Engineering poly(hydroxy butyrate-co-hydroxy valerate) based vascular scaffolds to mimic native artery

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Native arteries possess complex multi-layered structures with specific fiber alignments.
• Developing synthetic vascular grafts that mimic native artery architecture is crucial for cardiovascular disease treatment.
• Incorporating growth factors like Vascular Endothelial Growth Factor (VEGF) and Platelet Factor Concentrate (PFC) can enhance vascular regeneration.

Purpose of the Study:

• To design and fabricate a tri-layered electrospun fibrous scaffold that mimics the architecture of native arteries.
• To incorporate VEGF and PFC into the scaffold to promote vascular healing and regeneration.
• To evaluate the mechanical properties, blood compatibility, and cellular interactions of the developed scaffold.

Main Methods:

• Fabrication of a tri-layered scaffold using electrospinning with poly(hydroxy butyrate-co-hydroxy valerate) (PHBV) and poly(vinyl alcohol) (PVA) nanofibers.
• Incorporation of VEGF and PFC into different layers with varying fiber alignments (longitudinal, radial, random).
• Characterization using Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy, tensile testing, burst strength, compliance, and stiffness index measurements.
• In vitro biocompatibility assessment using human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs), and mesenchymal stem cells (MSCs), including cell infiltration and protein expression analysis.

Main Results:

• The tri-layered scaffold exhibited distinct longitudinal and radial fiber alignments, mimicking native artery structure.
• Mechanical properties (tensile strength, compliance, stiffness) were comparable to native small blood vessels.
• The scaffold demonstrated excellent blood compatibility, with minimal hemolysis and no platelet activation.
• Controlled release of VEGF and PFC was observed.
• HUVECs and SMCs showed good alignment and maintained specific protein expression (CD31, VE-Cadherin, αSMA) when cultured on the scaffold.

Conclusions:

• The bi-directional fiber alignment in the tri-layered electrospun scaffold is critical for mimicking native artery architecture.
• The scaffold is a promising prototype for vascular tissue engineering due to its mechanical properties, biocompatibility, and ability to support cell function.
• This approach offers a potential solution for developing advanced vascular grafts for treating cardiovascular diseases.