Microwave-assisted synthesis of thermo- and pH-responsive antitumor drug carrier through reversible addition–fragmentation chain transfer polymerization

Abstract

Abstract. This paper reports the rapid synthesis of a dual-responsive copolymer through reversible addition-fragmentation chain transfer (RAFT) polymerization under microwave irradiation. Through use of 2-ethoxycarbonothioylthio acetic acid (ECTA) as a RAFT agent, the microwave-assisted polymerization rate of N-isopropylacrylamide (NIPAM) was approximately 150 times faster than that observed under conventional heating conditions, and the resulting homopolymer can be reactivated as a macroinitiator to produce poly(N-isopropylacrylamide-block-methacrylic acid) (PNIPAM-b-PMAA) block copolymers through a similar method. Research into the detailed polymerization kinetics of the PNIPAM and PNIPAM-b-PMAA revealed living characteristics that included a linear relationship between M n and conversion, controlled molecular weights, and a relatively narrow molecular weight distribution. The solution of the block copolymers in phosphate-buffered saline buffer displayed a phase transition at a lower critical solution temperature transition of 42°C, and altering the pH from 7 to 3.5 resulted in various degrees of polymer aggregation in the solution. Cisplatin was loaded to the polymeric carrier through a ligand exchange to form a macromolecular prodrug. The observed critical micelle concentration was 0.25 mg/mL. Overall, these polymers offer considerable potential for developing a new multifunctional drug delivery system.

<p>Evaluation of Cytotoxic Effect of Cholesterol End-Capped Poly(<em>N</em>-Isopropylacrylamide)s on Selected Normal and Neoplastic Cells</p>

“…Hitachi F-7000 Fluorescence Spectrophotometer was used to determine critical micelle concentration (CMC) by pyrene fluorescent probe method adapted from literature. [20][21][22] Ten microliters of pyrene stock solution (0.15 mM) were poured into empty vials and acetone was evaporated by argon stream. Then, 3 mL of polymer aqueous solutions of various concentrations (10 −4 to 2 mg/mL) were added into vials and shaken vigorously.…”

Physically stimulus-responsive nanoparticles for therapy and diagnosis

“…Different types of cargo are loaded successfully on the PMs, and their release patterns are investigated ( Li N. et al, 2016 ; Qu et al, 2017 ). Anticonvulsant drug (clonazepam) ( Choi et al, 2006 ), ophthalmic drugs (e.g., prednisone acetate) ( Chang et al, 2008 ), diazepam ( Suksiriworapong et al, 2014 ), and mainly anticancer drugs, for example, DOX ( Panja et al, 2016a ), MTX ( Tu et al, 2018 ), PTX ( Song et al, 2016 ), CPT ( Meng et al, 2013 ), curcumin ( Yu et al, 2014 ), cis-Pt ( Wang Y. et al, 2017 ), and ADR ( Li et al, 2017 ). There are different strategies for reaching the drugs to target cells as depicted in Figure 1 ( Singh A. et al, 2016 ).…”

Comparative analysis of electrospun PNIPAAm blends with some biodegradable polymers

“…In some polymers, alteration of a property such as color, conformation, solubility, etc., may be a response to being subjected to certain external stimuli, which may include, among others, temperature [8,31], light [32,33], electric or magnetic fields [17,34], and pH [31,35]. Such polymers are called smart polymers and they can be applied in many areas, for example, in filtration [36,37], cell growth/detachment [38,39], and sensors [33,40], as well as those already mentioned above (drug delivery, tissue engineering scaffolds, wound dressing, and biomedicine).…”