bims-enlima 2025-01-05 papers

bims-enlima

Biomed News

on Engineered living materials

Issue of 2025–01–05
24 papers selected by
Rahul Kumar, Tallinna Tehnikaülikool

Engineering synthetic phosphorylation signaling networks in human cells.
Genetically Encoded Fluorogenic DNA Aptamers for Imaging Metabolite in Living Cells.
Living plastics from plasticizer-assisted thermal molding of silk protein.
Patterning Functional Proteins in Ultrabithorax-Based Materials.
Programming scheduled self-assembly of circadian materials.
Microgel-Guided MXene Assembly for High-Performance, Low-Solid Content Conductive Inks.
A Low-Cost, Open-Source 3D Printer for Multimaterial and High-Throughput Direct Ink Writing of Soft and Living Materials.
3D Bioprinting of Graphene Oxide-Incorporated Hydrogels for Neural Tissue Regeneration.
The use of hydrogel microspheres as cell and drug delivery carriers for bone, cartilage, and soft tissue regeneration.
Surface-functionalized bacteria: Frontier explorations in next-generation live biotherapeutics.
Tunable Bicontinuous Macroporous Cell Culture Scaffolds via Kinetically Controlled Phase Separation.
Structurally Transformable and Reconfigurable Hydrogel-Based Mechanical Metamaterials and Their Application in Biomedical Stents.
Engineering immunity using metabolically active polymeric nanoparticles.
Engineering biology and automation-Replicability as a design principle.
Printing rare-earth-free (REF) magnetic inks: synthesis, formulation, and device applications.
Degradation bottlenecks and resource competition in transiently and stably engineered mammalian cells.
Hemostasis Strategies and Recent Advances in Hydrogels for Managing Uncontrolled Hemorrhage.
Molecularly Designed and Nanoconfined Polymer Electronic Materials for Skin-like Electronics.
In Situ Gelling Silk Fibroin/ECM Hydrogel With Sustained Oxygen Release for Neural Tissue Engineering Applications.
Supercharging engineering biology with automation.
Advancements in GelMA bioactive hydrogels: Strategies for infection control and bone tissue regeneration.
Ultra-stretchable, self-recoverable, notch-insensitive, self-healable and adhesive hydrogel enabled by synergetic hydrogen and dipole-dipole crosslinking.
Genetically encoded biosensors for the circular plastics bioeconomy.
Coating of Threads with Fluorescent Curli Fibers for pH Sensing.

Science. 2025 Jan 03. 387(6729): 74-81

Engineering synthetic phosphorylation signaling networks in human cells.

Xiaoyu Yang, Jason W Rocks, Kaiyi Jiang, Andrew J Walters, Kshitij Rai, Jing Liu, Jason Nguyen, Scott D Olson, Pankaj Mehta, James J Collins, Nichole M Daringer, Caleb J Bashor.

Protein phosphorylation signaling networks have a central role in how cells sense and respond to their environment. We engineered artificial phosphorylation networks in which reversible enzymatic phosphorylation cycles were assembled from modular protein domain parts and wired together to create synthetic phosphorylation circuits in human cells. Our design scheme enabled model-guided tuning of circuit function and the ability to make diverse network connections; synthetic phosphorylation circuits can be coupled to upstream cell surface receptors to enable fast-timescale sensing of extracellular ligands, and downstream connections can regulate gene expression. We engineered cell-based cytokine controllers that dynamically sense and suppress activated T cells. Our work introduces a generalizable approach that allows the design of signaling circuits that enable user-defined sense-and-respond function for diverse biosensing and therapeutic applications.

DOI: https://doi.org/10.1126/science.adm8485
J Am Chem Soc. 2024 Dec 31.

Genetically Encoded Fluorogenic DNA Aptamers for Imaging Metabolite in Living Cells.

Yuting Wu, Wentao Kong, Jacqueline Van Stappen, Linggen Kong, Zhimei Huang, Zhenglin Yang, Yu-An Kuo, Yuan-I Chen, Yujie He, Hsin-Chih Yeh, Ting Lu, Yi Lu.

