Macroporous nanofibrous vascular scaffold with improved biodegradability and smooth muscle cells infiltration prepared by dual phase separation technique

Abstract

IntroductionThe fast degradation of vascular graft and the infiltration of smooth muscle cells (SMCs) into the vascular graft are considered to be critical for the regeneration of functional neo-vessels. In our previous study, a novel dual phase separation technique was developed to one-pot prepare macroporous nanofibrous poly(L-lactic acid) (PLLA)/poly(ε-caprolactone) (PCL) vascular scaffold by phase separating the immiscible polymer blend. However, the slow degradation of PLLA/PCL limited cell infiltration. Herein, we hypothesized that poly(lactic-co-glycolic acid) (PLGA) would be miscible with PLLA but immiscible with PCL. Then, PLGA can be introduced into the PLLA/PCL blend to fabricate macroporous nanofibrous scaffold with improved biodegradability by using dual phase separation technique.Materials and methodsThe miscibility of PLGA with PLLA and PCL was evaluated. Then, the PLLA/PLGA/PCL scaffold was prepared by dual phase separation technique. The prepared scaffolds were characterized in terms of the morphology, in vitro degradation, mechanical properties, and cells’ infiltration and viability for human vascular SMCs (HVSMCs). Finally, platelet-derived growth factor-BB (PDGF-BB) was immobilized on the scaffold and its effect on the bioactivity of HVSMCs was studied.ResultsPLGA is miscible with PLLA but immiscible with PCL as hypothesized. The addition of PLGA enlarged the pore size and improved the biodegradability of composite scaffold. Notably, PLLA/PLGA/PCL scaffold with the blend ratio of 30:40:30 possessed improved pore interconnectivity for cells’ infiltration and enough mechanical properties. Moreover, HVSMCs could grow and infiltrate into this scaffold, and surface modification with PDGF-BB on the nanofibrous scaffold enhanced HVSMCs migration and proliferation.ConclusionThis study provides a strategy to expand dual phase separation technique into utilizing ternary even multinary polymer blend to fabricate macroporous nanofibrous scaffold with improved physicochemical properties. The prepared PLLA/PLGA/PCL scaffold would be promising for the regeneration of functional tunica media in vascular tissue engineering.

Hypoxia-preconditioned adipose-derived stem cells combined with scaffold promote urethral reconstruction by upregulation of angiogenesis and glycolysis

“…In our previous study, we fabricated a porous bilayered nanofibrous scaffold using a PLLA/PCL/PLGA blend. This heterogeneous, porous, bilayered, nanofibrous graft closely mimics the microstructure of the extracellular matrix (ECM) and has two sides: the inner surface with a small pore size can prevent the infiltration of urine to internal cells or transplanted cells, and it can also facilitate the confluence of urethral epithelial cells on the lumen; the outer surface with a larger pore size provides adequate space for the infiltration and regeneration of blood vessel cells and smooth muscle cells [ 24 – 26 ].…”

Vascular Tissue Engineering: Polymers and Methodologies for Small Caliber Vascular Grafts

“…The mechanical tests showed sufficient mechanical properties, such elastic modulus (6.22 ± 1.89 MPa) and compressive modulus (0.98 ± 0.19 MPa), with enough strength to withstand external forces. However, the suture strength of the scaffold (0.27 ± 0.02 N) was less than that of human mammary artery (1.40 ± 0.01 N) and human saphenous vein (1.81 ± 0.02 N) ( 72 ). Lyophilization can also be associated with electrospinning in order to obtain a structure with adequate pores size ( 40 ).…”

Tissue engineering stent model with long fiber-reinforced thermoplastic technique

“…Thus, the gradually decomposed polymers influence the pH value to a lower extent. Likewise, common polyester (degradable polymer) and PVA generate acid ingredients after decomposing, and the solution appears to be slightly acidic accordingly [30]. As for the decomposition process in 1 month, three types of tissue engineering stents demonstrate differences after PBS immersion (Fig.…”