Supplementary MaterialsAs a service to our authors and readers, this journal provides supporting information supplied by the authors. photolabile em o /em \nitrobenzyl 1346574-57-9 derivatives to the hydrogel backbone, because such linkers can be cleaved by means of one\ and two\photon absorption. Herein we describe a cytocompatible click\based hydrogel containing em o /em \nitrobenzyl ester linkages between a hyaluronic acid backbone, which is photodegradable in the presence of cells. It is demonstrated for the first time that by using a cyclic benzylidene ketone\based small molecule as photosensitizer the efficiency of the two\photon 1346574-57-9 degradation process can be improved significantly. Biocompatibility of both the improved two\photon micropatterning process as well as the hydrogel itself is confirmed by cell culture studies. strong class=”kwd-title” Keywords: biomaterials, hyaluronic acid, hydrogels, photochemistry, sensitizers Hydrogels, crosslinked highly hydrated polymer networks with engineerable properties, are utilized in various strategies for tissue executive presently, regenerative medication, and cell delivery, because they enable mimicking the physicochemical properties from the indigenous extracellular matrix (ECM) of smooth biological cells.1 Since mammalian cells in?vivo are surrounded with a organic three\dimensional (3D) environment that’s remodeled as time passes, dynamically tunable biomaterials which permit the user to change the cell surrounding matrix at consumer\defined area and period are highly relevant for study about cell and cells physiology.2 A emerging lately, highly elaborated course of such dynamically tunable hydrogels contains photolabile functional organizations, which enable user\directed true\period control of the biomaterial’s chemical substance and mechanical properties at positions appealing by irradiation with cytocompatible dosages of light.3 Such photoresponsive hydrogels possess undergone a significant evolution lately from hydrogels containing photolabile organizations on the photostable backbone for led three\dimensional cell growth and migration,4 over hydrogels having a photodegradable backbone enabling postgelation 1346574-57-9 control of the physiochemical polymer properties,5 to a hydrogel matrix that allows photoreversible spatiotemporal immobilization of protein,6 to say just a few milestones of the fast development. The photodegradability of such biomaterials is most commonly enabled by the integration of em o /em \nitrobenzyl (oNB) ester derivatives, which beyond that have been utilized in several other dynamically light triggered materials.7 Alternatively, photocleavable hydrogels based on coumarin\derivatives or ruthenium\complexes have been reported.8 In general, photo\degradable hydrogels can be photo\eroded either by the use of UV/Vis light or upon two\photon excitation.9 While the use of UV/Vis light allows for the generation of 2D patterns by applying traditional photolithographic techniques involving masked light,5 two\photon excitation permits the generation of complex 3D patterns by the use of pulsed NIR laser light.10 As oNB derivatives typically exhibit relatively low two\photon absorption cross sections ( em /em a) and uncaging 1346574-57-9 action cross sections ( em /em u= em /em a? em Q /em u2, with em Q /em u2 being the quantum efficiency for uncaging by two\photon excitation) both in the sub\GM range,11 relatively high laser intensities and long irradiation times are required for photoscission, parameters at which living cells are prone to be damaged.12 Moreover, since the laser power required for two\photon absorption based processes increases with the square root of increasing scanning speed, designing more efficient two\photon active compounds and processes is a current key challenge in the advancement of high performance multiphoton lithography.13 There have been several optimization efforts to promote the efficiency of the oNB photocleavage reaction by varying the number and pattern of substituents on the benzyl group9c, 11a,11c, 14 or by including oNB derivatives into \conjugated molecular systems to particularly enhance u.11a,11c, 15 Alternatively, \conjugated compounds have been covalently linked to photocleavable oNB or 7\nitroindolinyl derivatives in order to sensitize the photoscission reaction by a F?rster resonance energy transfer (FRET) process.16 Nevertheless, chemical Rabbit polyclonal to PAI-3 modifications of this 1346574-57-9 kind are labor intensive and usually involve multistep synthesis, whereas certain photolabile oNB based macromer precursors which are known to be cytocompatible are commercially available.17 Moreover, the sensitivity of such permanently modified hydrogel systems towards two\photon excitation is an intrinsic property of the respective precursors that cannot be controlled nor adjusted independently..