Genetically encoded fluorescent protein and fluorogenic RNA sensors are indispensable tools for imaging biomolecules in cells. To expand the toolboxes and improve the generalizability and stability of this type of sensor, we report herein a genetically encoded fluorogenic DNA aptamer (GEFDA) sensor by linking a fluorogenic DNA aptamer for dimethylindole red with an ATP aptamer. The design enhances red fluorescence by 4-fold at 650 nm in the presence of ATP. Additionally, upon dimerization, it improves the signal-to-noise ratio by 2-3 folds. We further integrated the design into a plasmid to create a GEFDA sensor for sensing ATP in live bacterial and mammalian cells. This work expanded genetically encoded sensors by employing fluorogenic DNA aptamers, which offer enhanced stability over fluorogenic proteins and RNAs, providing a novel tool for real-time monitoring of an even broader range of small molecular metabolites in biological systems.

DOI: https://doi.org/10.1021/jacs.4c09855
Nat Commun. 2025 Jan 02. 16(1): 52

Living plastics from plasticizer-assisted thermal molding of silk protein.

Yushu Wang, Junqi Wu, Emily J Hartzell, Weiguo Hu, Reddhy Mahle, Xinxin Li, Ying Chen, Jugal Kishore Sahoo, Cameron Chan, Brooke N Longo, Charlotte S Jacobus, Chunmei Li, David L Kaplan.

The pursuit of materials, particularly plastics, with a minimal ecological footprint throughout their circular lifecycle, is crucial for advancing sustainable materials development. Living materials composed of embedded yet active organisms can leverage endogenous biotic resources to achieve functional materials that align with sustainability goals. However, current living material systems face challenges such as weak mechanical properties, limited environmental adaptability, and restricted cellular functionality. In this study, we propose an approach to sustainable living materials by incorporating active organisms into silk-based plastics through a plasticizer-assisted thermal molding process. We investigate the mechanism of structure formation in these materials, correlating manufacturing performance to the resulting secondary structure. These silk-based plastics provide a protective matrix for probiotics, ensuring their survival through the harsh gastrointestinal tract and enhancing intestinal delivery. Similarly, soil rhizobacteria encapsulated within the plastics exhibit long-term protease activity, accelerating plastic degradation upon soil exposure. This work demonstrates the potential of sustainable plastics as a form of living materials, where active organisms are processed, entrapped, retain metabolic functions, and are protected in harsh environments.

DOI: https://doi.org/10.1038/s41467-024-55097-x
Methods Mol Biol. 2025 ;2889 245-256

Patterning Functional Proteins in Ultrabithorax-Based Materials.

Britt Faulk, Amanda Jons, Brandon Look Fong, Maximillian Lara, Andrew R Irion, Sarah E Bondos.

  The ability to add bioactivities, such as cell signaling or ligand recognition, to biomaterials has generated the potential to include multiple bioactivities into a single material. In some cases, it is desirable to localize these activities to different areas of the biomaterial, creating functional patterns. While photolithography and 3D printing have been effective techniques for patterning functions in many materials, patterning remains a challenge in materials composed of protein, in part due to how these materials are artificially assembled. Protein fibers are often produced from protein films that co-acervate at the air-water interface. This chapter describes methods to leverage this coacervation process to pattern materials, using the Drosophila melanogaster Hox protein Ultrabithorax (Ubx) as a model self-assembling protein. Through gene fusion, Ubx and a functional protein are produced as a single polypeptide, capable of both forming materials and performing the activity of interest. This functionality is retained in the final materials. In this chapter, we describe how to use multiple Ubx fusion proteins to not only imbue the final materials with multiple functions, but also to create macroscale patterns of the appended proteins in fibrous protein-based materials. These patterned materials include striped fibers, bifunctional-faced fibers, gradient fibers, and core-shell fibers.

Keywords:  Biomaterials; Fibers; Functionalization; Gradient; Hox transcription factor; Pattern; Protein; Protein-based materials; Stripe

DOI:  https://doi.org/10.1007/978-1-0716-4322-8_17
Nat Commun. 2025 Jan 02. 16(1): 176

Programming scheduled self-assembly of circadian materials.

Gregor Leech, Lauren Melcher, Michelle Chiu, Maya Nugent, Shirlaine Juliano, Lily Burton, Janet Kang, Soo Ji Kim, Sourav Roy, Leila Farhadi, Jennifer L Ross, Moumita Das, Michael J Rust, Rae M Robertson-Anderson.

