Background: Injectable hydrogels are a thermo-responsive system based on biomaterials. Injectable hydrogels have been broadly investigated mainly as vehicles or scaffolds of therapeutic agents that include drugs, proteins, cells, and bioactive molecules among others, utilized in the treatment of diseases such as cancers and the repair and regeneration of tissues.

Results: There are several studies that have described the multiple features of hydrogels. However, the main aspect that breaks the paradigm in the application of hydrogels is the thermoresponsiveness that some of them have, which is an abrupt modification in their properties in response to small variations in temperature. For that reason, the thermo-responsive hydrogels with the unique property of sol-gel transition have received special attention over the past decades. These hydrogels show phase transition near physiological human body temperature. This feature is key for being applied in promising areas of human health-related research.

Conclusion: The purpose of this study is the overview of injectable hydrogels and their latest advances in medical applications including bioactive compound delivery, tissue engineering, and regenerative medicine.

背景：可注射水凝胶是一种基于生物材料的热响应系统。广泛地研究了可注射水凝胶，其主要用作治疗剂的载体或支架，所述治疗剂包括药物，蛋白质，细胞和生物活性分子等，用于治疗疾病如癌症以及组织的修复和再生。

结果：有几项研究描述了水凝胶的多种特征。但是，打破水凝胶应用范式的主要方面是其中一些具有的热响应性，这是响应温度的微小变化对其性能的突然改变。因此，在过去的几十年中，具有溶胶-凝胶转变独特性质的热敏性水凝胶受到了特别的关注。这些水凝胶在人体生理温度附近显示出相变。此功能对于在与人类健康有关的研究的有希望的领域中应用至关重要。

结论：本研究的目的是概述可注射水凝胶及其在医疗应用中的最新进展，包括生物活性化合物的输送，组织工程和再生医学。