Egg white improves the biological properties of an alginate-methylcellulose bioink for 3D bioprinting of volumetric bone constructs

Abstract

Three-dimensional microextrusion bioprinting has attracted great interest for fabrication of hierarchically structured, functional tissue substitutes with spatially defined cell distribution. Despite considerable progress, several significant limitations remain such as a lack of suitable bioinks which combine favorable cell response with high shape fidelity. Therefore, in this work a novel bioink of alginate-methylcellulose (AlgMC) blend functionalized with egg white (EW) was developed with the aim of solving this limitation. In this regard, a stepwise strategy was proposed to improve and examine the cell response in low-viscosity alginate inks (3 %, w/v) with different EW concentrations, and in high-viscosity inks after gradual methylcellulose (MC) addition for enhancing printability. The rheological properties and printability of these cell-responsive bioinks were characterized to obtain an optimized formulation eliciting balanced physicochemical and biological properties for fabrication of volumetric scaffolds. The bioprinted AlgMC+EW constructs exhibited excellent shape fidelity while encapsulated human mesenchymal stem cells (MSC) showed high post-printing viability as well as adhesion and spreading within the matrix. In a proof-of-concept experiment, the impact of these EW-mediated effects on osteogenesis of bioprinted primary human pre-osteoblasts (hOB) was evaluated. Results confirmed a high viability of hOB (93.7 ± 0.15 %) post-fabrication in an EW-supported AlgMC bioink allowing cell adhesion, proliferation and migration. EW even promoted the expression of osteogenic genes, coding for bone sialoprotein (IBSP) and osteocalcin (BGLAP) on mRNA level. To demonstrate the suitability of the novel ink for future fabrication of multi-zonal bone substitutes, AlgMC+EW was successfully co-printed together with a pasty calcium phosphate bone cement biomaterial ink to achieve a partly mineralized 3D volumetric environment with good cell viability and spreading. Along with the EW-mediated positive effects within bioprinted AlgMC-based scaffolds, this highlighted the promising potential of this novel ink for biofabrication of bone tissue substitutes in clinically relevant dimensions.

Cation-crosslinked κ-carrageenan sub-microgel medium for high-quality embedded bioprinting

“…Considerable efforts have been made to enhance 3D stability and shape fidelity of printed hydrogels, such as printing multi-material inks [3], employing photo-crosslinkable hydrogels [4], adding thickeners [5], and adopting embedded printing within sacrificial supporting materials [6]. Particularly, embedded 3D bioprinting deposits bioink into a matrix composed of granular hydrogels, which provides structural support throughout the printing process [7][8][9][10].…”

3D bioprinting of mouse pre-osteoblasts and human MSCs using bioinks consisting of gelatin and decellularized bone particles

“…With high surface area and unique structural shape, inorganic additives can significantly influence the properties of 3D scaffolds with tailored functionalities. In bone tissue engineering, inorganic materials-reinforced bioink formulations have been reported with successful outcomes in many studies using different materials and designs [4,[24][25][26][27][28]. Utilizing both organic and inorganic materials in a composite structure is a suitable approach to mimic the bone tissue extracellular matrix (ECM).…”

Bioinks for Space Missions: The Influence of Long‐Term Storage of Alginate‐Methylcellulose‐Based Bioinks on Printability as well as Cell Viability and Function

“…[11] During alginate crosslinking and the subsequent cultivation, the methylcellulose is partially released, forming a crosslinked construct of mainly alginate.. [11,12] This versatile ink has been successfully applied for bioprinting of various mammalian cell types such as pancreatic islets of Langerhans and chondrocytes, but also for bioprinting of microalgae. [13][14][15][16][17][18][19] Based on the promising results in these ground-based studies, Alg-MC was the first bioink to be selected by the company OHB for use in space. As part of the ISS mission Cosmic Kiss of the German ESA astronaut Matthias Maurer, it was used as one of two for the mission selected bioinks to generate constructs with the aid of a hand-held printer, which in combination with dermal fibroblasts should later provide rapid assistance in the wound closure of large-area skin injuries.…”

“…[ 11 ] During alginate crosslinking and the subsequent cultivation, the methylcellulose is partially released, forming a crosslinked construct of mainly alginate.. [ 11,12 ] This versatile ink has been successfully applied for bioprinting of various mammalian cell types such as pancreatic islets of Langerhans and chondrocytes, but also for bioprinting of microalgae. [ 13–19 ]…”