The presence of inorganic bioactive minerals with polymers can accelerate and promote several processes including: bone cell joining, proliferation, differentiation, and expression of osteogenic proteins. In this study, zinc (Zn), copper (Cu), and imidazole metal–organic framework (MOF) nanoparticles were synthesized and coated over poly‐l‐lactic acid (PLLA) nanofibrous scaffolds for bone tissue engineering application. The surface and bioactive features of the scaffolds were characterized. The osteogenic potential of the scaffolds on human adipose tissue‐derived mesenchymal stem cells (MSCs) was evaluated. Zn–Cu imidazole MOF coated PLLA scaffolds (PLLA@MOF) showed a comparable rate of MSC proliferation with the pure PLLA scaffolds and tissue culture plate (TCP). However, the PLLA@MOF potential of osteogenic differentiation was significantly greater than either pristine PLLA scaffolds or TCP. Hence, coating Zn–Cu imidazole MOF has a significant effect on the osteogenesis of MSC. Therefore, PLLA@MOF is novel scaffolds with bioactive components which are crucial for osteoconductivity and also able to provoke the osteogenesis and angiogenesis.

Poly-L-lactic acid (PLLA) nano fibrous scaffolds prepared by electrospinning technology have been used widely in tissue engineering applications. However, PLLA scaffolds are hydrophobic in nature, moreover the fibrous porous structure produced by electrospinning makes the scaffolds even more hydrophobic which generally limits cell attachment and proliferation. Polymer blending is one of the several efforts used so far to enhance hydrophilicity and recognized as an easy cost-effective approach for the manipulation physiochemical properties of polymeric biomaterials. Pluronic block copolymers containing hydrophilic poly(ethylene oxide) (PEO) blocks and hydrophobic poly(propylene oxide) (PPO) blocks are arranged in triblock structure: PEO-PPO-PEO. It is commonly used recently to blend hydrophobic polymers to enhance hydrophilicity for pharmaceutical and tissue engineering applications. In this study, novel pluronic P123 blend PLLA electrospun nanofibre scaffolds with improved hydrophilicity and biological properties were fabricated. The surface morphology and surface chemistry of the nanofibre scaffolds were characterized by scanning electron microscope (SEM) and FTIR analyses. Surface hydrophilicity and change in mechanical properties were studied. The ability of the scaffolds to support the attachment, and proliferation and differentiation of human adipose tissue derived MSCs, were evaluated generally. The fabricated scaffolds have completely improved, hydrophilicity, similar osteogenic differentiation potential with plasma-treated PLLA nanofibre scaffold, and hence P123 blend PLLA electrospun nanofibre scaffolds are a very good and cost effective choice as a scaffold for bone tissue engineering application.

SadatMahdavi (2019) Poly-l-lactic acid scaffold incorporated chitosan-coated mesoporous silica nanoparticles as pH-sensitive composite for enhanced osteogenic differentiation of human adipose tissue stem cells by dexamethasone delivery,

Aim and Objective: In this study, for the first time keplerate cluster [Cu20Cl(OH)24(H2O)12 (P8W48O184)]25- (hereafter [W48P8Cu20]) was supported on SMNP (Fe3O4-@SiO2) via amine functionality (ASMNP) as a magnetically-recoverable catalyst (hereafter [WPCu@ASMNP]). This nanocatalyst showed high activity for the synthesis of cyclic carbonates under solvent-free conditions. Materials and Methods: After preparation, the nanocatalyst was characterized by FT-IR, XRD, ICP-AES, TGA, TEM and SEM. Surface acidity was determined by a potentiometric titration with n-butyl amine. The effect of different parameters like catalyst amount, reaction time, temperature and pressure in the presence of [WPCu@ASMNP] were studied. Results: Optimal reaction conditions were obtained for 0.5mol% of catalyst, reaction temperature of 100°C and CO2 pressure of 1.5 MPa. The [WPCu@ASMNP] could be separated from the reaction and reused for five times with an external magnet without notable decrease in the activity. Finally, stability of the catalyst and its reusability were evaluated using a hot filtration method. The FT-IR and the control experiments (hot filtration) after five cycles confirmed the strongly catalyst immobilization to the ASMNP. Conclusion: The nanocatalyst is shown to be effective heterogeneous and recyclable catalyst for the synthesis of cyclic carbonates from CO2 and epoxides under mild conditions without any additional co-solvent and cocatalyst. This catalyst has a good substrate tolerance as demonstrated by its activity towards different epoxides. Importantly, the reaction could be carried out under solvent free conditions. The heterogeneous nature of the catalyst is proved by recovering and reusing this catalyst without any appreciable loss in catalytic activity and by the FT-IR spectroscopic characterization of the fresh and spent catalyst. The product separation and catalyst recycling are short using an external magnet.

Background: Polyacrylonitrile/Mo132 composite nanofibers mats was synthesized by an electrospinning technique using PAN and giant ball nano-polyoxomolybdateMo132. The nanocluster Mo132 was mixed with PAN solution and then electrospun to produce bead-free nanofibers. The aim of this study is to evaluate the adsorption ability of electrospun composite nanofibers against sulfur mustard stimulants and assess the possibility of using the electrospun nanofibers as protective membranes in chemical masks and warfare clothing. Adsorption of sulfur mustard stimulants was investigated on the surface of PAN nanofibers embedded with keplerate nano-polyoxomolybdate. Methods: In order to study the 2-CEES adsorption ability, the prepared PAN/Mo132 nanofibers composite was further prepared and exposed to 2-CEES solution. The surface morphology and other properties of the PAN/Mo132 nanofibers composite were characterized by various techniques, including SEM, TEM, FT-IR, UV-Vis. SEM images which showed that the average diameter of the fibers was found to be between 100-120 nm. Results: The adsorption efficiency of PAN/Mo132 composite in adsorption of 2-CEES was obtained 89% after 7h at room temperature. The results showed that composite nanofibers PAN/Mo132 will have a good ability as protective clothing and chemical masks against chemical warfare agents. Conclusion: PAN/Mo132 nanofibers were prepared by electrospinning method. The leaching of Mo132 from the nanofibers was not observed, meaning that the catalyst had excellent stability and could be used as a heterogeneous structure against the adsorption of sulfur mustard stimulant at room temperature. This composite nanofibers membrane exhibited good performance to adsorb 2-CEES in comparison with pure PAN. The adsorption rate of 2-CEES increases with increasing the amount of Mo132 embedded in the PAN nanofibers.