Synthesis and self-assembly properties of well-defined four-arm star poly(ε-caprolactone)-b-poly(N-vinylpyrrolidone) amphiphilic block copolymers

Recent Advances in the Synthesis of Complex Macromolecular Architectures Based on Poly(N-vinyl pyrrolidone) and the RAFT Polymerization Technique

Recent advances in the controlled RAFT polymerization of complex macromolecular architectures based on poly(N-vinyl pyrrolidone), PNVP, are summarized in this review article. Special interest is given to the synthesis of statistical copolymers, block copolymers, and star polymers and copolymers, along with graft copolymers and more complex architectures. In all cases, PNVP is produced via RAFT techniques, whereas other polymerization methods can be employed in combination with RAFT to provide the desired final products. The advantages and limitations of the synthetic methodologies are discussed in detail.

End-functionalized polymers by controlled/living radical polymerizations: synthesis and applications

This review focuses on end-functionalized polymers synthesized by controlled/living radical polymerizations and the applications in fields including bioconjugate formation, surface modification, topology construction, and self-assembly.

Doxorubicin loaded pH responsive biodegradable ABA-type Amphiphilic PEG-b-aliphatic Polyketal-b-PEG block copolymer for therapy against aggressive murine lymphoma

A novel ABA-type polyethylene glycol (PEG)-b-polyketal (PK)-b-PEG block copolymer was synthesized via click reactions between the monoazido-monomethoxy-PEG and dialkyne terminated aliphatic polyketal with no carboxylic/amide linkages. Formation of the novel block copolymer was confirmed by ¹H NMR, GPC, TGA, and DSC studies. The formed copolymer has shown faster degradation at acidic pH. Self-assembly of this block copolymer (average size 6.2 nm) was assessed by fluorescence study using pyrene as a probe. Doxorubicin loaded block copolymeric micelles (69.9 nm) have shown pH dependent elevated drug release at pH 6.4, indicating its potential as a pH responsive nano-carrier for anticancer therapy. The nano-sized copolymer demonstrated tumoricidal activities against the lymphoma of murine and human origin with significant levels of growth inhibition and apoptosis. Therapy with doxorubicin loaded copolymer reduced the tumor size and augmented the life span of the tumor bearing animals with improved histopathological parameters, compared with the untreated control.

Self-assembly, doxorubicin-loading and antibacterial activity of well-defined ABA-type amphiphilic poly(N-vinylpyrrolidone)-b-poly(d,l-lactide)-b-poly(N-vinyl pyrrolidone) triblock copolymers

Synthesis, self-assembly, DOX-loading and antibacterial activity of well-defined ABA-type amphiphilic poly(N-vinylpyrrolidone)-b-poly(d,l-lactide)-b-poly(N-vinylpyrrolidone) triblock copolymers.

Methotrexate-Loaded Four-Arm Star Amphiphilic Block Copolymer Elicits CD8+ T Cell Response against a Highly Aggressive and Metastatic Experimental Lymphoma

We have synthesized a well-defined four-arm star amphiphilic block copolymer [poly(DLLA)-b-poly(NVP)]4 [star-(PDLLA-b-PNVP)4] that consists of D,L-lactide (DLLA) and N-vinylpyrrolidone (NVP) via the combination of ring-opening polymerization (ROP) and xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthesis of the polymer was verified by 1H NMR spectroscopy and gel permeation chromatography (GPC). The amphiphilic four-arm star block copolymer forms spherical micelles in water as demonstrated by transmission electron microscopy (TEM) and 1H NMR spectroscopy. Pyrene acts as a probe to ascertain the critical micellar concentration (cmc) by using fluorescence spectroscopy. Methotrexate (MTX)-loaded polymeric micelles of star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer were prepared and characterized by fluorescence and TEM studies. Star-(PDLLA15-b-PNVP10)4 copolymer was found to be significantly effective with respect to inhibition of proliferation and lysis of human and murine lymphoma cells. The amphiphilic block copolymer causes cell death in parental and MTX-resistant Dalton lymphoma (DL) and Raji cells. The formulation does not cause hemolysis in red blood cells and is tolerant to lymphocytes compared to free MTX. Therapy with MTX-loaded star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer micelles prolongs the life span of animals with neoplasia by reducing the tumor load, preventing metastasis and augmenting CD8+ T cell-mediated adaptive immune responses.