Department of Mechanical Engineering, Tsinghua University.
Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing.
Biomed Mater. 2022 Jun 6;17(4). doi: 10.1088/1748-605X/ac6b04.
Hydrogels, three-dimensional (3D) networks of hydrophilic polymers formed in water, are a significant type of soft matter used in fundamental and applied sciences. Hydrogels are of particular interest for biomedical applications, owing to their soft elasticity and good biocompatibility. However, the high water content and soft nature of hydrogels often make it difficult to process them into desirable solid forms. The development of 3D printing (3DP) technologies has provided opportunities for the manufacturing of hydrogels, by adopting a freeform fabrication method. Owing to its high printing speed and resolution, vat photopolymerization 3DP has recently attracted considerable interest for hydrogel fabrication, with digital light processing (DLP) becoming a widespread representative technique. Whilst acknowledging that other types of vat photopolymerization 3DP have also been applied for this purpose, we here only focus on DLP and its derivatives. In this review, we first comprehensively outline the most recent advances in both materials and fabrication, including the adaptation of novel hydrogel systems and advances in processing (e.g. volumetric printing and multimaterial integration). Secondly, we summarize the applications of hydrogel DLP, including regenerative medicine, functional microdevices, and soft robotics. To the best of our knowledge, this is the first time that either of these specific review focuses has been adopted in the literature. More importantly, we discuss the major challenges associated with hydrogel DLP and provide our perspectives on future trends. To summarize, this review aims to aid and inspire other researchers investigatng DLP, photocurable hydrogels, and the research fields related to them.
水凝胶是由亲水性聚合物在水中形成的三维（3D）网络，是基础科学和应用科学中使用的重要软物质类型。由于其柔软的弹性和良好的生物相容性，水凝胶在生物医学应用中特别感兴趣。然而，水凝胶的高含水量和柔软性质通常使其难以加工成理想的固体形式。3D 打印（3DP）技术的发展为水凝胶的制造提供了机会，采用自由成型的制造方法。由于其高打印速度和分辨率，光聚合 3DP 最近因其在水凝胶制造方面的吸引力而受到相当大的关注，其中数字光处理（DLP）成为一种广泛使用的代表性技术。虽然承认其他类型的光聚合 3DP 也已被用于此目的，但我们这里仅关注 DLP 及其衍生物。在这篇综述中，我们首先全面概述了材料和制造方面的最新进展，包括新型水凝胶系统的适应和加工方面的进展（例如体积打印和多材料集成）。其次，我们总结了水凝胶 DLP 的应用，包括再生医学、功能微器件和软机器人。据我们所知，这是文献中首次采用这两种特定综述焦点之一。更重要的是，我们讨论了与水凝胶 DLP 相关的主要挑战，并对未来的趋势提出了看法。总之，本综述旨在帮助和启发其他研究人员研究 DLP、光固化水凝胶以及与之相关的研究领域。
