Given their native-like biological properties, high growth factor retention capacity and porous nature, sulfated-polysaccharide-based scaffolds hold great promise for a number of tissue engineering applications. Specifically, as they mimic important properties of tissues such as bone and cartilage they are ideal for orthopaedic tissue engineering. Their biomimicry properties encompass important cell-binding motifs, native-like mechanical properties, designated sites for bone mineralization and strong growth factor binding and signalling capacity. Even so, scientists in the field have just recently begun to utilise them as building blocks for tissue engineering scaffolds. Most of these efforts have so far been directed towards in vitro studies, and for these reasons the clinical gap is still substantial. With this review paper, we have tried to highlight some of the important chemical, physical and biological features of sulfated-polysaccharides in relation to their chondrogenic and osteogenic inducing capacity. Additionally, their usage in various in vivo model systems is discussed. The clinical studies reviewed herein paint a promising picture heralding a brave new world for orthopaedic tissue engineering.

Three-dimensional (3D) printing technology has revolutionized tissue engineering field because of its excellent potential of accurately positioning cell-laden constructs. One of the main challenges in the formation of functional engineered tissues is the lack of an efficient and extensive network of microvessels to support cell viability. By printing vascular cells and appropriate biomaterials, the 3D printing could closely mimic in vivo conditions to generate blood vessels. In vascular tissue engineering, many various approaches of 3D printing have been developed, including selective laser sintering and extrusion methods, etc. The 3D printing is going to be the integral part of tissue engineering approaches; in comparison with other scaffolding techniques, 3D printing has two major merits: automation and high cell density. Undoubtedly, the application of 3D printing in vascular tissue engineering will be extended if its resolution, printing speed, and available materials can be improved.

The increasing population of patients with heart disease and the limited availability of organs for transplantation have encouraged multiple strategies to fabricate healthy implantable cardiac tissues. One of the main challenges in cardiac tissue engineering is to direct cell behaviors to form functional three-dimensional (3D) biomimetic constructs. This article provides a brief review on various cell sources used in cardiac tissue engineering and highlights the effect of scaffold-based signals such as topographical and biochemical cues and stiffness. Then, conventional and novel micro-engineered bioreactors for the development of functional cardiac tissues will be explained. Bioreactor-based signals including mechanical and electrical cues to control cardiac cell behavior will also be elaborated in detail. Finally, the application of computational fluid dynamics to design suitable bioreactors will be discussed. This review presents the current state-of-the-art, emerging directions and future trends that critically appraise the concepts involved in various approaches to direct cells for building functional hearts and heart parts.

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In this research, nanocomposite scaffolds of chitosan/PLLA/nano calcium phosphate (average crystallite size of 16.5 nm) have been prepared via the freeze-casting method and then characterized. The effects of nano powder contents on the structure of scaffolds were investigated to provide an appropriate nanocomposite for bone tissue engineering applications. The results showed that the scaffolds had high porosity (up to 98%) with open pores of 80–380 μm in diameter. It was also shown that the porosity increased with decreasing nano powder content. Furthermore, the bioactive nano calcium phosphate was homogenously distributed within the polymeric matrix of scaffolds, which contained up to 40% of nano powder. Microstructure studies showed that the pores were distributed very well throughout the structures. This macropores structure with interconnected pores provides the properties of scaffolds required for bone tissue engineering applications.

In this research, we first performed a computational fluid dynamics (CFD) study of the effects of the inlet solution's concentration and channel height to produce microfibres in a microfluidic system by COMSOL 5.3 to find the optimum ratio of sheath to core flow rate. It proved that the ratio of sheath to core flow rate should considered more than 1 to have jet regime in the microchannel. The results show that the level of Ca2+ diffusion in an alginate inlet solution has a direct and reverse correlation with the initial sheath solution's concentration and initial core solution's concentration, respectively. Secondly, the response surface methodology (RSM) in Design Expert 7.0.0, was used to investigate the effects of alginate and calcium chloride flow rates on the average microfibres' diameter. We found that the best value of Ca2+ concentration in the core flow to produce fine appropriate microfibres is 150 mol/m3. Then, we developed a microchip using lithography, in which a silicon wafer was etched vertically instead of using a SU‐8 photo resist on glass, causing a significant improvement in the quality of channels and mould. The SEM images revealed low roughness of fabricated micro‐channels, which was eye‐catching. Eventually, the possibility of using the microfibres as polymeric carriers for hydrophobic drugs was investigated, and then fluorescent microscopic images of the loaded fibres indicated that the drug is well‐loaded onto the fibres: the results are promising.

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