Thiol-Ene Photo-Click Collagen-PEG Hydrogels: Impact of Water-Soluble Photoinitiators on Cell Viability, Gelation Kinetics and Rheological Properties
Thiol-Ene Photo-Click Collagen-PEG Hydrogels: Impact of Water-Soluble Photoinitiators on Cell Viability, Gelation Kinetics and Rheological Properties
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DOI：
10.3390/polym9060226
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发表时间：
2017-06-01
期刊：
影响因子：
5
通讯作者：
Tronci, Giuseppe
中科院分区：
文献类型：
--
作者：
Holmes, Roisin;Yang, Xuebin B.;Tronci, Giuseppe
利用巯基功能化的i型胶原蛋白和8臂聚乙二醇降冰片烯末端（PEG-NB）通过分步生长聚合制备了巯基光点击水凝胶，作为一种潜在的可注射再生装置。i型胶原通过与2-亚氨基硫烷（2IT）开环反应进行巯基功能化，通过2,4,6-三硝基苯磺酸（TNBS）比色法和圆二色性（CD）记录了高达80 Abs. %的功能化和90 RPN%的三螺旋保存。改变类型，即2-羟基-1-[4-（2-羟基乙氧基）苯基]-2-甲基-1-丙烷酮（I2959）或苯基锂-2,4,6-三甲基苯甲酰膦酸盐（LAP）和光引发剂的浓度，以确保最小的光引发剂诱导的细胞毒性，并使胶原- peg混合物能够形成巯基网络。G292细胞在添加光引发剂的培养基中培养24 h后的活力受到光引发剂浓度的很大影响，与添加lap的培养基（细胞存活率：86 -> 8 Abs. %）相比，添加I2959的培养基诱导的毒性反应更高（0.1 -> 0.5% (w/v) I2959，细胞存活率：62 -> 2 Abs. %）。与体外实验一致，选用一定浓度的光引发剂制备巯基键合水凝胶。凝胶动力学被证明在很大程度上受到特定光引发剂的影响，与含有i2959的混合物（tau: 1683 s）相比，含有lap的硫醇烯混合物导致完全凝胶时间（tau: 187 s）显著缩短。除了特定的光引发剂外，光引发剂浓度是调节水凝胶储存模量（G‘）的关键，在0.5% （w/v）的LAP制备的样品中，与0.1% （w/v）的LAP相比，G’增加了15倍（232 -> 3360 Pa）。进一步测试了含有0.5% (w/v) LAP和不同含量PEG-NB的硫烯配方，以制备具有多孔结构、可调存储模量（G′：540-4810 Pa）、凝胶时间（tau: 73-300 s）和膨胀比（SR: 1530-2840 wt %）的光点击水凝胶。本研究建立的光引发剂-凝胶-细胞毒性关系将有助于设计用于再生医学的正交胶原基壁龛。
Thiol-ene photo-click hydrogels were prepared via step-growth polymerisation using thiol-functionalised type-I collagen and 8-arm poly(ethylene glycol) norbornene-terminated (PEG-NB), as a potential injectable regenerative device. Type-I collagen was thiol-functionalised by a ring opening reaction with 2-iminothiolane (2IT), whereby up to 80 Abs. % functionalisation and 90 RPN% triple helical preservation were recorded via 2,4,6-Trinitrobenzenesulfonic acid (TNBS) colorimetric assay and circular dichroism (CD). Type, i.e., either 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (I2959) or lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), and concentration of photoinitiator were varied to ensure minimal photoinitiator-induced cytotoxicity and to enable thiol-ene network formation of collagen-PEG mixtures. The viability of G292 cells following 24 h culture in photoinitiator-supplemented media was largely affected by the photoinitiator concentration, with I2959-supplemented media observed to induce higher toxic response (0.1 -> 0.5% (w/v) I2959, cell survival: 62 -> 2 Abs. %) compared to LAP-supplemented media (cell survival: 86 -> 8 Abs. %). In line with the in vitro study, selected photoinitiator concentrations were used to prepare thiol-ene photo-click hydrogels. Gelation kinetics proved to be largely affected by the specific photoinitiator, with LAP-containing thiol-ene mixtures leading to significantly reduced complete gelation time (tau : 187 s) with respect to I2959-containing mixtures (tau : 1683 s). Other than the specific photoinitiator, the photoinitiator concentration was key to adjusting the hydrogel storage modulus (G'), whereby 15-fold G' increase (232 -> 3360 Pa) was observed in samples prepared with 0.5% (w/v) compared to 0.1% (w/v) LAP. Further thiol-ene formulations with 0.5% (w/v) LAP and varied content of PEG-NB were tested to prepare photo-click hydrogels with porous architecture, as well as tunable storage modulus (G': 540-4810 Pa), gelation time (tau : 73-300 s) and swelling ratio (SR: 1530-2840 wt %). The photoinitiator-gelation-cytotoxicity relationships established in this study will be instrumental to the design of orthogonal collagen-based niches for regenerative medicine.