Objective: In magnetic particle hyperthermia, a promising least-invasive cancer treatment, malignant regions in proximity with magnetic nanoparticles undergo heat stress, while unavoidably surrounding healthy tissues may also suffer from heat either directly or indirectly by the induced eddy currents, due to the developed electric fields as well. Here, we propose a facile upgrade of a typical magnetic particle hyperthermia protocol, to selectively mitigate eddy currents' heating without compromising the beneficial role of heating in malignant regions. Method:The key idea is to apply the external magnetic field intermittently (in an ON/OFF pulse mode), instead of the continuous field mode typically applied. The parameters of the intermittent field mode, such as time intervals (ON time: 25-100 s, OFF time: 50-200 s, Duty Cycle:16-100%) and field amplitude (30-70 mT) are optimized based on evaluation on healthy tissue and cancer tissue phantoms. The goal is to sustain in cancer tissue phantom the maximum temperature increase (preferably within 4-8 C above body temperature of 37 C), while in the healthy tissue phantom temperature variation is suppressed far below the 4 C dictating the eddy current mitigation. Results: Optimum conditions of intermittent field (ON/OFF: 50/100 in s, Duty Cycle: 33%, magnetic field: 45mT) are then examined in ex-vivo samples verifying the successful suppression of eddy currents. Simultaneously, a well-elaborated theoretical approach provides a rapid calculation of temperature increase and, furthermore, the ability to quickly simulate a variety of duty cycle times and field controls may save experimental time. Conclusion: Eventually, the application of an intermittent field mode in a magnetic particle hyperthermia protocol, succeeds in eddy current mitigation in surrounding tissues and allows for the application of larger field amplitudes that may augment hyperthermia efficiency without objecting typical biomedical applicability field constraints such as Brezovich criterion.

Cardiovascular stents are commonly used for the treatment of cardiovascular diseases that in developed societies are the most frequent causes of mortality and morbidity. In recent years, thorough research and development of drug-eluting stents has been done, with emphasis on coronary stenting to avoid the most common complication, in-stent thrombosis. Dipyridamole (DPM) is a medication that inhibits blood clot formation. Drug delivery nanoplatforms consisting of biodegradable polymers can be fabricated via electrospinning deposition, known for its cost-effective and versatile advantages, that produces fibrous scaffolds that are able to sustain and control drug release. A novel drug delivery nanosystem of polylactic acid fibrous scaffold loaded with the anti-platelet drug DPM was fabricated by electrospinning as coating for cardiovascular stents. The surface morphology and topography that were evaluated via atomic force microscopy, scanning electron microscopy and optical microscopy, were found to be good and suitable for tissue engineering. Contact angle measurements established the hydrophobic behavior of these fibrous nanoplatforms. Drug-release kinetics and degradation studies were conducted and revealed a sustained and controllable release of DPM, through this fibrous matrix over time. Finally, cytotoxicity studies took place to evaluate the cytocompatibility of the scaffold that confirmed its compatible behavior. The successful performance of this nanoplatform can lead to it being a valuable tool for atherosclerosis treatment.

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In vitro cell exposure to nanoparticles, depending on the applied concentration, can help in the development of theranostic tools to better detect and treat human diseases. Recent studies have attempted to understand and exploit the impact of magnetic field-actuated internalized magnetic nanoparticles (MNPs) on the behavior of cancer cells. In this work, the viability rate of MNP’s-manipulated cancerous (MCF-7, MDA-MB-231) and non-cancerous (MCF-10A) cells was investigated in three different types of low-frequency magnetic fields: static, pulsed, and rotating field mode. In the non-cancerous cell line, the cell viability decreased mostly in cells with internalized MNPs and those treated with the pulsed field mode. In both cancer cell lines, the pulsed field mode was again the optimum magnetic field, which together with internalized MNPs caused a large decrease in cells’ viability (50–55% and 70% in MCF-7 and MDA-MB-231, respectively) while the static and rotating field modes maintained the viability at high levels. Finally, F-actin staining was used to observe the changes in the cytoskeleton and DAPI staining was performed to reveal the apoptotic alterations in cells’ nuclei before and after magneto-mechanical activation. Subsequently, reduced cell viability led to a loss of actin stress fibers and apoptotic nuclear changes in cancer cells subjected to MNPs triggered by a pulsed magnetic field.

There is, as a matter of fact, an ever increasing number of patients requiring total hip replacement (Pabinger, C.; Geissler, A. Osteoarthritis Cartilage 2014, 22, 734–741). Implant-associated acute inflammations after an invasive orthopedic surgery are one of the major causes of implant failure. In addition, there are instability, aseptic loosening, infection, metallosis and fracture (Melvin, J. S.; Karthikeyan, T.; Cope, R.; Fehring, T. K. J. Arthroplasty 2014, 29, 1285–1288). In this work, a drug-delivery nanoplatform system consisting of polymeric celluloce acetate (CA) scaffolds loaded with dexamethasone was fabricated through electrospinning. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicated the successful fabrication of these structures. Cytotoxicity studies were performed by using MTT assay, methylene-blue staining and SEM fixation and showed very good cell adhesion and proliferation, indicating the cytocompatibility of these fibrous scaffolds. Drug-release kinetics was measured for the evaluation of a controllable and sustained release of anti-inflammatory drug onto the engineered implants and degradation study was conducted in order to assess the mass loss of polymers. This drug-delivery nanoplatform as coating on titanium implants may be a promising approach not only to alleviate but also to prevent implant-associated acute inflammations along with a simultaneous controlled release of the drug.