Polymer Colloid Formation with Oligo Hydrophilic and Hydrophobic Chains for Bioconjugation

Abstract

We investigated the bioconjugation on polymer colloids covered with a bioinert poly(ethylene glycol) chain. The polymer colloids would be expected to carry out a specific enzymatic reaction by conjugation of a substance at the shell part of the colloids. Therefore, the conjugated polymer colloid surface needs to possess a property for the conjugation of functional molecules. In this study, a water-soluble amphiphilic graft polymer with a substrate specific to the enzyme was designed to possess surface modification of the enzyme-substrate complex. The graft copolymer composed of hydrophilic and hydrophobic side chains was created by a new molecular design. The macromonomer with an oligo hydrophilic chain was modified by using p-nitrophenyl chloroformate to obtain the macromonomer with an active ester group (MEONP). The graft copolymer was prepared by conventional radical polymerization using poly(propylene glycol) methacrylate and MEONP. Their solution properties in an aqueous medium were also analyzed by using fluorescence measurement of sodium 8-anilino-1-naphthalene sulfonate (ANS) as a fluorescence probe to evaluate the hydrophobic domain in the polymer colloids, and were also measured by dynamic light scattering to determine the particle size. The conjugation efficiency was determined by UV-Vis spectroscopy at 400 nm.