Vascular Repair by Grafting Based on Magnetic Nanoparticles

Construction of bFGF/heparin and Fe3O4 nanoparticles functionalized scaffolds aiming at vascular repair and magnetic resonance imaging monitoring

This work develops a bioactive basic fibroblast growth factor (bFGF)/heparin and Fe3O4 nanoparticles (NPs) trifunctionalized degradable construct with the potential of using as a vascular tissue engineering scaffold with the aim of improving vascular repair and regeneration therapy. The covalent modification of heparin onto the poly(lactic acid) (PLA)-gelatin (Gel)-Fe3O4 (PGF) scaffold improves the hydrophilicity of the scaffold. Furthermore, the electrostatic adsorption of bFGF on heparin allows for a more consistent and prolonged release of bFGF in situ, hence increasing the stability and effectiveness of bFGF around the surrounding vascular tissues. The sustained release of bFGF promotes the M2 macrophage polarization, and adhesion and migration of macrophages and endothelial cells (ECs), providing a stable and favorable microenvironment for vascular regeneration. Furthermore, the covalently modified heparin minimizes platelet adhesion on the scaffold surface, potentially contributing to the long-term patency of the vascular tissue engineering scaffold. Including Fe3O4 NPs in the scaffold delays degradation and provides an in vivo magnetic resonance imaging (MRI) effect to monitor the scaffold's location and in vivo degradation. Furthermore, the mild photothermal effect of Fe3O4 NPs plays a facilitating role in bFGF release, immune modulation, and ECs manipulation, therefore contributary to the vascular tissue reconstruction.

Preparation and Characterization of Zinc Ferrite and Gadolinium Iron Garnet Composite for Biomagnetic Applications

Cancer is a major worldwide public health problem. Although there have already been astonishing advances in cancer diagnosis and treatment, the scientific community continues to make huge efforts to develop new methods to treat cancer. The main objective of this work is to prepare, using a green sol-gel method with coconut water powder (CWP), a new nanocomposite with a mixture of Gd3Fe5O12 and ZnFe2O4, which has never been synthesized previously. Therefore, we carried out a structural (DTA-TG and X-ray diffraction), morphological (SEM), and magnetic (VSM and hyperthermia) characterization of the prepared samples. The prepared nanocomposite denoted a saturation magnetization of 11.56 emu/g at room temperature with a ferromagnetic behavior and with a specific absorption rate (SAR) value of 0.5 ± 0.2 (W/g). Regarding cytotoxicity, for concentrations < 10 mg/mL, it does not appear to be toxic. Although the obtained results were interesting, the high particle size was identified as a problem for the use of this nanocomposite.

A Single Infusion of Polyethylene Glycol-Coated Superparamagnetic Magnetite Nanoparticles Alters Differently the Expressions of Genes Involved in Iron Metabolism in the Liver and Heart of Rats

This study investigated genotype- and tissue-related differences in the biodistribution of superparamagnetic magnetite (Fe₃O₄) nanoparticles (IONs) into the heart and liver of normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats after a single i.v. infusion of polyethylene glycol-coated IONs (~30 nm, 1mg Fe/kg) 100 min post-infusion. The effects of IONs on the expression of selected genes involved in the regulation of iron metabolism, including Nos, Sod and Gpx4, and their possible regulation by nuclear factor (erythroid-derived 2)-like 2 (NRF2, encoded by Nfe2l2) and iron-regulatory protein (encoded by Irp1) were investigated. In addition, superoxide and nitric oxide (NO) production were determined. Results showed reduced ION incorporations into tissues of SHR compared to WKY and in the hearts compared to the livers. IONs reduced plasma corticosterone levels and NO production in the livers of SHR. Elevated superoxide production was found only in ION-treated WKY. Results also showed differences in the regulation of iron metabolism on the gene level in the heart and liver. In the hearts, gene expressions of Nos2, Nos3, Sod1, Sod2, Fpn, Tf, Dmt1 and Fth1 correlated with Irp1 but not with Nfe2l2, suggesting that their expression is regulated by mainly iron content. In the livers, expressions of Nos2, Nos3, Sod2, Gpx4, and Dmt1 correlated with Nfe2l2 but not with Irp1, suggesting a predominant effect of oxidative stress and/or NO.

Myocardial Cell Preservation from Potential Cardiotoxic Drugs: The Role of Nanotechnologies

Cardiotoxic therapies, whether chemotherapeutic or antibiotic, represent a burden for patients who may need to interrupt life-saving treatment because of serious complications. Cardiotoxicity is a broad term, spanning from forms of heart failure induction, particularly left ventricular systolic dysfunction, to induction of arrhythmias. Nanotechnologies emerged decades ago. They offer the possibility to modify the profiles of potentially toxic drugs and to abolish off-target side effects thanks to more favorable pharmacokinetics and dynamics. This relatively modern science encompasses nanocarriers (e.g., liposomes, niosomes, and dendrimers) and other delivery systems applicable to real-life clinical settings. We here review selected applications of nanotechnology to the fields of pharmacology and cardio-oncology. Heart tissue-sparing co-administration of nanocarriers bound to chemotherapeutics (such as anthracyclines and platinum agents) are discussed based on recent studies. Nanotechnology applications supporting the administration of potentially cardiotoxic oncological target therapies, antibiotics (especially macrolides and fluoroquinolones), or neuroactive agents are also summarized. The future of nanotechnologies includes studies to improve therapeutic safety and to encompass a broader range of pharmacological agents. The field merits investments and research, as testified by its exponential growth.

Magnetoresponsive Functionalized Nanocomposite Aggregation Kinetics and Chain Formation at the Targeted Site during Magnetic Targeting

Drug therapy for vascular disease has been promoted to inhibit angiogenesis in atherosclerotic plaques and prevent restenosis following surgical intervention. This paper investigates the arterial depositions and distribution of PEG-functionalized magnetic nanocomposite clusters (PEG_MNCs) following local delivery in a stented artery model in a uniform magnetic field produced by a regionally positioned external permanent magnet; also, the PEG_MNCs aggregation or chain formation in and around the implanted stent. The central concept is to employ one external permanent magnet system, which produces enough magnetic field to magnetize and guide the magnetic nanoclusters in the stented artery region. At room temperature (25 °C), optical microscopy of the suspension model’s aggregation process was carried out in the external magnetic field. According to the optical microscopy pictures, the PEG_MNC particles form long linear aggregates due to dipolar magnetic interactions when there is an external magnetic field. During magnetic particle targeting, 20 mL of the model suspensions are injected (at a constant flow rate of 39.6 mL/min for the period of 30 s) by the syringe pump in the mean flow (flow velocity is Um = 0.25 m/s, corresponding to the Reynolds number of Re = 232) into the stented artery model. The PEG_MNC clusters are attracted by the magnetic forces (generated by the permanent external magnet) and captured around the stent struts and the bottom artery wall before and inside the implanted stent. The colloidal interaction among the MNC clusters was investigated by calculating the electrostatic repulsion, van der Waals and magnetic dipole-dipole energies. The current work offers essential details about PEG_MNCs aggregation and chain structure development in the presence of an external magnetic field and the process underlying this structure formation.