Abstract:

Enzymes that play an essential role in life activities as biocatalysts have been reported to exhibit enhanced diffusion during the bioconversion of substrate to product. This self-driven diffusion-enhanced phenomenon provides a new angle to study enzymes: enzyme molecular motors (EMMs). Inspired by natural biomolecular motors, EMM was used as the “engine” to fabricate various enzyme-powered micro-/nanomotors (EMNMs) and micropumps (EMPs), converting chemical energy to mechanical energy and propelling movement at the micro-/nanoscale. Through ingenious design, EMNMs have been functionalized for accomplishing various tasks, attracting more and more attention. However, the precise movement mechanisms of EMM and EMNM are still under debate in current literature. The effects of size, structure, and enzyme properties on the micro-/nanoscale movement are still unclear. These limit the investigation of the application of EMNM and EMP. This article is devoted to reviewing the self-propelled molecular movement of EMM, as well as the movement of EMNM and EMP using an enzyme as the “engine”. First, the condition for realizing the molecular and micro-/nanoscale movement in the ultralow Reynolds number regime, the self-propulsion and chemotaxis of EMM, and the movement mechanism of the reported EMM were introduced. Then, the classification of the various EMNM and EMP are discussed, emphasizing the approach of enzyme-powered microscale movement and the potential application of EMNM. Finally, major challenges in the development of enzyme-powered devices are addressed and future research into this crucial field is proposed.

Key words: enzyme, biocatalysis, nanotechnology, self-propulsion, chemotaxis

摘要：

在生命活动中扮演重要角色的生物催化剂酶，被发现在催化底物转化的过程中能表现分子水平的扩散增强行为。这种自驱动的扩散增强现象提供了一个研究酶的新角度：酶分子马达(EMM)。受到天然生物分子马达的启发，EMM被用作“引擎”开发出了一系列的酶驱动微纳马达和微泵，将催化过程中的化学能转化为动能，驱动微纳尺度的运动。通过巧妙的设计，酶驱动微纳设备可以实现功能化、完成各种任务，引起了广泛的关注。然而，EMM和酶驱动微纳设备的运动机理尚处于争论之中，酶驱动设备尺寸、结构、酶的性质对运动性能的影响也尚未明晰，制约着EMM和微纳设备的研究和应用。因此，本文综述EMM的自驱动运动以及作为“引擎”驱动的微纳马达和微泵。首先，简述低Reynolds数环境中实现微观自驱动运动的条件，阐述酶分子的自驱动和趋化行为，归类EMM运动机理；其次，归纳酶驱动微纳马达和微泵，重点评述酶分子作为“引擎”驱动人工合成微纳马达的实现途径及其潜在应用；最后，总结酶分子自驱动及其驱动微纳尺度运动存在的主要挑战，并提出进一步研究的重点方向。

关键词: 酶, 生物催化, 纳米技术, 自驱动, 趋化性