Fabrication of Cell-Loaded Two-Phase 3D Constructs for Tissue Engineering

Abstract

Hydrogel optimisation for biofabrication considering shape stability/mechanical properties and cell response is challenging. One approach to tackle this issue is to combine different additive manufacturing techniques, e.g., hot-melt extruded thermoplastics together with bioplotted cell loaded hydrogels in a sequential plotting process. This method enables the fabrication of 3D constructs mechanically supported by the thermoplastic structure and biologically functionalised by the hydrogel phase. In this study, polycaprolactone (PCL) and polyethylene glycol (PEG) blend (PCL-PEG) together with alginate dialdehyde gelatine hydrogel (ADA-GEL) loaded with stromal cell line (ST2) were investigated. PCL-PEG blends were evaluated concerning plotting properties to fabricate 3D scaffolds, namely miscibility, wetting behaviour and in terms of cell response. Scaffolds were characterised considering pore size, porosity, strut width, degradation behaviour and mechanical stability. Blends showed improved hydrophilicity and cell response with PEG blending increasing the degradation and decreasing the mechanical properties of the scaffolds. Hybrid constructs with PCL-PEG blend and ADA-GEL were fabricated. Cell viability, distribution, morphology and interaction of cells with the support structure were analysed. Increased degradation of the thermoplastic support structure and proliferation of the cells not only in the hydrogel, but also on the thermoplastic phase, indicates the potential of this novel material combination for biofabricating 3D tissue engineering scaffolds.

Poly(caprolactone)-Based Coatings on 3D-Printed Biodegradable Implants: A Novel Strategy to Prolong Delivery of Hydrophilic Drugs

“…PCL is known to have a long degradation time, up to two years, but this is dependent on molecular weight. 42 As such, a low-molecular-weight PCL was chosen to be added to H-PCL to assess the effect on degradation. PCL is also easily miscible with other polymers and can form copolymers and blends.…”

Long-Term Evaluation of Dip-Coated PCL-Blend-PEG Coatings in Simulated Conditions

“…Such features are an indicative of blend formation. In addition, the broad bands centered at 2945 cm -1 (corresponding to C-H stretching vibrations of CH2 within the PCL polymer), respectively, at 2868 cm -1 (attributed to C-H stretching vibration of the PEG polymer) evidence the presence of association forms between the functional groups of constituent polymers [40,42]. The FTIR spectra of PCL-blend-PEG exhibited the main characteristic peaks of both polymers, evidencing the retention of main functional groups within pristine organic precursors.…”

Cell-laden alginate dialdehyde–gelatin hydrogels formed in 3D printed sacrificial gel

“…Biofabrication encompasses processing techniques that allow to create 3D structures of cell-laden hydrogels for tissue engineering applications [1]. Different strategies have been used in order to provide mechanical support to 3D printed constructs like depositing bioinks into a liquid bath [2,3] or the co-printing of hard [4] and soft [5] supporting materials. Methylcellulose (MC) hydrogels have also been tested as a sacrificial material for 3D printing [6].…”