Migration of endothelial cells into photo-responsive hydrogels with tunable modulus under the presence of pro-inflammatory macrophages

Abstract

Cell migration in three-dimensional environment is extremely important for tissue regeneration and other biological processes. In this work, a model system was developed to study how endothelial cells (ECs) migrate into photo-responsive hydrogels under the presence of pro-inflammatory macrophages. The hydrogel was synthesized from hyaluronic acid grafted with coumarin and methacrylate moieties by both carbon–carbon covalent linking and coumarin dimerization under UV irradiation at 365 nm. The structure of the hydrogel was conveniently modulated by UV irradiation at 254 nm to decompose the coumarin dimers, leading to the significant decrease of modulus and increase of swelling ratio and mesh size. Under the presence of M1 macrophages, ECs were induced to migrate into the hydrogels with a different degree. A significant larger net displacement of ECs was found in the softer hydrogel obtained by irradiation with UV at 254 nm than in the stiffer original one at day 7.

Bio-sourced monomers and cationic photopolymerization–The green combination towards eco-friendly and non-toxic materials

“…The advantage of this photocrosslinking system is initiator-free so that the formation of photoreaction by-products is minimized. These systems are mainly applied for biological applications, particularly as drug delivery systems, for the synthesis of hydrogels for migration of vascular endothelial cells [445][446][447].…”

In vitro immunomodulation of magnesium on monocytic cell toward anti-inflammatory macrophages

“…At one end of the spectrum, there is the ‘classically activated’ pro-inflammatory macrophages (M1) and at the other end ‘alternatively activated’ anti-inflammatory macrophages (M2) state [ 7 , 11–13 ]. M1 phenotype has typical surface markers CD86 and CCR7, produces interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) cytokines and enhances T helper 1 cell-mediated inflammation [ 14 ], while M2 phenotype has the typical surface markers CD206 and CD163, secretes IL-10 and transforming growth factor-β cytokines, enhances T helper 2 cell-mediated inflammation, relieves inflammation and improves tissue repair and regeneration [ 7 ].…”

Simple Technique for Microscopic Evaluation of Active Cellular Invasion into 3D Hydrogel Constructs

“…To address this limitation, some experiments utilize fluorescently labeled cells and subsequently image via confocal microscopy. 24 Migration depth can be determined by stacking images and measuring z-axis focal distance. This technique is also limited by the requirement of transferring the chamber insert from the sterile culture environment for imaging as well as the required use of fixatives and staining.…”

“…At each time point the hydrogel and uninvaded cells can be swabbed from the chamber, the trans-well membrane removed, and the migrated cells on the bottom of the membrane can be stained or counted . This technique been successfully applied to assess the invasiveness of certain cell types, the increased motility of cells in response to different ligand inclusions, , and cell migration responses to matrix mechanical strength . This approach is an absolute assessment of migration and will only show the number cells that have migrated through the hydrogel; active cell migration or cells that have adhered to the internal hydrogel matrix are removed with the hydrogel in order to stain the well-insert membrane.…”

“…To address this limitation, some experiments utilize fluorescently labeled cells and subsequently image via confocal microscopy . Migration depth can be determined by stacking images and measuring z -axis focal distance.…”