New amphiphilic terpolymers of N -vinylpyrrolidone with poly(ethylene glycol) methyl ether methacrylate and triethylene glycol dimethacrylate as carriers of the hydrophobic fluorescent dye

New amphiphilic terpolymers of N -vinylpyrrolidone, poly(ethylene glycol) methyl ether methacrylate ( M n 500 g/mol) and triethylene glycol dimethacrylate (branching agent) were synthesized via radical polymerization with and without 1-decanethiol as a chain transfer agent. They consisted of ca . 10 mol% (di)methacrylate units and had effective absolute molecular weight of about 26–600 kDa. The terpolymers were studied in polar media with dynamic light scattering, and critical concentration of aggregation and sizes of individual macromolecules and their aggregates were determined. Nanostructures of terpolymers containing 0.25–0.75% of fluorescent zinc tetraphenylporphyrinate (ZnTPP) were obtained that had the hydrodynamic radii less than 100 nm in aqueous solutions. The molar extinction coefficient of the Soret band at 425 nm of the encapsulated ZnTPP and the effective terpolymer binding constant for ZnTPP and the stability of terpolymers were found to be dependent on the presence of hydrophobic –SC 10 H 21 groups in terpolymer chains. Terpolymer 1 did not affect significantly the viability of Vero or HeLa cells and was able to penetrate cells with high efficiency. Thus, new non-toxic amphiphilic terpolymers of N-vinylpyrrolidone can be promising platforms for delivery of hydrophobic biologically active compounds. Graphic abstract