Novel porous scaffolds for tissue engineering applications

Abstract

Bicontinuous interfacially jammed emulsion gels (“bijels”) are a new class of soft matter containing two continuous immiscible phases. Bijels or bijels-derived materials with bicontinuous inner structures are promising for biomedical applications on the controlled release of drugs. In this study, a phase inversion- based technique was developed for fabricating bijels and bijels-derived structures. The effects of varying the composition of casting solutions for the fabrication of bijels on the porosity, oil-to-water percentage, and domain size of bijels were investigated. Composite bijels prepared from two organic monomers were also made, demonstrating the flexibility of the phase inversion-based technique for the fabrication of bijels. Interestingly, the incorporation of a second monomer into the casting solution also affected the porosity and domain size of bijels formed, which may provide a new strategy for the controlled fabrication of bijels. Doxorubicin hydrochloride (DOX, as a model drug)-loaded bijels-derived hybrid hydrogel comprising two continuous phases were successfully made, with one phase being cross-linked alginate that carried the drug. Controlled release of DOX from the bijels-derived structures could be achieved. In vitro degradation study indicated that cross-linking of alginate in bijels-derived hybrid hydrogels-controlled alginate degradation, thereby affecting the DOX release behavior. Our current work has provided a facile and reproducible protocol for the controlled fabrication of bijels and bijels-derived structures. Multiwalled carbon nanotube (MWCNT)/bijel nanocomposites with interconnected channels were fabricated via a facile phase-inversion technique. The MWCNTs adsorption process was investigated, in which MWCNTs were physically absorbed into the oil-rich phase without disrupting the bicontinuous structure. The successful fabrication of non-crosslinked and crosslinked MWCNT/bijel nanocomposites was evidenced by confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM), respectively. Fourier-transform infrared spectroscopy (FTIR) and Brunauer Emmet Teller (BET) testing were employed to characterize the resulting MWCNT/bijel nanocomposites. The release profile of DOX from bijels and MWCNT/bijel-derived hydrogels suggested that the photothermal effect of MWCNTs could be initiated by near-infrared (NIR) irradiation to modulate drug delivery behavior. Our research developed a facile approach to fabricating bicontinuous structure with nanomaterial incorporation, which opens an avenue for MWCNT/bijel nanocomposite fabrication and demonstrates their potential applications in controlled drug release. 3D printed Poly(e-caprolactone)/Laponite-XLG(PCL/LAP) scaffolds were fabricated by a high-temperature extrusion printing technique. The printing parameters were studied and optimized to fabricate 3D multi-layer grid structure. The morphology, water contact angle, and mechanical properties of 3D-printed scaffolds were investigated, which opens an avenue for 3D printing fabrication of nanocomposite for bone tissue engineering. Different concentration of LAP aqueous solutions was cocultured with HUVEC to test the cytotoxicity. The cell attachment performance on the PCL/LAP was also studied by the coculture HUVEC with the PCL casting membranes of various LAP concentrations. We believe that the combination of nanoclay with degradable PCL can provide an affordable and simple strategy for the application of 3D printed nanocomposite in bone regeneration.