Construction of 3D biological matrices using rapid prototyping technology

Abstract

PurposeHydrogels with low viscosities tend to be difficult to use in constructing tissue engineering (TE) scaffolds used to replace or restore damaged tissue, due to the length of time it takes for final gelation to take place resulting in the scaffolds collapsing due to their mechanical instability. However, recent advances in rapid prototyping have allowed for a new technology called bioplotting to be developed, which aims to circumvent these inherent problems. This paper aims to present details of the process.Design/methodology/approachThe paper demonstrates how by using the bioplotting technique complex 3D geometrical scaffolds with accurate feature sizes and good pore definition can be fabriated for use as biological matrices. PEG gels containing the cell‐adhesive RGD peptide sequence were patterned using this method to produce layers of directional microchannels which have a functionalised bioactive surface. Seeding these gels with C2C12 myoblasts showed that the cells responded to the topographical features and aligned themselves along the direction of the channels.FindingsThis process allows plotting of various materials into a media bath containing material of similar rheological properties which can be used to both support the structure as it is dispensed and also to initiate cross‐linking of the hydrogel. By controlling concentrations, viscosity and the temperature of both the plotting material and the plotting media, the speed of the hydrogel gelation can be enhanced whilst it is cross‐linking in the media bath. TE scaffolds have been produced using a variety of materials including poly(ethylene glycol) (PEG), gelatin, alginic acid and agarose at various concentrations and viscosities.Originality/valueThis paper describes one of the very few examples of accurate construction of 3D biological microporous matrices using hydrogel material fabricated by the bioplotting technique. This demonstrates that this technique can be used to produce 3D scaffolds which promote tissue regeneration.

Engineering alginate as bioink for bioprinting

“…Among the various liquid-dispensing systems, piston-driven deposition has recently received significant attention because it offers a significantly high fabrication speed and is capable of fabricating anatomically shaped, clinically relevant-sized constructs [29,30]. They require a bioink with a suitable density and viscosity as well as the capability to retain printing fidelity and high cell viability post-printing [31,32]. In this study, we used a custom-made, piston-driven deposition system, as a test bed to examine the printability of biodegradable alginates.…”

Standardized 3D Bioprinting of Soft Tissue Models with Human Primary Cells

“…[33][34][35] The instrument can process a variety of bioinks with light-, ionic-, or thermal-induced Dermal equivalents were printed and cultured for (C and D) 7, (E) 14, (F) 21, and (G and H) 42 days prior to seeding with human primary keratinocytes on top. The models were cultured for 5 days submerged and 14 days at the air-liquid interface.…”

Bioimpressão e produção de mini-órgãos com células tronco

“…Inúmeros polímeros de hidrogel biocompatíveis podem ser utilizados como biotintas para a bioprintação por extrusão, vale a pena comentar que neste processo o material do biotinta deve ser escolhido de acordo com o tipo de célula a ser utilizada para a bioimpressão e ter a capacidade de proporcionar uma concentração celular relativamente elevada. O êmbolo de parafuso mecânico promove um melhor controle sobre o fluxo de biotinta, o que é importante para melhorar a padronização (Pati et al 2015, Maher et al 2009, Campos et al 2012. No entanto, para a impressão de células-tronco, a extrusão por parafuso mecânico e/ou pneumático pode produzir grandes quedas de pressão ao longo do bico da impressora.…”