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The emergence of engineered living materials (ELMs) has led to the development of functional composites by combining living microorganisms with nonliving components, particularly hydrogels. Hydrogels, which mimic the extracellular matrix, support microbial growth by providing essential nutrients and promoting cell adhesion, making them ideal for ELM production. However, hydrogel-based materials often face challenges in three-dimensional printing due to poor structural integrity and limited printability, frequently requiring additional processes, precise control, and/or material modifications to enhance their printing performance. This study focuses on developing a microorganism-laden gelatin microgel and gelatin solution-based composite bioink for self-supported printing of ELMs, enhanced via microbial-induced calcium carbonate precipitation. Gelatin microgels are utilized as rheology modifiers, enabling the yield-stress fluid behavior of the bioink for improved printability and postprinting shape retention, while transglutaminase enzymatically cross-links printed structures completely, resulting in good printability. Furthermore, Sporosarcina pasteurii in the bioink enables calcium carbonate deposition during postprinting culturing, forming robust, biomineralized structures. Fabricated samples are found to have significant successful mineral deposition with over 50 wt% calcium carbonate content, and they exhibit compressive strengths of up to 1.4 MPa. This approach offers a cost-effective, energy-efficient method for creating high-strength, biocompatible biocomposites with potential applications such as bone tissue engineering, coral restoration, and sustainable building development.
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Influence of Microgel and Interstitial Matrix Compositions on Granular Hydrogel Composite Properties
Abstract Granular hydrogels are an emerging class of biomaterials formed by jamming hydrogel microparticles (i.e., microgels). These materials have many advantageous properties that can be tailored through microgel design and extent of packing. To enhance the range of properties, granular composites can be formed with a hydrogel interstitial matrix between the packed microgels, allowing for material flow and then stabilization after crosslinking. This approach allows for distinct compartments (i.e., microgels and interstitial space) with varied properties to engineer complex material behaviors. However, a thorough investigation of how the compositions and ratios of microgels and interstitial matrices influence material properties has not been performed. Herein, granular hydrogel composites are fabricated by combining fragmented hyaluronic acid (HA) microgels with interstitial matrices consisting of photocrosslinkable HA. Microgels of varying compressive moduli (10–70 kPa) are combined with interstitial matrices (0–30 vol.%) with compressive moduli varying from 2–120 kPa. Granular composite structure (confocal imaging), mechanics (local and bulk), flow behavior (rheology), and printability are thoroughly assessed. Lastly, variations in the interstitial matrix chemistry (covalent vs guest–host) and microgel degradability are investigated. Overall, this study describes the influence of granular composite composition on structure and mechanical properties of granular hydrogels towards informed designs for future applications.
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- Award ID(s):
- 1720530
- PAR ID:
- 10405386
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Science
- Volume:
- 10
- Issue:
- 10
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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