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Superparamagnetic iron oxide nanoparticles (SPIONs) exhibit unique properties for diverse biomedical applications, including drug delivery and diagnostic imaging. Actively targeted SPIONs enhance delivery to diseased sites, reducing side effects and enhancing treatment efficacy. However, development of reproducible functionalization protocols is challenged by the erratic behavior of nanoparticles in suspensions, such as agglomeration and sedimentation. In this study, we develop and systematically optimize a functionalization method to attach the Fc-region of antibodies onto silica coated SPIONs via click chemistry, ensuring controlled ligand orientation on the particle surface. The synthesis and successive modifications of silica coated SPIONs with organic moieties is presented resulting in the final click conjugation with anti-ICAM1 antibodies. These antibodies target ICAM1, upregulated on epithelial cell surfaces during gastrointestinal inflammation. Thermogravimetric analysis and infrared spectroscopy confirm successful SPION functionalization after each modification step. Cell viability assessment indicates no adverse effects of bioconjugated particles. Quantitative elemental analysis reveals significantly higher iron concentration in inflammation-induced Caco-2 cells exposed to ICAM1-modified particles compared to non-conjugated counterparts. Furthermore, laser scanning confocal microscopy of these cells suggests surface interaction and internalization of bioconjugated SPIONs, underscoring their potential for targeted imaging and therapy in inflammatory diseases.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant global healthcare challenge, causing a range of life-threatening infections, including osteomyelitis, septic arthritis, skin and soft tissue infections, and wound infections. These infections are difficult to treat, often requiring aggressive therapeutic strategies at high antibiotic doses that increase the risk of adverse effects and drive the development of antimicrobial resistance. An alternative strategy to enhance antibiotic efficacy involves the use of locally elevated temperatures to increase the bacterial susceptibility to drugs. This can be achieved non-invasively, using magnetic hyperthermia induced by superparamagnetic iron oxide nanoparticles (SPIONs) in an alternating magnetic field (AMF). This study, presents a synergistic platform combining magnetic hyperthermia and antibiotic therapy to combat MRSA infections. Magnetic microfibers were fabricated by electrospinning using poly(methyl methacrylate) and tributyl citrate, incorporating functional Mn0.25Fe2.75O4 nanoparticles. The microfibers were systematically optimized to attain necessary tensile strength and heating efficiency for localized treatment of MRSA. Upon AMF exposure, the SPION-loaded microfiber discs achieved tunable temperatures exceeding 60 degrees C, controlled by varying the microfiber disc weight. The combination of doxycycline and magnetic hyperthermia exposure for 15 min demonstrated significant synergistic effects against MRSA at temperatures above 50 degrees C. In vitro, the antibiotic efficacy of doxycycline was enhanced by up to 35 % against MRSA, even at sub-inhibitory drug doses. The use of biocompatible materials in magnetic microfibers makes them well suited for localized therapy, particularly for treating wound infections. Additionally, the synergistic combination of magnetic hyperthermia with antibiotic therapy could enable lower drug doses, reducing the antibiotic burden and helping to combat antimicrobial resistance.

Magnetic hyperthermia holds significant therapeutic potential, yet its clinical adoption faces challenges. One obstacle is the large-scale synthesis of high-quality superparamagnetic iron oxide nanoparticles (SPIONs) required for inducing hyperthermia. Robust and scalable manufacturing would ensure control over the key quality attributes of SPIONs, and facilitate clinical translation and regulatory approval. Therefore, we implemented a risk-based pharmaceutical quality by design (QbD) approach for SPION production using flame spray pyrolysis (FSP), a scalable technique with excellent batch-to-batch consistency. A design of experiments method enabled precise size control during manufacturing. Subsequent modeling linked the SPION size (6–30 nm) and composition to intrinsic loss power (ILP), a measure of hyperthermia performance. FSP successfully fine-tuned the SPION composition with dopants (Zn, Mn, Mg), at various concentrations. Hyperthermia performance showed a strong nonlinear relationship with SPION size and composition. Moreover, the ILP demonstrated a stronger correlation to coercivity and remanence than to the saturation magnetization of SPIONs. The optimal operating space identified the midsized (15–18 nm) Mn_0.25Fe_2.75O₄ as the most promising nanoparticle for hyperthermia. The production of these nanoparticles on a pilot scale showed the feasibility of large-scale manufacturing, and cytotoxicity investigations in multiple cell lines confirmed their biocompatibility. In vitro hyperthermia studies with Caco-2 cells revealed that Mn_0.25Fe_2.75O₄ nanoparticles induced 80% greater cell death than undoped SPIONs. The systematic QbD approach developed here incorporates process robustness, scalability, and predictability, thus, supporting the clinical translation of high-performance SPIONs for magnetic hyperthermia.