Innovation and Technology

Dr Leung King-chi, Franco
Assistant Professor, Department of Applied Biology and Chemical Technology
Awardee of the Outstanding Young Alumni Award in Scholarly Achievement of PolyU Faculty of Science, 2023

Our research programmes are designed and oriented to harness the full intrinsic potential of synthetic organic chemistry for building new supramolecular structures, functions and hierarchical systems. Inspired by the beauty of nature’s structures and the sophistication of its functional processes, our major objective is to design novel supramolecular functional systems spanning various length-scales into stimuli-responsive functional soft materials, with a focus on the following two major areas:


(1) Supramolecular Robotic Systems
Movement is one of the vital features in living systems, allowing various functions related to survival and reproduction. Some naturally existing protein motors, e.g., myosin in muscle tissue, are employed to produce motility by amplifying collective molecular motions from the nanoscale up to macroscopic dimensions.

For instance, conversional hard robotic systems, produced from rigid structural materials, enable the conversion of energy into mechanical motions for animal-like functions. With such perspective, soft robotic systems are now considered as complementary counterparts to hard robotics, enabling the next generation of biocompatible and safe robotic systems.

To unlock the full functional potential of soft robotic systems, in addition to shape transformation and cargo transport, some crucial parameters and characteristics have to be considered: (1) the use of more dynamic and non-polymeric backbone materials; (2) the feasibility of preparation through facile and simple methods; (3) the capacity for systematic control of intrinsic structural parameters, which is unattainable with bulk polymeric materials; (4) the ability to create complex assembling systems, and (5) biocompatibility.

Since 2018, we have developed the first UV-light responsive hierarchical supramolecular soft robotic material, derived from molecular motor amphiphiles with precise control of molecular organization and cooperativity, allowing energy conversion, accumulation of strain, and amplification of the molecular rotation to macroscopic motions.

The nanofibers of motor amphiphiles were formed in an aqueous medium, and the macroscopic unidirectional alignment as prepared by using of a shear-flow method, was also identified. Furthermore, our supramolecular soft robotic materials offer the ability to adjust the orientational structural order through electrostatic interactions, providing precise control of actuation speed with UV-light irradiation.

In addition, as a proof of concept in complex soft robotic systems, we have successfully introduced the first soft robotic material controlled by UV-light and a magnet field to complete a cargo transport process. Recently, our soft robotic materials also demonstrated excellent biocompatibility with their mesenchymal stem cell structure. Looking forward, our major focus will be developing the advanced biocompatibility of the supramolecular robotic systems, such as substituting bio-damaging UV-light with visible-light.

(2) Controlled Supramolecular Transformations of Photoresponsive Molecular Amphiphiles

The research program is designed for the reversible control of supramolecular assembly transformations of photoresponsive amphiphiles in aqueous media, with the aim to construct new supramolecular soft materials both in solutions and at interfaces. These photoresponsive amphiphile designs encompass molecular motors, stiff stilbenes, DASAs, indigos, and more.

Using principles from supramolecular chemistry, which focuses on non-covalent intermolecular interactions, our team are able to fabricate novel supramolecular soft functional materials with what is described as the smallest machine in the world, “artificial molecular machinery”.

Besides, the team is also designing novel photoresponsive amphiphiles composed of photoresponsive molecular switching units, with oil-soluble and water-soluble motifs, providing these amphiphiles with intrinsic properties with their nanostructure.

超分子化學於仿生物料上的應用

梁敬池博士
應用生物及化學科技學系助理教授
2023 年傑出理大理學院青年校友學術成就得獎者

我們的研究充份運用了合成有機化學的潛力，建構出新的超分子結構、功能和分層系統。受大自然的奧妙和複雜運作原理所啓發，本研究的主要目標是設計出不同長度的新型超分子功能系統，並將其轉化成對刺激具反應的軟性功能物料，當中有兩項重點研究範圍：

(1) 超分子機械人系統
運動作爲生命系統的重要特徵之一，主宰著與生存和繁殖有關的各種功能。一些本身具有天然馬達的蛋白，如肌肉組織中的肌凝蛋白，能夠透過將分子運動從納米層面叠加起來提升至宏觀層面，來產生運動效果。

因此，一些由堅硬結構物料製成的轉換型硬體機械人系統，可以將能量轉換為機械運動，從而執行一些類似動物的功能。目前，軟體機械人系統一般都用作補助硬體機械人技術上的不足，並且用以幫助推動並發展新一代能夠與生物兼容且安全的機械人系統。

然而，軟體機械人系統的潛能能否完全發揮，除了在形狀轉換方面以及能否應用於貨物運輸外，還必須考慮一些重要參數。當中要考慮的是一些軟體機械人系統應具有的特點：（1）能否應用更具活力的非聚合骨幹物料；（2）能否通過簡單的方法製備；（3）系統能夠控制固有結構參數，而相比之下，大規模聚合物物料則無法達致相關效果；（4）能夠創造出複雜的組裝系統；（5）具有生物兼容性。

自2018 年以來，我們研發出首次面世的紫外綫反應分層超分子軟體機械人物料。這物料源自分子馬達兩親化合物，可精確控制分子的組織和合作效能，達致能量轉換、應變積累，以及能夠將分子旋轉增強為宏觀運動。

當中，馬達雙親化合物納米纖維是在水性介質中形成，並利用剪力流方式成功製作出以宏觀單向方式排列的納米纖維。此外，這種超分子軟體機械人物料還能夠透過靜電相互作用調整定向結構順序，在紫外綫照射下精確控制驅動速度。

為了驗證軟體機械人系統的複雜概念，我們首次利用了紫外綫和磁場來控制軟體機械人物料，並成功完成了一次貨物運輸流程。最近，我們更驗證了軟體機械人物料內的間質幹細胞結構具有良好的生物兼容性。展望未來，我們將集中資源為超分子機械人系統帶來更高階的生物兼容性，例如以可見光取代具破壞性的紫外線。

(2) 光敏分子雙親化合物的可控超分子轉化
此研究計劃的另一目的，是要在水介質中針對光敏雙親化合物的超分子組裝轉化進行可逆控制，從而在溶液和介面中建構出新型超分子軟體物料。這類型的光敏雙親化合物設計包括分子馬達、硬二苯乙烯、DASAs等等。

為此，我們的團隊利用了超分子化學原理（該原理側重於非共價分子間的相互作用），透過被稱為世界上最小的機器「人工分子機器」，製造出新型超分子軟性功能物料。

此外，研究團隊亦正在設計新型光致抗性雙親化合物，當中它以光敏開關分子作基礎、具備油溶性和水溶性式樣，並能為這些雙親化合物的納米結構帶來固有特性。