Atomic force microscopy of 3T3 and SW-13 cell lines: an investigation of cell elasticity changes due to fixation

Mechanical properties of single cells are of increasing interest both from a fundamental cell biological perspective and in the context of disease diagnostics. In this respect, atomic force microscopy (AFM) has become a powerful tool for imaging and assessing mechanical properties of biological samples. However, while these tests are typically carried out on chemically fixed cells, the most important data is that on living cells. The present study applies AFM technique to assess the Young\u2019s modulus of two cells lines: mouse embryonic fibroblasts (NIH/3T3) and human epithelial cancer cells (SW-13). Both living cells and those fixed with paraformaldehyde were investigated. This analysis quantifies the difference between Young\u2019s modulus for these two conditions and provides a coefficient to relate them. Knowing the relation between Young modulus of living and fixed cells, allows carrying out and comparing data obtained during steady-state measurements on fixed cells that are more frequently available in the clinical and research settings and simpler to maintain and probe

Design, Prototyping and Testing of a Rotating Electrical Machine with Linear Geometry for Shipboard Applications

Conventional rotating electrical machines are characterized by stator and rotor structures featuring a cylindrical geometry around the shaft rotational axis. Although advantageous for mechanical reasons, the cylindrical geometry results in overall machine shapes and dimensions that may be unsuitable for installation. This particularly occurs in shipboard applications, where electric motors and generators are subject to stringent room constraints and need to be fit in unusually shaped compartments. This paper presents the development and test of a dual-shaft rotating permanent-magnet electric machine prototype having a linear structure that facilitates its onboard use for such applications as electric propulsion and rudder actuation. In fact, the proposed machine topology has overall dimensions which can be adjusted to fit the space available for installation. The operating concept and the detailed electromechanical design of the machine are first described. Then the manufacturing and factory test of the prototype under inverter supply are illustrated. Finally, the validation of the prototype as a boat propulsion variable-speed inverter-fed motor is presented. It is proved that, despite of its highly non-conventional electromechanical design, the machine can be effectively fed from a general-purpose inverter for permanent magnet motors

A study on the cellular structure during stress solicitation induced by BioMEMS

4The investigation of single cells is a topic in continuous evolution. The complexity of the cellular matrix, the huge variety of cells, the interaction of one cell with the other are all factors that must be taken into consideration in the study of the cellular structure and mechanics. In this project, we developed different types of bioMEMS for cell's stretching, both transparent devices based on silicon nitride and non-transparent silicon based. While the use of silicon devices is limited to reflection microscopes, transparent bioMEMS can be used with transmission and reflection microscopes but can also be easily coupled with other tools such as patch clamp analyzers or atomic force microscope. This improvement will open brand new possibilities in the biological investigation field. We used these two BioMEMS to stretch a single cell in a controlled way and, as a first investigation, we focused on its morphology. We noticed that during a controlled stretch, cells react to the applied deformation. A hysteretic behavior on the ratio between area and perimeter has been highlighted.nonenoneFior R.; Maggiolino S.; Codan B.; Sbaizero O.Fior, Raffaella; Maggiolino, Stefano; Codan, B.; Sbaizero, Orfe

A new BioMEMS for the study of mechanosensitive ion channels

A novel completely transparent bioMEMS (bio - Micro Electro Mechanical System) has been designed and produced using finite element analysis (FEA) and micro-fabrication techniques. This device has been thought to be used for testing the mechanical properties of single living cells. Our bioMEMS is versatile and can be coupled to other analysis techniques and being completely transparent can be used with either transmission or reflection microscopes. This device is based on a silicon dioxide \u2013 silicon nitride structure

Lithographic patterned substrate with nanotips for cell indentation

We present a method based to an in situ chemical etching strategy to synthesize glass nano tips arrays. The chemical etching can generate nanotips with controllable tip morphologies on various substrates, and the nanotips density is tunable via etching. This general in situ chemical etching method might advance the research in the nano tips based devices for biotechnolog