In this study, poly(ε-caprolactone) (PCL)/poly(ethylene oxide) (PEO) (50:50 wt%) immiscible blend was used as a model system to investigate the feasibility of a novel solventless fabrication approach that combines cryomilling, compression molding and porogen leaching techniques to prepare interconnected porous scaffolds for tissue engineering. PCL was cryomilled with PEO to form blend powders. Compression molding was used to consolidate and anneal the cryomilled powders. Selective dissolution of the PEO with water resulted in interconnected porous scaffolds. Sodium chloride salt (NaCl) was subsequently added to cryomilled powder to increase the porosity of scaffolds. The prepared scaffolds had homogeneous pore structures, a porosity of ~50% which was increased by mixing salt with the blend (~70% for 60% wt% NaCl), and a compressive modulus and strength (ε = 10%) of 60 and 2.8 MPa, respectively. The results of the study confirm that this novel approach offers a viable alternative to fabricate scaffolds.

In this study, machine learning algorithms (MLA) were employed to predict and classify the tensile strength of polymeric films of different compositions as a function of processing conditions. Two film production techniques were investigated, namely compression molding and extrusion-blow molding. Multi-factor experiments were designed with corresponding parameters. A tensile test was conducted on samples and the tensile strength was recorded. Predictive and classification models from nine MLA were developed. Performance analysis demonstrated the superior predictive ability of the support vector machine (SVM) algorithm, in which a coefficient of determination and mean absolute percentage error of 96% and 4%, respectively were obtained for the extrusion-blow molded films. The classification performance of the MLA was also evaluated, with several algorithms exhibiting excellent performance.

Three-dimensional interconnected porous poly(ε-caprolactone) scaffolds have been prepared by a novel solventless scaffold fabrication approach combining cryomilling and compression molding/porogen leaching techniques. This study investigated the effects of processing parameters on scaffold morphology and properties for tissue regeneration. Specifically, the effects of molding temperature, cryomilling time, and porogen mix were examined. Fifty percentage of porous scaffolds were fabricated with a range of properties: mean pore size from ∼40 to 125 μm, water uptake from ∼50 to 86%, compressive modulus from ∼45 to 84 MPa, and compressive strength at 10% strain from ∼3 to 4 MPa. Addition of 60 wt % NaCl salt resulted in a ∼50% increase in porosity in multimodal pore-size structures that depended on the method of NaCl addition. Water uptake ranged from ∼61 to 197%, compressive modulus from ∼4 to 8.6 MPa, and compressive strength at 10% strain from ∼0.36 to 0.40 MPa. Results suggest that this approach provides a controllable strategy for the design and fabrication of 3D interconnected porous biodegradable scaffolds for load-bearing tissue regeneration.

The epoxide addition sol-gel method has been utilized to synthesize porous zinc-copper composite aerogels in the zinc-to-copper molar ratios of 50 : 50 to 90 : 10. A two-step mixing approach has been employed to produce aerogels composed of nano- to micrometer sized particles. The aerogels were characterized by ultrahigh resolution scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The as-synthesized aerogels had a thin flake- or petal-like microstructure comprised of clustered flakes on two size scales; they were identified as being crystalline with the crystalline species identified as copper nitrate hydroxide, zinc hydroxide chloride hydrate, and zinc hydroxide nitrate hydrate. Annealing of the aerogel materials at a relatively low temperature (400°C) resulted in a complete phase transition of the material to give highly crystalline ZnO-CuO aerogels; the aerogels consisted of networked nanoparticles in the ~25–550 nm size range with an average crystallite size of ~3 nm and average crystallinity of 98%. ZnO-CuO aerogels are of particular interest due to their particular catalytic and sensing properties. This work emphasizes the versatility of this sol-gel route in synthesizing aerogels; this method offers a possible route for the fabrication of aerogels of different metal oxides and their composites.

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