Fabrication of Poly(ε-caprolactone)-embedded Lignin-Chitosan Nanocomposite Porous Scaffolds from Pickering Emulsions

Abstract

Poly(ε-caprolactone) (PCL)-incorporated lignin-chitosan biomass-based nanocomposite porous scaffolds have been effectively prepared by templating oil-in-water Pickering high internal phase emulsions (HIPEs). PCL is dissolved in oil and chitosan and lignin nanoparticles originate in water. The continuous phase of the emulsions is gelled by cross-linking of chitosan with genipin and then freeze-dried to obtain porous scaffolds. The resulting scaffolds display interconnected and tunable pore structures. An increase in PCL content increases the mechanical strength and greatly reduces the water absorption capacity of the scaffolds. Scaffolds loaded with the anti-bacterial drug enrofloxacin show a slow drug release profile, adjustable release rate, and favorable long-term anti-bacterial activity. Moreover, Pickering emulsion templates with suitable viscosity are used as 3D printing inks to construct porous scaffolds with personalized geometry. The results imply that the simplicity and versatility of the technique of combining freeze-drying with Pickering HIPE templates is a promising approach to fabricate hydrophobic biopolymerincorporated biomass-based nanocomposite porous scaffolds for biomedical applications.

Ultrastable High Internal Phase Pickering Emulsions: Forming Mechanism, Processability, and Application in 3D Printing

“…High internal phase Pickering emulsions (HIPPEs) are special-structured emulsion systems with an internal phase volume fraction (φ) exceeding 0.74, exhibiting high viscous property and showing more versatile applicability in various fields, like functional foods, porous material templates, , tissue engineering, nutrient/drug carrier, personal care products, etc. With the increase of the φ value, the emulsion droplets could be deformed into polyhedral structure, which was separated with only a thin layer of the continuous phase .…”

Mechanism of Interconnected Pore Formation in High Internal Phase Emulsion-Templated Polymer

“…High internal phase emulsion (HIPE), an emulsion containing internal phase of >74% dispersed as individual droplets, has been known for many years and has found applications in fields such as food, fuels, oil recovery, biphasic interfacial catalysis, and cosmetics. − In the past 20 years, a growing interest focuses on its application in materials science, i.e., as template to fabricate highly porous structure (so-called HIPE-templating technique). ,− HIPE is commonly stabilized by high content of nonionic surfactant (5–50%, relative to its continuous phase) owing to its high volume ratio of disperse phase/continuous phase. − When the HIPE contains monomers in its continuous phase, polymerization of the monomers and removal of the dispersed phase could cause a highly open-cell foam, named polyHIPE. − The HIPE-templating technique provides the advantages of generating porous materials with a diverse morphology, for example, polymer foams, membranes, beads, or rods. Since the structure of polyHIPE replicates from its precursor HIPE-template, by tuning the droplet size and the chemical nature of HIPE phases, polyHIPEs with designed performance can be fabricated. − Moreover, in situ or postpolymerization approaches can be also adapted to tune the surface area or endow polyHIPE with additional chemical properties. − PolyHIPEs could be used in a wide range of areas, including energy storage applications, , tissue engineering, chromatography, separation, , microreactors, , sound absorption, , and catalysis. − The implementation of these applications largely depends on their highly open-cellular structure, i.e., the presence of interconnected pores (also named pore throats or windows) between adjacent voids.…”