Rice University researchers have made a groundbreaking advancement in the field of engineered living materials (ELMs), revealing intricate sequence-structure-property relationships that allow for enhanced customization of these materials. This innovative research was undertaken to address the limitations previously faced in controlling the structure and mechanical responses of ELMs under various forces such as stretching and compression. As the study demonstrates, the ability to tailor these properties represents a significant leap toward more functional and adaptive living materials.
The core of the study centers around protein matrices, which play a crucial role in shaping the structural integrity of ELMs. By integrating small genetic modifications, the research team has shown that it is possible to significantly influence the behavior of these materials. In detailing their findings, the researchers believe this progress could revolutionize several applications, particularly tissue engineering, drug delivery, and even the 3D printing of living devices, which promise to offer new frontiers in biomedical technologies.
Caroline Ajo-Franklin, a professor of biosciences at Rice University and the leading author of the study, eloquently encapsulated their findings, stating, “We are engineering cells to create customizable materials with unique properties.” Ajo-Franklin emphasized how synthetic biology has provided a toolkit of techniques to manipulate material properties, yet the explicit connections among genetic sequences, structural arrangements, and material behaviors had not been fully explored prior to this study. This assertion underlines the crucial exploration of foundational principles governing living materials.
The research team’s experimentation involved a bacterium known as Caulobacter crescentus, which had previously been engineered to produce a specific protein termed BUD (which stands for “bottom-up de novo”). This protein facilitates cell adhesion, enabling bacteria to aggregate into a supportive matrix. By employing this engineered approach, the researchers were able to cultivate centimeter-sized structures known as BUD-ELMs that serve as the foundation for their investigations into customizable materials.
In their exploration, the researchers varied the lengths of elastin-like polypeptides (ELPs)—segments of proteins found within these matrices—resulting in the creation of various new materials. They studied three distinct variants: BUD40, BUD60, and BUD80. Each variant presented a unique set of properties correlating to its specific structural characteristics. For instance, the BUD40 variant was noted for its short ELPs, leading to the production of thicker, stiffer fibers. In contrast, BUD60, with mid-length ELPs, exhibited synergistic properties, showcasing a combination of fibers and globules, which together allowed it to withstand oscillation stress more effectively.
The third variant, BUD80, had the longest ELPs compared to its counterparts. This composition produced thinner fibers but unfortunately resulted in a less durable material prone to breaking under deformation stress. These varying structural modifications illuminated the profound impact of genetic modifications on material properties, revealing that even subtle changes can yield significant differences in performance.
Furthermore, advanced imaging techniques and mechanical evaluations highlighted that these variations were not merely cosmetic. They fundamentally influenced how each material responded to external stress and the way they flowed under pressure. Remarkably, BUD60 surfaced as the most adaptable of the three, capable of enduring more force and adjusting to environmental changes with ease. These characteristics render it particularly suitable for applications involving 3D printing or controlled drug delivery systems.
It is noteworthy that all three material variants shared two essential characteristics: their shear-thinning behavior, which refers to a decrease in viscosity under stress, and their remarkable capacity to retain water—approximately 93% of their total weight. These qualities further enhance their utility in biomedical applications, including functional scaffolds that support cell proliferation in tissue engineering and drug delivery systems designed to release medications in a controlled manner.
The implications of this study extend well beyond the biomedical realm. The self-assembling nature of these engineered living materials opens avenues for innovative applications in environmental remediation and green energy solutions. For instance, they could be adapted to form biodegradable structures or leveraged to harness natural processes for energy generation, highlighting their advanced multifunctionality.
Graduate student Esther Jimenez, who served as the first author of the study, encapsulated the significance of their findings, stating, “This study is one of the first to focus on building living materials from the ground up with tailored mechanical properties rather than just adding biological functions.” Her insights reinforce the research’s importance in transitioning towards a deeper understanding of how minute changes in protein sequences can lead to breakthroughs in material design.
Moreover, senior author Carlson Nguyen articulated the importance of identifying specific genetic modifications and their effects on material properties. “This work emphasizes the importance of understanding sequence-structure-property relationships,” Nguyen noted, as they aim to lay a solid groundwork for the future of living materials designed to meet specific engineering needs.
The rigorous exploration and conclusions drawn from this research signify a pivotal moment in the ongoing dialog within synthetic biology. By elucidating the connections between genetic engineering, material design, and physical performance, these findings pave the way for the next generation of living materials, which hold promise not only in healthcare but also in diverse environmental and technological sectors.
This exploration of engineered living materials is supported by funding from various esteemed institutions, including the National Science Foundation Graduate Research Fellowship, the Cancer Prevention and Research Institute of Texas, and the Welch Foundation. These collaborations highlight the relevance and urgency of innovative research in this field, propelling it to the forefront of scientific inquiry.
As researchers continue to expand their understanding of the interplay between genetic engineering and material science, the potential applications seem limitless. From enhancing traditional medical practices to designing environmentally friendly solutions with self-sustaining capabilities, the horizon of engineered living materials is ripe with possibilities, making this an exciting time for enthusiasts of science and innovation.
Ultimately, this research not only pushes the boundaries of current technology but also fosters a greater appreciation for the complexity of living materials and their interactions with biological systems. The journey toward mastering engineered living materials may very well signify a new era in bioengineering, wherein the marriage of biology and engineering opens new doors to unexplored territories in science.
Subject of Research: Engineered Living Materials and Customization Through Genetic Engineering
Article Title: Genetically Modifying the Protein Matrix of Macroscopic Living Materials to Control Their Structure and Rheological Properties
News Publication Date: 27-Nov-2024
Web References: ACS Synthetic Biology
References: DOI 10.1021/acssynbio.4c00336
Image Credits: Credit: Rice University
Keywords: Synthetic biology, tissue engineering, protein structure, genetic engineering, scaffold proteins.
