Orsellinic acid-loaded chitosan nanoparticles in gelatin/nanohydroxyapatite scaffolds for bone formation in vitro.

AIM: Orsellinic acid (2,4-Dimethoxy-6-methylbenzoic acid) (OA) is a hydrophobic polyphenolic compound with therapeutic potential, but its impact on actuating osteogenesis remains unknown. The bioavailability of OA is hampered by its hydrophobic nature. This study aimed to fabricate nano-drug delivery system-based scaffolds for OA and test its potential for osteogenesis in vitro. MATERIALS AND METHODS: OA was loaded into chitosan nanoparticles (nCS + OA) using the ionic gelation technique at different concentrations. nCS + OA were incorporated onto the scaffolds containing gelatin (Gel) and nanohydroxyapatite (nHAp) by the lyophilization method. Biocomposite scaffolds were examined for their physicochemical and material characteristic properties. The effect of OA in the scaffolds for osteoblast differentiation was determined by alizarin red and von Kossa staining at the cellular level and by reverse transcriptase-qPCR and western blot analysis at the molecular level. KEY FINDINGS: The scaffolds showed excellent physiochemical and material characteristics and remained cyto-friendly to mouse mesenchymal stem cells (mMSCs, C3H10T1/2). The release of OA from Gel/nHAp/nCS scaffolds enhanced the differentiation of mMSCs towards osteoblasts, as observed through cellular and molecular studies. Moreover, the osteogenic potential of OA was mediated by the activation of FAK and ERK signaling pathways through integrins. SIGNIFICANCE: The inclusion of OA into Gel/nHAp/nCS biocomposite scaffolds at 80 µM concentration promoted osteoblast differentiation via cell adhesion mediated signaling, compared with that shown by Gel/nHAp/nCS alone. Overall, this study identified the potential therapeutic OA containing Gel/nHAp/nCS scaffolds, accelerating its potential for clinical application towards bone regeneration.

Chitosan-based 3D-printed scaffolds for bone tissue engineering.

Despite the spontaneous regenerative properties of autologous bone grafts, this technique remains dilatory and restricted to fractures and injuries. Conventional grafting strategies used to treat bone tissue damage have several limitations. This highlights the need for novel approaches to overcome the persisting challenges. Tissue-like constructs that can mimic natural bone structurally and functionally represent a promising strategy. Bone tissue engineering (BTE) is an approach used to develop bioengineered bone with subtle architecture. BTE utilizes biomaterials to accommodate cells and deliver signaling molecules required for bone rejuvenation. Among the various techniques available for scaffold creation, 3D-printing technology is considered to be a superior technique as it enables the design of functional scaffolds with well-defined customizable properties. Among the biomaterials obtained from natural, synthetic, or ceramic origins, naturally derived chitosan (CS) polymers are promising candidates for fabricating reliable tissue constructs. In this review, the physicochemical-biological properties and applications of CS-based 3D-printed scaffolds and their future perspectives in BTE are summarized.

3D-poly (lactic acid) scaffolds coated with gelatin and mucic acid for bone tissue engineering.

Three-dimensional (3D) printing is a promising technology to fabricate the intricate biomimetic structure. The primary focus of this study was to develop the bioactive 3D-scaffolds to enhance bone regeneration. The 3D-poly (lactic acid) (PLA) scaffolds were extruded based on a computer-aided design (CAD) model and coated with gelatin (Gel) containing different concentrations of mucic acid (MA) and were investigated for their osteogenic potential. Coating the PLA scaffolds with Gel/MA improved their physicochemical properties, and the addition of MA did not alter these properties. The viability of mouse mesenchymal stem cells (mMSCs, C3H10T1/2) seeded onto the PLA/Gel/MA scaffolds remained unaffected both at metabolic and cell membrane integrity levels. Alkaline phosphatase and von Kossa staining indicated the promotion of osteoblast differentiation of mMSCs by MA in the PLA/Gel scaffolds. Inclusion of MA in PLA/Gel scaffolds also increased the expression of the master bone transcription factor, Runx2, and other osteoblastic differentiation marker genes in mMSCs. Thus, our results suggested that the 3D-printed PLA scaffolds coated with Gel/MA favor osteoblast differentiation and have potential applications in bone tissue engineering.