pH- and temperature-responsive amphiphilic diblock copolymers of 4-vinylpyridine and oligoethyleneglycol methacrylate synthesized by RAFT polymerization

Macromolecular Bioscience

Elalmış

İşoğlu

2016

Self Cite

Solution behavior of thermo-responsive polymers and their complexes with biological macromolecules may be affected by environmental conditions, such as the concentration of macromolecular components, pH, ion concentration, etc. Therefore, a thermo-responsive polymer and its complexes should be characterized in detail to observe their responses against possible environments under physiological conditions before biological applications. To briefly indicate this important issue, thermo-responsive block copolymer of quaternized poly(4-vinylpyridine) and poly(oligoethyleneglycol methyl ether methacrylate) as a potential nonviral vector has been synthesized. Polyelectrolyte complexes of this copolymer with the antisense oligonucleotide of c-Myc oncogene are also thermo-responsive but, have lower LCST (lower critical solution temperature) values compared to individual copolymer. LCST values of complexes decrease with molar ratio of macromolecular components and presence of salt. Dilution of solutions also affects solution behavior of complexes and causes a significant decrease in size and an increase in LCST, which indicates possible effects of severe dilutions in the blood stream.

Section: Resultsmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Thermo‐Responsive Complexes of c‐Myc Antisense Oligonucleotide with Block Copolymer of Poly(OEGMA) and Quaternized Poly(4‐Vinylpyridine)

Macromolecular Bioscience

Elalmış

İşoğlu

2016

Self Cite

“…PVP‐ b ‐POEGMA amphiphilic block copolymer was synthesized as described previously . Briefly, OEGMA was polymerized with [M] 0 /[CTA] 0 /[I] 0 = 75/1/0.2 ratio.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we have synthesized an amphiphilic block copolymer of PVP‐ b ‐poly(OEGMA) (POEGMA) for drug delivery and gene therapy purposes . Herein, we prepared positively charged core‐crosslinked micelles of the PVP‐ b ‐POEGMA copolymer by quaternization reaction.…”

Section: Introductionmentioning

confidence: 99%

Core‐crosslinking as a pathway to develop inherently antibacterial polymeric micelles

Kadayifci

Gökkaya

J of Applied Polymer Sci

et al. 2019

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Positively charged polymeric materials have been an alternative to combat bacteria as they exhibit inherently antibacterial potency via bacteria membrane disruption. In this study, we report facile preparation of positively charged core‐crosslinked polymeric micelles with inherent antibacterial properties. Spherical micelles were prepared by self‐assembling of poly(4‐vinylpyridine)‐b‐(oligoethylene glycol methyl ether methacrylate) copolymer in aqueous solution. Herein, quaternization reaction was utilized for the first time to core crosslink the micelles through the pyridine rings utilizing their hydrophobic core and thus resulting positively charged nanostructures. Dynamic light scattering (DLS) results identified that the micelles have an average hydrodynamic diameter of 114 nm with a polydispersity index ranging between 0.105 and 0.114. The electrophoretic light scattering (ELS) measurements demonstrated that the micelles have zeta potential values ranging from +38 to +63 mV. It was evident from both ELS and DLS results that the micelles in solution exhibit long‐term stability as the samples were able to maintain their size and charge even after a year of storage. Further, the micelles exhibited inherently antibacterial activity against Escherichia coli and furthermore, this antibacterial efficacy was sustained over a period of 1 year. These stable core‐crosslinked micelles are proposed to have great potential as antibacterial materials for long‐term applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48393.

HER2‐Targeted, Degradable Core Cross‐Linked Micelles for Specific and Dual pH‐Sensitive DOX Release

Bayram

Ulu

Macromolecular Bioscience

et al. 2021

Here, a targeted, dual‐pH responsive, and stable micelle nanocarrier is designed, which specifically selects an HER2 receptor on breast cancer cells. Intracellularly degradable and stabilized micelles are prepared by core cross‐linking via reversible addition−fragmentation chain‐transfer (RAFT) polymerization with an acid‐sensitive cross‐linker followed by the conjugation of maleimide–doxorubicin to the pyridyl disulfide‐modified micelles. Multifunctional nanocarriers are obtained by coupling HER2‐specific peptide. Formation of micelles, addition of peptide and doxorubicin (DOX) are confirmed structurally by spectroscopical techniques. Size and morphological characterization are performed by Zetasizer and transmission electron microscope (TEM). For the physicochemical verification of the synergistic acid‐triggered degradation induced by acetal and hydrazone bond degradation, Infrared spectroscopy and particle size measurements are used. Drug release studies show that DOX release is accelerated at acidic pH. DOX‐conjugated HER2‐specific peptide‐carrying nanocarriers significantly enhance cytotoxicity toward SKBR‐3 cells. More importantly, no selectivity toward MCF‐10A cells is observed compared to HER2(+) SKBR‐3 cells. Formulations cause apoptosis depending on Bax and Caspase‐3 and cell cycle arrest in G2 phase. This study shows a novel system for HER2‐targeted therapy of breast cancer with a multifunctional nanocarrier, which has higher stability, dual pH‐sensitivity, selectivity, and it can be an efficient way of targeted anticancer drug delivery.