Active biological molecules present a powerful, yet largely untapped, opportunity to impart autonomous regulation of materials. Because these systems can function robustly to regulate when and where chemical reactions occur, they have the ability to bring complex, life-like behavior to synthetic materials. Here, we achieve this design feat by using functionalized circadian clock proteins, KaiB and KaiC, to engineer time-dependent crosslinking of colloids. The resulting material self-assembles with programmable kinetics, producing macroscopic changes in material properties, via molecular assembly of KaiB-KaiC complexes. We show that colloid crosslinking depends strictly on the phosphorylation state of KaiC, with kinetics that are synced with KaiB-KaiC complexing. Our microscopic image analyses and computational models indicate that the stability of colloidal super-structures depends sensitively on the number of Kai complexes per colloid connection. Consistent with our model predictions, a high concentration stabilizes the material against dissolution after a robust self-assembly phase, while a low concentration allows for oscillatory material structure. This work introduces the concept of harnessing biological timers to control synthetic materials; and, more generally, opens the door to using protein-based reaction networks to endow synthetic systems with life-like functional properties.

DOI: https://doi.org/10.1038/s41467-024-55645-5
ACS Appl Mater Interfaces. 2025 Jan 02.

Microgel-Guided MXene Assembly for High-Performance, Low-Solid Content Conductive Inks.

Farivash Gholamirad, Monirosadat Sadati, Nader Taheri-Qazvini.

  Rapid evolution of smart devices necessitates high-performance, lightweight materials for effective electromagnetic interference (EMI) shielding. Ti3C2Tx MXene nanosheets are promising for such applications, yet the high solid content typically required for 3D-printable MXene inks limits their scalability and cost efficiency. In this study, we present an MXene-based ink with an ultralow solid content (0.1 vol %) and a high water content (up to 98 wt %) enabled by cross-linked poly(acrylic acid) Carbopol microgels. The microgels facilitate a jammed network, creating a percolated structure that allows MXene assembly at minimal concentrations and achieving the lowest reported solid content for MXene inks to date. The MXene/microgel hybrid ink demonstrates superior rheological properties, matching or surpassing existing formulations, and is readily extrudable for 3D printing complex structures and coatings. Following freeze-drying, the printed MXene aerogels exhibit an electrical conductivity of 360 S/m, an EMI shielding efficiency of 57 dB, and a compression modulus of 1750 kPa, all achieved at an ultralow density of 25 mg/cm3. This work provides a detailed analysis of the MXene/Carbopol ink's structure-processing-performance relationship, highlighting its transformative potential for scalable 3D printing of conductive, EMI shielding materials across diverse applications.

Keywords:  3D printing; Carbopol; EMI shielding; Ti3C2Tx MXene; jamming; percolation; rheology

DOI:  https://doi.org/10.1021/acsami.4c19700
Adv Mater. 2025 Jan 02. e2414971

A Low-Cost, Open-Source 3D Printer for Multimaterial and High-Throughput Direct Ink Writing of Soft and Living Materials.

Jonathan D Weiss, Alana Mermin-Bunnell, Fredrik S Solberg, Tony Tam, Luca Rosalia, Amit Sharir, Dominic Rütsche, Soham Sinha, Perry S Choi, Masafumi Shibata, Yellappa Palagani, Riya Nilkant, Kiruthika Paulvannan, Michael Ma, Mark A Skylar-Scott.

  Direct ink writing is a 3D printing method that is compatible with a wide range of structural, elastomeric, electronic, and living materials, and it continues to expand its uses into physics, engineering, and biology laboratories. However, the large footprint, closed hardware and software ecosystems, and expense of commercial systems often hamper widespread adoption. This work introduces a compact, low-cost, multimaterial, and high-throughput direct ink writing 3D printer platform with detailed assembly files and instructions provided freely online. In contrast to existing low-cost 3D printers and bioprinters, which typically modify off-the-shelf plastic 3D printers, this system is built from scratch, offering a lower cost and full customizability. Active mixing of cell-laden bioinks, high-throughput production of auxetic lattices using multimaterial multinozzle 3D (MM3D) printing methods, and a high-toughness, photocurable hydrogel for fabrication of heart valves are introduced. Finally, hardware for embedded multinozzle and 3D gradient nozzle printing is developed for producing high-throughput and graded 3D parts. This powerful, simple-to-build, and customizable printing platform can help stimulate a vibrant biomaker community of engineers, biologists, and educators.

