Preparation Of Amphiphilic Poly Research Articles

A versatile method to deliver platinum (II) drugs via thiol-ene/yne click reaction of polypeptide

Platinum (II) demonstrates potent anticancer activity, but it is hampered by drawbacks such as poor solubility, facile decomposition, bone marrow suppression, and nephrotoxicity, which severely restrict its clinical use. To overcome these limitations, polymer prodrugs were developed by conjugation of platinum drugs onto polymers. The protective shield provided by polymers enables drugs to evade enzymatic degradation and immune system attacks in the physiological environment, achieving sustained release and long-term efficacy. In this study, we synthesized novel vinyl- or alkynyl-substituted cysteine N-carboxyanhydride (NCA) monomers, followed by the preparation of amphiphilic poly(ethylene glycol)-poly(amino-acid) copolymers through the copolymerization of PEG with the NCAs. Next, 1,2-didentate dicarboxylic groups were introduced into the side chains of the block copolymer by employing the “Thiol-ene” or “Thiol-yne” reactions. These carboxylic acid groups were then chelated with (1R,2R)-1,2-diaminocyclohexane platinum (II)(DACH-Pt) and simultaneously assembled into nanoparticles. The morphology and particle size were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Remarkably, the chelation of platinum (II) led to a decrease in micellar size. In vitro drug release experiments demonstrated a significantly faster release rate in the intracellular environment (pH 5.0) compared to physiological conditions (pH 7.4). MTT assays confirmed the excellent biocompatibility of the polymer. Moreover, concentration-dependent inhibition of cancer cell growth was observed with poly(amino acid)-platinum (II) chelate micelles. Overall, these findings suggest that self-assembled nanoparticles of poly(amino acid)-platinum (II) chelates hold immense potential for drug delivery applications.

Preparation of Amphiphilic Poly(ethylene glycol)-b-poly(γ-butyrolactone) Diblock Copolymer via Ring Opening Polymerization Catalyzed by a Cyclic Trimeric Phosphazene Base or Alkali Alkoxide

Biobased poly(γ-butyrolactone) (PγBL) as a fully biodegradable and bioabsorbable biomaterial has shown superior properties compared to those of other aliphatic polyesters. It is of great importance to prepare amphiphilic block copolymer containing PγBL block to make ordered nano-objects for biomedical applications such as drug delivery systems. However, such an amphiphilic copolymer containing PγBL segment was never successfully prepared mostly due to the synthetic challenges of ring-opening polymerization (ROP) of nonstrained γ-butyrolactone (γBL) monomer. Here, we reported the first preparation of amphiphilic poly(ethylene glycol)- b-poly(γ-butyrolactone) (PEG- b-PγBL) diblock copolymer by using PEG as a macroinitiator. We applied two types of bases to initiate the ROP of γBL. An organic cyclic trimeric phosphazene base (CTPB) was first applied to activate the terminal hydroxyl group of PEG as macroinitiator for ROP of γBL. On the other hand, sodium hydride was used to activate the hydroxyl group of PEG to form sodium alkoxide as an initiating system for ROP of γBL. Both catalytic/initiating system showed moderate control on ROP of γBL and successfully produced PEG- b-PγBL diblock copolymers with varied molecular weights and relatively narrow molecular weight distributions. The effects of catalytic systems, activation temperatures, and monomer concentrations on γBL conversion and molecular weight of PEG- b-PγBL were carefully explored. The thermal properties and phase behaviors of obtained PEG- b-PγBL were also investigated.

Preparation of amphiphilic poly(ethylene oxide)‐block‐polystyrene macrocycles via glaser coupling reaction under CuBr/pyridine system

AbstractThe amphiphilic cyclic poly(ethylene oxide)‐block‐polystyrene [c‐(PEO‐b‐PS)] was synthesized by cyclization of propargyl‐telechelic poly(ethylene oxide)‐block‐polystyrene‐block‐poly(ethylene oxide) (PEO‐b‐PS‐b‐PEO) via the Glaser coupling. The hydroxyl‐telechelic ABA triblock PEO‐b‐PS‐b‐PEO was first prepared by successive living anionic polymerization of styrene and ring‐opening polymerization of ethylene oxide, and then the hydroxyl ends were reacted with propargyl bromide to obtain linear precursors with propargyl terminals. Finally, the intramolecular cyclization was conducted in pyridine under high dilution by Glaser coupling of propargyl ends in the presence of CuBr under ambient temperature, and the c‐(PEO‐b‐PS) was directly obtained by precipitation in petroleum ether with high efficiency. The cyclic products and their corresponding linear precursor PEO‐b‐PS‐b‐PEO were characterized by means of GPC, 1H NMR, and FTIR. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Perfectly Alternating Amphiphilic Poly(p-phenylene) Graft Copolymers by Combination of Controlled Radical Polymerization and Suzuki Coupling Processes

