Page 288 - IJB-9-5

International Journal of Bioprinting Blood components for tissue graft bioprinting

Figure 2. Types of blood-derived products. Abbreviations: FFP, fresh-frozen plasma; PPP, platelet-poor plasma; PC, platelet concentrate; RBC, red blood
cell concentrate; SDFFP, serum-converted fresh-frozen plasma; PL, platelet lysate; FTPL, frozen thawed platelet lysate; SCPL, serum-converted platelet
lysate; PPL, platelet pellet lysate; PLEv, platelet extracellular vesicles.

[24]
to expand cells for transplantation . In addition, factors and cytokines is often compromised by these
biofabrication/bioprinting technologies can be upgraded treatments. A potential procedure to avoid this drawback
by introducing platelet lysate into the bioink formulation, is lyophilization, which allows the availability of ready-to-
[29]
thereby harnessing the unique features of the platelet use bioink components .
[25]
secretome . The bioink composition determines the
functional characteristics of the construct. A bioink is 2.2. Platelet-rich plasma
designed not only to deliver cell/biological molecules but 2.2.1. Platelet secretome
also to function as a system to support cellular function Information regarding both the physiology of platelets
and organization or to trigger communication between and the properties of plasma is crucial to take advantage
various cellular compartments in vivo. The addition of of these cells for tissue regeneration [30,31] . Platelets are
the platelet secretome, rich in neurotrophic factors and anucleated cells originating from the partitioning of the
anti-oxidative and anti-inflammatory molecules, can megakaryocyte cytoplasm in the bone marrow. They enter
[26]
upgrade the functionality of biomaterial inks . Blood- the blood stream, where they circulate at a concentration
derived products reliant on the properties of the platelet of 250,000 plt/µL for approximately 10 days before being
secretome include platelet lysate, frozen-thawed platelet destroyed in the spleen. Traditionally, they have been best
lysate, serum-converted platelet lysate, and platelet pellet known for their role in hemostasis. However, less than
lysate [27,28] . On the other hand, platelet-poor plasma (PPP), 1/10 of the circulating platelets are needed to fulfill this
frozen-thawed PPP, serum-derived PPP, and fibrinogen function .
[24]
can be obtained after platelet and/or fibrinogen depletion
and therefore confer different biological properties on Thus, what other roles do platelets perform in
the final bioink formulation (Figure 2). Because bioinks regenerative medicine, and what advantages could they
contain cells from allogeneic donors, in some instances, provide in bioprinting technologies?
heat treatment at 56°C for 30–60 min is performed to The platelet proteome contains approximately 5200
inactivate the immunological components (C3, C4, and proteins, of which a large pool is stored in the 50–80
other major proteins in the complement pathways and alpha granules present per platelet . Alpha granules are
[32]
immune system). Moreover, proteolytic enzymes such as dense vesicles (200–500 nm) containing growth factors
thrombin are inactivated. However, the stability of growth and cytokines, antioxidants, and adhesion molecules

Volume 9 Issue 5 (2023) 280 https://doi.org/10.18063/ijb.762