Polymeric piezoelectric actuator substrate for osteoblast mechanical stimulation

Abstract

a b s t r a c tBone mass distribution and structure are dependent on mechanical stress and adaptive response at cellular and tissue levels. Mechanical stimulation of bone induces new bone formation in vivo and increases the metabolic activity and gene expression of osteoblasts in culture. A wide variety of devices have been tested for mechanical stimulation of cells and tissues in vitro. The aim of this work was to experimentally validate the possibility to use piezoelectric materials as a mean of mechanical stimulation of bone cells, by converse piezoelectric effect. To estimate the magnitude and the distribution of strain, finite numerical models were applied and the results were complemented with the optical tests (Electronic Speckle Pattern Interferometric Process). In this work, osteoblasts were grown on the surface of a piezoelectric material, both in static and dynamic conditions at low frequencies, and total protein, cell viability and nitric oxide measurement comparisons are presented.

Strategies for the development of three dimensional scaffolds from piezoelectric poly(vinylidene fluoride)

“…Different techniques have been used to process PVDF and its polymer/composites based in different strategies (Table 1) to obtain various morphologies including micropillars [21], particles [20,22], films [23][24][25] and fibers [15,[26][27][28][29][30][31] in order to better suit specific tissue engineering strategies. Further, it has been shown that substrates based on PVDF have different influence on cell adhesion, proliferation and differentiation [7] depending on their morphology.…”

Microbead-guided reconstruction of the 3D osteocyte network during microfluidic perfusion culture

“…Importantly, there has been a very limited effort in replicating the 3D network structure of osteocytes in vitro. Osteoblasts by themselves during in vitro culture cannot be transformed into 3D-networked osteocytes with physiologically relevant dimensions, even when osteoblast culture is aided by biomaterial scaffolds for 3D culture [18,19], dynamic flow and/or perfusion in bioreactors [20,21], and application of mechanical loading [22]. For example, Boukhechba et al [18] showed that primary human osteoblasts cultured with biphasic calcium phosphate (BCP) particles differentiated significantly towards osteocyte-like phenotype with down-regulated osteoblastic-specific markers and up-regulated osteocytic markers, in comparison to those cultured in 2D.…”

A New Piezoelectric Actuator Induces Bone FormationIn Vivo: A Preliminary Study

“…The actuator device was composed of a microboard containing an ultra-low power 16-bit microcontroller (eZ430-RF2500, Texas Instruments, USA), powered by lithium battery and encapsulated in PMMA and a set of six actuators composed of polyvinylidene fluoride (PVDF) and silver electrodes, electrically insulated by dip-coating as described elsewhere [10]. Each actuator measured 15 mm width and 40 mm length, with an active area of 12 × 31 mm 2 .…”

“…Finite Numerical Method studies and Electronic Speckle Pattern Interferometry Process (ESPI) studies have shown the lower deformation levels occurred in the clamped region of the films, for a potential differential of 5 V, and the higher deformation occurred in the opposite extremity of the film [10]. …”

“…The displacement was higher where the cells were seeded, in the central area of the coated devices, in the order of 700 nm along the z -axis, in a semisinusoidal fashion. On the substrates submitted to dynamic conditions, stimulation was done with an alternating sinusoidal current (AC), of 5 V, at 1 Hz and 3 Hz for 15 minutes at each frequency [10]. In this exploratory in vivo study, the same coating procedures and daily stimulation regimens were applied.…”