Hierarchically porous materials: synthesis strategies and structure design

3D printing techniques are utilized to produce biomaterial scaffolds with porous architectures that enable cell attachment, biological factors, and appropriate mechanical strength. As the basic building block of a scaffold, the individual filaments should have sufficient mechanical properties, comprising high compressive loading, and fracture resistance to mimic the natural tissue organisation. In this contribution, process–structure–property relationships in melt extruded polycaprolactone filaments are investigated by considering crystalline features, tensile properties, and an array of processing parameters. The tensile properties of the filaments are improved significantly with relatively higher screw rotational speed and relatively lower processing temperature resulting in considerable increase in Young's modulus. The favorable properties are attributed to the increased crystal volume fraction and anisotropy. Thus, this study provides initial pathways for the potential control of mechanical properties of bioscaffolds via engineering crystalline structural features in printed filaments.

Section: Introductionmentioning

confidence: 99%

Process‐Driven Microstructure Control in Melt‐Extrusion‐Based 3D Printing for Tailorable Mechanical Properties in a Polycaprolactone Filament

Liu

Vyas

Poologasundarampillai

et al. 2018

“…Hydrophilic porous polymeric materials are fundamental materials that can be obtained from a series of synthesis methods, such as gas foaming, phase separation, solvent‐generated pore method, and templating method . Among the majority of template methods, oil‐in‐water emulsion template is widespread in the field.…”

Section: Introductionmentioning

confidence: 99%

High‐Performance Composite Monolith Synthesized via HKUST‐1 Stabilized HIPEs and Its Adsorptive Properties

Yang

Cao

et al. 2018

This paper presents a green and facile method for generating a composite monolith. HKUST‐1 (Pickering emulsifier) and PVA (co‐emulsifier), are used to stabilize supercritical carbon dioxide in water as high internal phase emulsion template to prepare interconnected hydrophilic porous monoliths. The effects of HKUST‐1 contents and CO2 densities on the performance of MOF/ polyacrylamide (PAM) polyHIPEs are investigated. The as‐synthesized MOF/PAM composites are characterized by FT‐IR, SEM, XRD, and TGA. The SEM patterns show that the composites are interconnected, the void sizes are 10–80 µm, and the interconnected pore throats are approximately 0.5–25 µm. The rheological and DMA measurement results indicate that the viscoelasticity and mechanical properties of the composites greatly improve after HKUST‐1 is embedded. Furthermore, the adsorptive properties of MOF/PAM to bovine serum albumin (BSA) are studied, and the adsorption capacity of MOF/PAM enhances with the increase in HKUST‐1 content. The adsorption capacity of the composite with 7 wt% HKUST‐1 reached 350.4 mg g−1 in 1.0 g L−1 BSA solution.

“…However, the scaffold‐based approach is very frequently used in tissue engineering. Scaffolds are 3D biocompatible and biodegradable porous structures that provide substrates for cell attachment, differentiation, and proliferation . Scaffold design also requires the control of material properties, surface topography, chemistry, and stiffness that significantly influence biological processes .…”

Section: Introductionmentioning

confidence: 99%

Structural Evolution of PCL during Melt Extrusion 3D Printing

Liu

Vyas

Poologasundarampillai

et al. 2017

Screw‐assisted material extrusion technique is developed for tissue engineering applications to produce scaffolds with well‐defined multiscale microstructural features and tailorable mechanical properties. In this study, in situ time‐resolved synchrotron diffraction is employed to probe extrusion‐based 3D printing of polycaprolactone (PCL) filaments. Time‐resolved X‐ray diffraction measurements reveals the progress of overall crystalline structural evolution of PCL during 3D printing. Particularly, in situ experimental observations provide strong evidence for the development of strong directionality of PCL crystals during the extrusion driven process. Results also show the evidence for the realization of anisotropic structural features through the melt extrusion‐based 3D printing, which is a key development toward mimicking the anisotropic properties and hierarchical structures of biological materials in nature, such as human tissues.