The endothelial glycocalyx is a carbohydrate–rich layer overlying the outermost surface of endothelial cells. It mediates intercellular interactions by specific chemical compositions (e.g., proteoglycans containing glycosaminoglycan (GAG) side chains) and micro/nanotopography. Inspired by the endothelial glycocalyx, we fabricated a series of glycocalyx–mimetic surfaces with tunable chemical compositions (GAG–like polymers with different functional units) and topographical structures (micro/nanopatterns with pillars different in size). The combination of micro/nanopatterns and GAG–like polymers was flexibly and precisely controlled by replica molding using silicon templates (Si templates) and visible light–initiated polymerization. Human umbilical vein endothelial cells (HUVECs) and human umbilical vein smooth muscle cells (HUVSMCs) were suppressed on surfaces modified with polymers of 2–methacrylamido glucopyranose (MAG) but promoted on surfaces modified with polymers of sodium 4–vinyl–benzenesulfonate (SS) and copolymers of SS and MAG. Surface micro/nanopatterns showed highly complicated effects on surfaces grafted with different GAG–like polymers. Moreover, the spread of HUVSMCs was highly promoted on all flat/patterned surfaces containing sulfonate units, and the elongation effect was stronger on surfaces with smaller pillars. On all the flat/patterned surfaces modified with GAG–like polymers, the adsorption of human vascular endothelial growth factor (VEGF) and human basic fibroblast growth factor (bFGF) was improved, and the amount of VEGF and bFGF absorbed on patterned surfaces containing sulfonate units decreased with pattern dimensions. The decreasing trend of VEGF and bFGF adsorption was in accordance with HUVEC density, suggesting that glycocalyx–mimetic surfaces influence the adsorption of VEGF and bFGF and further influence the growth behavior of vascular cells.
Min Wu,Yitao Zhao,Meihan Tao,Meimei Fu,Yue Wang,Qi Liu,Zhihui Lu,Jinshan Guo
The latest advancements in cellular bioenergetics have revealed the potential of transferring chemical energy to biological energy for therapeutic applications. Despite efforts, a three-dimensional (3D) scaffold that can induce long-term bioenergetic effects and facilitate tissue regeneration remains a big challenge. Herein, the cellular energetic metabolism promotion ability of l-malate, an important intermediate of the tricarboxylic acid (TCA) cycle, was proved, and a series of bioenergetic porous scaffolds were fabricated by synthesizing poly(diol l-malate) (PDoM) prepolymers via a facial one-pot polycondensation of l-malic acid and aliphatic diols, followed by scaffold fabrication and thermal-cross-linking. The degradation products of the developed PDoM scaffolds can regulate the metabolic microenvironment by entering mitochondria and participating in the TCA cycle to elevate intracellular adenosine triphosphate (ATP) levels, thus promoting the cellular biosynthesis, including the production of collagen type I (Col1a1), fibronectin 1 (Fn1), and actin alpha 2 (Acta2/α-Sma). The porous PDoM scaffold was demonstrated to support the growth of the cocultured mesenchymal stem cells (MSCs) and promote their secretion of bioactive molecules [such as vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and basic fibroblast growth factor (bFGF)], and this stem cells-laden scaffold architecture was proved to accelerate wound healing in a critical full-thickness skin defect model on rats.