Photopolymerized hydrogels, such as gelatin methacryloyl (GelMA), have desirable biological and mechanical characteristics for a range of tissue engineering applications.

Objective

This study aimed to optimize a new method to photopolymerize GelMA using a dental curing light (DL).

Methods

Lithium acylphosphinate photo-initiator (LAP, 0.05, 0.067, 0.1% w/v) was evaluated for its ability to polymerize GelMA hydrogel precursors (10% w/v) encapsulated with odontoblast-like cells (OD21). Different irradiances (1650, 2300 and 3700 mW/cm²) and photo-curing times (5–20 s) were tested, and compared against the parameters typically used in UV light photopolymerization (45 mW/cm², 0.1% w/v Irgacure 2959 as photoinitiator). Physical and mechanical properties of the photopolymerized GelMA hydrogels were determined. Cell viability was assessed using a live and dead assay kit.

Results

Comparing DL and UV polymerization methods, the DL method photopolymerized GelMA precursor faster and presented larger pore size than the UV polymerization method. The live and dead assay showed more than 80% of cells were viable when hydrogels were photopolymerized with the different DL irradiances. However, the cell viability decreased when the exposure time was increased to 20 s using the 1650 mW/cm² intensity, and when the LAP concentration was increased from 0.05 to 0.1%. Both DL and UV photocrosslinked hydrogels supported a high percentage of cell viability and enabled fabrication of micropatterns using a photolithography microfabrication technique.

Significance

The proposed method to photopolymerize GelMA cell-laden hydrogels using a dental curing light is effective and represents an important step towards the establishment of chair-side procedures in regenerative dentistry.

中文翻译：

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使用牙科光固化机再生含细胞明胶甲基丙烯酰基水凝胶的光聚合

光聚合水凝胶，例如明胶甲基丙烯酰基（GelMA），具有一系列组织工程应用所需的生物学和机械特性。

客观的

这项研究旨在优化一种使用牙科光固化机（DL）光聚合GelMA的新方法。

方法

评估了酰基次膦酸锂光引发剂（LAP，0.05，0.067，0.1％w / v）聚合成囊成牙本质细胞样细胞（OD21）的GelMA水凝胶前体（10％w / v）的能力。不同辐照度（1650，2300和3700毫瓦/厘米²）和光固化时间（5-20多个）进行了测试，并与对通常的UV光的光聚合（45毫瓦/平方厘米所用的参数²，0.1％w / v的Irgacure 2959作为光引发剂）。测定了光聚合的GelMA水凝胶的物理和机械性能。使用活和死分析试剂盒评估细胞活力。

结果

与DL和UV聚合方法相比，DL方法比UV聚合方法更快地光聚合了GelMA前体，并呈现出更大的孔径。生死分析表明，当水凝胶在不同的DL辐照度下进行光聚合时，超过80％的细胞是有活力的。但是，当使用1650 mW / cm ²强度将暴露时间增加至20 s ，并且当LAP浓度从0.05％增加至0.1％时，细胞活力降低。DL和UV光交联的水凝胶均支持高百分比的细胞活力，并能够使用光刻微细加工技术制造微细图案。

意义

所提出的使用牙科光固化剂来光聚合含GelMA细胞的水凝胶的方法是有效的，并且代表了在再生牙科领域建立椅旁程序的重要步骤。