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International Journal of Bioprinting Bioprinted plasma biocarriers for MSC delivery

group consisted of chemokines. Chemokine profiling present in MSK conditions. Principal component analyses
has been proposed to predict leukocyte recruitment and grouped nude carriers and plasma-licensed carriers into
immunomodulatory mechanisms of BMSCs. In addition, separate categories. Additionally, carriers activate various
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we demonstrated that serum-converted PRP provides interleukin signaling pathways differently, highlighting key
additional chemokines to reinforce the actions of BMSCs. interactions between adaptive and immune cells.
Thus, following biocarrier delivery and the establishment
A similar pattern of carrier grouping was observed
of chemokine gradients, we can anticipate the infiltration when comparing canonical pathways related to
of both myeloid and lymphoid cells, thereby organizing the neuroinflammation and pain signaling. Notably, FFP
immune response.
carriers exposed to IL-1β differed from other plasma
The number of platelets in plasma preparations, i.e., carriers exposed to IL-1β or TNF-α, with the main
platelet doses, is a debated topic in clinical PRP therapies. differentially activated pathway being neurotrophin/
In our study, we employed two outdated allogeneic plasma TRK signaling. In the context of GF signaling, canonical
products obtained from our local blood bank. Firstly, PRP pathways were clustered into two main groups: one
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had a twofold increase in platelet concentration relative associated with angiogenesis and the other with ECM
to peripheral blood; conversely, FFP had a significantly turnover. These comparative analyses generate further
reduced platelet concentration (threefold below peripheral hypotheses to establish tailored tissue delivery for optimal
blood). Both variants were utilized for hydrogel doping therapeutic benefits.
and bioink formulations. Our data revealed differences
between serum-converted PRP or FFP and their A significant achievement of bioinformatics analyses is
interactions with MSCs, thereby modifying the secretome the creation of theoretical frameworks and well-supported
of the biocarriers and providing a model to investigate hypotheses. Our thorough analysis of biocarriers’
the influence of platelet concentration. PRP biocarriers proteomes led us to hypothesize that TGF-β1 could be
can activate canonical GF signaling pathways (TGF-β, a crucial component in plasma biomaterials, greatly
PDGF, VEGF, EGFR, and BMP), whereas FFP-biocarriers affecting BMSC activation. However, additional research is
do not significantly affect these mechanisms. Since GFs necessary to elucidate the molecular mechanisms through
are primary components of platelet α-granules, these which TGF-β1 facilitates tissue repair.
differences highlight the variability of plasma biomaterials. This study has several limitations. Firstly, we utilized
A common line of research is improving the efficacy a commercial GelMA (CellInk) but did not report its
of MSC therapies by preconditioning them with pro- rheological properties. Another limitation is the absence
inflammatory mediators, also known as cell priming or of detailed spectral analysis, including X-ray diffraction
licensing. Priming can be done with pro-inflammatory (XRD), nuclear magnetic resonance (NMR), and Fourier
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cytokines, such as IFN-γ and IL-17. Other methods transform infrared (FTIR) spectra, for both the initial and
include priming with hypoxia, biomaterials, or 3D culture final materials. While the core findings remain robust,
systems. As demonstrated here, PRP-converted serum the inclusion of these spectra would have facilitated a
contains inflammatory cytokines that could prime BMSCs more comprehensive understanding and comparison of
alongside the hypoxic conditions in our 3D culture model. the compositional changes during material processing.
Future studies should aim to incorporate these analyses to
In cell transplantation, the aim of carriers is to provide a deeper insight into the structural and chemical
mitigate environmental fluctuations in host tissues that transformations involved.
could diminish cell survival and therapeutic efficacy.
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The most common carriers include alginate, hyaluronan, Our bioprinted carriers were intended to enhance
chitosan, and gelatin-based hydrogels. We selected the paracrine effects of BMSCs rather than support cell
gelatin as the vehicle due to its immunocompatibility and differentiation, leading us to maintain the constructs in
biodegradability (non-toxic degradation by-products). cell media without supplements. The preliminary study
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Additionally, gelatin is thermosensitive, printable at involved short cell culture times (96 h), but considering
various concentrations, and allows chemical modification the constructs’ interaction with immune cells, in vivo
with methacrylate groups for UV-crosslinking after experiments to evaluate inflammatory cell infiltration and
extrusion. In our biocarriers, GelMA encapsulates BMSCs angiogenic capabilities are crucial for advancing these
and plasma secretomes, placing interleukins, chemokines, biocarriers toward clinical use. Another limitation of
and GFs in close contact with BMSCs. To investigate this study is the lack of experimental validation of MSC
how these carriers behave in a harsh environment, we differentiation, particularly osteogenesis, which would
exposed them to IL-1β or TNF-α, which are commonly strengthen the bioinformatics findings.

Volume 10 Issue 6 (2024) 313 doi: 10.36922/ijb.4426