Keywords:  3D bioprinting; active mixing; auxetic lattice; embedded 3D printing; multinozzle

DOI:  https://doi.org/10.1002/adma.202414971
3D Print Addit Manuf. 2024 Dec;11(6): e2022-e2032

3D Bioprinting of Graphene Oxide-Incorporated Hydrogels for Neural Tissue Regeneration.

Jiahui Lai, Xiaodie Chen, Helen H Lu, Min Wang.

  Bioprinting has emerged as a powerful manufacturing platform for tissue engineering, enabling the fabrication of 3D living structures by assembling living cells, biological molecules, and biomaterials into these structures. Among various biomaterials, hydrogels have been increasingly used in developing bioinks suitable for 3D bioprinting for diverse human body tissues and organs. In particular, hydrogel blends combining gelatin and gelatin methacryloyl (GelMA; "GG hydrogels") receive significant attention for 3D bioprinting owing to their many advantages, such as excellent biocompatibility, biodegradability, intrinsic bioactive groups, and polymer networks that combine the thermoresponsive gelation feature of gelatin and chemically crosslinkable attribute of GelMA. However, GG hydrogels have poor electroactive properties, which hinder their applications in neural tissue engineering where electrical conductivity is required. To overcome this problem, in this study, a small amount of highly electroactive graphene oxide (GO) was added in GG hydrogels to generate electroactive hydrogels for 3D bioprinting in neural tissue engineering. The incorporation of GO nanoparticles slightly improved mechanical properties and significantly increased electrical conductivity of GG hydrogels. All GO/GG composite hydrogels exhibited shear thinning behavior and sufficient viscosity and hence could be 3D printed into 3D porous scaffolds with good shape fidelity. Furthermore, bioinks combining rat bone marrow-derived mesenchymal stem cells (rBMSCs) with GO/GG composite hydrogels could be 3D bioprinted into GO/GG constructs with high cell viability. GO nanoparticles in the constructs provided ultraviolet (UV) shading effect and facilitated cell survival during UV exposure after bioprinting. The GO/GG composite hydrogels appear promising for 3D bioprinting applications in repairing damaged neural tissues.

Keywords:  3D bioprinting; graphene oxide; hydrogel scaffold; mesenchymal stem cell; neural tissue engineering

DOI:  https://doi.org/10.1089/3dp.2023.0150
Biomater Transl. 2024 ;5(3): 236-256

The use of hydrogel microspheres as cell and drug delivery carriers for bone, cartilage, and soft tissue regeneration.

Chung-Hsun Lin, Jesse R Srioudom, Wei Sun, Malcolm Xing, Su Yan, Le Yu, Jian Yang.

  Bone, cartilage, and soft tissue regeneration is a complex process involving many cellular activities across various cell types. Autografts remain the "gold standard" for the regeneration of these tissues. However, the use of autografts is associated with many disadvantages, including donor scarcity, the requirement of multiple surgeries, and the risk of infection. The development of tissue engineering techniques opens new avenues for enhanced tissue regeneration. Nowadays, the expectations of tissue engineering scaffolds have gone beyond merely providing physical support for cell attachment. Ideal scaffolds should also provide biological cues to actively boost tissue regeneration. As a new type of injectable biomaterial, hydrogel microspheres have been increasingly recognised as promising therapeutic carriers for the local delivery of cells and drugs to enhance tissue regeneration. Compared to traditional tissue engineering scaffolds and bulk hydrogel, hydrogel microspheres possess distinct advantages, including less invasive delivery, larger surface area, higher transparency for visualisation, and greater flexibility for functionalisation. Herein, we review the materials characteristics of hydrogel microspheres and compare their fabrication approaches, including microfluidics, batch emulsion, electrohydrodynamic spraying, lithography, and mechanical fragmentation. Additionally, based on the different requirements for bone, cartilage, nerve, skin, and muscle tissue regeneration, we summarize the applications of hydrogel microspheres as cell and drug delivery carriers for the regeneration of these tissues. Overall, hydrogel microspheres are regarded as effective therapeutic delivery carriers to enhance tissue regeneration in regenerative medicine. However, significant effort is required before hydrogel microspheres become widely accepted as commercial products for clinical use.

