Biofunctionalized microfiber-assisted formation of intrinsic three-dimensional capillary-like structures.
OBJECTIVE
A vascular supply network is essential in engineered tissues >100-200-μm thickness. To control vascular network formation in vitro, we hypothesize that capillarization can be achieved locally by using fibers to position and guide vessel-forming endothelial cells within a three-dimensional (3D) matrix.


METHODS
Biofunctionalization of poly-(L-lactic acid) (PLLA) fibers was performed by amino-functionalization and covalent binding of RGD peptides. Human foreskin fibroblasts (HFFs) and human umbilical vein endothelial cells (HUVECs) were seeded on the fibers in a mould and subsequently embedded in fibrin gel. After 9-21 days of coculture, constructs were fixed and immunostained (PECAM-1). Capillary-like structures with lumen in the 3D fibrin matrix were verified and quantified using two-photon microscopy and image analysis software.


RESULTS
Capillary-like networks with lumen formed adjacent to the PLLA fibers. Increased cell numbers were observed to attach to RGD-functionalized fibers, resulting in enhanced formation of capillary-like structures. Cocultivation of HFFs sufficiently supported HUVECs in the formation of capillary-like structures, which persisted for at least 21 days of coculture.


CONCLUSIONS
The guidance of vessel growth within tissue-engineered constructs can be achieved using biofunctionalized PLLA microfibers. Further methods are warranted to perform specified spatial positioning of fibers within 3D formative scaffolds to enhance the applicability of the concept.
1 Department of Tissue Engineering and Textile Implants, AME-Helmholtz Institute for Biomedical Engineering, RWTH Aachen University , Aachen, Germany .
Stefan
S
Weinandy
Simone
S
Laffar
Ronald E
RE
Unger
Thomas C
TC
Flanagan
Robert
R
Loesel
C James
CJ
Kirkpatrick
Marc
M
van Zandvoort
Benita
B
Hermanns-Sachweh
Agnieszka
A
Dreier
Doris
D
Klee
Stefan
S
Jockenhoevel
D001672:Biocompatible Materials / Q000494:pharmacology*; D002196:Capillaries / Q000187:drug effects* / Q000254:growth & development*; D016923:Cell Death / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D018920:Coculture Techniques; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D019344:Lactic Acid / Q000494:pharmacology; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011091:Polyesters; D011108:Polymers / Q000494:pharmacology
D001672:Biocompatible Materials; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)