A Thermal-Responsive Y-Shaped Miktoarm Amphiphilic Block Copolymer Composed of Poly(ε-caprolactone) and Poly(N-isopropylacrylamide) as a Nano-micellar Carrier for Anti-cancer Drugs

A thermal-responsive Y-shaped amphiphilic block copolymer, namely poly( N -isopropylacrylamide- block -[poly(ε-caprolactone)] 2 (PNIPAAm- b -PCL 2 ), was synthesized through the combination of atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP) techniques, and its potential as smart anti-cancer drug delivery system was investigated preliminary. The fabricated polymers were characterized using FTIR and 1 H NMR spectroscopy, and GPC analysis. The self-assembly behavior of the fabricated PNIPAAm- b -PCL 2 copolymer under thermal stimuli was investigated using dynamic light scattering and UV–Vis spectroscopy. The lower critical solution temperature of the synthesized PNIPAAm- b -PCL 2 was found to be 39–41°C. The doxorubicin hydrochloride loading and encapsulation capacities of the fabricated PNIPAAm- b -PCL 2 were calculated to be 62 ± 3%, and 75 ± 4%, respectively; the drug release value was up to 46.5% during 40 h at 37°C and up to 88% at 40°C.