The biomedical industry has witnessed a transformative evolution with the advent of 3D printing technology. However, inherent limitations, such as the inability to produce dynamic human tissues due to the absence of the temporal dimension, have persisted, resulting in static and inanimate printed products. To address this challenge and enable the creation of dynamic and living constructs, the concept of 4D printing has emerged, marking a paradigm shift in additive manufacturing. In 4D printing, time becomes the fourth dimension, breathing life into previously static creations. This review paper explores the journey from 3D to 4D printing and the pivotal role of time in the additive manufacturing process. Specifically, it highlights the integration of time-dependent responsive materials, focusing on stimuli-responsive hydrogels, as a cornerstone in 4D printing advancements. These materials exhibit a remarkable ability to adapt and respond to various stimuli, encompassing physical, chemical, and biological signals. The review delves into recent publications on the synergy between these stimuli and responsive materials, shedding light on their intricate interactions and potential applications. One of the primary areas of interest lies in medical applications, notably tissue engineering, where 4D printing holds immense promise. The paper explores the utilization of 4D printing in creating biomimetic scaffolds that can dynamically adapt to complex tissue environments. Furthermore, the review discusses the technical considerations and prospects of 4D printing technology, emphasizing its potential to revolutionize the biomedical landscape. The amalgamation of 4D printing and stimuli-responsive materials opens new avenues for personalized medicine, localized drug delivery, and regenerative therapies, bridging the gap between static 3D printing and the dynamic requirements of modern healthcare. The present review offers a complete examination of the evolution, challenges, and prospects of 4D printing in biomedical applications, paving the way for transformative innovations in the field.

中文翻译：

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用于局部药物递送和组织工程的物理刺激响应水凝胶的 4D 打印


随着 3D 打印技术的出现，生物医学行业见证了变革性的发展。然而，固有的局限性，例如由于缺乏时间维度而无法产生动态的人体组织，一直存在，导致了静态和无生命的印刷品。为了应对这一挑战并能够创建动态和有生命的结构，4D 打印的概念应运而生，标志着增材制造的范式转变。在 4D 打印中，时间成为第四维度，为以前静态的创作注入活力。这篇评论论文探讨了从 3D 到 4D 打印的旅程以及时间在增材制造过程中的关键作用。具体来说，它强调了时间依赖性响应材料的整合，重点是刺激响应水凝胶，作为 4D 打印进步的基石。这些材料表现出适应和响应各种刺激的非凡能力，包括物理、化学和生物信号。该综述深入研究了最近关于这些刺激和响应材料之间协同作用的出版物，阐明了它们错综复杂的相互作用和潜在应用。人们感兴趣的主要领域之一是医疗应用，尤其是组织工程，4D 打印在这方面具有巨大的前景。本文探讨了 4D 打印在创建可以动态适应复杂组织环境的仿生支架中的应用。此外，该综述讨论了 4D 打印技术的技术考虑因素和前景，强调了其彻底改变生物医学领域的潜力。 4D 打印和刺激响应材料的融合为个性化医疗、局部药物输送和再生疗法开辟了新的途径，弥合了静态 3D 打印与现代医疗保健的动态需求之间的差距。本综述全面研究了 4D 打印在生物医学应用中的演变、挑战和前景，为该领域的变革性创新铺平了道路。