The preparation of amphiphilic poly(p-phenylene) (PP) possessing completely and perfectly alternating hydrophilic poly(ethylene oxide) (PEO) and hydrophobic polystyrene (PS) side chains is described. First, PS macromonomer with suitable functionality for polyphenylation was prepared by atom transfer radical polymerization (ATRP). The antagonist macromonomer, PEO, was synthesized by etherification reaction. Both macromonomers were reacted in the final stage via Suzuki cross coupling in the presence of Pd(PPh3)4 as catalyst to form the desired amphiphilic graft copolymer (Mn: 32 400 g/mol and Mw/Mn: 2.28). The intermediates obtained in various stages and graft copolymers were characterized by 1H NMR and IR analysis. The optical absorption properties of the polymer were monitored with UV, and an additional absorption at around 280−320 nm evidenced the formation of PP chain. Thermal properties of PP were investigated by DSC. The thermogram displayed two transitions at 51.98 and 89.60 °C, indicating the presen...

Synthesis of poly(isobornyl acrylate) containing copolymers by atom transfer radical polymerization

AbstractFor the first time, a detailed study of the atom transfer radical polymerization of isobornyl acrylate (iBA) is reported. On the basis of these results, well‐defined PiBA‐containing block copolymers were synthesized, focussing on the preparation of amphiphilic poly(acrylic acid) (PAA) containing block copolymers. The precursor monomers 1‐ethoxyethyl acrylate (EEA) as well as tert‐butyl acrylate have been used to synthesize the PAA‐segments of the PiBA‐b‐PAA block copolymers. Finally, the synthesis of “block‐like” copolymers of PiBA and PEEA via a one‐pot procedure was investigated. By optimizing the copper and ligand concentration, and choosing the appropriate solvent, a controlled polymerization behaviour was obtained in all cases, as evidenced by a detailed kinetic analysis, GPC, NMR, and MALDI‐TOF data. Thermogravimetric analysis confirmed the quantitative transformation of the precursor polymer PEEA to the corresponding PAA‐containing copolymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1649–1661, 2008

Preparation of Amphiphilic Poly(L-lactide)-graft-Chondroitin Sulfate Copolymer Self-aggregates and Its Aggregation Behavior

Novel polymeric amphiphilic copolymers were synthesized using chondroitin sulfate (CS) as a hydrophilic segment and poly(L-lactide) (PLLA) as a hydrophobic segment. Micelles of those copolymers were formed in an aqueous phase and were characterized by 1H NMR spectra, fluorescence techniques, dynamic light scattering (DLS), atomic force microscopy (AFM), and confocal microscopy. Their critical aggregation concentrations (CAC) are in the range of 0.0043-0.0091 mg/mL at 25 degrees C. The partition equilibrium constants, Kv, of the pyrene probe in the aqueous solution were from 3.65 x 10(5) to 1.41 x 10(6) at 25 degrees C. The mean diameters of the micelles were below 200 nm, and their sizes were narrowly distributed. The AFM images revealed that the self-aggregates were spherical. Additionally, the CSn-PLLA micelles can efficiently transport within the cells via endocytosis as observed from confocal microscopy.

Preparation of amphiphilic poly(thiophene)s and their application for the construction of organic–inorganic superlattices

We prepared three types of poly(thiophene)s having aminoalkyl substituents: poly(3-aminoethylthiophene), poly(3-aminododecylthiophene), and poly[2,5-(3-octadecylthiophene)-alt-2,5-(3-aminomethlthiophene)]. From the absorption spectra of the poly(thiophene) films, it was demonstrated that their mean π-conjugation length was shortened compared to poly(3-alkylthiophene) prepared by the same chemical way. When a spin-coated film of hydrogen bromide salt of poly(3-aminododecylthiophene) was soaked in aqueous solution of PbBr 2, PbBr-based layered perovskite structure combined with a semiconductor layer of two-dimensional sheets of PbBr 6 octahedra and an organic semiconductor layer of poly(thiophene) was formed; sharp exciton absorption of approximately 400 nm, which is the characteristic of PbBr-based layered perovskite was observed.