Engineering alginate as bioink for bioprinting (original) (raw)
Related papers
Importance of Alginate Bioink for 3D Bioprinting in Tissue Engineering and Regenerative Medicine
Alginates - Recent Uses of This Natural Polymer [Working Title], 2019
Among many bioinks used for extrusion 3D bioprinting, the most commonly used bioink is the polysaccharide alginate because of its various cellular-friendly property like gelation. Erratic degradation and cell-binding motifs are not present in alginate which are the limitations of alginate bioinks, which can be improved by blending various low concentrations of natural or artificial polymers. Here in this chapter, we will discuss the various important properties of the alginate which make it as the bioink for almost all bioprinting scaffold designs as well as how improve the cellular properties like its cell-material interaction by blending it with other polymer solutions.
Storable Cell-Laden Alginate Based Bioinks for 3D Biofabrication
Bioengineering
Over the last decade, progress in three dimensional (3D) bioprinting has advanced considerably. The ability to fabricate complex 3D structures containing live cells for drug discovery and tissue engineering has huge potential. To realise successful clinical translation, biologistics need to be considered. Refinements in the storage and transportation process from sites of manufacture to the clinic will enhance the success of future clinical translation. One of the most important components for successful 3D printing is the ‘bioink’, the cell-laden biomaterial used to create the printed structure. Hydrogels are favoured bioinks used in extrusion-based bioprinting. Alginate, a natural biopolymer, has been widely used due to its biocompatibility, tunable properties, rapid gelation, low cost, and easy modification to direct cell behaviour. Alginate has previously demonstrated the ability to preserve cell viability and function during controlled room temperature (CRT) storage and shipmen...
2020
To realize the promise of 3D bioprinting, it is imperative to develop bioinks that possess the biological and rheological characteristics needed for the printing of cell-laden tissue grafts. Alginate is widely used as a bioink because its rheological properties can be modified through pre-crosslinking or the addition of thickening agents to increase printing resolution. However, modification of alginate’s physicochemical characteristics using common crosslinking agents can affect its cytocompatibility. Therefore, we evaluated the printability, physicochemical properties, and osteogenic potential of four common alginate bioinks: alginate-CaCl2 (alg-CaCl2), alginate-CaSO4 (alg-CaSO4), alginate-gelatin (alg-gel) and alginate-nanocellulose (alg-ncel) for the 3D bioprinting of patient-specific osteogenic grafts. While all bioinks possessed similar viscosity, printing fidelity was lower in the pre-crosslinked bioinks. When used to print geometrically defined constructs, alg-CaSO4 and alg-...
Printability of Double Network Alginate-Based Hydrogel for 3D Bio-Printed Complex Structures
Frontiers in Bioengineering and Biotechnology
Three-dimensional (3D) bio-printing has recently emerged as a crucial technology in tissue engineering, yet there are still challenges in selecting materials to obtain good print quality. Therefore, it is essential to study the influence of the chosen material (i.e., bio-ink) and the printing parameters on the final result. The “printability” of a bio-ink indicates its suitability for bio-printing. Hydrogels are a great choice because of their biocompatibility, but their printability is crucial for exploiting their properties and ensuring high printing accuracy. However, the printing settings are seldom addressed when printing hydrogels. In this context, this study explored the printability of double network (DN) hydrogels, from printing lines (1D structures) to lattices (2D structures) and 3D tubular structures, with a focus on printing accuracy. The DN hydrogel has two entangled cross-linked networks and a balanced mechanical performance combining high strength, toughness, and bio...
Materials
Hydrogels tested and evaluated in this study were developed for the possibility of their use as the bioinks for 3D direct bioprinting. Procedures for preparation and sterilization of hydrogels and the speed of the bioprinting were developed. Sodium alginate gelatine hydrogels were characterized in terms of printability, mechanical, and biological properties (viability, proliferation ability, biocompatibility). A hydrogel with the best properties was selected to carry out direct bioprinting tests in order to determine the parameters of the bioink, adapted to print with use of the designed and constructed bioprinter and provide the best conditions for cell growth. The obtained results showed the ability to control mechanical properties, biological response, and degradation rate of hydrogels through the use of various solvents. The use of a dedicated culture medium as a solvent for the preparation of a bioink, containing the predicted cell line, increases the proliferation of these cel...
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2020
The concept of adding inorganic fillers into hydrogels to form hydrogel nanocomposites often provides advantageous properties which can be exploited for successful 3D biofabrication. In this study, a new composite hydrogel combining oxidized alginate-gelatin (ADA-GEL) hydrogel and laponite nanoclay as inorganic nanofiller was successfully developed and characterized. The results showed that the addition of 0.5% (wt/vol) laponite nanoplatelets improved the printability of ADA-GEL hydrogels enabling the fabrication of detailed structures since a low effect of material spreading and reduced tendency to pore closure appeared. Furthermore, a comparison of different needle types (cylindrical and conical; same inner diameter of 250 μm) in filament fusion test showed that the pattern dispensed by cylindrical tip has enhanced printing accuracy and pattern fidelity when compared with the pattern from conical tip. A glass flip test determined a processing window of 1-2 h after composite ink preparation. Overall, laponite/ADA-GEL hydrogel composites are confirmed as promising inks for 3D bioprinting.
