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International Journal of Bioprinting Printing organoids in peptide matrices

concentration of the parent peptide, while the gelation expression. We demonstrated the potential of these
of FIB mixtures is kept constant when the concentration matrices to influence organoid morphology and gene
of the decorated peptide is higher or equal to the expression. Moreover, the bioprinting evaluation suggests
decorated LAM peptide. We determined the nanofibers’ the feasibility of organoid fabrication using bioprinting
characteristics in each mixture, such as LAM (high) fibers techniques, offering a promising alternative for in vitro
presenting right-handedness. Likewise, we evaluated the organoid manipulation and fabrication.
biocompatibility of these hydrogels and the effect each We demonstrated the potential enhancement of
had on colorectal organoid fabrication. We concluded USAPs by using biofunctional peptides to obtain the most
that these hydrogels are cytocompatible and facilitate cell suitable combination of characteristics for CRC organoid
proliferation in a magnitude similar to that of Matrigel. development and their use in a bioprinting setup. We
By colony morphology evaluation, we obtained two believe that our findings have important implications for
promising peptide formulations (FIB [high] and LAM advancing the field of organoid culture, bioprinting, and its
[low]) to be used as organoid matrices. Accordingly, we applications in CRC research. The detailed characterization
characterized the organoids cultured in these promising and optimization of the novel biofunctional peptide bioink
peptide formulations and the FIB-LAM mixture. For this, provide insights into its potential as a valuable tool in
we assessed lumen formation on these three formulations. regenerative medicine, disease modeling, and drug testing.
We concluded that organoids cultured in peptide FIB
(low) exhibit a polar arrangement and a gene expression 5. Conclusion
profile closer to those cultured in Matrigel. However,
the effect between the peptide fibers and cells warrants In this study, we introduced and characterized two
further investigation to understand the impact of peptide novel biofunctional peptides designed to enhance
hydrogels on cell adhesion and differentiation. the capabilities of USAPs for bioprinting colon
organoids. These peptides demonstrated the ability
Moreover, our investigation into the bioprinting
capabilities of the biofunctionalized peptides FIB (low) to form nanofibers when mixed with the parent
self-assembling peptide, and their physicochemical
and LAM (high) has provided valuable insights into properties were systematically evaluated based on
their performance and suitability for generating stable sequence, concentration, and ratio. We found that the
3D structures. Through a systematic evaluation of their gelation behavior of these peptide mixtures varied
gelation properties, we observed that FIB (low) exhibited significantly; for instance, FIB peptides required a
superior gel retention even at lower concentrations than higher concentration of the parent peptide to achieve
LAM (high), forming a less stable hydrogel at similar gelation compared to LAM peptides. Biocompatibility
concentrations. For optimal bioprinting applications, assessments revealed that these peptide hydrogels
a concentration of at least 4.0 mg/mL of LAM (high) is support cell proliferation similarly to Matrigel, with
recommended, with increased gel stability achieved at promising formulations identified for organoid culture.
6.0 mg/mL. To meet the mechanical requirements typical Specifically, FIB (low) and LAM (high) formulations
of colorectal organoid culture, we explored the lower were highlighted for their favorable effects on
concentration limits of these bioinks, highlighting the organoid morphology and gene expression, resembling
need for precise concentration control in bioprinting characteristics seen with Matrigel. Notably, organoids
applications. Evaluation of the printability of the cultured in FIB (low) exhibited polar arrangements and
bioinks at varying concentrations revealed improved gene expression profiles closer to natural colon tissue.
shape definition using FIB (low) at 6.0 mg/mL.
Additionally, the bioprinting of CRC cells demonstrated In exploring their bioprinting capabilities, we
morphological differences between colonies printed with determined optimal concentrations for achieving stable
FIB and LAM peptides. While FIB bioprinted structures 3D structures, emphasizing the importance of precise
exhibited more colonies with reduced lumen size and concentration control. FIB (low) demonstrated enhanced
increased polarization, LAM peptide structures have a shape fidelity at higher concentrations, whereas LAM
predominance of 2D-like colonies with smaller lumens (high) favored stable gelation at lower concentrations
and minimal polarization. suitable for bioprinting. Bioprinted structures of CRC
cells using these peptides revealed distinct morphological
Our findings indicate the successful fabrication and differences, suggesting their potential for modeling
characterization of various hydrogel formulations derived disease-specific phenotypes.
from biofunctional peptides and their use in bioprinting.
We systematically evaluated the effects of these matrices Overall, our study underscores the potential of
on viability, proliferation, organoid formation, and gene biofunctional peptides in enhancing USAPs for organoid

Volume 10 Issue 5 (2024) 358 doi: 10.36922/ijb.3033