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Pakhomova, et al.
3 Scaffolds and bioimplants printing bioprinting. The selected method should be based
on the properties of the tissue, for which the
In the field of biomedicine, there are many important scaffold is created. The mechanical properties
purposes for each component of the created device. of scaffolds can be enhanced using various
The task of finding a material that will satisfy all crosslinking technologies.
these needs is a complicated issue. Therefore, Ionic crosslinking can be used to deplete
creating biomedical devices must be heterogeneous mechanical energy. Personalized scaffolds should
in most cases. According to Shi and Wang , provide an environment with micro-stress that
[34]
current researches on 3D printing technology for is equal to the natural habitat for cells. It should
biomedical applications in the field of printing of maintain structural stability and integrity. It must
non-living objects can be classified into two main possess mechanical strength, which matches those
areas: Personalized manufacturing of permanent of the subchondral bone and adjacent cartilage of
non-invasive implants and fabrication of local the implant location to provide an immediate and
scaffolds, which could be biodegradable or bioactive. long-term load-bearing function . Crosslinking
[37]
The advantage of 3D printing of implants over technologies were adopted to improve the
traditional machine technology is that 3D printing mechanical properties of widely used gel materials
can achieve personalized real-time manufacturing due to their disadvantages such as poor mechanical
of any sophisticated implant with high-dimensional properties, natural shrinking, and others .
[38]
accuracy and short production cycles. Multi-material Considering Hutmacher, Wu et al. [37,38] , 3D printed
3D printing is a widespread technology in the field bioactive glass scaffolds were manufactured with
of implants manufacturing. For example, in Yan a hierarchical pore architecture and well-ordered
et al. , a bone prosthesis of 3D hydroxyapatite mesopores in various shapes. Then, polyvinyl
[35]
(HA)-coated porous titanium with osteoconductivity alcohol as a thermo-crosslinking agent was used to
composed of an osteoinductive composite material improve the mechanical properties. A combination
was successfully created. The new bone successfully of materials can be used to resist cracking and
grew through it after 24 weeks. The porous Ti, which fatigue, to obtain desired physicochemical
also acted as an osteoinductor, provided the required properties, to avoid extra cost, and for antibacterial
mechanical strength. purposes which is crucial in health care .
[39]
3D printing technologies could be used for 3D printing technologies can be useful for the
the manufacturing of various scaffolds for the creation of high-fidelity clinical organ models for
bioprinting of living tissues or whole organs. clinical treatments and medical education. Thanks
Scaffolds must satisfy such requirements as bio- to 3D printing technologies, these models could be
physicochemical properties, structural features, created at a lower cost and taking into account of the
mechanical properties, and other necessary individual differences among patients. Advantages
characteristics. According to Mogali et al. , these of 3D printed models are physical dimension and
[36]
essential characteristics could be a 3D porous durability, as well as the opportunity to be color-
interconnected network for cell growth, flow or material-coded by tissue type. Future materials
transport of nutrients and metabolic waste; suitable with different elasticity, color, and composition
surface chemistry for cell adhesion, proliferation to simulate the appearance of human tissues and
and differentiation; biocompatibility, and matching organs can be developed .
[40]
with the controlled degradation and absorption To achieve different functions, scaffolds
rate of cell or tissue growth; and properties that should integrate different materials, for example,
match the tissues to be implanted. Scaffolds with metal with ceramic and polymer can be used to
high water content, excellent biocompatibility, and fabricate a porous scaffold to satisfy the implant
controllable biodegradation can be manufactured requirements [33,41] . 3D printed smart materials,
using different technique such as extrusion-based, which can switch their shape or properties under
inkjet-based, microvalve-based, or laser-assisted the specific external stimulus, can show high

International Journal of Bioprinting (2020)–Volume 6, Issue 3 43