Ultrasound-assisted size tuning of polyacrylic acid coated magnetic nanoparticle clusters for biomedical applications

Heinen L, Blersch PR, Schnell C, Meyer K, Nagy R, Halik M, Janko C, Lyer S, Alexiou C, Tietze R (2026)


Publication Type: Journal article

Publication year: 2026

Journal

Original Authors: Lukas Heinen, Pascal-Raphael Blersch, Constantin Schnell, Karsten Meyer, Roland Nagy, Marcus Halik, Christina Janko, Stefan Lyer, Christoph Alexiou, Rainer Tietze

Book Volume: 130

Article Number: 107876

DOI: 10.1016/j.ultsonch.2026.107876

Abstract

The hydrodynamic size of magnetic nanoparticle clusters is a critical determinant of their in vivo behaviour and therapeutic efficacy. While alkaline co-precipitation offers a scalable route for polyacrylic acid (PAA) coated superparamagnetic iron oxide nanoparticles (SPIONs), it typically yields polydisperse agglomerates. This work establishes a predictive engineering process using controlled, post-synthesis ultrasound treatment to precisely tune SPION cluster size. Utilising a D-optimal Design of Experiments (DoE) approach, we modelled the influences of sonication parameters on the hydrodynamic diameter, identifying specific energy input as the governing factor for de-agglomeration. The resulting verified regression model enables predictable laboratory scale-up across varying volumes (1–10 ml) and concentrations (1–10 mg/ml) while maintaining material integrity. Quantitative magnetic characterisation revealed that ultrasound-induced fragmentation increases the mass-specific susceptibility, which is attributed to the magnetic de-locking of frustrated cores as inter-cluster spacing increases. Crucially, biological evaluations in B16-F10 melanoma cells demonstrate that this ultrasound-assisted size tuning directly influences cellular loading. Cellular iron mass post SPION incubation was found to follow a dual-variable dependency: while iron loading increases with cluster diameter for a fixed core size, it is significantly impacted by the primary core dimensions. SPION clusters with 12 nm cores exhibited a two-fold higher iron loading (8.23 pg Fe/cell) compared to those with 8 nm cores at equivalent hydrodynamic sizes, highlighting the importance of the magnetic payload per cluster. These findings establish a robust framework for engineering SPIONs with tailored dimensions to maximise and predict the magnetic responsiveness of loaded cells, providing a reliable foundation for future applications such as cell tracking, magnetic drug targeting, and hyperthermia.

Authors with CRIS profile

How to cite

APA:

Heinen, L., Blersch, P.-R., Schnell, C., Meyer, K., Nagy, R., Halik, M.,... Tietze, R. (2026). Ultrasound-assisted size tuning of polyacrylic acid coated magnetic nanoparticle clusters for biomedical applications. Ultrasonics Sonochemistry, 130. https://doi.org/10.1016/j.ultsonch.2026.107876

MLA:

Heinen, Lukas, et al. "Ultrasound-assisted size tuning of polyacrylic acid coated magnetic nanoparticle clusters for biomedical applications." Ultrasonics Sonochemistry 130 (2026).

BibTeX: Download