Design and development of biodegradable POSS-PCL-Zeolite (β) nano-scaffold for potential applications in bone regeneration

Evaluation of the Mechanical Strength and Cell Adhesion Capacity of POSS Doped PVA/CMC Hernia Patch

Peritoneal adhesion typically occurs in applications such as abdominal, pelvic, and vascular surgery. It is necessary to develop a mechanical barrier to prevent adhesion. In this study, a novel biomaterial as a mechanical barrier is developed by combining polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC), doped with polyhedral oligomeric silsesquioxane (POSS) to prevent peritoneal adhesion. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods reveal that POSS nanoparticles in the PVA matrix disrupted the intramolecular hydroxyl groups and structure of the crystal region. Electron microscopy (EM) images reveal that high concentrations of POSS (2 wt.%) cause irregular clustering in the composite matrix. As the concentration of POSS increases in the matrix, the degradation of the membranes increases, and protein adhesion decreases. In vitro cytotoxicity tests show a toxic effect on cells for PVA/CMC composite membranes, while on the other hand, the addition of POSS increases cell viability. According to the MMT test the POSS decreases cell adhesion of membranes. When comparing the POSS doped membrane to the undoped PVA/CMC membrane, an increase in the total antioxidant level and a decrease in the total oxidant level is observed.

Enhancement of the chondrogenic differentiation capacity of human dental pulp stem cells via chondroitin sulfate-coated polycaprolactone-MWCNT nanofibers

Most of the conditions involving cartilaginous tissues are irreversible and involve degenerative processes. The aim of the present study was to fabricate a biocompatible fibrous and film scaffolds using electrospinning and casting techniques to induce chondrogenic differentiation for possible application in cartilaginous tissue regeneration. Polycaprolactone (PCL) electrospun nanofibrous scaffolds and PCL film were fabricated and incorporated with multi-walled carbon nanotubes (MWCNTs). Thereafter, coating of chondroitin sulfate (CS) on the fibrous and film structures was applied to promote chondrogenic differentiation of human dental pulp stem cells (hDPSCs). First, the morphology, hydrophilicity and mechanical properties of the scaffolds were characterized by scanning electron microscopy (SEM), spectroscopic characterization, water contact angle measurements and tensile strength testing. Subsequently, the effects of the fabricated scaffolds on stimulating the proliferation of human dental pulp stem cells (hDPSCs) and inducing their chondrogenic differentiation were evaluated via electron microscopy, flow cytometry and RT‒PCR. The results of the study demonstrated that the different forms of the fabricated PCL-MWCNTs scaffolds analyzed demonstrated biocompatibility. The nanofilm structures demonstrated a higher rate of cellular proliferation, while the nanofibrous architecture of the scaffolds supported the cellular attachment and differentiation capacity of hDPSCs and was further enhanced with CS addition. In conclusion, the results of the present investigation highlighted the significance of this combination of parameters on the viability, proliferation and chondrogenic differentiation capacity of hDPSCs seeded on PCL-MWCNT scaffolds. This approach may be applied when designing PCL-based scaffolds for future cell-based therapeutic approaches developed for chondrogenic diseases.

Thermoplastic polyurethane/POSS nanohybrids: Synthesis, morphology, and biological properties

Recent studies show good osteoinductive properties of polyurethanes modified with polyhedral oligomeric silsesquioxanes (POSS). In this work, three types of POSS; propanediolisobutyl-POSS (PHI-POSS), disilanolisobutyl-POSS (DSI-POSS), and octahydroxybutyl-POSS (OCTA-POSS) were chemically incorporated into linear polyurethane based on an aliphatic isocyanate, hexamethylene diisocyanate (HDI), to obtain new nanohybrid PU-POSS materials. The full conversion of POSS was confirmed by Fourier transform infrared spectroscopy (FTIR-ATR) spectra of the model reactions with pure HDI. The materials obtained were investigated by FTIR, SEM-EDS, and DSC. The DSC studies showed the thermoplasticity of the obtained materials and apparently good recovery. 30-day immersion in SBF (simulated body fluid) revealed an increase in the rate of deposition of hydroxyapatite (HAp) for the highest POSS loadings, resulting in thick layers of hydroxyapatite (~60-40 μm), and the Ca/P ratio 1.67 (even 1.785). The structure and properties of the inorganic layer depend on the type of POSS, the number of hard segments, and those containing POSS, which can be tailored by changing the HDI/poly(tetramethylene glycol) (PTMG) ratio. Furthermore, the obtained composites revealed good biocompatibility, as confirmed by cytotoxicity tests conducted on two cell lines; normal human dermal fibroblasts (NHDF) and primary human osteoblasts (HOB). Adherent cells seeded on the tested materials showed viability even after a 48-h incubation. After this time, the population of viable, and proliferating cells exceeded 90%. Bioimaging studies have shown the fibroblast and osteoblast cells were well attached to the surface of the tested materials.

Potential application of inorganic nano-materials in modulation of macrophage function: Possible application in bone tissue engineering

Nanomaterials indicate unique physicochemical properties for drug delivery in osteogenesis. Benefiting from high surface area grades, high volume ratio, ease of functionalization by biological targeting moieties, and small size empower nanomaterials to pass through biological barriers for efficient targeting. Inorganic nanomaterials for bone regeneration include inorganic synthetic polymers, ceramic nanoparticles, metallic nanoparticles, and magnetic nanoparticles. These nanoparticles can effectively modulate macrophage polarization and function, as one of the leading players in osteogenesis. Bone healing procedures in close cooperation with the immune system. Inflammation is one of the leading triggers of the bone fracture healing barrier. Macrophages commence anti-inflammatory signaling along with revascularization in the damaged site to promote the formation of a soft callus, bone mineralization, and bone remodeling. In this review, we will discuss the role of macrophages in bone hemostasis and regeneration. Furthermore, we will summarize the influence of the various inorganic nanoparticles on macrophage polarization and function in the benefit of osteogenesis.

Fabrication and characterization of Persian gum-based hydrogel loaded with gentamicin-loaded natural zeolite: An in vitro and in silico study

The main purpose of this study is to synthesize and characterize Persian gum-based hydrogel composited with gentamicin (Gen)-loaded natural zeolite (Clinoptilolite) and to evaluate its biological properties. Clinoptilolite (CLN) was decorated with Gen, and the conjugation was confirmed using computational and experimental assessments. The Monte Carlo adsorption locator module was used to reveal the physicochemical nature of the adsorption processes of Gen on CLN and ALG and gum on Gen@ CLN in Materials Studio 2017 software. Based on the high negative results, the adsorption process was found to be endothermic in all studied cases, and the interaction energies were in the range of physisorption for Gen on CLN and ALG and gum on Gen@CLN. Dynamic light scattering (DLS) and zeta potential analysis showed that the size of pristine CLN was around 2959 nm and the conjugation decreased the size significantly to approximately 932 nm. The hydrogel characterizations showed that the Gen-decorated CLNs are homogenously dispersed into the hydrogel matrix, and the resultant hydrogels have a porous structure with interconnected pores. The release kinetics evaluation showed that around 80 % of Gen was released from the nanocomposite drug during the first 10 h. In vitro studies revealed hemocompatibility and cytocompatibility of the nanocomposite. Microbial assessments indicated dose-dependent antibacterial activity of the hydrogel against gram (+) and gram (-) bacteria. The results showed that the fabricated hydrogel nanocomposite exhibits favorable physicochemical and biological properties.