Work

Genetically Modifying the Protein Matrix of Macroscopic Living Materials to Control Their Structure and Rheological Properties

Year: 2024

Type: article

Abstract: The field of engineering living materials (ELMs) seeks to engineer cells to form macroscopic materials with tailorable structures and properties. While centimeter-scale ELMs can be grown from Caulobacter crescentus engineered to secrete a protein matrix, how the sequence of the protein matrix affects structural and rheological properties remains poorly understood. Here, we explore how changing the elastin-like polypeptide (ELP) length impacts ELM microstructure and viscoelastic behavior. We demonstrate that shortening ELP produces fibers almost 2x thicker than other variants, resulting in a stiffer material at rest. Interestingly, the mid-length ELP forms a complex structure with globules and multidirectional fibers with increased yield stress under flow conditions. Lengthening ELP creates thinner strands between cells with similar storage and loss moduli to the mid-length ELP. This study indicates that sequence-structure-property relationships in these ELMs are complex with few parallels to other biocomposite models. Furthermore, it highlights that fine-tuning genetic sequences can create significant differences in rheological properties, uncovering new design principles of ELMs.

Source: ACS Synthetic Biology

DOI: 10.1021/acssynbio.4c00336