3D-Printable Bioactivated Nanocellulose-Alginate Hydrogels
ACS applied materials & interfaces, 2017
We describe herein a nanocellulose-alginate hydrogel suitable for 3D printing. The composition of the hydrogel was optimized based on material characterization methods and 3D printing experiments, and its behavior during the printing process was studied using computational fluid dynamics simulations. The hydrogel was biofunctionalized by the covalent coupling of an enhanced avidin protein to the cellulose nanofibrils. Ionic cross-linking of the hydrogel using calcium ions improved the performance of the material. The resulting hydrogel is suitable for 3D printing, its mechanical properties indicate good tissue compatibility, and the hydrogel absorbs water in moist conditions, suggesting potential in applications such as wound dressings. The biofunctionalization potential was shown by attaching a biotinylated fluorescent protein and a biotinylated fluorescent small molecule via avidin and monitoring the material using confocal microscopy. The 3D-printable bioactivated nanocellulose-a...
3D Printability of Alginate-Carboxymethyl Cellulose Hydrogel
Materials (Basel, Switzerland), 2018
Three-dimensional (3D) bio-printing is a revolutionary technology to reproduce a 3D functional living tissue scaffold in-vitro through controlled layer-by-layer deposition of biomaterials along with high precision positioning of cells. Due to its bio-compatibility, natural hydrogels are commonly considered as the scaffold material. However, the mechanical integrity of a hydrogel material, especially in 3D scaffold architecture, is an issue. In this research, a novel hybrid hydrogel, that is, sodium alginate with carboxymethyl cellulose (CMC) is developed and systematic quantitative characterization tests are conducted to validate its printability, shape fidelity and cell viability. The outcome of the rheological and mechanical test, filament collapse and fusion test demonstrate the favorable shape fidelity. Three-dimensional scaffold structures are fabricated with the pancreatic cancer cell, BxPC3 and the 86% cell viability is recorded after 23 days. This hybrid hydrogel can be a po...
Bioengineering
Layer-by-layer additive manufacturing process has evolved into three-dimensional (3D) “bio-printing” as a means of constructing cell-laden functional tissue equivalents. The process typically involves the mixing of cells of interest with an appropriate hydrogel, termed as “bioink”, followed by printing and tissue maturation. An ideal bioink should have adequate mechanical, rheological, and biological features of the target tissues. However, native extracellular matrix (ECM) is made of an intricate milieu of soluble and non-soluble extracellular factors, and mimicking such a composition is challenging. To this end, here we report the formulation of a multi-component bioink composed of gelatin and alginate -based scaffolding material, as well as a platelet-rich plasma (PRP) suspension, which mimics the insoluble and soluble factors of native ECM respectively. Briefly, sodium alginate was subjected to controlled oxidation to yield alginate dialdehyde (ADA), and was mixed with gelatin a...
Bioprinting three-dimensional cell-laden tissue constructs with controllable degradation OPEN
Alginate hydrogel is a popular biologically inert material that is widely used in 3D bioprinting, especially in extrusion-based printing. However, the printed cells in this hydrogel could not degrade the surrounding alginate gel matrix, causing them to remain in a poorly proliferating and non-differentiating state. Here, we report a novel study of the 3D printing of human corneal epithelial cells (HCECs)/collagen/gelatin/alginate hydrogel incubated with a medium containing sodium citrate to obtain degradation-controllable cell-laden tissue constructs. The 3D-printed hydrogel network with interconnected channels and a macroporous structure was stable and achieved high cell viability (over 90%). By altering the mole ratio of sodium citrate/sodium alginate, the degradation time of the bioprinting constructs can be controlled. Cell proliferation and specific marker protein expression results also revealed that with the help of sodium citrate degradation, the printed HCECs showed a higher proliferation rate and greater cytokeratin 3(CK3) expression, indicating that this newly developed method may help to improve the alginate bioink system for the application of 3D bioprinting in tissue engineering. The technology to fabricate three-dimensional (3D) engineered tissue analogue structures, called 3D printing 1 , would enable researchers and clinicians to tackle the current shortage of tissues and organs needed for transplants and provide platforms for drug testing and studying tissue morphogenesis 2. There are two different approaches using 3D printing technology in tissue engineering 3-9. The first approach is used to create acellular 3D scaffolds and molds, which must be seeded with cells after fabrication 3-6 ; the second approach is used to build tissue constructs by directly depositing cells or cell aggregates, a process known as bioprinting 7-9. A crucial aspect of bioprinting is that the bioink must have printability and biocompatibility because it requires the dispensing of cell-containing media 1,10. The need to operate in an aqueous or aqueous gel environment limits the choice of materials, a situation cited as a significant inhibitor to the growth of bioprinting 11. In extrusion-based printing, hydrogels are solidified through either thermal processes or post-print cross-linking and are used for the printing of cells to produce diverse tissues, ranging from the liver to bone, using materials such as alginate/gelatin chitosan/ gelatin, gelatin/fibrinogen and gelatin methacrylate 12-16. The alginate material system (such as alginate/gelatin) is the most popular material system in use, although it uses biologically inert material that meets the osmolar requirements of the cells, maintains their viability and hardens simply by brief exposure to calcium chloride 17-20. However, there are some concerns over the outcomes of alginate studies. Derby noted that alginate systems are clearly useful for technology development purposes but are unlikely to have any long-term role because of the poor cellular adhesion that has been observed 21. Pati et al. analysed the drawbacks of alginate gels and concluded that cells cannot degrade the surrounding alginate gel matrix; thus, they remain located specifically in their original deposited position during the entire culture period, limiting their capacity to proliferate and differentiate 11. Thus, although there were some successful reports concerning the use of alginate gels to bioprint cell-printed structures, the slow and uncontrollable degradation rates of the bioprinted constructs, which induce minimal cell-proliferation and inferior cell-differentiation, are the foremost concerns. It was already known that, after cross-linking with calcium ions, the slow degradation rate of alginate is due to the low level of released calcium ions 22. Sodium citrate, whose citrate ion can chelate to calcium ions and