Novel technologies are emerging that incorporate cells as part of the building blocks for various biomanufacturing processes, such as solid freeform fabricated tissue constructs for tissue regeneration, three-dimensional pharmacokinetic models, cell-based microelectromechanical systems, sensors, and microfluidic devices. However, the effects of these biomanufacturing processes on cells have not been fully studied. This paper examines the effect of solid freeform fabrication-based direct cell writing process, focusing on dispensing pressure and nozzle size, on the viability and functional behavior of HepG2 cells encapsulated within alginate. Our experimental results revealed a process-induced mechanical damage to cell membrane integrity, causing a quantifiable loss in cell viability due to incremental increases and decreases in the studied process parameters of dispensing pressure and nozzle size, respectively. The experimental results also suggested that cells may require a recovery period following direct cell writing biofabrication. The general finding of this study may be applicable to freeform fabrication of cell-based tissue constructs and three-dimensional biological models.

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Purpose -To introduce recent research and development of biopolymer deposition for freeform fabrication of three-dimensional tissue scaffolds that is capable of depositing bioactive ingredients. Design/methodology/approach -A multi-nozzle biopolymer deposition system is developed, which is capable of extruding biopolymer solutions and living cells for freeform construction of 3D tissue scaffolds. The deposition process is biocompatible and occurs at room temperature and low pressures to reduce damage to cells. In contrast with other systems, this system is capable of, simultaneously with scaffold construction, depositing controlled amount of cells, growth factors, or other bioactive compounds with precise spatial position to form complex cell-seeded tissue constructs. The examples shown are based on sodium alginate solutions and poly-1-caprolactone (PCL). Studies of the biopolymer deposition feasibility, structural formability, and different material deposition through a multi-nozzle heterogeneous system are conducted and presented.Findings -Provides information about the biopolymer deposition using different nozzle systems, the relations of process parameters on deposition flow rate and scaffold structural formability. Three-dimensional alginate-based scaffolds and scaffold embedded with living cells can be freeform constructed according to various design configurations at room temperature without using toxic materials.Research limitations/implications -Other biopolymers may also be studied for structure formation. Studying cell viability and cellular tissue engineering behavior of the scaffolds after the cell deposition should be further investigated. Practical implications -A very useful and effective tool for construction of bioactive scaffolds for tissue engineering applications based on a multinozzle biopolymer deposition. Originality/value -This paper describes a novel process and manufacturing system for fabrication of bioactive tissue scaffolds, automatic cell loading, and heterogeneous tissue constructs for emerging regenerative medicine.

Advances in computer-aided technology and its application with biology, engineering and information science to tissue engineering have evolved a new field of computer-aided tissue engineering (CATE). This emerging field encompasses computer-aided design (CAD), image processing, manufacturing and solid free-form fabrication (SFF) for modelling, designing, simulation and manufacturing of biological tissue and organ substitutes. The present Review describes some salient advances in this field, particularly in computer-aided tissue modeling, computer-aided tissue informatics and computer-aided tissue scaffold design and fabrication. Methodologies of development of CATE modelling from high-resolution non-invasive imaging and image-based three-dimensional reconstruction, and various reconstructive techniques for CAD-based tissue modelling generation will be described. The latest development in SFF to tissue engineering and a framework of bio-blueprint modelling for three-dimensional cell and organ printing will also be introduced.

Flammulina velutipes is a fungus with health and medicinal benefits that has been used for consumption and cultivation in East Asia. F. velutipes is also known to degrade lignocellulose and produce ethanol. The overlapping interests of mushroom production and wood bioconversion make F. velutipes an attractive new model for fungal wood related studies. Here, we present the complete sequence of the F. velutipes genome. This is the first sequenced genome for a commercially produced edible mushroom that also degrades wood. The 35.6-Mb genome contained 12,218 predicted protein-encoding genes and 287 tRNA genes assembled into 11 scaffolds corresponding with the 11 chromosomes of strain KACC42780. The 88.4-kb mitochondrial genome contained 35 genes. Well-developed wood degrading machinery with strong potential for lignin degradation (69 auxiliary activities, formerly FOLymes) and carbohydrate degradation (392 CAZymes), along with 58 alcohol dehydrogenase genes were highly expressed in the mycelium, demonstrating the potential application of this organism to bioethanol production. Thus, the newly uncovered wood degrading capacity and sequential nature of this process in F. velutipes, offer interesting possibilities for more detailed studies on either lignin or (hemi-) cellulose degradation in complex wood substrates. The mutual interest in wood degradation by the mushroom industry and (ligno-)cellulose biomass related industries further increase the significance of F. velutipes as a new model.