Synthesis, self-assembly, and degradation of amphiphilic triblock copolymers with fully photodegradable hydrophobic blocks

2015 ◽  
Vol 93 (1) ◽  
pp. 126-133 ◽  
Author(s):  
J. Trevor McIntosh ◽  
Ali Nazemi ◽  
Colin V. Bonduelle ◽  
Sebastien Lecommandoux ◽  
Elizabeth R. Gillies

The development of stimuli-responsive materials is of significant interest for many applications including drug delivery, medical imaging, sensors, and microfluidic devices. Among the available stimuli, light is particularly attractive as it can be applied with high spatial and temporal resolution. We describe here the synthesis of amphiphilic triblock copolymers composed of poly(ethylene glycol) and a hydrophobic block containing o-nitrobenzyl esters throughout the backbone using copper-catalyzed azide–alkyne cycloaddition chemistry. These materials were designed to have a high weight fraction of the hydrophobic block to favour nonmicellar aggregates. The self-assembly in water was studied using nanoprecipitation and the resulting assemblies were characterized by dynamic light scattering and transmission electron microscopy. Under optimized conditions, it was possible to prepare polymer vesicles, commonly referred to as polymersomes, with diameters of approximately 100 nm. The degradation of these materials in response to UV light was studied by spectroscopy, light scattering, and electron microscopy, demonstrating that the vesicles were broken down. These results suggest the potential of these materials for applications such as encapsulation and release.

2014 ◽  
Vol 998-999 ◽  
pp. 95-98
Author(s):  
Xu Du ◽  
Qin Wang ◽  
Chuan Dong Wang ◽  
Yang Liu

Three biodegradable amphiphilic triblock copolymers: polylactide-poly (ethylene glycol)-polylactide (PLA-PEG-PLA), poly (ε-caprolactone)-poly (ethylene glycol)-poly (ε-caprolactone) (PCL-PEG-PCL) and poly (lactide-glycolide)-poly (ethylene glycol)-poly (lactide-glycolide) (PLGA-PEG-PLGA) were synthesized. Their chemical structures were characterized. In aqueous solution, their self-assembly and degradation were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Spherical micelles were formed in aqueous solution via self-assembly of the amphiphilic triblock copolymers. After degradation, the PLA-PEG-PLA and PCL-PEG-PCL micelles became smaller and the PLGA-PEG-PLGA micelles change to vesicles, which should mainly attribute to their different degradation speed.


2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.


2021 ◽  
Vol 12 (1) ◽  
pp. 270-281
Author(s):  
Stefan Bitter ◽  
Moritz Schlötter ◽  
Markus Schilling ◽  
Marina Krumova ◽  
Sebastian Polarz ◽  
...  

The self-organization properties of a stimuli responsive amphiphile can be altered by subjecting the paramagnetic oxidized form to a magnetic field of 0.8 T and monitored in real time by coupling optical birefringence with dynamic light scattering.


RSC Advances ◽  
2016 ◽  
Vol 6 (29) ◽  
pp. 24142-24153
Author(s):  
Andreea S. Voda ◽  
Kevin Magniez ◽  
Nisa V. Salim ◽  
Cynthia Wong ◽  
Qipeng Guo

We report for the first time the use of Nα-Boc-l-tryptophan for the synthesis of amphiphilic BAB triblock copolymers for potential drug delivery applications.


2014 ◽  
Vol 47 (18) ◽  
pp. 6373-6381 ◽  
Author(s):  
Yali Qiao ◽  
Rachel Ferebee ◽  
Bongjoon Lee ◽  
Indranil Mitra ◽  
Nathaniel A. Lynd ◽  
...  

2013 ◽  
Vol 538 ◽  
pp. 181-184 ◽  
Author(s):  
Xin De Tang ◽  
Ye Chen ◽  
Fa Qi Yu ◽  
Mei Shan Pei

Organic/inorganic hybrid materials based upon stimuli-responsive copolymers have attracted an inceasing attention. Compared with the polymeric materials, these hybrid materials can form aggregates in aqueous solution with much more stable shape-persistance due to the inorganic structure, which facilitate the mass delivery and long-term life. A novel hybrid material based on a new reactive block copolymer, poly(ethylene oxide)-block-poly{3-(trimethoxysilyl)propyl methacrylate-co-N-isopropylacrylamide-co-6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} [PEO-P(TMSPMA-NIPAM-AzoMA)] was synthesized via atom transfer radical polymerization (ATRP). The vesicles were obtained by self-assembly of the resulting block copolymer in a selective solvent, and then the PTMSPMA block was subjected to hydrolysis and polycondensation reaction to fix vesicle wall in the presence of triethylamine as a catalyst. The photo- and thermo- dual-responsive properties of the vesicles were investigated.


2021 ◽  
Author(s):  
Daniela M. Zanata ◽  
Maria Isabel Felisberti

Amphiphilic and stimuli-responsive triblock copolymers are an important class of smart materials due to their low critical micellar concentration in solution and capacity of self-assembly into different structures depending on...


2020 ◽  
Vol 16 ◽  
pp. 2017-2025
Author(s):  
Goutam Ghosh ◽  
Gustavo Fernández

Peptide-based biopolymers represent highly promising biocompatible materials with multiple applications, such as tailored drug delivery, tissue engineering and regeneration, and as stimuli-responsive materials. Herein, we report the pH- and concentration-dependent self-assembly and conformational transformation of the newly synthesized octapeptide PEP-1. At pH 7.4, PEP-1 forms β-sheet-rich secondary structures into fractal-like morphologies, as verified by circular dichroism (CD), Fourier-transform infrared (FTIR) spectroscopy, thioflavin T (ThT) fluorescence spectroscopy assay, and atomic force microscopy (AFM). Upon changing the pH value (using pH 5.5 and 13.0), PEP-1 forms different types of secondary structures and resulting morphologies due to electrostatic repulsion between charged amino acids. PEP-1 can also form helical or random-coil secondary structures at a relatively low concentration. The obtained pH-sensitive self-assembly behavior of the target octapeptide is expected to contribute to the development of novel drug nanocarrier assemblies.


RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64170-64179 ◽  
Author(s):  
Jing Song ◽  
Qun Ye ◽  
Wang Ting Lee ◽  
Xiaobai Wang ◽  
Tao He ◽  
...  

A series of perfluoropolyether/poly(ethylene glycol) (PFPE/PEG) triblock copolymers PEG/PFPE/PEG (P1–P3) and PFPE/PEG/PFPE (P4–P5) were prepared via thiol–ene click reaction in high yields.


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