pH-Responsive robust polymer micelles with metal–ligand coordinated core cross-links

A family of hybrid polymer gels is described, in which covalent cross-links create a permanent, stiff scaffold onto which reversible metal–ligand coordinative cross-links are added. The reversible metal–ligand interactions are shown to bear mechanical stress within the hybrid gel, and relaxations in response to that applied stress are consistent with the stress-free kinetics of ligand exchange in systems that model the reversible cross-links. The stress-induced dissociation of a model metal–ligand complex is examined by a single-molecule force spectroscopy, and its mechanical response is compared with a previously studied complex. The mechanical response of the individual interactions is relevant to those found in the family of hybrid gels, and the modular platform is therefore suitable for the study of stress-induced molecular dissociations, and their subsequent repair, within a macroscopic material of fixed structure.

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pH-responsive polymer micelles for methotrexate delivery at tumor microenvironments

e-Polymers ◽

10.1515/epoly-2020-0064 ◽

2020 ◽

Vol 20 (1) ◽

pp. 624-635

Author(s):

Teresa Darlen Carrillo-Castillo ◽

Javier Servando Castro-Carmona ◽

Antonia Luna-Velasco ◽

Erasto Armando Zaragoza-Contreras

Keyword(s):

Breast Cancer Cells ◽

Morphological Analysis ◽

Loading Capacity ◽

Ph Responsive ◽

Polymer Micelles ◽

Clear Trend ◽

Tumor Microenvironments ◽

Vis Spectroscopy ◽

Mcf 7

AbstractMethotrexate (MTX) anticancer drug was successfully loaded and released in a controlled manner from polymer micelles made of a diblock copolymer of poly(monomethoxy ethylene glycol)-b-poly(ε-caprolactone) (mPEG-PCL). The empty and MTX-loaded micelles (MTX/mPEG-PCL) were characterized by electron microscopy. The drug release dependence upon pH 5.4, 6.5, and 7.4 for 30 days was proven and characterized by UV-Vis spectroscopy. The cytotoxic effect of MTX/mPEG-PCL micelles on MCF-7 breast cancer cells was evaluated through an MTT assay. The morphological analysis indicated the successful formation of micelles of 76 and 131 nm for empty and MTX-loaded micelles, respectively. An encapsulation efficiency of 70.2% and a loading capacity of 8.8% were obtained. The in vitro release of MTX showed a gradual and sustained profile over 22 days, with a clear trend to much higher release at acidic pH (80 and 90% for pH 6.7 and 5.5, respectively). The MTX/mPEG-PCL micelles showed an IC50 of MCF-7 cells at 30 µg mL−1. The results suggested that MTX/mPEG-PCL could be a promising drug delivery system for cancer treatment.

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pH-responsive single-chain polymer nanoparticles utilising dynamic covalent enamine bonds

Chemical Communications ◽

10.1039/c3cc48733d ◽

2014 ◽

Vol 50 (15) ◽

pp. 1871-1874 ◽

Cited By ~ 102

Author(s):

Ana Sanchez-Sanchez ◽

David A. Fulton ◽

José A. Pomposo

Keyword(s):

Polymer Chains ◽

Polymer Nanoparticles ◽

Linear Polymer ◽

Ph Responsive ◽

Single Chain ◽

Chain Polymer ◽

Cross Links

Dynamic covalent enamine cross-links facilitate the reversible structural interconversion of dynamic single-chain polymer nanoparticles into linear polymer chains using pH as a trigger.

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