Polymer–Aptamer Hybrid Emulsion Templating Yields Bioresponsive Nanocapsules

Abstract

This article describes the synthesis of a DNA–polymer, being the nucleotide sequence an aptamer selected in vitro to target specifically the immunoglobulin E (IgE) protein, an allergy biomarker. Subsequent to coupling to poly(2‐alkyl‐2‐oxazoline) with N ‐Boc protected amino acid side chains, the resulting amphiphilic DNA–polymer hybrid composed of the water‐soluble DNA fragment grafted to the hydrophobic polymer segment can be regarded as a high molecular weight analogue of a surfactant. It is demonstrated that the copolymer–aptamer stabilizes efficiently submicrometer size oil‐in‐water and water‐in‐oil emulsions, by dynamic light scattering, microscopy, and reflectometry. Particularly interesting is that the aptamer remains functional after coupling to a polymer backbone, stabilization of the emulsion droplets, and locking of the structure subsequent to cross‐linking polymerization. The resulting nanocapsules still target specifically the IgE protein. The biological‐stimulus responsiveness of the structures is of high potential for future developments of carriers for sustained and targeted delivery.