Cytocompatible shape memory polymers activated by thermal or photothermal triggers have been developed and established as powerful "smart material" platforms for both basic and translational research. Shape memory polymers (SMPs) that could be triggered directly by biological activity have not, in contrast, been reported. The goal of this study was to develop an SMP that responds directly to enzymatic activity and can do so under isothermal cell culture conditions. To achieve this goal, we designed an SMP with a shape fixing component, poly(ε-caprolactone) (PCL), that is vulnerable to enzymatic degradation and a shape memory component, Pellethane, that is enzymatically stable - as the shape fixing component undergoes enzymatically-catalyzed degradation, the SMP returns to its original, programmed shape. We quantitatively and qualitatively analyzed material properties, shape memory performance, and cytocompatibility of the enzymatically-catalyzed shape memory response. The results demonstrate enzymatic recovery, as contraction of tensile specimens, using bulk enzymatic degradation experiments and show that shape recovery is achieved by degradation of the PCL shape-fixing phase. The results further showed that both the materials and the process of enzymatic shape recovery are cytocompatible. Thus, the SMP design reported here represents both an enzyme responsive material capable of applying a programmed shape change or direct mechanical force and an SMP that could respond directly to biological activity. STATEMENT OF SIGNIFICANCE: Cytocompatible shape memory polymers activated by thermal or photothermal triggers have become powerful "smart material" platforms for basic and translational research. Shape memory polymers that could be triggered directly by biological activity have not, in contrast, been reported. Here we report an enzymatically triggered shape memory polymer that changes its shape isothermally in response to enzymatic activity. We successfully demonstrate enzymatic recovery using bulk enzymatic degradation experiments and show that shape recovery is achieved by degradation of the shape-fixing phase. We further show that both the materials and the process of enzymatic shape recovery are cytocompatible. This new shape memory polymer design can be anticipated to enable new applications in basic and applied materials science as a stimulus responsive material.

中文翻译：

---

酶促触发的形状记忆聚合物。

通过热或光热触发器激活的细胞相容性形状记忆聚合物已经被开发并建立为功能强大的“智能材料”平台，可用于基础研究和转化研究。相比之下，尚未报道可能由生物活性直接触发的形状记忆聚合物（SMP）。这项研究的目的是开发一种SMP，它可以直接对酶活性产生反应，并且可以在等温细胞培养条件下进行。为了实现此目标，我们设计了一种SMP，其形状固定组分聚（ε-己内酯）（PCL）易受酶降解，而形状记忆组分Pellethane具有酶稳定性，因为形状固定组分经过酶催化降解后，SMP恢复到其原始的程序化形状。我们定量和定性地分析了材料特性，形状记忆性能和酶催化形状记忆反应的细胞相容性。结果表明，使用批量酶降解实验可恢复拉伸样品的酶活性，并且可通过PCL形状固定相的降解实现形状恢复。结果进一步表明，材料和酶促形状恢复过程均具有细胞相容性。因此，此处报道的SMP设计既代表能够施加程序化形状变化或直接施加机械力的酶响应材料，也代表可以直接响应生物活性的SMP。意义声明：通过热触发或光热触发激活的细胞相容性形状记忆聚合物已经变得功能强大。相比之下，尚未报道可能由生物活性直接引发的形状记忆聚合物。在这里，我们报告了一种酶促触发的形状记忆聚合物，可响应酶活性等温地改变其形状。我们成功地证明了使用批量酶降解实验的酶恢复，并显示了通过形状固定相的降解实现了形状恢复。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。相比之下，尚未报道可能由生物活性直接引发的形状记忆聚合物。在这里，我们报告了一种酶促触发的形状记忆聚合物，可响应酶活性等温地改变其形状。我们成功地证明了使用批量酶降解实验的酶恢复，并显示了通过形状固定相的降解实现了形状恢复。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。在这里，我们报告了一种酶促触发的形状记忆聚合物，可响应酶活性等温地改变其形状。我们成功地证明了使用批量酶降解实验的酶恢复，并显示了通过形状固定相的降解实现了形状恢复。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。在这里，我们报告了一种酶促触发的形状记忆聚合物，可响应酶活性等温地改变其形状。我们成功地证明了使用批量酶降解实验的酶恢复，并显示了通过形状固定相的降解实现了形状恢复。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。我们进一步表明，材料和酶促形状恢复过程均具有细胞相容性。可以预期，这种新的形状记忆聚合物设计将在基础和应用材料科学中作为刺激响应材料实现新的应用。