Mehran Solati-Hashjin

One of the most interesting and recent insights into biomimetic scaffold nano-biomaterial is smart scaffolding with targeted drug delivery ability. In recent decades, the use of graphene-based materials, such as nano-graphene oxide (nGO), as a drug carrier with amphiphilic properties, has attracted considerable attention of scientists and researchers in this field. In addition, one of the important global problems is increased vitamin D deficiency, particularly in pregnant and postmenopausal women. Therefore, in this work, by considering hydrophobic properties of vitamin D, we attempted to examine its loading and release both in the presence of surfactant and surfactant-free nGO-aqueous solution. At first, nGO powder was synthesized by the modified Hummer’s method. After the preparation of vitamin D and Tween 80 (TW) solution, they were added to nGO aqueous solution. Simultaneously, the next vitamin D and nGO aqueous solution was prepared in a surfactant-free mode. In order to evaluate the loading content, both solutions were centrifuged, and their supernatant was analyzed by UV-Visible spectroscopy. Additionally, FTIR spectroscopy was employed to determine the TW 80 effects on vitamin D and nGO. The results have shown that vitamin D loading in surfactant-free solution was approximately 0% while in the presence of TW 80 it was 75.37% ± 4.12. Therefore, the combination of vitamin D, TW 80, and nGO can be a suitable candidate for carrying hydrophobic drugs in smart scaffolding, especially in bone tissue engineering.

In recent years, nanotechnology in merging with biotechnology has been employed in the area of cancer management to overcome the challenges of chemopreventive strategies in order to gain promising results. Since most biological processes occur in nano scale, nano-particles can act as carriers of certain drugs or agents to deliver it to specific cells or targets. In this study, we intercalated Epigallocatechin-3-Gallate (EGCG), the most abundant poly-phenol in green tea, into Ca/Al-NO3 Layered double hydroxide (LDH) nanoparticles, and evaluated its efficacy compared to EGCG alone on PC3 cell line. The EGCG loaded LDH nanohybrids were characterized by X-ray diffraction, Fourier transform infrared spectros-copy, transmission electron microscopy (TEM) and nanosizer analyses. The anticancer activity of the EGCG-loaded LDH was investigated in prostate cancer cell line (PC3) while the release behavior of EGCG from LDH was observed at pH 7.45 and 4.25. Besides enhancing of apoptotic activit...

Calcium silicate-based cements are known for their wide applications in dentistry and orthopedics. The alkaline pH (up to 12) of these cements limits their application in other orthopedic areas. In this study, the effect of dicalcium phosphate dihydrate (DCPD) coating on set cement on pH reduction and biocompatibility improvement was examined. Samples with 0 and 10 weight ratio DCPD were prepared and characterized by XRD, FTIR, and SEM. The DCPD coating on the set cement was performed by a 7-day immersion in 1% monocalcium phosphate (MCP) solution and characterized by XRD, FTIR, SEM, and EDX. Also, the compressive strength and cytotoxicity of the samples were tested. The results showed that DCPD coating did not significantly change the compressive strength of the cement, but by decreasing the pH of the culture medium to the physiological range, it led to enhance adhesion, spreading and proliferation of human osteosarcoma cell line (Saos-2). The novel DCPD coated calcium silicate-based cement could be served as a bulk or porous bone substitute and scaffold.

ABSTRACT This study deals with synthesizing hydroxyapatite bone cement as a bone substitute for clinical applications. The powder part of the cement is using B-tricalcium phosphate, calcium carbonate, dicalcium phosphate and the liquid part contains NaH(2)PO(4)center dot 2H(2)O solution with different concentrations. The effects of liquid concentration on the setting times of the cement have been investigated. XRD analysis and FTIR spectroscopy were used to study the phase composition of calcium phosphate cement. Morphology and chemical analysis of the synthesized cement was performed using a scanning electron microscope equipped with an energy dispersive X-ray analyser. In addition, the effect of soaking time of synthesized bone cement in simulated body fluid (SBF) on the final phase and strength has been studied. Soaking prepared cement in SBF solution for appropriate time resulted in transformation of the composition of the cement into hydroxyapatite and hence the strength of the cement has been increased. Crown Copyright

ABSTRACT Hydroxyapatite (HA) is the main component of hard tissue and because of its high biocompatibility and bioactivity makes a strong bond with hard tissue. In this research, hydroxyapatite powders were uniaxially compacted at 86 MPa to form cylindrical shaped samples and sintered at 700-1300 oC with one hour soaking time. The density measured was between 2.89 and 3.49 g/cm3. Phase analyses were performed using X- ray diffraction and the results revealed there was no sign of HA decomposition. Three and four point bending strengths were measured between 7 to 44 MPa. Microstructural studies with a scanning electron microscope (SEM) showed that hydroxyapatite ceramics formed a highly integrated structure with an increase in the sintering temperature up to 1300 oC. It was proved that the sintered samples of hydroxyapatite did not contain any unwanted phase. These results imply that the blocks prepared in this study have the potential for use as biomedical implants.

