Biodegradation by Cancer Cells of Magnetite Nanoflowers with and without Encapsulation in PS‑b‑PAA Block Copolymer Micelles

• Published in: ACS applied materials & interfaces Vol. 16; no. 27; pp. 34772 - 34782
• Main Authors: Benassai, Emilia, Daffé, Niéli, Aygun, Elif, Geeverding, Audrey, Ulku Saritas, Emine, Wilhelm, Claire, Abou-Hassan, Ali
• Format: Journal Article
• Language: English
• Published: American Chemical Society 10.07.2024; Washington, D.C. : American Chemical Society
• Subjects: Biological and Medical Applications of Materials and Interfaces; Chemical Sciences; biodegradation; PS-b-PAA block copolymer; magnetic nanoparticles; cancer cells spheroids; magnetic micelles; Biodegradation; Magnetic nanoparticles PS-b-PAA block copolymer Magnetic micelles; Biodegradation Cancer cells spheroids; Magnetic nanoparticles; Magnetic micelles; Cancer cells spheroids
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.4c08727

Magnetomicelles were produced by the self-assembly of magnetite iron oxide nanoflowers and the amphiphilic poly­(styrene)-b-poly­(acrylic acid) block copolymer to deliver a multifunctional theranostic agent. Their bioprocessing by cancer cells was investigated in a three-dimensional spheroid model over a 13-day period and compared with nonencapsulated magnetic nanoflowers. A degradation process was identified and monitored at various scales, exploiting different physicochemical fingerprints. At a collective level, measurements were conducted using magnetic, photothermal, and magnetic resonance imaging techniques. At the nanoscale, transmission electron microscopy was employed to identify the morphological integrity of the structures, and X-ray absorption spectroscopy was used to analyze the degradation at the crystalline phase and chemical levels. All of these measurements converge to demonstrate that the encapsulation of magnetic nanoparticles in micelles effectively mitigates their degradation compared to individual nonencapsulated magnetic nanoflowers. This protective effect consequently resulted in better maintenance of their therapeutic photothermal potential. The structural degradation of magnetomicelles occurred through the formation of an oxidized iron phase in ferritin from the magnetic nanoparticles, leaving behind empty spherical polymeric ghost shells. These results underscore the significance of encapsulation of iron oxides in micelles in preserving nanomaterial integrity and regulating degradation, even under challenging physicochemical conditions within cancer cells.