Keywords:  drug delivery; fabrication techniques; hydrogel microspheres; microgels; tissue regeneration

DOI:  https://doi.org/10.12336/biomatertransl.2024.03.003
Biomaterials. 2024 Dec 15. pii: S0142-9612(24)00565-9. [Epub ahead of print]317 123029

Surface-functionalized bacteria: Frontier explorations in next-generation live biotherapeutics.

Jia-Ni Jiang, Fan-Hui Kong, Qi Lei, Xian-Zheng Zhang.

  Screening robust living bacteria to produce living biotherapeutic products (LBPs) represents a burgeoning research field in biomedical applications. Despite their natural abilities to colonize bio-interfaces and proliferate, harnessing bacteria for such applications is hindered by considerable challenges in unsatisfied functionalities and safety concerns. Leveraging the high degree of customization and adaptability on the surface of bacteria demonstrates significant potential to improve therapeutic outcomes and achieve tailored functionalities of LBPs. This review focuses on the recent laboratory strategies of bacterial surface functionalization, which aims to address these challenges and potentiate the therapeutic effects in biomedicine. Firstly, we introduce various functional materials that are used for bacterial surface functionalization involving organic, inorganic, and biological materials. Secondly, the methodologies for achieving bacterial surface functionalization are categorized into three primary approaches including covalent bonding, non-covalent interactions, and hybrid techniques, while various advantages and limitations of different modification strategies are compared from multiple perspectives. Subsequently, the current status of the applications of surface-functionalized bacteria in bioimaging and disease treatments, especially in the treatment of inflammatory bowel disease (IBD) and cancer is summarized. Finally, challenges and pressing issues in the development of surface-functionalized bacteria as LBPs are presented.

Keywords:  Bacteria; Biomedical application; Live biotherapeutic products; Surface functionalization; Synthetic biology

DOI:  https://doi.org/10.1016/j.biomaterials.2024.123029
Adv Mater. 2025 Jan 02. e2410452

Tunable Bicontinuous Macroporous Cell Culture Scaffolds via Kinetically Controlled Phase Separation.

Oksana Y Dudaryeva, Lucien Cousin, Leila Krajnovic, Gian Gröbli, Virbin Sapkota, Lauritz Ritter, Dhananjay Deshmukh, Yifan Cui, Robert W Style, Riccardo Levato, Céline Labouesse, Mark W Tibbitt.

  3D scaffolds enable biological investigations with a more natural cell conformation. However, the porosity of synthetic hydrogels is often limited to the nanometer scale, which confines the movement of 3D encapsulated cells and restricts dynamic cell processes. Precise control of hydrogel porosity across length scales remains a challenge and the development of porous materials that allow cell infiltration, spreading, and migration in a manner more similar to natural ECM environments is desirable. Here, a straightforward and reliable method is presented for generating kinetically-controlled macroporous biomaterials using liquid-liquid phase separation between poly(ethylene glycol) (PEG) and dextran. Photopolymerization-induced phase separation resulted in macroporous hydrogels with tunable pore size. Varying light intensity and hydrogel composition controlled polymerization kinetics, time to percolation, and complete gelation, which defined the average pore diameter (Ø = 1-200 µm) and final gel stiffness of the formed hydrogels. Critically, for biological applications, macroporous hydrogels are prepared from aqueous polymer solutions at physiological pH and temperature using visible light, allowing for direct cell encapsulation. Human dermal fibroblasts in a range of macroporous gels are encapsulated with different pore sizes. Porosity improved cell spreading with respect to bulk gels and allowed migration in the porous biomaterials.

Keywords:  Biomaterials; Phase separation; Porosity; hydrogels; kinetic control

DOI:  https://doi.org/10.1002/adma.202410452
ACS Appl Mater Interfaces. 2025 Jan 02.

Structurally Transformable and Reconfigurable Hydrogel-Based Mechanical Metamaterials and Their Application in Biomedical Stents.

