Page 379 - IJB-9-4

International Journal of Bioprinting Evolution of bioprinting

3D hierarchical organizations with the aim of recreating subjected [47] . The importance of dopants in hydrogels,
multicellular tissues and organs was observed, and new such as silica and zinc oxide in tricalcium phosphate
developments in material transfer processes at micrometer scaffolds, was also uncovered, and the dopants allowed
and nanometer scales were seen . In addition, the key faster cell proliferation compared to pure tricalcium
[23]
message from the First Annual Charleston Bioprinting phosphate scaffolds [48] . In addition, printing of
Symposium, organized by the Medical University of South cardiac tissue with a combination of biomaterials and
Carolina’s Bioprinting Research Center, demonstrated that cardiomyocyte progenitor cells [49] , as well as the 3D
despite many technological challenges, bioprinting which printing of an aortic valve [49] , was tested, and good results
was a rapidly evolving technology at that time is a feasible were obtained.
solution to organ shortage .
[24]
3.2.3. Early achievements in bioprinting
In 2007, articles concerning the huge potential of
bioprinting and its possibilities in tissue engineering In 2013, a bioabsorbable airway splint was created to
treat tracheobronchomalacia, a condition that makes
began to surface [25,26] , and new symposia were held on the some newborns difficult to breathe . Apart from that,
[50]
subject . In 2008, owing to the emergence of new studies the feasibility of manufacturing complex heterogeneous
[27]
connecting bioprinting and bone regeneration and studies tissue constructs containing multiple cell types was also
on the use of hydroxyapatite in scaffolds, the importance of demonstrated using inkjet printing technologies , and
[51]
exploring the use of bioprinting in bone regeneration was with regard to laser-assisted bioprinting, successful 3D
repeatedly highlighted [28-33] .
printing of a cellular construct with subsequent in vivo
In 2009, a multi-drug implant containing isoniazid and tissue formation was achieved for the creation of a skin-like
timed-release rifampicin was developed using 3D printing tissue consisting of different cell types forming a complex
to treat bone tuberculosis, implying another important pattern .
[52]
potential application of this technique . Direct printing A very important milestone was represented
[34]
of living cells in alginate gel was also performed with an by the bioprinting of a heterogeneous aortic valve
inkjet printing system , and the recreation of skin grafts using alginate-gelatin hydrogels, demonstrating that
[35]
was achieved by printing collagen hydrogel precursors, anatomically complex and heterogeneously encapsulated
fibroblasts, and keratinocytes . Besides, the introduction aortic valve hydrogel conduits could be fabricated
[36]
of light-curing inks [37,38] and the successful bioprinting of with 3D bioprinting [53] . The time most people saw
microvasculature and also vascular tissue without the the budding, real potential of hydrogels in the field of
[39]
use of scaffolds had catapulted bioprinting technique to bioprinting is when the use of methacrylated gelatine
[40]
a new height. (GelMA) started to gain traction; upon exposure to
Throughout 2010, there was a continuous development ultraviolet light, GelMA is able to increase its stiffness
of high-performance laser printing of cells and and swelling properties, which are the mechanical
biomaterials , and the hydrogels were established as properties conducive for bioprinting [54] . Another
[41]
the materials of choice for the future development of breakthrough in the development of bionic tissues and
direct biofabrication techniques [42,43] . In addition, a 3D organs is represented by the reproduction of a human ear
microscale liver tissue analog was biofabricated to evaluate that was achieved by 3D-printing a cell-seeded hydrogel
pharmacokinetic profiles . In 2011, a bioprinter that was matrix with an inductive coil antenna inside, which
[44]
quite similar to the current inkjet printers was developed; provides radiofrequency reception capability [55] .
its mechanism was based on the layer-by-layer deposition In 2014, a printing method was developed to build
of customized ink in adherence to complex image data, vascular channels inside the printed structures, which
increasing the printer’s ability to mimic the conformation allows cell viability to be maintained in thicker tissues,
of tissue structures .
[45]
allowing the cells to grow and mature after printing [56-58] .
In 2012, the possibility of using amniotic fluid- Tumor recreations were also carried out for study. For
derived cells in bioprinting was studied, with very instance, HeLa cells were 3D-printed to generate an
positive results in the treatment of wounds, in which the in vitro cervical tumor model , and it was shown that the
[59]
rate of angiogenesis was higher than that of the single pressure and shape of the needle used in bioprinting could
application of mesenchymal cells or fibrocollagen gel [46] . affect cell viability . Furthermore, due to the complexity
[60]
The great importance of endowing 3D engineered tissues of the composition of the extracellular matrix and its
with perfused vascular channels is also demonstrated, important role in cell development and survival, bioinks
which solved the problem of nuclear necrosis to which made of decellularized extracellular matrix were created
densely populated tissues lacking such channels were and became more tissue-specific .
[61]

Volume 9 Issue 4 (2023) 371 https://doi.org/10.18063/ijb.742