Leachable Poly(Trimethylene Carbonate)/CaCO3 Composites for Additive Manufacturing of Microporous Vascular Structures

Abstract

The aim of this work was to fabricate microporous poly(trimethylene carbonate) (PTMC) vascular structures by stereolithography (SLA) for applications in tissue engineering and organ models. Leachable CaCO3 particles with an average size of 0.56 μm were used as porogens. Composites of photocrosslinkable PTMC and CaCO3 particles were cast on glass plates, crosslinked by ultraviolet light treatment and leached in watery HCl solutions. In order to obtain interconnected pore structures, the PTMC/CaCO3 composites had to contain at least 30 vol % CaCO3. Leached PTMC films had porosities ranging from 33% to 71% and a pore size of around 0.5 μm. The mechanical properties of the microporous PTMC films matched with those of natural blood vessels. Resins based on PTMC/CaCO3 composites with 45 vol % CaCO3 particles were formulated and successfully used to build vascular structures of various shapes and sizes by SLA. The intrinsic permeabilities of the microporous PTMC films and vascular structures were at least one order of magnitude higher than reported for the extracellular matrix, indicating no mass transfer limitations in the case of cell seeding.

One-Step Fabrication of Porous Membrane-Based Scaffolds by Air-Water Interfacial Phase Separation: Opportunities for Engineered Tissues

“…Furthermore, a combination of techniques is often needed to achieve the desired scaffold properties. For example, to create hierarchical pores, a combination of particle leaching and stereolithography can be applied [ 12 ]. However, membrane-based scaffolds produced by such methods have limitations for TE, such as poor control over pore size, limited porous hierarchy, undesirable morphology that does not mimic tissues or limited construct volume.…”

Creation of adjacent monolithic and self‐forming porous fragments in a polymerizing layer by optical scanning stereolithography

“…The possibility to produce materials with the structure, which combines adjacent monolithic and porous fragments, in one technological process opens up a new potential for optical printing of various skeletons for tissue engineering, 1–8 nano‐ and macro‐porous filters, 9,10 flowing nano‐ and micro‐reactors with enhanced operating surface area 11–13 . Stereolithography is a modern high‐resolution method to make polymeric 2D‐ and 3D‐objects of complex geometry 3,14–17 .…”

“…Another way to obtain porous polymer materials is the PPC curing in the presence of a nonreactive component (NC), which does not participate in the polymerization reaction and is incompatible with the polymer 1,8,27–35 . After NC removal from in the polymer matrix, pores remain, and their parameters are determined by the nature and amount of the pore‐generating additive.…”

“…By acting with inhomogeneous light, or by moving illumination boundary, it is possible to form spatial distribution of the NC concentration, and, consequently, to vary the structure of the resulting polymer 36–42 . That will expand the capabilities of existing optical stereolithographic systems, which use the PPC of one original formulation to form an object 8,33,34 …”