Multiresponsive Core–Shell Microgels Functionalized by Nitrilotriacetic Acid

Biomacromolecules, vol. 25, pp. 903–923

Abstract

Stimuli-responsive microgels with ionizable functional groups offer versatile applications, e.g., by the uptake of oppositely charged metal ions or guest molecules such as drugs, dyes, or proteins. Furthermore, the incorporation of carboxylic groups enhances mucoadhesive properties, crucial for various drug delivery applications. In this work, we successfully synthesized poly{ N -vinylcaprolactam-2,2′-[(5-acrylamido-1-carboxypentyl)azanediyl]diacetic acid} [p(VCL/NTAaa)] microgels containing varying amounts of nitrilotriacetic acid (NTA) using precipitation polymerization. We performed fundamental characterization by infrared (IR) spectroscopy and dynamic and electrophoretic light scattering. Despite their potential multiresponsiveness, prior studies on NTA-functionalized microgels lack in-depth analysis of their stimuli-responsive behavior. This work addresses this gap by assessing the microgel responsiveness to temperature, ionic strength, and pH. Morphological investigations were performed via NMR relaxometry, nanoscale imaging (AFM and SEM), and reaction calorimetry. Finally, we explored the potential application of the microgels by conducting cytocompatibility experiments and demonstrating the immobilization of the model protein cytochrome c in the microgels.

Authors 5

1. Isabel Katja Sommerfeld Aachen DWI-Leibniz-Institute for Interactive Materials e.V Functional and Interactive Polymers Institute of Technical and Macromolecular Chemistry

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   DWI─Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, 52074 Aachen, Germany

   Functional and Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany

2. Hanna Malyaran Aachen Department of Orthodontics BioInterface Group Interdisciplinary Center for Clinical Research (IZKF)

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Orthodontics, University Hospital of RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany

   Helmholtz Institute for Biomedical Engineering, BioInterface Group, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany

   Interdisciplinary Center for Clinical Research (IZKF), RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany

3. Sabine Neuß Aachen BioInterface Group Institute of Pathology

   RWTH Aachen University

   Affiliation as printed

   Helmholtz Institute for Biomedical Engineering, BioInterface Group, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany

   Institute of Pathology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany

4. Dan E. Demco Aachen DWI-Leibniz-Institute for Interactive Materials e.V

   DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI─Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, 52074 Aachen, Germany

5. Andrij Pich corresponding Aachen DWI-Leibniz-Institute for Interactive Materials e.V Functional and Interactive Polymers Institute of Technical and Macromolecular Chemistry

   Maastricht University · DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands

   DWI─Leibniz-Institute for Interactive Materials e.V., Forckenbeckstraße 50, 52074 Aachen, Germany

   Functional and Interactive Polymers, Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany