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Measuring the physical and chemical parameters of substrates in the cells of nursery containers during production is difficult. Monitoring these parameters, however, is required for optimizing the use of substrates and their components in nursery production, specifically important in the progressive reduction in the use of peat. A new solution—leachate tables—for those studies is presented. The leachate tables enable the collection of liquid samples draining from individual cells in nursery containers during long-term irrigation and fertilization. During our 2-month-long experiment, changes in the physical and chemical parameters of the substrate were analyzed, as well as the process of accumulation of elements fed to the substrate via fertilizer and irrigation water. It was found that, due to the different cell volumes, filling the containers with the substrate under the same parameters of vibration and initial moisture resulted in different fractions of the substrate ending up inside the cells. In the smaller cells, the larger diameter fraction was dominant, and in the larger cells, the smaller fraction was dominant. This may have influenced the differences in air and water capacity of the substrate in cells of different volumes and confirmed the need for the selection of individual vibration parameters for the containers. In addition, over time, the granulometric composition of the substrate in the containers changed. Along with the systematic administration of elements via fertilization from the sprinkler ramp, their leachate content increased as a result of increased leaching from the substrate. With time, the physical parameters of the substrate in the cells stabilized, which may have affected the accumulation and leaching of elements during irrigation and fertilization. [ABSTRACT FROM AUTHOR]

Bone diseases can often result in patient bone fragility. Different bone problems include low bone density, osteoporosis, and other bone diseases. Such bone diseases, ailments, and malfunctions often require complex and expensive treatments. In this study, we synthesized a new type of DLP resin for 3D printing purposes based on poly(ethylene glycol diacrylate) (PEGDA) and acrylic acid (AAc). In addition, using a porogen within the photopolymerizable resin allowed us to fabricate hierarchical interconnected porous structures. These structures combine the pores resulting from the CAD design with those obtained by the lixiviation of the porogen. Finally, bioactive particles were added to the mixture to increase the material's biocompatibility, thus proving the strategy's potential to include active compounds for particular purposes. Our results demonstrate that including the photoabsorber, Orange G, considerably increases the printing precision and resolution of the synthesized resin, making it possible to obtain printed parts with intricate and complex geometries with high accuracy and definition. Nano-hydroxyapatite (nHA) inclusion significantly increases the material's biocompatibility and mechanical stiffness (∼47 % increase, from 5.47 MPa to 8.02 MPa).

Although most cellular polymers are made from thermoplastics using different foaming technologies, gelatin and many other natural polymers can form hydrogels and convert them to cellular solids using various techniques, many of which differ from traditional plastic foaming, and so does their resulting structures. Cellular solids from natural hydrogels are porous materials that often exhibit a combination of desirable properties, including high specific surface area, biochemical activity, as well as thermal and acoustic insulation properties. Among natural hydrogels, gelatin-based porous materials are widely explored due to their availability, biocompatibility, biodegradability and relatively low cost. In addition, gelatin-based cellular solids have outstanding properties and are currently subject to increasing scientific research due to their potential in many applications, such as biocompatible cellular materials or biofoams to facilitate waste treatment. This article aims at providing a comprehensive review of gelatin cellular solids processing and their processing-properties-structure relationship. The fabrication techniques covered include aerogels production, mechanical foaming, blowing agents use, 3D printing, electrospinning and particle leaching methods. It is hoped that the assessment of their characteristics provides compiled information and guidance for selecting techniques and optimization of processing conditions to control material structure and properties to meet the needs of the finished products. [ABSTRACT FROM AUTHOR]

[Display omitted] • DLP resin was synthesized from polyethylene glycol and acrylic acid monomers. • 3D printed parts were fabricated using synthetic resin and compared with a commercially available resin. • Porogen and bioactive agents were added to the mixture to improve material biocompatibility. • Hydroxyapatite inclusion dramatically increases material mechanical response. Bone diseases can often result in patient bone fragility. Different bone problems include low bone density, osteoporosis, and other bone diseases. Such bone diseases, ailments, and malfunctions often require complex and expensive treatments. In this study, we synthesized a new type of DLP resin for 3D printing purposes based on poly(ethylene glycol diacrylate) (PEGDA) and acrylic acid (AAc). In addition, using a porogen within the photopolymerizable resin allowed us to fabricate hierarchical interconnected porous structures. These structures combine the pores resulting from the CAD design with those obtained by the lixiviation of the porogen. Finally, bioactive particles were added to the mixture to increase the material's biocompatibility, thus proving the strategy's potential to include active compounds for particular purposes. Our results demonstrate that including the photoabsorber, Orange G, considerably increases the printing precision and resolution of the synthesized resin, making it possible to obtain printed parts with intricate and complex geometries with high accuracy and definition. Nano-hydroxyapatite (nHA) inclusion significantly increases the material's biocompatibility and mechanical stiffness (∼47 % increase, from 5.47 MPa to 8.02 MPa). [ABSTRACT FROM AUTHOR]

