Development of Resorbable Phosphate-Based Glass Microspheres as MRI Contrast Media Agents

Molinar-Díaz, Jesús; Arjuna, Andi; Abrehart, Nichola; McLellan, Alison; Harris, Roy; Islam, Md Towhidul; Alzaidi, Ahlam; Bradley, Chris R.; Gidman, Charlotte; Prior, Malcolm J.W.; Titman, Jeremy; Blockley, Nicholas P.; Harvey, Peter; Marciani, Luca; Ahmed, Ifty

Abstract

In this research, resorbable phosphate-based glass (PBG) compositions were developed using varying modifier oxides including iron (Fe2O3), copper (CuO), and manganese (MnO2), and then processed via a rapid single-stage flame spheroidisation process to manufacture dense (i.e., solid) and highly porous microspheres. Solid (63–200 µm) and porous (100–200 µm) microspheres were produced and characterised via SEM, XRD, and EDX to investigate their surface topography, structural properties, and elemental distribution. Complementary NMR investigations revealed the formation of Q2, Q1, and Q0 phosphate species within the porous and solid microspheres, and degradation studies performed to evaluate mass loss, particle size, and pH changes over 28 days showed no significant differences among the microspheres (63–71 µm) investigated. The microspheres produced were then investigated using clinical (1.5 T) and preclinical (7 T) MRI systems to determine the R1 and R2 relaxation rates. Among the compositions investigated, manganese-based porous and solid microspheres revealed enhanced levels of R2 (9.7–10.5 s−1 for 1.5 T; 17.1–18.9 s−1 for 7 T) and R1 (3.4–3.9 s−1 for 1.5 T; 2.2–2.3 s−1 for 7 T) when compared to the copper and iron-based microsphere samples. This was suggested to be due to paramagnetic ions present in the Mn-based microspheres. It is also suggested that the porosity in the resorbable PBG porous microspheres could be further explored for loading with drugs or other biologics. This would further advance these materials as MRI theranostic agents and generate new opportunities for MRI contrast-enhancement oral-delivery applications.

Citation

Molinar-Díaz, J., Arjuna, A., Abrehart, N., McLellan, A., Harris, R., Islam, M. T., Alzaidi, A., Bradley, C. R., Gidman, C., Prior, M. J., Titman, J., Blockley, N. P., Harvey, P., Marciani, L., & Ahmed, I. (2024). Development of Resorbable Phosphate-Based Glass Microspheres as MRI Contrast Media Agents. Molecules, 29(18), Article 4296. https://doi.org/10.3390/molecules29184296

• Journal Article Type: Article
• Acceptance Date: Sep 4, 2024
• Online Publication Date: Sep 10, 2024
• Publication Date: 2024-09
• Deposit Date: Sep 12, 2024
• Publicly Available Date: Sep 12, 2024
• Journal: Molecules
• Electronic ISSN: 1420-3049
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 29
• Issue: 18
• Article Number: 4296
• DOI: https://doi.org/10.3390/molecules29184296
• Keywords: Magnetic Resonance Imaging; phosphate-based glasses; oral contrast agents; porous microspheres; resorbable materials
• Public URL: https://nottingham-repository.worktribe.com/output/39459972
• Publisher URL: https://www.mdpi.com/1420-3049/29/18/4296