Dielectric screening of early differentiation patterns in mesenchymal stem cells induced by steroid hormones.

In the framework of this study, target identification and localization of differentiation patterns by means of dielectric spectroscopy is presented. Here, a primary pre-osteoblastic bone marrow-derived MBA-15 cellular system was used to study the variations in the dielectric properties of mesenchymal stem cells while exposed to differentiation regulators. Using the fundamentals of mixed dielectric theories combined with finite numerical tools, the permittivity spectra of MBA-15 cell suspensions have been uniquely analyzed after being activated by steroid hormones to express osteogenic phenotypes.

The effect of irregularity on the dielectric dispersion characteristics of spherical cellular suspension.

The dielectric dispersion characteristics of cellular suspensions are fundamentally determined based on the analogy to composite dielectric materials when periodically and discrete arrangement of cells is assumed. However, under native physiological conditions, when flocculation and clamping events usually occur, those assumptions are usually not valid. In the framework of this study, an examination of irregularity effect on the dispersion characteristics of spherical cellular suspensions is presented.

Dielectric dispersion of suspended cells using 3D reconstructed morphology model.

In the framework of this study, novel method for dispersion analysis of cellular suspensions is presented. The method is fundamentally based on the ability to reconstruct the exact 3D morphology of a given cell with resolution accuracy of few nanometers using AFM imaging. By applying a reverse engineering approach, the morphology of the cell is constructed based on a set of measured spatial points that describes its geometry.

Theoretical examination of aggregation effect on the dielectric characteristics of spherical cellular suspension.

Dielectric dispersion analysis of cellular suspension is generally based on the analogy to equivalent periodic material made up of identical inclusions. However, under true physiological conditions, when coupling and aggregation events usually occur, this analogy can introduce severe errors when attempting to probe the dielectric characteristics of the suspended fraction. In the framework of this study, a theoretical examination of the effect of aggregation on the dielectric characteristics of spherical cellular suspension is presented.

Cell-based screening for membranal and cytoplasmatic markers using dielectric spectroscopy.

Dielectric spectroscopy (DS) of living biological cells is based on the analysis of the complex dielectric permittivity of cells suspended in a physiological medium. It provides knowledge on the polarization-relaxation response of cells to external electric field as function of the excitation frequency. This response is strongly affected by both structural and molecular properties of cells and therefore, can reveal rare insights on cell physiology and behaviour.

Site localization of membrane-bound proteins on whole cell level using atomic force microscopy.

This study presents molecular recognition method, which is based on specific force measurements between modified AFM (atomic force microscopy) tip and mammalian cell. The presented method allows recognition of specific cell surface proteins and receptor sites by nanometer accuracy level. Here we demonstrate specific recognition of membrane-bound Osteopontin (OPN) sites on preosteogenic cell membrane.