The aim of this study was to mimic the specific structure of bone and fabricate a biomimetic nano-hydroxyapatite (HA)/chitosan (Cs)/gelatin scaffolds using combination of particle leaching and freeze drying methods eliminating mold effects. To achieve an optimum structure, scaffolds with different gelatin/Cs weight ratio were fabricated. Morphological characterization of scaffolds by scanning electron microscopy method showed highly interconnected porous structures similar to cancellous bone with mean pore size ranging from 140 to 190 μm. Nano-HA crystals were dispersed homogeneously in the polymer matrix according to the energy-dispersive X-ray spectroscopy and transmission electron microscopy images. Fourier transform infrared and X-ray diffraction results disclosed that chemical interactions were formed between nano-HA, Cs, gelatin and crystallinity of each material decreased with blending. It was found that increasing the gelatin content significantly improved water uptake, degradation rate as well as attachment, infiltration and proliferation of Saos2 cells to the scaffolds. The presented results confirm that the designed biomimetic nano-HA /Cs/gelatin scaffolds can be used as promising substitutes for bone tissue engineering. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1882-1892, 2015. [ABSTRACT FROM AUTHOR]

Microcellular injection molding, a process capable of mass-producing complex plastic parts, and particle leaching methods were combined to fabricate porous thermoplastic polyurethane tissue engineering scaffolds. Water soluble polyvinyl alcohol (PVOH) and sodium chloride (NaCl) were used as porogens to improve the porosity and interconnectivity as well as the hydrophilicity of the scaffolds. It was found in the study that the microcellular injection molding process was effective at producing high pore density and porosity. The addition of PVOH decreased the pore diameter and increased the pore density. Furthermore, scaffolds with NaCl and PVOH porogens showed more interconnected pores. The 3T3 fibroblast cell culture was used to confirm the biocompatibility of the scaffolds. Residual PVOH content after leaching increased the hydrophilicity of the scaffolds and further improved cell adhesion and proliferation. The resulting scaffolds offer an alternative scalable tissue scaffold fabrication method for soft tissue scaffold production. [ABSTRACT FROM PUBLISHER]

In this study, a kind of biodegradable material was developed by blending polylactide (PLA) with natural biodegradable dextran, and a novel sponge-like scaffold made of it was fabricated thereof using solvent-casting and particle-leaching technique. To obtain a uniform blend of PLA and dextran by simple solvent-casting method, hydroxyls of dextran should be protected via trimethylsilyl (TMS) groups to make dextran soluble in organic solvents. Benzene was found among the few solvents that could dissolve this TMS-protected dextran (TMSD) well, however, it was not a good solvent for PLA. Therefore, a homogeneous mixed solution of PLA and TMSD could be obtained when a mixture of dichloroform (DCM) and benzene (v/v=6/4) was used. By this technique, PLA–dextran blend films and even PLA films were observed a microporous structure (pore size around 5–10 μm) formation throughout the films under scanning electron microscope (SEM). Scaffolds that were prepared by dissolving PLA and TMSD in mixed solvent of DCM and benzene and using salt as porogen, were observed the formation of micropores (pore size around 5–10 μm) in the cellular walls of macropores (pore size around 100–200 μm). This microporous structure was closely related to the phase separation occurring during films or foams formation, which was mainly due to the different solubility of PLA and TMSD in benzene, as well as the different evaporation rates of DCM and benzene. In comparison with PLA, the surface and bulk hydrophilicity of PLA–dextran blend films or foams were significantly improved after the TMS groups were removed in methanol, and the results of cell culture on these polymeric substrates exhibited an enhancement on cell attachment and proliferation. [Copyright &y& Elsevier]