Magnetic Nanoparticles Synergize with Pulsed Magnetic Fields to Stimulate Osteogenesis In Vitro

Harnessing electromagnetic fields to assist bone tissue engineering

Bone tissue engineering (BTE) emerged as one of the exceptional means for bone defects owing to it providing mechanical supports to guide bone tissue regeneration. Great advances have been made to facilitate the success of BTE in regenerating bone within defects. The use of externally applied fields has been regarded as an alternative strategy for BTE. Electromagnetic fields (EMFs), known as a simple and non-invasive therapy, can remotely provide electric and magnetic stimulation to cells and biomaterials, thus applying EMFs to assist BTE would be a promising strategy for bone regeneration. When combined with BTE, EMFs improve cell adhesion to the material surface by promoting protein adsorption. Additionally, EMFs have positive effects on mesenchymal stem cells and show capabilities of pro-angiogenesis and macrophage polarization manipulation. These advantages of EMFs indicate that it is perfectly suitable for representing the adjuvant treatment of BTE. We also summarize studies concerning combinations of EMFs and diverse biomaterial types. The strategy of combining EMFs and BTE receives encouraging outcomes and holds a promising future for effectively treating bone defects.

Synergistic Effect Evaluation of Magnetotherapy and a Cationic-Magnetic Nanocomposite Loaded with Doxorubicin for Targeted Drug Delivery to Breast Adenocarcinoma

This work investigates the synergistic effect of magnetotherapy and a novel cationic-magnetic drug delivery system on inhibiting breast cancer cell growth and other tissues. First, super-paramagnetic magnetite (Fe₃O₄) nanoparticles were coated with doxorubicin-imprinted poly(methacrylic acid-co-diallyl dimethylammonium chloride) [Fe₃O₄/poly(MAA-DDA)]. The cationic-magnetic nanocomposite (CMC) was characterized using XRD, FT-IR, VSM, TGA, TEM, FESEM, EDS, DLS, and BET. In vitro analyses, including drug release kinetics, cytotoxicity, and hemolytic assays, confirmed this novel CMC's good drug release profile and biocompatibility. Finally, in vivo experiments on BALB/c mice were designed to evaluate the synergistic effect of magnetotherapy on targeted drug delivery using the CMC. In vivo fluorescence imaging evaluated the drug distribution in different tissues of mice. Tumor volume evaluation demonstrated the efficiency of the CMC and magnetotherapy in preventing tumor growth; the two techniques significantly reduced tumor volume. Histopathological analysis proved that applying magnetotherapy in conjunction with the cationic-magnetic drug delivery system significantly prevented tumor cell proliferation and increased apoptosis with limited impact on other tissues. Also, Dox and Fe concentrations in different tissues confirmed the efficient drug delivery to tumor cells.

The Role of Low-Frequency Electromagnetic Fields on Mesenchymal Stem Cells Differentiation: A Systematic Review

BACKGROUND

Low-frequency electromagnetic fields (EMFs) influence biological processes. This present study was aimed at the scientific literature on the use of EMFs in the mesenchymal stem cell differentiation process.

MATERIALS AND METHODS

The electronic search was carried out in PubMed and Web of Science, a database with a combination of the sinusoidal and pulsed low- and extremely low-frequency electromagnetic fields stimulation and mesenchymal stem cells differentiation, considering the period of publication until December 2021. The literature search identified 118 references in PubMed and Web of Science of which 46 articles were selected, respectively, according to the eligibility requirements.

CONCLUSION

The analysis of research indicated that EMFs are an easy-to-apply and practical way in cell therapy and tissue engineering when regulation of stem cells is required. Studies have shown that EMFs have positive effects on stem cell differentiation, accelerating its process regardless of the parameters and type of stem cells. However, the exact amplitude, frequency, duration of the electrical field, and application method remain elusive and need more study in future work.

Mg.ATP-decorated ultrafine magnetic nanofibers: A bone scaffold with high osteogenic and antibacterial properties in the presence of an electromagnetic field

In this study, ultrafine magnetic nanofibers were developed for bone regeneration purposes. Nanofibers were acquired by electrospinning using a two-component nanofiber matrix (CP: chitosan (Cs) and polyvinyl alcohol (PVA)) containing different concentrations of succinate conjugated-magnetic hydroxyapatite nanocomposites (SMHA). Hybrid nanofibers (CP&SMHA) containing 5 mg ml^-1 of SMHA nanocomposite showed well-defined properties in terms of physicochemical properties and cell behavior. Then, they were modified with adenosine 5'-triphosphate (ATP) and Mg²⁺ ions. The initial adhesion of mesenchymal stem cells and their proliferation rate on the surface of modified nanofibers (Mg.ATP.CP&SMHA) were significantly increased as compared to those of bare nanofibers. Analysis of common osteogenic markers such as alkaline phosphatase activity and the expression of Runt-related transcription factor 2 and osteocalcin confirmed the osteogenic efficacy enhancement of CP&SMHA nanofibers when they were functionalized with ATP and Mg²⁺. The utilization of the antagonist of purine receptor, P2X7, revealed that this receptor has a major role in the osteogenesis process induced by Mg.ATP.CP&SMHA. Moreover, the results showed that cell adhesion, proliferation, and differentiation improved as nanofibers were under the influence of the electromagnetic field (EMF), displaying synergistic effects in the process of bone formation. Mg.ATP.CP&SMHA also showed an antibacterial effect against gram-negative and gram-positive bacteria, Escherichia coli and Staphylococcus aureus, respectively. Considering the high osteogenic potential and antibacterial activity of Mg.ATP.CP&SMHA nanofibers particularly in combination with EMF, it can serve as a great candidate for use in bone tissue engineering applications.