Design and synthesis of fluorescent shell functionalized polymer micelles for biomedical application

Abstract

pH‐sensitive polymers can be defined as polyelectrolytes that include in their structure weak acidic or basic groups that either accept or release protons in response to a change in the environmental pH. This work summarizes the design, synthesis, and potential applications of pH‐responsive fluorescent copolymers in the biomedical field. This was achieved using atom transfer radical polymerization (ATRP) of tert‐butyl acrylate using a CuBr/N,N,N′,N″N″‐pentamethyldiethylenetriamine catalyst system in conjunction with an alkyl bromide as the initiator. Well‐defined macroinitiators based on poly(tert‐butyl acrylate) with narrow molecular weight distributions were obtained by the addition of an appropriate solvent system in order to create a homogeneous catalytic system. The addition of n‐butyl acrylate as a second building block in order to create well‐defined poly(tert‐butyl acrylate)‐b‐poly(n‐butyl acrylate) block copolymers (PtBA‐b‐PnBA) followed by chemical modification of the block copolymers and functionalization with an appropriate fluorescent compound are the basis for the preparation of well‐defined fluorescent pH‐sensitive micelles. Thus, prepared water soluble nanosized pH‐sensitive micelles consisting of hydrophobic poly(n‐butyl acrylate) core and hydrophilic polyacrylic acid shell decorated with an appropriate fluorescent compound determined their potential applications of these systems in the field of biomedicine as biosensors, controlled drug delivery systems, and so on. In this respect, the cell viability and internalization of the polymer micelles were studied.