Response of human mesenchymal stem cells to intrafibrillar nanohydroxyapatite content and extrafibrillar nanohydroxyapatite in biomimetic chitosan/silk fibroin/nanohydroxyapatite nanofibrous membrane scaffolds

Abstract

Incorporation of nanohydroxyapatite (nHAP) within a chitosan (CS)/silk fibroin (SF) nanofibrous membrane scaffold (NMS) may provide a favorable microenvironment that more closely mimics the natural bone tissue physiology and facilitates enhanced osteogensis of the implanted cell population. In this study, we prepared pristine CS/SF NMS, composite CS/SF/nHAP NMS containing intrafibrillar nHAP by in situ blending of 10% or 30% nHAP before the electrospinning step, and composite CS/SF/nHAP NMS containing extrafibrillar nHAP by depositing 30% nHAP through alternative soaking surface mineralization. We investigated the effect of the incorporation of HAP nanoparticles on the physicochemical properties of pristine and composite NMS. We confirmed the presence of ~30 nm nHAP in the composite nanofibrous membranes by thermogravimetry analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM), either embedded in or exposed on the nanofiber. Nonetheless, the alternative soaking surface mineralization method drastically influenced the mechanical properties of the NMS with 88% and 94% drop in Young’s modulus and ultimate maximum stress. Using in vitro cell culture experiments, we investigated the effects of nHAP content and location on proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs). The proliferation of hMSCs showed no significant difference among pristine and composite NMS. However, the extent of osteogenic differentiation of hMSCs was found to be positively correlated with the content of nHAP in the NMS, while its location within the nanofiber played a less significant role. In vivo experiments were carried out with hMSCs seeded in CS/SF/30%nHAP NMS prepared by in situ blending and subcutaneous implantation in nude mice. Micro-computed tomography images as well as histological and immunohistochemical analysis of the retrieved hMSCs/NMS construct 1 and 2 months postimplantation indicated that NMS had the potential for bone regeneration and can be suggested as a promising scaffold for bone tissue engineering.

Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells

“…The amplified PCR products were analyzed by ethidium bromide staining after 1.5% agarose gel electrophoresis. The PCR primers were designed with the Oligo 7 primer design software [ 32 – 36 ].…”

An update on the Application of Nanotechnology in Bone Tissue Engineering

“…Both synthetic and natural materials have been electrospun for bone regeneration [ 16 - 18 ]. Polymers alone have been shown to be effective in the regeneration of bone.…”

“…The incorporation of nanohydroxyapatite (nHAP) with scaffolds has been shown to create a more favourable microenvironment that closely mimics the natural bone state has also been shown with other combinations of biomaterials [ 22 ]. Chitoson/silk fibroin scaffolds with nHAP nanofibrous membrane also promoted the osteogenic differentiation of hMSCS [ 16 ]. Collagen/nHA/PPLA scaffolds also demonstrated that the incorporation of nHA supported bone formation to a greater degree than poly-L-lactide (PLLA)/Col and PLLA/HA scaffolds [ 22 ].…”

Enhancing the Cell Growth Using Conductive Scaffolds

“…These polymer scaffolds have been used for numerous applications, including regeneration of blood vessels (i.e. coronary arteries), bone, skin, cartilage, as well as to enhance cell proliferation and differentiation [3][4][5]. Another material that has shown rapid expansion among biocompatible scaffolds are electroactive materials.…”