Novel carboxymethyl cellulose-halloysite-polyethylene glycol nanocomposite for improved 5-FU delivery

Drug nano-carriers are crucial for achieving targeted treatment against cancer disorders with minimal side effects. In this study, a pH-responsive nanocomposite based on halloysite nanotube (HNT) coated with carboxymethyl cellulose (CMC)/polyethylene glycol (PEG) hydrogel for controlled delivery of 5-Fluorouracil (5-FU), a hydrophobic chemotherapy drug prescribed for different types of cancers was synthesized for the first time using the water-in-oil-in-water (W/O/W) technique. The developed CMC/PEG/HNT/5-FU nanocomposite was characterized by dynamic light scattering (DLS), zeta potential, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Field emission scanning electron microscope (FE-SEM) to get information about the particle size, surface charge, interactions between functional groups, crystalline structure and morphology, respectively. High efficiencies in terms of drug entrapment and loading (46 % and 87 %, respectively) were attained. In-vitro drug release results revealed an improved and sustained 5-FU delivery in an acid environment compared to the physiological medium, corroborating the pH-sensitivity of the developed nano-carrier. Flow cytometry and MTT assays demonstrated that the 5-FU loaded nanocomposite had considerable cytotoxicity on MCF-7 breast cancer cells while it is not toxic against L929 fibroblast cells. The nanocomposite synthesized herein could serve as a platform for the pH-sensitive release of anti-cancer drugs.

Design and Development of D‒α‒Tocopheryl Polyethylene Glycol Succinate‒block‒Poly(ε-Caprolactone) (TPGS-b-PCL) Nanocarriers for Solubilization and Controlled Release of Paclitaxel

The objective of this study was to synthesize and characterize a set of biodegradable block copolymers based on TPGS-block-poly(ε-caprolactone) (TPGS-b-PCL) and to assess their self-assembled structures as a nanodelivery system for paclitaxel (PAX). The conjugation of PCL to TPGS was hypothesized to increase the stability and the drug solubilization characteristics of TPGS micelles. TPGS-b-PCL copolymer with various PCL/TPGS ratios were synthesized via ring opening bulk polymerization of ε-caprolactone using TPGS, with different molecular weights of PEG (1–5 kDa), as initiators and stannous octoate as a catalyst. The synthesized copolymers were characterized using ¹H NMR, GPC, FTIR, XRD, and DSC. Assembly of block copolymers was achieved via the cosolvent evaporation method. The self-assembled structures were characterized for their size, polydispersity, and CMC using dynamic light scattering (DLS) technique. The results from the spectroscopic and thermal analyses confirmed the successful synthesis of the copolymers. Only copolymers that consisted of TPGS with PEG molecular weights ≥ 2000 Da were able to self-assemble and form nanocarriers of ≤200 nm in diameter. Moreover, TPGS₂₀₀₀-b-PCL₄₀₀₀, TPGS₃₅₀₀-b-PCL₇₀₀₀, and TPGS₅₀₀₀-b-PCL₁₅₀₀₀ micelles enhanced the aqueous solubility of PAX from 0.3 µg/mL up to 88.4 ug/mL in TPGS₅₀₀₀-b-PCL₁₅₀₀₀. Of the abovementioned micellar formulations, TPGS₅₀₀₀-b-PCL₁₅₀₀₀ showed the slowest in vitro release of PAX. Specifically, the PAX-loaded TPGS₅₀₀₀-b-PCL₁₅₀₀₀ micellar formulation showed less than 10% drug release within the first 12 h, and around 36% cumulative drug release within 72 h compared to 61% and 100% PAX release, respectively, from the commercially available formulation (Ebetaxel^®) at the same time points. Our results point to a great potential for TPGS-b-PCL micelles to efficiently solubilize and control the release of PAX.

Novel Amphiphilic, Biodegradable, Biocompatible, Thermo-Responsive ABA Triblock Copolymers Based on PCL and PEG Analogues via a Combination of ROP and RAFT: Synthesis, Characterization, and Sustained Drug Release from Self-Assembled Micelles

Well-defined novel, linear, biodegradable, amphiphilic thermo-responsive ABA-type triblock copolymers, poly[2-(2-methoxyethoxy) ethyl methacrylate-co-oligo(ethylene glycol) methacrylate]-b-poly(ε-caprolactone)-b-poly[2-(2-methoxyethoxy) ethyl methacrylate-co-oligo(ethylene glycol) methacrylate] [P(MEO₂MA-co-OEGMA)-b-PCL-b-P(MEO₂MA-co-OEGMA)] (tBPs), were synthesized via a combination of ring-opening polymerization (ROP) of ε-caprolactone (εCL) and reversible addition-fragmentation chain transfer polymerization (RAFT) of MEO₂MA and OEGMA comonomers. The chemical structures and compositions of these copolymers were characterized using Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H NMR). The molecular weights of the copolymers were obtained using gel permeation chromatography (GPC) measurements. Thermo-responsive micelles were obtained by self-assembly of copolymers in aqueous medium. The temperature sensitivity and micelllization behavior of amphiphilic triblock copolymers solutions were studied by transmittance, fluorescence probe, surface tension, dynamic light scattering (DLS) and transmission electron microscopy (TEM). A hydrophobic drug, anethole, was encapsulated in micelles by using the dialysis method. The average particle sizes of drug-loaded micelles were determined by dynamic light scattering measurement. In vitro, the sustained release of the anethole was performed in pH 7.4 phosphate-buffered saline (PBS) at different temperatures. Results showed that the triblock copolymer's micelles were quite effective in the encapsulation and controlled release of anethole. The vial inversion test demonstrated that the triblock copolymers could trigger the sol-gel transition which also depended on the temperature, and its sol-gel transition temperature gradually decreased with increasing concentration. The hydrogel system could also be used as a carrier of hydrophobic drugs in medicine.

Graphene-assisted fabrication of poly(ε-caprolactone)-based nanocomposites with high mechanical properties and self-healing functionality

A fast NIR light-induced self-healing PCL nanocomposite with superior mechanical properties was achieved by tailoring the cyclic mechanical annealing process.

Dimensionally controlled water-dispersible amplifying fluorescent polymer nanoparticles for selective detection of charge-neutral analytes

Fluorescent nanoparticles composed of poly(p-phenylenevinylene) block copolymers were prepared by the facile one-step process and exhibited discriminative detection of neutral explosives against charged molecules.

Poly(ε-caprolactone)-based shape memory polymers crosslinked by polyhedral oligomeric silsesquioxane

A POSS–PCL shape memory network is synthesized. The cage-like POSS not only serves as a chemical netpoint, also causes improvement in mechanical properties. Optimized networks exhibit both excellent tensile strength and nearly complete recovery.