Visible light photoinitiation of mesenchymal stem cell-laden bioresponsive hydrogels

Abstract

Biological activity can be added to synthetic scaffolds by incorporating functional peptide sequences that provide enzyme-mediated degradation sites, facilitate cellular adhesion or stimulate signaling pathways. Poly(ethylene glycol) diacrylate is a popular synthetic base for tissue engineering scaffolds because it creates a hydrophilic environment that can be chemically manipulated to add this biological functionality. Furthermore, the acrylate groups allow for encapsulation of cells using photopolymerization under physiological conditions. One complication with the addition of these peptides is that aromatic amino acids absorb light at 285nm and compete with the ultraviolet (UV)-sensitive photoinitiators such as Irgacure TM 2959 (I2959), the most commonly used initiator for cytocompatible photoencapsulation of cells into synthetic scaffolds. In this study we defi ne non-toxic conditions for photoencapsulation of human mesenchymal stem cells (hMSC) in PEGDA scaffolds using a visible light photoinitiator system composed of eosin Y, triethanolamine and 1-vinyl-2-pyrrolidinone. This visible light photoinitiator produced hydrogel scaffolds with an increased viability of encapsulated hMSCs and a more tightly crosslinked network in one-third the time of UV polymerization with I2959.

The design of pH-sensitive chitosan-based formulations for gastrointestinal delivery

“…Another approach to eliminate the toxicity of cross-linkers is the utilization of photo-cross-linking in formulation construction with considerable advantages such as ease of formation, high formation speed and low cost [51]. Zhang et al prepared carboxymethyl chitosan-graft-poly(N-isopropyl acrylamide)-glycidyl Poly(g-glutamic acid) Chitosan Amine Para -acetaminophen…”

Microfabrication of Photo-Cross-Linked Hyaluronan Hydrogels by Single- and Two-Photon Tyramine Oxidation

“…Short and intense irradiation (30% laser power, 15.95 mW at sample, with 600 Hz scanning rate and 8 scans) induced the formation of higher di-tyramine fluorescence that would shrink within minutes. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Photo-polymerization of HA-Tyr Previously, HA-Tyr was crosslinked enzymatically in the presence of horseradish peroxidase and hydrogen peroxide (H 2 O 2 ).…”

“…[11][12][13] Here, photo-crosslinkable, biodegradable, HATyr hydrogels are introduced allowing temporal and micrometer-scale control of fabrication with single-photon lithography. Visible light has been described for crosslinking of modified polyethylene glycol (PEG) [14][15][16] and hyaluronic acid 17 with eosin Y (EO) as photo-initiators. However, the use of cytotoxic coinitiator e.g.…”

Photo-irradiation paradigm: Mapping a remarkable facile technique used for advanced drug, gene and cell delivery

“…So some investigators evaluated their biological damage through cytotoxicity studies on selected cell lines, with the aim of investigating the extent of toxicity and cytocompatible dose for each PI (Table 1) [57][58][59][60][61]. Therefore the ultimate selection or preference of any PIS is principally based upon the reported assemblage with the highest cytcompatibility in the literature e.g Irgacure 2959 [58].…”

“…Also, it cannot be overlooked here that some delivery carriers can be photo-formulated without using a PI, instead they depend on long time exposure of the photo-responsive molecules to the light energy. Such as the formulation using inulin-methacrylic anhydride [15] and A C C E P T E D M A N U S C R I P T [60].…”