Towards Vascularized Tissue blocks Using a
Suspension Bioprinted Blood Vessel
Vasileios D. Trikalitis
1
*, Fabian Stein1*, Julia Perea Paizal1, Nasim Salehi-Nik1 and Jeroen Rouwkema1.
1
Department of Biomechanical Engineering, Faculty of Engineering Technology, University of Twente,
7500 AE Enschede, The Netherlands.
Presenting Author’s Email: v.trikalitis@utwente.nl *Authors contributed equally to this work.
VEGF
VEGF
This work is supported by an ERC Consolidator Grant under grant agreement no 724469. The samples of Alginate microparticles was generously provided by IamFluidics.
The Challenge
Results
Acknowledgements
Future Direction
Our Approach
Artificial tissue constructs are being developed in order to address the need for organ transplants and accurate dis-ease models. The current artificial tissue construct up-scaling has been hindered by the lack of controlled vas-cularization. Without vasculature, the tissue constructs cannot receive nutrients essential for their survival, but also lack the stimuli that determine the tissue’s biophysi-cal properties i.e. cell fate determination, cell to cell junc-tions, and cell orientation. Contemporary biofabrication methods, have not yet managed to combine the high res-olution necessary (<20μm for the fine features of the cap-illary vessels) with the ability to intervene to the construct at different time points, in order to mimic the natural pro-cess of angiogenesis.
Liquid-like hydrogel suspensions have offered the ability to print structurally complex designs which do not need support structures. We focus on the effect of the interstitial space between the microparticles forming the embedding bath, as well as the interaction of spheroids with the material comprising the hydrogel suspension. a)Approach illustration b) spheroid compaction over time c) Size distribution of achieved microgel suspensions and indicative pictures.d) Bright-field microscopy images of the particles comprising the embedding baths.
Cell composition of a vessel
Vascular endothelial growth factor(VEGF)
expression from hypoxia
Patterning from fluid shear stress
Endothelial
Cells Muscle cellsSmooth Perivascular adipose tissue cells a) Spheroid ink embedded bioprinting
Perfusion chamber
c) Embedding bath size distribution d) Brightfield image of embedding bath particles Spheroids in proximity fuse
Spheroid cell composition variation b) Spheroid size distribution
MSCs HUVEC/SMC 1:1
Different embedding bath materials mitigate a different response from the spheroids
Inert allows attachment allows penetration
0 50 100 150 200 250
Al Ag Ag-Coll Coll GelMa
Fe re t di am et er (µ m )
Embedding Bath Materials
Embedding Bath Par�cle Size Agarose Collagen Agarose-Collagen Alginate GelMA
Agarose Before Suspension
MSC Spheroids
1:1 SMC/HUVEC
Alginate Agarose-Collagen Collagen GelMA
Printing Trials Confocal 3D reconstruction
of Co-culture spheroid Zoom in on the sprouting area Sprouting after print
For suspension printing:
<F>
particle<
<F>
spheroidS MC s pher oi d co mpac tion
time [d ] m ea n sp he ro id d ia m et e r [ µ m ] 1 2 3 4 5 6 7 0 2 0 4 0 6 0 8 0 1 00 1 20 1 40 1 60 1 80 2 00
M SC s pher oi d co mpac tion
time [d ] m ea n sp he ro id d ia m et e r [ µ m ] 1 2 3 4 5 6 7 0 2 0 4 0 6 0 8 0 1 00 1 20 1 40 1 60 1 80 2 00 SMC spheroid compaction MSC spheroid compaction Time (d) Time (d) mean diameter (μm) mean diameter (μm)
Red: α-Actin Antibody (alpha-SM1)
Blue: 4′,6-diamidino-2-phenylindole (DAPI)
Green: Von Willebrand Factor antibody (ab6994)
Staining agents used for 1:1 SMC/HUVEC spheroids
Blue: 4′,6-diamidino-2-phenylindole (DAPI)
Green: Alexa Fluor 488 Phalloidin
Staining agents used for MSC spheroids:
Our next goal is to optimize the printing process of spheroids within the embedding baths, and place different spheroid types in proximity in order to observe their interaction and fusion with the purpose to form the tunica intima and tunica media thus mimicking accurattely the natural tissue architecture. Finally we will perfuse the artificial blood vessel in order to modulate the angiogenic sprouting.
**** **** **** **** ** * **** ~118μm ~65μm
