Abstract

Peptide Inks: Bio-printing Self-Assembling Ultrashort Peptides to Build Nanofibrous Scaffolds for Regenerative Medicine Applications

Charlotte A E Hauser, Team Leader/Principal Research Scientist, Nanyang Technological University

Self-assembling peptides which are stimuli-responsive can serve as inks for bio-printing and building blocks for bio-scaffolds, enabling the development of high-throughput cell screening, and printing of organotypic biological constructs. We discovered a subclass of amphiphilic ultrashort peptides containing lysine or lysine-mimetic residues that demonstrate salt and pH-enhanced self-assembly into nanofibrous hydrogels. Consisting of only 3 to 7 aliphatic amino acids, their characteristic motif stimulates self-assembly into helical fibers which further aggregate into three-dimensional nanofibrous networks that entrap water. These peptides are intrinsically biocompatible and non-immunogenic, and are of interest as implantable scaffolds for tissue engineering. Tuning the gelation kinetics and mechanical properties, we developed formulations that gel instantaneously upon exposure to physiologically-relevant salt solutions. Exploiting their stimuli-responsiveness, we encapsulated various human primary and pluripotent stem cells to create three-dimensional cell-scaffold arrays. These constructs were stable for more than 21 days under standard culture conditions, enabling long term culture of cells. To influence cell behavior, genes, small molecules and growth factors can be co-encapsulated. The resulting biological constructs can be used as organoid models for screening small molecules, studying cell behavior and disease progression, as well as tissue-engineered implants for regenerative medicine. Authors: Yihua Loo, Charlotte A.E. Hauser