3D Printed\nHierarchical Porous Poly(ε-caprolactone)\nScaffolds from Pickering High Internal Phase Emulsion Templating

Abstract

In the realm of biomaterials, particularly bone tissue\nengineering,\nthere has been a great increase in interest in scaffolds with hierarchical\nporosity and customizable multifunctionality. Recently, the three-dimensional\n(3D) printing of biopolymer-based inks (solutions or emulsions) has\ngained high popularity for fabricating tissue engineering scaffolds,\nwhich optimally satisfies the desired properties and performances.\nHerein, therefore, we explore the fabrication of 3D printed hierarchical\nporous scaffolds of poly(ε-caprolactone) (PCL) using the water-in-oil\n(w/o) Pickering PCL high internal phase emulsions (HIPEs) as the ink\nin 3D printer. The Pickering PCL HIPEs stabilized using hydrophobically\nmodified nanoclay comprised of aqueous poly(vinyl alcohol) (PVA) as\nthe dispersed phase. Rheological measurements suggested the shear\nthinning behavior of Pickering HIPEs having a dispersed droplet diameter\nof 3–25 μm. The pore morphology resembling the natural\nextracellular matrix and the mechanical properties of scaffolds were\ncustomized by tuning the emulsion composition and 3D printing parameters. <i>In vitro</i> biomineralization and drug release studies proved\nthe scaffolds’ potential in developing the apatite-rich bioactive\ninterphase and controlled drug delivery, respectively. During <i>in vitro</i> osteoblast (MG63) growth experiments for up to\n7 days, good adhesion and proliferation on PCL scaffolds confirmed\ntheir cytocompatibility, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl\ntetrazolium bromide (MTT) analysis. This study suggests that the assembly\nof HIPE templates and 3D printing is a promising approach to creating\nhierarchical porous scaffolds potentially suitable for bone tissue\nengineering and can be stretched to other biopolymers as well.