Amphiphilic Graft Copolymers of Quaternized Alginate-g-Polytetrahydrofuran for Anti-protein Surfaces, Curcumin Carriers, and Antibacterial Materials

Abstract

Amphiphilic quaternized alginate-g-polytetrahydrofuran (QA-g-PTHF) graft copolymers were successfully synthesized via nucleophilic substitution of living PTHF + chains obtained via cationic ring-opening polymerization with the −OH side functional groups in QA. This unique graft copolymer exhibits low cytotoxicity and anti-protein adsorption. The QA-g-PTHF nanospheres (328 ± 21 nm) loaded with curcumin exhibit ninefold higher anticancer effect to HeLa cells than pure curcumin due to the synergistic roles from the graft copolymer. Both the interactions of cationic quaternary ammonium with the negatively charged HeLa cell surface and the hydrophobic PTHF branches with the hydrophobic cell membrane result in a great improvement in the entrance of nanospheres into HeLa cells and effective drug release therein. The QA-g-PTHF/Ag nanocomposites prepared in situ during the synthetic process demonstrate more than 98% killing efficiency for Escherichia coli and Staphylococcus aureus. To the best of our knowledge, this is the first example of an amphiphilic, anti-protein, and antibacterial QA-g-PTHF copolymer with low cytotoxicity for potential anticancer applications.

Amphiphilic Graft Copolymer of Polylysine-g-polytetrahydrofuran and Its Biological Properties

“…The living cationic ring-opening polymerization of THF initiated by the AllylBr/AgClO 4 system was carried out in bulk at 0 °C for 4 h to synthesize the desired living PTHF + chains according to our previous works. − …”

“…The integral values of characteristic resonances in 1 H NMR spectra were used to calculate the number-average molecular weight of PTHF chains ( M n , PTHF ) according to our previous works. − …”

“…The PZLL and PZLL- g -PTHF films were produced on a glass piece as mentioned in Section , then immersed in PBS with 0.5 mg/mL bovine serum albumin labeled with fluorescein isothiocyanate (BSA-FITC) for 2 h in an aphotic environment, and finally washed with deionized water more than three times. Confocal laser scanning microscopy (CLSM, TCS–SP8) was performed on the above films to obtain the images, and fluorescence intensity data were obtained by Image J software. − …”

“…Poly­(tetrahydrofuran) (PTHF) is a hydrophobic aliphatic saturated polyether elastomer synthesized from THF cationic ring-opening polymerization, having biological inertness and biocompatibility, wet strength, flexibility, and hydrolytic stability. − A series of PTHF-grafted copolymers have been synthesized in our previous works. − …”

“…In addition, Ag NPs can cause cell membrane denaturation . Ag NPs can be prepared by chemical reduction, electrochemical reaction, irradiation-assisted chemical reaction, or pyrolysis. − It is a plain and economical way to synthesize Ag NPs in situ through the coinitiator (AgClO 4 ) used for the synthesis of PTHF + living polymers in our works. – …”