A Comparative Study on In Vitro Osteogenic Priming Potential of Electron Spun Scaffold PLLA/HA/Col, PLLA/HA, and PLLA/Col for Tissue Engineering Application

Abstract

A comparative study on the in vitro osteogenic potential of electrospun poly-L-lactide/hydroxyapatite/collagen (PLLA/HA/Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical composition, and surface roughness of the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200–950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When compared with PLLA/H%A and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization (P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based therapies for bone repair, when compared with the other two scaffolds.

Proliferation and Osteogenic Differentiation of Mesenchymal Stromal Cells in a Novel Porous Hydroxyapatite Scaffold

“…BDHA and CHA scaffold exhibited significant cell proliferation than monolayer due to the fact that the surface area of the 2D monolayer limits the cell proliferation while the 3D scaffolds produce a larger surface area providing favorable environment for cell expansion. This finding appears to corroborate with a study conducted by Hosseinkhani and coworkers where 3D collagen-PGA nanofiber sheets significantly increased the cell number compared with static 2D culture method [30,31].…”

“…Production of ALP and OC during 21 days of culture period is shown sufficient to demonstrate the osteogenic differentiation using scaffolds [30]. In the present study, ALP activity in BDHA and CHA increases 5.7-fold and 6.2 from day 0 to day 21, respectively.…”

Nanotechnology in bone tissue engineering

“…These scaffolds can stimulate osteoconduction and osteoinduction, provide a fertile ground for stem cell proliferation, and be made out of biodegradable synthetic polymers that trigger little immunogenic response. 113,114 Indeed, inflammation and adhesion of macrophages, with formation/release of bioreactive agents such as reactive oxygen intermediates, digestive enzymes, and acidic phagolysosomes, may result in premature degradation of scaffolds. Control and manipulation of this response to enhance bone repair and regeneration has therefore been a goal of immunobioengineering, and some progress has been made through electrospun nanofibers which may minimize host response.…”

“…Recently, Raghavendran et al 114 explored the benefits of combining different biomaterials into a single scaffold to balance the advantages and disadvantages of each material in isolation in order to obtain the ideal biocompatible scaffold for stimulating osseous union using stem cell based therapy. They discovered that integrating PLA, HA, and collagen into a single scaffold improved the viability of engrafted hMSCs, increased the osteogenic gene expression as shown by significantly elevated levels of osteocalcin, improved matrix mineralization as demonstrated by elevated calcium and Alizarin Red staining, and augmented osteoinduction.…”

“…They discovered that integrating PLA, HA, and collagen into a single scaffold improved the viability of engrafted hMSCs, increased the osteogenic gene expression as shown by significantly elevated levels of osteocalcin, improved matrix mineralization as demonstrated by elevated calcium and Alizarin Red staining, and augmented osteoinduction. 114 Expanding the clinical potential of electrospun scaffolds, Xue et al 121 offered a promising solution to the clinical problem of failure of guided tissues regeneration/guided bone regeneration due to infections when they showed that electrospinning metronidazole into membranes could significantly decrease anaerobic colonization. Overcoming the relatively tight structure of electrospun nanoscaffolds that can prevent 3D cell penetration, airbrushed composite nanofiber scaffolds present an arguably simpler alternative that produce a more open network allowing, in one study, more than double the depth of cell penetration.…”