Mineralization Content Alters Osteogenic Responses of Bone Marrow Stromal Cells on Hydroxyapatite/Polycaprolactone Composite Nanofiber Scaffolds

Abstract

Synthetic tissue scaffolds have a high potential impact for patients experiencing osteogenesis imperfecta. Using electrospinning, tissue scaffolds composed of hydroxyapatite/polycaprolactone (HAp/PCL) composite nanofibers were fabricated with two different HAp concentrations—1% and 10% of the solid scaffold weight. After physico-chemical scaffold characterization, rat bone marrow stromal cells were cultured on the composite scaffolds in maintenance medium and then in osteogenic medium. Quantitative PCR, colorimetric assays, immunofluorescent labeling, and electron microscopy measured osteogenic cell responses to the HAp/PCL scaffolds. In maintenance conditions, both Hap/PCL scaffolds and control scaffolds supported cell colonization through seven days with minor differences. In osteogenic conditions, the 10% HAp scaffolds exhibited significantly increased ALP assay levels at week 3, consistent with previous reports. However, qPCR analysis demonstrated an overall decrease in bone matrix-associated genes on Hap/PCL scaffolds. Osteopontin and osteocalcin immunofluorescent microscopy revealed a trend that both mineralized scaffolds had greater amounts of both proteins, though qPCR results indicated the opposite trend for osteopontin. Additionally, type I collagen expression decreased on HAp scaffolds. These results indicate that cells are sensitive to minor changes in mineral content within nanofibers, even at just 1% w/w, and elucidating the sensing mechanism may lead to optimized osteogenic scaffold designs.

Photobiomodulation in 3D tissue engineering

“…For example, one should expect the osteogenic differentiation in rigid mineral-containing scaffolds, the neural differentiation in soft hydrogel systems, and the angiogenic differentiation in fibrin-based hydrogels. 141 – 144 …”

“…For example, one should expect the osteogenic differentiation in rigid mineral-containing scaffolds, the neural differentiation in soft hydrogel systems, and the angiogenic differentiation in fibrin-based hydrogels. [141][142][143][144] One of interesting PBM effects, which can be of great practical importance, is its protective ability. It was reported in neurotraumas and neonatal hypoxia-ischemia.…”

Engineered electrospun poly(caprolactone)/polycaprolactone-g-hydroxyapatite nano-fibrous scaffold promotes human fibroblasts adhesion and proliferation

“…In this study, it was observed that the PCL/PCL-g-HAp nano-composite scaffold improved the cells proliferation and cell-cell connections until the end of day 21 of culture as according to MTT assay results as well as cell morphology studies (Figure 9). A remarkable increase in integrin binding sites is prerequisite for such event [31]. Integrin transmembrane proteins act similar to other protein receptors (proteins that play a role in cell-cell signaling and at the meanwhile integrins are known as focal points of the cell cytoskeleton.…”

Physical and mass transfer properties of electrospun ɛ-polycaprolactone nanofiber membranes

“…The significant number of works published on the subject in the past few years and also the increase in published patents [7] reflect the above-mentioned interest, as well as the variety of purposes for this technology. Applications for ENf are as wide as tissue engineering and biomedical devices [8,9], oral drug delivery [10], functional materials (e.g. nano-sensors and fuel cells) [6,11] enzyme (protein) surface immobilization or nanoencapsulation [12].…”