In Situ formation of pH-/thermo-sensitive nanohybrids via friendly-assembly of poly(N-vinylpyrrolidone) onto LAPONITE®

Abstract

The development of delivery nanosystems with a high payload, desirable release controllability, and cell responsiveness is important for an efficient and safe cancer therapy. In this study, multifunctional nanohybrids are successfully constructed by self-assembling a pH sensitive poly(N-vinylpyrrolidone) (PVP) onto LAPONITE® with a nanodisk structure (25 nm in diameter and 0.92 nm in thickness) in the absence of any organic solvent. The nanohybrids can effectively encapsulate a cationic anticancer drug, doxorubicin (DOX) through its electrostatic interactions with negatively-charged LAPONITE®. The hydrophobic component (alkane polymeric chain) of PVP can bind to the surface of LAPONITE®, with its hydrophilic components (ketone and tertiary amine residues) as a protective stealth shell for stabilization of the whole system. The deprotonation/protonation switchability of PVP endows the nanohybrids with good pH- and thermo-dual sensitivity in delivery of DOX drug, as compared to that modified with the polyethylene glycol (PEG, a common hydrophilic polymer for improving the stability of nanoparticles). In vitro biological evaluation indicated that the DOX-loaded nanocarriers can be effectively taken up by KB cells (a human epithelial carcinoma cell line), and exhibit uncompromising anticancer cytotoxicity as compared to free DOX, indicating their potential therapeutic delivery application.