Synthesis and characterization of a pH‐ and glucose‐responsive triblock copolymer via RAFT technique and its conjugation with gold nanoparticles for biomedical applications

Abstract

A combination of ring-opening polymerization (ROP) and reversible addition of fragmentation chain transfer (RAFT) polymerization techniques was successfully employed for the synthesis of a novel pH-and glucose-responsive thiol-end-capped ABC triblock copolymer, namely, poly(acrylic acid)-block-poly(vinylphenylboronic acid)-block-poly(ε-caprolactone)-SH (PAA-b-PVPBA-b-PCL-SH). The synthesized triblock copolymer was characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance ( 1 H NMR) spectroscopies. The molecular weights of each segment in the synthesized triblock copolymer were calculated using both gel permeation chromatography (GPC) and 1 H NMR spectroscopy. The self-assembly behavior of the fabricated triblock copolymer under various pHs as well as in the presence of glucose were investigated using dynamic light scattering (DLS) measurement. The PAA-b-PVPBA-b-PCL-SH triblock copolymer was conjugated with gold nanoparticles (GNPs). In addition, the morphologies of GNPs, PAA-b-PVPBA-b-PCL-SH triblock copolymer, and GNPs@polymer were observed using transmission electron microscopy (TEM). As the results, the fabricated GNPs@Polymer can be employed as drug delivery system and micellar glucose biosensor.

Fabrication and characterization of gold nanospheres‐cored pH‐sensitive thiol‐ended triblock copolymer: A smart drug delivery system for cancer therapy

“…As demonstrated in Figures and , 1 H NMR and FTIR spectroscopies were used to describe the PMAA‐b‐PAM‐b‐PCL‐SH triblock copolymer. The most important bands in the FTIR spectrum of the (CTA‐PCL‐S) 2 sample (Figure A) can be listed as the stretching vibration of carbonyl group at 1724 cm −1 , the bending vibrations of –CH 2 groups at 1462 and 1362 cm −1 , the stretching vibration of the cyanide group at 2254 cm −1 , the stretching vibrations of aliphatic C–H at 2950 and 2850 cm −1 , and symmetric and asymmetric stretching vibrations of C–O–C group at 1176 and 1242 cm −1 …”

“…The FTIR spectra of the GNSs and GNSs conjugated PMAA‐b‐PAM‐b‐PCL‐SH (GNPs@polymer) nanosystem are shown in Figure . The FTIR spectrum of GNSs demonstrated antisymmetric and symmetric stretching vibrations of carboxylate ions (corresponded to the citrate groups) on the surface of GNSs at 1589 and 1397 cm −1 , respectively, the stretching vibrations of aliphatic C–H (related to citrate groups) at 2950 to 2850 cm −1 region, carbonyl stretching vibration at 1719 cm −1 , and surface hydroxyl groups of GNSs or adsorbed water as a broad band centered at 3430 cm −1 . The successful conjugation of GNPs with PMAA‐b‐PAM‐b‐PCL‐SH triblock copolymer is established through the appearance of some new bands or significant changes in the FTIR spectrum as follows.…”

“…At the end of this time, in order to remove free polymeric chains, GNSs@polymer was dialyzed against DI water for about 72 hours. The solution containing GNSs@polymer transformed from transparent red to cloudy red over the dialysis, which establish the production of Au–S bond …”

“…Nevertheless, nonspecific delivery of anticancer agents leads to harmful and adverse side effects on human normal cells and inadequate dosages to kill cancer cells . So, to overcome these problems, nanoscale drug delivery systems (DDS) such as polymeric micelles have achieved remarkable consideration, in the field of cancer therapy because of their self‐assembly ability in the aqueous solvent upon responding to external stimuli initiates, for example, temperature, special enzymes, ionic light, pH, and electric field . Various nanomicelles containing nanorods, vesicles, core‐shell–corona nanospheres, and multicompartment nanoparticles have been arranged, depending on the process of micellization, solvent character, and copolymer structure .…”

Polystyrene‐modified novolac epoxy resin/clay nanocomposite: Synthesis, and characterization

“…The most important advantage of RDRP approaches over ionic polymerizations is their tolerance to functional groups and impurities. This polymerization strategy is divided into three main category known as atom transfer radical polymerization (ATRP), nitroxide‐mediated polymerization (NMP), and reversible addition‐fragmentation chains transfer (RAFT) polymerization . Among the three, ATRP is developed as an efficient and versatile approach for the synthesis of polymeric materials with excellent control over the molecular weight because of its controlled chain growth and “living” feature.…”