Regulation of conjugated hemoglobin on micelles through copolymer chain sequences and the protein's isoelectric aggregation

Abstract

Amphiphilic triblock copolymers with carbonyl groups located either in the middle segment or in the third side block are synthesized by adjusting feeding sequence of the comonomers. The conjugation of hemoglobin (Hb) on the copolymer micelles is realized by condensation reactions of carbonyl with the amino groups of Hb, and the gas-binding capacity of Hb is well preserved. Interestingly, the reassembly behavior of Hb-conjugated micelles (HbM) is explored by adjusting the pH. As for triblock copolymers with a carbonyl-functionalized segment as the third block, Hb is rearranged into the inner core of micelles when the pH is adjusted close to the isoelectric point of Hb. Therefore, it may provide a new needed route for fabrication of protein carriers, which is different from the traditional encapsulation technique.

Keywords: biocompatibility; chain sequences; hemoglobin; isoelectric aggregation; micelles.