AI 中文总结
研究提出IceCAPA技术，通过在图案化底物上定向冷冻颗粒或细菌悬浮液来进行图案化。该技术适用于多种材料，不受底物润湿性影响，图案化细菌细胞活力良好，还为冷冻过程提供见解，强调温度梯度重要性及与空气 - 水界面相互作用的类比。
AI 中文摘要
在表面精确图案化微米和纳米级物体的能力对多种应用很重要。例如，胶体图案化可用于制造等离子体表面、发光二极管或认证标记，微生物细胞图案化可用于单细胞水平筛选抗生素反应和细胞相互作用。然而，缺乏能在不同类型底物上图案化多种合成和生物物体的通用技术。本文提出一种基于在图案化底物上对颗粒或细菌悬浮液进行定向冷冻的稳健图案化技术。生长的冰将所需物体推到底物陷阱中，同时扫去未捕获的物体，留下高保真图案。该方法适用于多种不同材料，不受底物润湿性影响，且图案化细菌细胞组装后仍具良好活力。此外，研究结果还为涉及颗粒悬浮液冷冻的过程提供了见解，强调了温度梯度作为决定颗粒与冷冻前沿相互作用的关键控制因素的重要性，还指出颗粒与冷冻前沿和空气 - 水界面相互作用之间存在紧密类比。
英文摘要
The ability to precisely pattern micro- and nano-scale objects on surfaces is important for a range of different applications. For example, colloidal patterning has been used to create plasmonic surfaces, light-emitting diodes or authentication marks, while microbial cell patterning can be applied to screening antibiotic response and cellular interactions over larger populations at the single-cell level. However, we still lack versatile techniques that can pattern a wide range of synthetic and biological objects on a spectrum of different substrate types. Here, we present a robust patterning technique based on the directional freezing of a particle or bacterial suspension over a patterned substrate. Growing ice pushes the desired objects into traps in the substrate, while sweeping away non-trapped ones, leaving behind high-fidelity patterns. We show that this method works for a range of different materials (both synthetic particles and microbial cells), and is unaffected by substrate wettability. Furthermore, patterned bacterial cells retain excellent post-assembly viability, highlighting the gentle nature of the assembly technique. Beyond patterning applications, our results also give insights into processes involving the freezing of particulate suspensions. In particular, we demonstrate the importance of the temperature gradient as a key control which determines how particles interact with freezing fronts. Finally, we highlight a tight analogy between particles interacting with a freezing front and with air-water interfaces, suggesting that results from capillarity may shed light on freezing phenomena.
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