (17) ◽  
pp. 7305-7311 ◽  
Author(s):  
Chun-Yu Chen ◽  
Shu-Hua Chan ◽  
Jian-Yi Li ◽  
Kuan-Han Wu ◽  
Hsin-Lung Chen ◽  
...  
Keyword(s):  
Small Angle ◽  
Thermally Induced ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

In-Situ Synchrotron X-ray Scattering Studies of the Thermally-Induced Self-Assembly of High-Performance Aromatic Copolyesters

2014 ◽  
Vol 6 (11) ◽  
pp. 2352-2357
Author(s):  
Young Yong Kim ◽  
Kyuyoung Heo ◽  
Kyeong Sik Jin ◽  
Jehan Kim ◽  
Jong Ryang Kim ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Thermally Induced ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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