Influence of nanoparticle encapsulation and encoding on the surface chemistry of polymer carrier beads

verfasst von
Lena Scholtz, Isabella Tavernaro, J. Gerrit Eckert, Marc Lutowski, Daniel Geißler, Andreas Hertwig, Gundula Hidde, Nadja C. Bigall, Ute Resch-Genger
Abstract

Surface-functionalized polymer beads encoded with molecular luminophores and nanocrystalline emitters such as semiconductor nanocrystals, often referred to as quantum dots (QDs), or magnetic nanoparticles are broadly used in the life sciences as reporters and carrier beads. Many of these applications require a profound knowledge of the chemical nature and total number of their surface functional groups (FGs), that control bead charge, colloidal stability, hydrophobicity, and the interaction with the environment and biological systems. For bioanalytical applications, also the number of groups accessible for the subsequent functionalization with, e.g., biomolecules or targeting ligands is relevant. In this study, we explore the influence of QD encoding on the amount of carboxylic acid (COOH) surface FGs of 2 µm polystyrene microparticles (PSMPs). This is done for frequently employed oleic acid and oleylamine stabilized, luminescent core/shell CdSe QDs and two commonly used encoding procedures. This included QD addition during bead formation by a thermally induced polymerization reaction and a post synthetic swelling procedure. The accessible number of COOH groups on the surface of QD-encoded and pristine beads was quantified by two colorimetric assays, utilizing differently sized reporters and electrostatic and covalent interactions. The results were compared to the total number of FGs obtained by a conductometric titration and Fourier transform infrared spectroscopy (FTIR). In addition, a comparison of the impact of QD and dye encoding on the bead surface chemistry was performed. Our results demonstrate the influence of QD encoding and the QD-encoding strategy on the number of surface FG that is ascribed to an interaction of the QDs with the carboxylic acid groups on the bead surface. These findings are of considerable relevance for applications of nanoparticle-encoded beads and safe-by-design concepts for nanomaterials.

Organisationseinheit(en)
Institut für Physikalische Chemie und Elektrochemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme
Externe Organisation(en)
Bundesanstalt für Materialforschung und -prüfung (BAM)
Freie Universität Berlin (FU Berlin)
Typ
Artikel
Journal
Scientific reports
Band
13
ISSN
2045-2322
Publikationsdatum
12.2023
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Allgemein
Elektronische Version(en)
https://doi.org/10.1038/s41598-023-38518-7 (Zugang: Offen)