Irregular-Shaped Fe3O4 Nanoparticles-Mediated Magneto-Mecha nical Force for Killing Tumor Cell / 医用生物力学

Objective To investigate tumor cell killing effect of superparamagnetic Fe3O4 nanoparticles with cubic phase through magneto-mechanical force under a low-frequency vibrating magnetic field ( VMF). Methods A kind of strong magnetic and irregular-shaped Fe3O4 nanoparticles with cubic phase was synthesized by coprecipitation method. The Fe3O4 nanoparticles were exposed to a self-developed VMF and cell killing efficiency of the Fe3O4-mediated magneto-mechanical force was investigated. Results VMF alone had no effects on cell viability. After Fe3O4 nanoparticles were added, the cell viability significantly decreased with prolonging the VMF treatment time and increasing the Fe3O4 nanoparticle concentration. Lactate dehydrogenase released by damaged cells also increased with prolonging the VMF exposure time. Conclusions The irregular-shaped Fe3O4 nanoparticles can transfer magneto-mechanical force to tumor cells under VMF, cause structural damage of cells and result in cell death. The VMF generator developed in this study has simple structure and it is safe for use and convenient for operation. The developed magnetic nanoparticles and the corresponding cancer cell killing technique have the potential for clinical transformation.

Axonal cytomechanics in neuronal development

For more than a century, mechanical forces have been predicted to govern many biological processes duringdevelopment, both at the cellular level and in tissue homeostasis. The cytomechanics of the thin and highlyextended neuronal axons have intrigued generations of biologists and biophysicists. However, our knowledgeof the biophysics of neurite growth and development is far from complete. Due to its motile behavior and itsimportance in axonal pathfinding, the growth cone has received significant attention. A considerable amount ofinformation is now available on the spatiotemporal regulation of biochemical signaling and remodeling of thegrowth cone cytoskeleton. However, the cytoskeletal organization and dynamics in the axonal shaft werepoorly explored until recently. Driven by advances in microscopy, there has been a surge of interest in theaxonal cytoskeleton in the last few years. A major emerging area of investigation is the relationship betweenthe axonal cytoskeleton and the diverse mechanobiological responses of neurons. This review attempts tosummarize our current understanding of the axonal cytoskeleton and its critical role in governing axonalmechanics in the context of neuronal development.

Airway remodelling in asthma: role for mechanical forces

Asthma is a chronic airway inflammatory disease with functional and structural changes, leading to bronchial hyperresponsiveness and airflow obstruction. Airway structural changes or airway remodelling consist of epithelial injury, goblet cell hyperplasia, subepithelial layer thickening, airway smooth muscle hyperplasia and angiogenesis. These changes were previously considered as a consequence of chronic airway inflammation. Even though inhaled corticosteroids can suppress airway inflammation, the natural history of asthma is still unaltered after inhaled corticosteroid treatment. As such there is increasing evidence for the role of mechanical forces within the asthmatic airway contributing to airway structural changes.