School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
Department of Chemistry, Royal College of Surgeons in Ireland, Dublin, Ireland.
Small. 2021 Feb;17(5):e2004452. doi: 10.1002/smll.202004452. Epub 2020 Dec 28.
Multifunctional nanocomposites that exhibit well-defined physical properties and encode spatiotemporally controlled responses are emerging as components for advanced responsive systems, for example, in soft robotics or drug delivery. Here an example of such a system, based on simple magnetic hydrogels composed of iron oxide magnetic nanoflowers and Pluronic F127 that generates heat upon alternating magnetic field irradiation is described. Rules for heat-induction in bulk hydrogels and the heat-dependence on particle concentration, gel volume, and gel exposed surface area are established, and the dependence on external environmental conditions in "closed" as compared to "open" (cell culture) system, with controllable heat jumps, of ∆T 0-12°C, achieved within ≤10 min and maintained described. Furthermore the use of extrusion-based 3D printing for manipulating the spatial distribution of heat in well-defined printed features with spatial resolution <150 µm, sufficiently fine to be of relevance to tissue engineering, is presented. Finally, localized heat induction in printed magnetic hydrogels is demonstrated through spatiotemporally-controlled release of molecules (in this case the dye methylene blue). The study establishes hitherto unobserved control over combined spatial and temporal induction of heat, the applications of which in developing responsive scaffold remodeling and cargo release for applications in regenerative medicine are discussed.
多功能纳米复合材料具有明确的物理性质，并能编码时空控制的响应，它们正在成为先进响应系统的组成部分，例如在软机器人或药物输送中。本文介绍了一种基于简单的磁性水凝胶的系统，该水凝胶由氧化铁磁性纳米花和 Pluronic F127 组成，在交变磁场辐射下会产生热量。建立了在体水凝胶中诱导加热的规则以及加热对颗粒浓度、凝胶体积和凝胶暴露表面积的依赖性，并比较了“封闭”（细胞培养）系统和“开放”系统（细胞培养）中对外界环境条件的依赖性，在 10 分钟内实现了可控的热跃变，达到了 0-12°C 的 ∆T，保持不变。此外，还提出了使用基于挤出的 3D 打印来操纵具有 150µm 以下空间分辨率的明确打印特征中热量的空间分布，空间分辨率足够精细，与组织工程相关。最后，通过时空控制的分子（在这种情况下是染料亚甲蓝）释放，证明了打印磁性水凝胶中的局部加热诱导。该研究确立了对热的时空综合诱导的前所未有的控制，讨论了其在开发用于再生医学的响应性支架重塑和货物释放中的应用。
