New Class of Biodegradable Polymers Formed from Reactions of an Inorganic Functional Group

Abstract

Although numerous small molecules have been synthesized with sulfenamide bonds (R₂N–SR), this is the first report of the synthesis of polysulfenamides. These polymers are readily synthesized at room temperature using secondary diamines and dithiosuccinimides. The dithiosuccinimides were readily synthesized in one step by the reaction of dithiols such as HS(CH₂)₆SH with N-chlorosuccinimide. The resulting dithiosuccinimides were either recrystallized or readily purified by chromatography on silica gel and required no special handling. The conversions of polymerization ranged from 95 to 98%, and the molecular weights of the polymer reached as high as 6300 g mol^–1. The sulfenamide bond was very stable in organic solvents, and no degradation was observed under atmospheric conditions in C₆D₆ for 30 days. In contrast, the sulfenamide bond readily decomposed in less than 12 h in D₂O. Polysulfenamides were fabricated into micrometer-sized particles loaded with dye and endocytosed into JAWSII immature dendritic and HEK293 cells. Polysulfenamides represent a new class of polymers that are readily synthesized, stable in aprotic solvents, and readily degrade in water.