Engineering aligned electrospun PLLA microfibers with nano-porous surface nanotopography for modulating the responses of vascular smooth muscle cells

Abstract

In tissue engineering research, aligned electrospun ultrafine fibers have been shown to regulate cellular alignment and relevant functional expression, but the imposed effect of individual fiber surface nanotopography on cell behaviour has not been examined closely. This work investigates the impact of superimposing a nano-pore feature atop individual fiber surfaces on the responsive behaviour of human vascular smooth muscle cells (vSMCs) for blood vessel tissue engineering. Well-aligned ultrafine poly(L-lactic acid) (PLLA) microfibers with an average fiber diameter of ca. 1.6 mm were fabricated by using a novel stable jet electrospinning (SJES) method. Ellipse-shaped nano-pores with varied aspect ratios (defined as longto-short axis ratio) of 2.7-3.9, corresponding to a surface nano-roughness in the range of 54.8-110.0 nm, were in situ generated onto individual fiber surfaces by varying ambient humidity from 45% to 75% during the SJES process. The presence of elliptical nano-pores on fiber surfaces affected the characteristic anisotropic wettability of the aligned PLLA fibers and contributed to greater protein adsorption (up to 17.59 mg mg À1 ). A 7 day in vitro assessment of human umbilical arterial SMCs cultured on these aligned nano-porous fiber substrates indicated that cellular responses were in close correlation with the elliptical nano-pore feature. A pronounced fiber surface nanotopography was superior in soliciting favorable cellular responses, leading to enhanced cell attachment, proliferation, alignment, expression of the vascular matrix proteins and maintenance of a contractile phenotype. This study thus suggests that introduction of an elliptical nano-pore feature to the aligned microfiber surfaces could provide additional dimensionality of topographical cues to modulate the vSMC responses when using the aligned electrospun ultrafine fibers for engineering vascular constructs.

Enhanced Anti-corrosion Ability and Biocompatibility of PLGA Coatings on MgZnYNd Alloy by BTSE-APTES Pre-treatment for Cardiovascular Stent

“…Besides, the direct PLGA-coated samples (MgZnYNd-P) showed acceptable smooth surface with a few polishing grooves. It has been reported that corrosion behavior of polymer coated Mg-based materials and cell behavior on it could be affected by film morphologies (porous or dense structure) [34][35][36] , while the smooth coating of MgZnYNd-B-A-P in the present study could well fit the anti-corrosive and biocompatible requirements. Moreover, for the cross-section of MgZnYNd-B-A-P, an obvious double layer could be distinguished ( Fig.…”

Griffithsin-Modified Electrospun Fibers as a Delivery Scaffold To Prevent HIV Infection

“…To minimize GRFT adsorption to the fiber prior to use, the number of washes could be increased postreaction (currently, 3 are conducted) or the fiber could be presoaked to eliminate surface-adsorbed GRFT. Furthermore, while factors such as surface roughness and fiber diameter can contribute to protein adsorption (97,98), with these factors being constant, the role of surface chemistry often plays a significant role in protein adsorption. To this end, many groups have employed surface modification strategies to alter the surface properties of EFs to reduce protein adsorption.…”

Winner of the Young Investigator Award of the Society for Biomaterials (USA) for 2016, 10th World Biomaterials Congress, May 17–22, 2016, Montreal QC, Canada: Aligned microribbon‐like hydrogels for guiding three‐dimensional smooth muscle tissue regeneration

“…Furthermore, densely packed cell sheets poses a great challenge for cell survival due to lack of diffusion, and lacks porosity, that is, desirable for cell infiltration, proliferation, and new matrix deposition. An alternative strategy for achieving cell alignment utilizes aligned electrospun fiber meshes composed of biodegradable polymers such as poly(lactic‐ co ‐glycolic acid) and poly(ε‐caprolactone) . Since electrospinning process is not cell friendly, cells can only be seeded after the scaffold fabrication.…”

“…Since electrospinning process is not cell friendly, cells can only be seeded after the scaffold fabrication. While electrospun fiber meshes provide a 3D scaffold with aligned cues, cell penetration is challenging due to the nanoporosity, and cell infiltration is typically limited to within ∼ 100 s of µm from the scaffold surface with inhomogeneous cell distribution . As such, there remains a critical need to develop novel strategies that would support cell alignment in 3D.…”