Keratins as a Sustainable Material for Biomedical Applications and Beyond

Guest Speaker：Prof. Ng Kee Woei，Nanyang Technological University，Singapore

Inviter: Prof. Qing Dai

Date&Time: Wednesday, 25 June, 10:00-11:30

Venue: Yiucheng Lecture Hall (500), Xu Zuyao Building

Biography:

Professor Ng Kee Woei is currently the Chair at the School of Materials Science and Engineering at NTU, Singapore. He holds the concurrent position of Technology Leader in Nanomaterials and Nanotoxicology at the Nanyang Environment and Water Research Institute (NEWRI). He was the Program Director of the NTU-Harvard School of Public Health Initiative on Sustainable Nanotechnology from 2016 to 2022. In addition, Professor Ng serves as a member of the Technical Committee on Nanotechnology within the Chemical Standards Committee commissioned by Enterprise Singapore and a Subject Expert in Nanotechnology, in the SingHealth Institutional Biosafety Committee. Professor Ng’s research is highly interdisciplinary and translational in nature, spanning across disciplines including food & agriculture, biomaterials and nanotechnology. In the area of sustainability, he is interested in developing novel approaches of valorising wastes to produce novel biomaterials and bioplastics.

Abstract:

The demand for sustainable biomaterials is expected to intensify. Nature derived biomaterials are not new and have been widely discussed in the literature. Keratins are a more recent example and are one of the very few human-derived materials that are readily accessible in abundance. Other than human hair, animal keratins are also easily obtained from farming waste streams such as feathers and wool. Keratins are unique because they contain high proportions of functional groups, especially thiols, to support chemical interactions. Together with their inherent propensity to self-assemble into organized structures, keratins have been demonstrated to be easily processable into a variety of physical formats. These keratin formats have been found to be biocompatible and capable of inducing positive cell responses to support the regeneration of different tissues.

Our group has developed a cryogelation technique which allowed 3D keratin-based hydrogels with tunable physical properties and microarchitectures to be produced. Strain-stiffening behavior can also be induced by crosslinking keratins and dopamine through a similar cryogelation process. We further made use of thiolate interaction with cations to provide the possibility of a rapid gelling system for bioink development. This cationic induced gelation method allowed the production of a gradient hydrogel through a single-step fabrication process. By using silver ions as the cationic crosslinker, a gradient hydrogel that releases silver ions as an antimicrobial agent, as the gel degrades, is produced. More recently, we adopted the technique of Interfacial Polyelectrolyte Complexation (IPC) to produce keratin-based fibers. Keratins were partnered together or with established polycations such as chitosan and drawn to produce micrometer-sized fibers. These fibers exhibited good mechanical properties that were comparable to commercial suture materials. An in vivo study found these fibers to function well as a suture for closing full-thickness cutaneous wounds in mice, resulting in minimal host tissue response over a 3-week period. Our work has demonstrated that keratin-based templates are versatile, functional and could provide meaningful outcomes in tissue engineering applications.