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International Journal of Bioprinting 3D bioprinting for vascularized skin tissue engineering

microvascular networks, laser-assisted bioprinters low because of the uniform nozzle diameter, which results
provide an effective technique for vascularizing skin in droplets larger than those produced by inkjet-based
tissue constructions. Given their excellent speed and bioprinters. In the Kenzan method, aggregated cells or
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precision, these bioprinters offer an avenue to improve the spheroids are deposited onto a platform using a needle-
development of functional and perfusable skin tissue for array technique. LaBarge et al. developed a solution for
regenerative medicine applications. depositing spheroids on needle arrays by simultaneously
producing entire constructed layers, allowing one-by-
4.2.4. Stereolithography bioprinter one spherical deposition. Utilizing microscale droplets
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Stereolithography utilizes light for layer-by-layer of cells and bioinks, droplet-based bioprinting enables
crosslinking of light-responsive bioinks inside reservoirs. precise construction of vascular structures inside skin
Stereolithography can reduce the fabrication time of tissue constructs. By promoting the growth of functioning
3D volumetric structures because it can polymerize blood vessels, this ground-breaking method improves the
the two-dimensional plane and stack them in layer- viability and functionality of engineered skin tissues that
by-layer. Choi et al. irradiated methacrylated silk enable regenerative medicine applications.
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fibroin and gelatin bioinks to bioprint a 3D skin model
with a digital light processing printer. The skin model 4.2.6. Handheld skin bioprinter
exhibited excellent mechanical properties, promoted The revolutionary medical technology developed by Navid
cellular growth, and demonstrated therapeutic effects, Hakimi—a portable skin printer—changed how skin
making them adaptable for various skin layer thicknesses. transplantation and wound healing are performed. This
Another innovative approach involved the development bioprinter has been utilized by clinicians to treat burns,
of biocompatible gelatin methacrylamide- and hyaluronic chronic wounds, and various other skin-related disorders.
acid methacrylamide-based scaffolds featuring a dermal It exemplifies the convergence of biomedical engineering
layer that supports keratinocyte attachment and facilitates with cutting-edge medical applications. A handheld
efficient vascularization. The exploration of an optimal skin printer is a small portable tool that allows medical
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light-sensitive bioink and a practical stereolithography has personnel to apply multiple layers of bioink directly to a
laid a novel foundation for potential applications in skin patient’s skin, accurately locating and curing damaged or
tissue engineering, drug development, cosmetic testing, diseased regions. A variety of bioinks, which are composed
and future advancements in wound-healing strategies. of specific mixtures of live cells, proteins, and growth factors
Stereolithography enables the creation of intricate internal that support skin regeneration and tissue healing, are
structure such as vascularized skin tissue. The development included in this portable tool. This type of portable skin
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of intricate circulatory networks by this technique is bioprinter holds promise for improving vascularization
crucial to ensure the availability of nutrition to the in skin tissue constructions. Its precise bioink deposition
biofabricated skin, while improving regenerative medicine can generate complex blood vessel networks that are
and developing applications for wound healing. A major essential for tissue survival. The technique might advance
drawback of stereolithography is that the reservoirs may regenerative medicine and patient care by revolutionizing
be filled with photopolymerization materials, resulting in skin grafting and wound healing.
waste production and high research costs compared to
alternative methods that use smaller amounts of bioinks. 4.3. Bioink candidates for skin
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In 3D bioprinting, biomaterials-based hydrogels utilized to
4.2.5. Other bioprinters encapsulate particular cells are known as bioinks, and they
Acoustic and microvalve bioprinters are classified as are essential to the replication of healthy and physiological
droplet-based. An acoustic bioprinter discharges droplets microenvironments (Table 3). It is difficult to replicate
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when an acoustic wave generates force. Gudapati skin structure and function, and developing bioink entails
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et al. have compared the significant advancements in a step for selecting appropriate cells and biomaterial. The
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extrusion- and inkjet-based bioprinters and found that most commonly utilized biomaterials in 3D bioprinting
the presence of heat and high pressure, which can induce are synthetic and natural polymers. 106,107 Although natural
cellular damage, did not affect cell viability in bioinks. materials such as collagen, alginate, gelatin, fibrin, and
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A microvalve bioprinter uses a valve coil to generate an chitosan have limited immunogenicity, biocompatibility,
electromechanical microvalve that releases droplets. The and biodegradability, they may have insufficient mechanical
valve coil produces a magnetic field that pushes the plunger properties as well as present immunological risks. The
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higher, and the resulting pneumatic pressure pressurizes mechanical and structural properties of synthetic polymers
the bioinks in the barrel, which are subsequently can be controlled. They can be biodegradable, like PCL
discharged from the open barrel. However, the resolution is and PLA, or non-biodegradable, like PEG. For skin
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Volume 10 Issue 3 (2024) 98 doi: 10.36922/ijb.1727