Synthesis and properties of non-cytotoxic poly(l-malic acid acetate-co-l-lysine ester)s with thermo-sensitivity as hydrophobic drug nanocarrier

In this investigation, a group of poly( l -malic acid acetate- co - l -lysine ester)s (PMALs) with excellent thermo-sensitivity and non-cytotoxicity were prepared by an optimized synthetic route from natural l -malic acid and l -lysine. The structure and properties of PMALs including monomers were systematically characterized by FTIR, 1 H NMR, UV, gel permeation chromatograph, scanning electron microscope, contact angle measurement, cell counting kit assess (CCK-8), and confocal laser scanning microscopy (CLSM). Three PMALs show a reversible lower critical solution temperature of 8–36 °C depending on their chemical structure. The contact angle measurement revealed a considerable discrepancy in the hydrophilicity/hydrophobicity of PMALs and further influence on their thermo-sensitivity. The viability of HeLa cells exposed to 0.2–100 μg/mL PMALs solution was found to be in a range 80–103% after 24, 48, and 72 h of incubation, indicating no cytotoxicity. Moreover, a spherical nanocarrier with core-shell structure was facilely fabricated via the thermo-sensitivity of PMALs and hydrophobicity of drug. CLSM observations manifested that the hydrophobic-curcumin-enwrapped nanocarriers can clearly internalize into the cellular inside. The sustained release of curcumin from nanocarriers in vitro provided a possibility of depressing fast hydrolytic degradation at physiological pH or other side-effects. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45984.