Effect of Combined Iron Oxide Magnetic Nanoparticles and Magnetic Field Exposure on Osteogenic Differentiation of Mesenchymal Stem Cells: A Systematic Review and Meta-Analysis

Combined iron oxide magnetic nanoparticles (MNPs) and external magnetic fields (MFs) are explored to direct osteogenic differentiation of mesenchymal stem cells (MSCs) in bone tissue engineering, yet exposure parameters vary widely. This systematic review and meta-analysis searched PubMed and Dimensions, with Consensus and SciSpace as exploratory scoping aids (final search 22 November 2025). Twenty-five studies entered qualitative synthesis and twenty-two quantitative synthesis (‘MNP + MF’ vs. ‘MNP without MF’; standardized mean difference [SMD] as Hedges’ g; restricted maximum likelihood random-effects model with Hartung–Knapp–Sidik–Jonkman confidence intervals [CIs]). Across nine outcomes, effect directions were predominantly positive; uncorrected significance held only for alkaline phosphatase (ALP) activity (SMD = +4.42; 95% CI 0.97–7.86; k = 14) and mineralization (SMD = +2.41; 0.03–4.80; k = 7). After Holm correction, no outcome remained significant. Heterogeneity was critical (I2 > 75% for five outcomes). Funnel–plot asymmetry for ALP suggested possible small-study effects; trim-and-fill reduced the pooled SMD to +1.34 (−1.60–4.27). Findings constitute a low-certainty, hypothesis-generating signal rather than confirmed efficacy; standardized protocols and blinded designs are needed before translational claims.