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Elemoso, et al.
to be an extremely promising approach in the that particularly have to be polymerized instantly
fabrication of cell material-containing biomimetic in the wound without any influence from additional
scaffolds (substrates) that serves as the basis for factors such as ultraviolet radiation or chemical
the creation of living and functional 3D constructs cross-linking agents. Nevertheless, in situ
for the benefit of regenerative medicine. bioprinting has several significant advantages over
Thus, 3D bioprinting is the technology of other bioprinting techniques. Thus, applying direct
layer-by-layer fabrication of 3D tissue and organ bioprinting in tissue defect excludes the need to
constructs according to the assumed digital model prepare the substrate that minimizes the risks of in
using living cells as printing material. vitro contamination. Furthermore, in situ bioprinting
For now, however, the lack of cell material can exclude the need of stem and progenitor cell
is one of the limiting factors for bioprinting differentiation in vitro for critical or large defects,
technology development. With advances in cell and reducing fabrication time and costs. The stem
technology, this situation is going to change, but cells are immediately placed in the natural, growth-
today, the bioprinting technology depends on factor-rich environment that ensures organotypic
development; it has niche implementation. It is differentiation when printed by stem or progenitor
like having Google or Baidu web search engines cells in situ. More importantly, in situ bioprinting
without the development of the internet. Therefore, can achieve the needed hierarchy of different cells’
the technology comes into use in new areas, such placement and orientation in the defect, while in
as food arrangement, fashion industry, and space technologies of prepared scaffolds transplantation
science. We have also noticed the development of the substrate can change its shape due to swelling
bioprinting technology itself; the new technologies compression or any other deformations.
for cell materials positioning in 3D space are There are few experiments on in situ bioprinting
emerging in addition to the “golden triad” (inkjet, but they confirm its advantages as stated above.
extrusion, and laser bioprinting). Some of them Skardal et al. have demonstrated the possibility
will be discussed in more detail later on. of inkjet in situ bioprinting using fibroblasts and
keratinocytes for burns restoration . Kerikel
[8]
2 In situ bioprinting et al. have published the results of successful
experiments on bone defect restoration using
One of the new approaches developed in 3D laser in situ bioprinting . This technology seems
[9]
bioprinting is in situ bioprinting that is the particularly advantageous in terms of using it in
replacement of tissues and organ defects using hospitals to restore lost functions.
bioprinters directly during surgery. This method is At present, we can find the presence of
considered advantageous in view of the possible bioprinters in hospitals. For example, a bioprinting
“physiological” solution to the vascularization center has opened in Brisbane, Australia (Institute
problem due to progenitor cell migration in the printed of Health and Biomedical Innovation 2017). These
tissue-engineered construct and vascularization developments lead to the appearance of a business
process that starts in surrounding recipient tissues. model which allows the printing of constructs in
The idea of in situ bioprinting was first proposed specialized labs, and the direct application of in
by Weiss et al. in 2007 . However, there were only situ bioprinting at the patient’s hospital bed.
[7]
few experiments on in situ bioprinting since then Poietis, a French-based company, has entered into
due to the difficulties with forming of the construct a clinical research collaboration with the Assistance
directly in the wound (on non-horizontal surfaces). Publique – Hôpitaux de Marseille (AP-HM) to pursue
As a consequence, it is necessary to have interactive a clinical trial for bioprinted skin tissue. Through the
software for analyzing the shape and depth of the partnership, Poietis and AP-HM aim to carry out
tissue defect with the immediate consideration of a Phase I clinical trial for an Innovative Advanced
this information for bioprinting. Moreover, there Therapeutic Medicinal Product for skin healing
are special requirements for extrusion biomaterials issues. The timeline for this phase is 2 years .
[10]
International Journal of Bioprinting (2020)–Volume 6, Issue 3 63
