Development of zinc oxide/hydroxyapatite/poly(D,L-lactic acid) fibrous scaffold for tissue engineering applications

Tissue engineering is a branch of regenerative medicine, which comprises the combination of biomaterials, cells and other bioactive molecules to regenerate tissues. Biomaterial scaffolds act as substrate and as physical support for cells and they can also reproduce the extracellular matrix cues. Although tissue engineering applications in cellular therapy tend to focus on the use of specialized cells from particular tissues or stem cells, little attention has been paid to endothelial progenitors, an important cell type in tissue regeneration. We combined 3D printed poly(lactic acid) scaffolds comprising two different pore sizes with human adipose-derived stromal cells (hASCs) and expanded CD133+ cells to evaluate how these two cell types respond to the different architectures. hASCs represent an ideal source of cells for tissue engineering applications due to their low immunogenicity, paracrine activity and ability to differentiate. Expanded CD133+ cells were isolated from umbilical cord blood and represent a source of endothelial-like cells with angiogenic potential. Fluorescence microscopy and scanning electron microscopy showed that both cell types were able to adhere to the scaffolds and maintain their characteristic morphologies. The porous PLA scaffolds stimulated cell cycle progression of hASCs but led to an arrest in the G1 phase and reduced proliferation of expanded CD133+ cells. Also, while hASCs maintained their undifferentiated profile after 7 days of culture on the scaffolds, expanded CD133+ cells presented a reduction of the von Willebrand factor (vWF), which affected the cells’ angiogenic potential. We did not observe changes in cell behavior for any of the parameters analyzed between the scaffolds with different pore sizes, but the 3D environment created by the scaffolds had different effects on the cell types tested. Unlike the extensively used mesenchymal stem cell types, the 3D PLA scaffolds led to opposite behaviors of the expanded CD133+ cells in terms of cytotoxicity, proliferation and immunophenotype. The results obtained reinforce the importance of studying how different cell types respond to 3D culture systems when considering the scaffold approach for tissue engineering.

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Hierarchical starch-based fibrous scaffold for bone tissue engineering applications

Journal of Tissue Engineering and Regenerative Medicine ◽

10.1002/term.132 ◽

2009 ◽

Vol 3 (1) ◽

pp. 37-42 ◽

Cited By ~ 141

Author(s):

Albino Martins ◽

Sangwon Chung ◽

Adriano J. Pedro ◽

Rui A. Sousa ◽

Alexandra P. Marques ◽

...

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Engineering Applications ◽

Fibrous Scaffold

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Collagen-Inspired Nano-fibrous Poly(L-lactic acid) Scaffolds for Bone Tissue Engineering Created from Reverse Solid Freeform Fabrication

MRS Proceedings ◽

10.1557/proc-823-w11.13 ◽

2004 ◽

Vol 823 ◽

Cited By ~ 2

Author(s):

Victor J. Chen ◽

Laura A. Smith ◽

Peter X. Ma

Keyword(s):

Tissue Engineering ◽

Lactic Acid ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Computer Aided Design ◽

Type I Collagen ◽

Polymer Concentration ◽

Three Dimensional ◽

Type I ◽

Fibrous Scaffold

AbstractReverse solid freeform (SFF) fabrication was used to create highly-controlled macroporous structures in nano-fibrous poly (L-lactic acid) (PLLA) scaffolds. By using a computer-aided design (CAD) program to create a negative template for the scaffold, the three-dimensional (3-D) mold was created on a 3-D printer using a wax. After the template was printed, a solution of PLLA in tetrahydrofuran (THF) was cast into the mold, and was subsequently phase separated at -70°C which gives the nano-fibrous morphology. This resulted in a 3-D nano-fibrous scaffold with a uniform fiber mesh throughout the entire matrix, and greatly increased the surface area within the scaffold. Fiber diameters in these scaffolds were 50-500 nm, similar to type I collagen, and the densities of the fiber meshes can be altered by changing the polymer concentration. To examine the scaffold's potential for tissue regeneration, MC3T3-E1 osteoblasts were seeded and cultured on the scaffolds. Results show that the osteoblasts attached and proliferated on the scaffolds. After 6 weeks in culture, bone-like tissue was evident within the nano-fibrous scaffolds. By having the ability to control the macroporous architecture, interconnectivity, orientation, and external shape of the scaffold, as well as the nanometer-scaled fibrous features in the pore walls, this SFF fabrication/phase separation technique has great potential to design and create ideal scaffolds for bone tissue engineering.

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