Biomimetic thermoresponsive superstructures by colloidal soft-and-hard co-assembly

Figure 1. Microscale spine-mimicking structure, MicroSpine, has been created via colloidal assembly of soft and hard components, which can change shape by controlling temperature and can be utilised for cargo encapsulation and delivery

A research team led by Dr Yufeng WANG from the Department of Chemistry of The University of Hong Kong (HKU) have developed a new method to create microscale superstructures called MicroSpine that mimic the soft-hard structure of the human spine and can act as microactuators with shape-transforming properties.

The breakthrough was achieved through colloidal assembly, a process in which nano- and microparticles spontaneously organize into ordered spatial patterns. Dr Wang and his team invented new particles derived from metal-organic frameworks (MOFs) that combine with soft liquid droplets to form linear chains. The hard and soft components take alternating positions in the chain, mimicking the spine structure. The soft component of the chain can expand and shrink when MicroSpine is heated or cooled, so it can change shape reversibly. Using the system, the research team demonstrated various precise actuation modes when the soft parts of the chain are selectively modified. The chains have also been used for encapsulation and release of guest objects, solely controlled by temperature. The team believes this technology represents an important step towards creating complex microscale devices and machine.

According to Dr. WANG, 'If you think about modern machinery such as cars, they are assembled by tens of thousands of different parts. We aim to achieve the same level of complexity using different colloidal parts.'. The team hopes to design more biomimetic systems capable of performing complex tasks at the microscopic level and beyond.

Link of journal paper can be accessed from: https://www.science.org/doi/10.1126/sciadv.adh2250