Enhancement of adhesion and promotion of osteogenic differentiation of human adipose stem cells by poled electroactive poly(vinylidene fluoride)

Abstract

Poly(vinylidene fluoride) (PVDF) is a biocompatible material with excellent electroactive properties. Nonelectroactive α-PVDF and electroactive β-PVDF were used to investigate the substrate polarization and polarity influence on the focal adhesion (FA) size and number as well as on human adipose stem cells (hASCs) differentiation. hASCs were cultured on different PVDF surfaces adsorbed with fibronectin and FA size and number, total adhesion area, cell size, cell aspect ratio and FA density were estimated using cells expressing vinculin fused to enhanced green fluorescent protein. Osteogenic differentiation was also determined using a quantitative alkaline phosphatase assay. The surface charge of the poled PVDF films (positive or negative) influenced the hydrophobicity of the samples, leading to variations in the conformation of adsorbed extracellular matrix proteins, which ultimately modulated the stem cell adhesion on the films and induced their osteogenic differentiation.

Piezoelectric poly(vinylidene fluoride) microstructure and poling state in active tissue engineering

“…Contrary to the effects observed for muscle cells, higher adhesion and proliferation of MC3T3‐E1 preosteoblast was observed in “poled +” β‐PVDF samples . However, with human adipose stem cells, “poled −” β‐PVDF exhibited significantly larger total focal adhesion than nonpoled and “poled +” samples, and consequently an improved cell differentiation . These results indicate, as mentioned above, that cell adhesion is improved by the charged surfaces.…”

On mechanical properties and bioactivity of PVDF-BCP composites

“…In fact, studies conducted in cell culture have indicated some advantageous aspect of PVDF polymer for animal implants. These results indicated high proliferation of the osteoblast cells, which are bone cells, in PVDF films [28], and more bioactivity in the polar PVDF phase (β-PVDF) and poled PVDF films, mainly under mechanical stimuli [29,30]. Currently, a novel generation of highly advanced PVDF-based implants has been thought and developed, as those where PVDF-based nanogenerators, that were successfully implanted/tested in rats [31], attested the applicability of PVDF for bio-applications.…”

“…In this way, considering previous reports where the influence of the electric charge surface on the activity of biomaterials [25] was pointed out and discussed, it is ease to intuit that piezoelectric materials can be used to catalyze biological responses. Recent studies have been conducted in order to understand the potentialities of the polyvinylidene fluoride [(C 2 H 2 F 2 ) n or PVDF] matrix composites in human implants [26][27][28][29][30][31][32]. In this way, different biological applications have been thought for PVDF polymer, leading to different synthesis technique and sample architectures, as scaffold, for example [27].…”

Processing and size range separation of pristine and magnetic poly( l -lactic acid) based microspheres for biomedical applications

“…Piezoelectric polymers can be used as a bioactive electromechanically responsive materials for improving tissue engineering strategies [3]. Studies reveal that electrical stimulation influences cell proliferation, differentiation and regeneration [2] both under static [4,5] and dynamic conditions [6]. These results show the potential of such materials for the development of a new generation of wireless electrically active scaffolds and structures for biomedical applications [2].…”