Effect of electrical polarization and composition of biphasic calcium phosphates on early stage osteoblast interactions

Abstract

In spite of having excellent biocompatibility and osteogenic property of hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP), concerns have been raised regarding their degradation kinetics. Complete in vivo degradation of HAp takes years because of its slow degradation rate, and fast degradation rate of β-TCP limits its application. Biphasic calcium phosphates (BCPs) composed of both HAp and β-TCP have controlled degradation to some extent. Here, we have prepared three different BCPs composed of β-TCP and HAp. These BCP composites are successfully electrically polarized to generate surfaces with positive (P-poled) and negative (N-poled) charges. Thermally stimulated depolarized current measurement (TSDC) exhibits increased stored charge density with the increase in HAp percentage in the composites. Our study focuses on understanding the effect of composition variation as well as electrical polarization of these composites on early stage osteoblast-cell adhesion, proliferation, and extracellular matrix (ECM) formation capability. No matter what the composition is, N-poled (Negatively poled) surfaces show early stage osteoblast-cell adhesion, proliferation, and ECM formation when compared with U-poled (unpoled) and P-poled (positively poled) surfaces. Irrespective of the surface charge, an improved cell-material interactions are observed as the percentage of HAp content in the composites is increased. These electrically polarized BCP composites can have potential use in the area of orthopedics and dentistry.

Adherent cells avoid polarization gradients on periodically poled LiTaO3 ferroelectrics

“…In comparison to non-poled ones, Tarafder et al, however, observed fewer cell-cell attachments with the extension of filopodia on positively poled surfaces. These morphological differences went along with a delayed initial proliferation [41], irrespective of the sign of the surface charge. Research on osteoblast-like cells in some cases supports the preference of negatively charged surfaces [42], albeit in other cases contradicts this trend [43].…”

Preparation, characterization, and in vitro osteoblast functions of a nano-hydroxyapatite/polyetheretherketone biocomposite as orthopedic implant material

“…Contact angle depends on many factors, for instance, surface roughness, surface chemistry, and grain size. 27 Because nHA is more hydrophilic as an inorganic material than PEEK, and the nHA/ PEEK composite is rougher than PEEK, the improvement in hydrophilicity seen with the nHA/PEEK composite may stem from changes in the surface roughness and chemistry, 27,28 which may have affected the functions of the osteoblasts in this study.…”

Instructive Conductive 3D Silk Foam‐Based Bone Tissue Scaffolds Enable Electrical Stimulation of Stem Cells for Enhanced Osteogenic Differentiation

“…We observe that levels of ALP expression relative to the smooth non-conductive silk foams were increased on the rougher conductive scaffolds both without and with electrical stimulation ( Figure 2D). We believe that this is a result of differences in the surface chemistry altering protein deposition from the medium onto the scaffolds, [30] which Bose and coworkers show to modify cell-material interactions in vitro, [32] yet Epinette and Manley conclude that microstructure and surface charge are not the sole factors at play in osteoinduction in the clinic. [33] Indeed, our experimental data for non-conductive silk foams and conductive silk foams without/with electrical stimulation enabled us to observe that electrical stimulation markedly enhanced calcium deposition and collagen production (Figures 2E and F and 3).…”