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In this review, few established cell printing techniques along with their parameters that affect the cell viability during bioprinting are considered. 3D bioprinting is developed on the principle of additive manufacturing using biomaterial inks and bioinks. Different bioprinting methods impose few challenges on cell printing such as shear stress, mechanical impact, heat, laser radiation, etc., which eventually lead to cell death. These factors also cause alteration of cells phenotype, recoverable or irrecoverable damages to the cells. Such challenges are not addressed in detail in the literature and scientific reports. Hence, this review presents a detailed discussion of several cellular bioprinting methods and their process‐related impacts on cell viability, followed by probable mitigation techniques. Most of the printable bioinks encompass cells within hydrogel as scaffold material to avoid the direct exposure of the harsh printing environment on cells. However, the advantages of printing with scaffold‐free cellular aggregates over cell‐laden hydrogels have emerged very recently. Henceforth, optimal and favorable crosslinking mechanisms providing structural rigidity to the cell‐laden printed constructs with ideal cell differentiation and proliferation, are discussed for improved understanding of cell printing methods for the future of organ printing and transplantation.

Solid-state diffusion bonding of Ti-6Al-4V and type 304 SS was investigated in the temperature range of 750 °C to 950 °C, under a uniaxial load for 5.4 ks in vacuum. The diffusion bonds were characterized using light and scanning electron microscopy. The scanning electron microscopic images in backscattered mode show the existence of different reaction layers in the diffusion zone. The composition of these layers was determined by energy-dispersive X-ray spectroscopy (EDS) to contain the ␣-Fe, , , FeTi, ␤-Ti, and Fe 2 Ti 4 O phases. The presence of these intermetallics was confirmed by X-ray diffraction. The bond strength was evaluated, and the maximum tensile strength of ϳ342 MPa and the maximum shear strength of ϳ237 MPa were obtained for the diffusion couple processed at 800 °C due to the finer width of the brittle intermetallic layers. With a rise in joining temperature, the bond strength drops owing to an increase in the width of the reaction layers. The activation energy and growth constant were calculated in the temperature range of 750 °C to 950 °C for the reaction products. The phase showed the fastest growth rate. A fracture-surface observation in a scanning electron microscope (SEM) using EDS demonstrates that failure takes place mainly through the ␤-Ti phase for the diffusion couples processed in the aforementioned temperature range.

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