Abstract While providing a proper matrix for cellular responses, bone tissue engineering scaffolds can deal with the shortcomings of conventional treatment methods and enhance bone regeneration. In the current study, graphene oxide (GO) nanoparticles were reduced using L-ascorbic acid, a green reductant. Electrospun polycaprolactone (PCL) and polycaprolactone-reduced graphene oxide (PCL/rGO) scaffolds were fabricated. Fourier transform infrared spectroscopy confirmed the correct synthesis of reduced graphene oxide (rGO). The addition of rGO to electrospun PCL has increased the fiber diameter and surface roughness. Mechanical properties evaluation in a dry environment indicated that elastic modulus and ultimate tensile strength declined in PCL/rGO scaffolds while strain at break improved; however, all mechanical values decreased in wet conditions. Studies on bioactivity suggest that apatite deposition requires time to occur on PCL/rGO scaffolds in vitro. This phenomenon was confirmed by Ca/P ratios obtained from EDX quantitive data. Furthermore, the degradation rate of electrospun PCL accelerated in the scaffolds enriched with rGO. Biological evaluations such as cell viability, cell attachment, and alkaline phosphatase activity were carried out using MG-63 cell lines. A significant difference has been observed in cell viability and alkaline phosphatase activity in the PCL scaffold containing 1 wt% rGO compared to pure PCL (P

ABSTRACT Layered double hydroxides (LDHs), well known as anionic clays or hydrotalcite-like compounds consist of positively charged layers. Net positive charges on the layers are balanced by exchangeable anions along with water molecules in the interlayer space. In the present research, the potential for use of Ca/Al-LDH as local hemostatic agent is evaluated in vitro by measuring the coagulation time of human fresh blood in the presence of LDH powder. Crystalline Ca/Al-LDH powders required for these experiments were synthesized ...

The design of porous gradient scaffolds for bone tissue engineering scaffolds is a relatively new approach. This strategy is based on imitating bone tissue in order to stimulate enhanced cellular responses. An additive manufacturing (AM) method, such as the fused filament fabrication (FFF) system, provides precise and repeatable pore size control. FFF is a well‐known AM manufacturing process for producing high‐quality parts at a low cost. In this study, polycaprolactone (PCL) and variable hydroxyapatite (HA) amounts were fed into a FFF printer to print four scaffold designs with different porosity gradients. These porous gradient scaffolds were constructed using simple (Si) and shifting (Sh) models, with gradient pore diameters ranging from 400–600 to 400–800 μm. The specimens featured thicker walls but more open cores. The scaffolds' structural, mechanical, and biological properties were evaluated. The results showed that higher gradient porosity and larger pore size led to better biological results, but lower mechanical strength resulted. Furthermore, adding HA increased mechanical strength from 81.8% to 100% and enhanced cellular response. In all scaffolds, an increase in porosity and a decrease in density led to a reduction in compressive strength. The toxicity of the samples and cellular adhesion was evaluated using MTT and DAPI tests on hFOB (human Fetal OsteoBlastic) cells. Alkaline phosphatase and Red Alizarin analyses demonstrated an increase in mineralization as HA content increased.

Titania (TiO2) nanotube gaining predominance as a bioceramic due to its excellent features such as high specific surface area and exhibiting appropriate cellular response. At present, we showed a conversion from titania nanoparticle to nanotube by hydrothermal treatment with 10M soduim hydroxide and 1M HCl solutions at 150°C over 48h. Then the sample annealed at various temperatures. Results indicate the reaction temperature is a main factor in determining the aspect ratio of the tubes. FESEM image conformed the synthesis of nanotube. In vitro study by using 150 °C-synthesized nanotube calcined at different temperatures are also presented establishing the potential of nanotubes in biomedical applications

Hydroxyapatite was synthesized by the wet chemical technique. Diammonium hydrogen phosphate and calcium nitrate 4-hydrate were used as starting materials and sodium hydroxide solution was used as the agent for pH adjustment. The powder sample was characterized by the commonly used bulk techniques of scanning electron microscopy (SEM), transmission electron microscopy, Fourier transform infra-red spectroscopy, differential thermal analysis, thermal gravimetric analysis, X-ray diffraction, atomic absorption spectroscopy and EDTA titration analyses. With respect to the results achieved from the above analyses, it was found that nanocrystalline hydroxyapatite can successfully be produced through the wet precipitation method. The bulk Ca/P molar ratio of synthesized hydroxyapatite was determined as 1.71, which was higher than the stoichiometric ratio (1.667) that is expected for a pure HA phase. SEM investigations revealed that, there is a distribution of small particles and large agglom...

Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)–hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration. Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)–hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration. Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)–hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration.

Microwave assisted synthesis method is a relatively new approach employed to decrease synthesis time and form a more homogenous structure in biphasic calcium phosphate bioceramics. In this study, nanocrystalline HA/β-TCP composites were prepared by microwave assisted synthesis method and, for comparison reason, by conventional wet chemical methods. The chemical and phase composition, morphology and particle size of powders were characterized

The liver is one of the vital organs in the body, and the gold standard of treatment for liver function impairment is liver transplantation, which poses many challenges. The specific 3D structure of liver, which significantly impacts the growth and function of its cells, has made biofabrication with the 3D printing of scaffolds suitable for this approach. In this study, to investigate the effect of scaffold geometry on the performance of HepG2 cells, Poly-Lactic acid (PLA) polymer was used as the input of the Fused Deposition Modeling (FDM) 3D-printing machine. Samples with simple square and bioinspired hexagonal cross-section designs were printed. 1% and 2% of gelatin-coating were applied to the 3D printed PLA to improve the wettability and surface properties of the scaffold. SEM pictures were used to analyze the structural properties of PLA-Gel hybrid scaffolds, EDS to investigate the presence of gelatin, water contact angle measurement for wettability, and weight loss for degrada...