Sirawit Pruksawan, Rigel Lu Jun Teo, Yu Hong Cheang, Yi Ting Chong, Evelyn Ling Ling Ng, FuKe Wang.

  Mechanical metamaterials exhibit several unusual mechanical properties, such as a negative Poisson's ratio, which impart additional capabilities to materials. Recently, hydrogels have emerged as exceptional candidates for fabricating mechanical metamaterials that offer enhanced functionality and expanded applications due to their unique responsive characteristics. However, the adaptability of these metamaterials remains constrained and underutilized, as they lack integration of the hydrogels' soft and responsive characteristics with the metamaterial design. Here, we propose structurally transformable and reconfigurable hydrogel-based mechanical metamaterials through three-dimensional (3D) printing of lattice structures composed of multishape-memory poly(acrylic acid)-chitosan hydrogels. By incorporating reversible shape-memory mechanisms that control the structural arrangements of the lattice, these metamaterials can exhibit transformable and reconfigurable mechanical characteristics under various environmental conditions, including auxetic behavior, with Poisson's ratios switchable from negative to zero or positive. These adaptable mechanical responses across different states arise from structural changes in lattice, surpassing the gradual changes observed in conventional stimuli-responsive materials. The application of these metamaterials in multimode biomedical stents demonstrates their adaptability in practical settings, allowing them to transition between expandable, nonexpandable, and shrinkable states, with corresponding Poisson's ratios. By integrating multishape-memory soft materials with metamaterial design, we can significantly enhance their functionality, advancing the development of smart biomaterials.

Keywords:  hydrogel; mechanical metamaterial; mechanical property; smart material; stent

DOI:  https://doi.org/10.1021/acsami.4c20599
Trends Biotechnol. 2024 Dec 27. pii: S0167-7799(24)00345-7. [Epub ahead of print]

Engineering immunity using metabolically active polymeric nanoparticles.

Kate V Griffin, Michael N Saunders, Costas A Lyssiotis, Lonnie D Shea.

  Immune system functions play crucial roles in both health and disease, and these functions are regulated by their metabolic programming. The field of immune engineering has emerged to develop therapeutic strategies, including polymeric nanoparticles (NPs), that can direct immune cell phenotype and function by directing immunometabolic changes. Precise control of bioenergetic processes may offer the opportunity to prevent undesired immune activity and improve disease-specific outcomes. In this review we discuss the role that polymeric NPs can play in shaping immunometabolism and subsequent immune system activity through particle-mediated delivery of metabolically active agents as either structural components or cargo.

Keywords:  immunoengineering; immunometabolism; metabolic reprogramming; polymeric nanoparticle

DOI:  https://doi.org/10.1016/j.tibtech.2024.11.016
Eng Biol. 2024 Dec;8(4): 53-68

Engineering biology and automation-Replicability as a design principle.

Matthieu Bultelle, Alexis Casas, Richard Kitney.

  Applications in engineering biology increasingly share the need to run operations on very large numbers of biological samples. This is a direct consequence of the application of good engineering practices, the limited predictive power of current computational models and the desire to investigate very large design spaces in order to solve the hard, important problems the discipline promises to solve. Automation has been proposed as a key component for running large numbers of operations on biological samples. This is because it is strongly associated with higher throughput, and with higher replicability (thanks to the reduction of human input). The authors focus on replicability and make the point that, far from being an additional burden for automation efforts, replicability should be considered central to the design of the automated pipelines processing biological samples at scale-as trialled in biofoundries. There cannot be successful automation without effective error control. Design principles for an IT infrastructure that supports replicability are presented. Finally, the authors conclude with some perspectives regarding the evolution of automation in engineering biology. In particular, they speculate that the integration of hardware and software will show rapid progress, and offer users a degree of control and abstraction of the robotic infrastructure on a level significantly greater than experienced today.

Keywords:  automation; bioinformatics; synthetic biology

DOI:  https://doi.org/10.1049/enb2.12035
Nanoscale. 2025 Jan 02.

Printing rare-earth-free (REF) magnetic inks: synthesis, formulation, and device applications.

Hur-E-Jannat Moni, Bahareh Rezaei, Ioannis H Karampelas, Mortaza Saeidi-Javash, Jenifer Gómez-Pastora, Kai Wu, Minxiang Zeng.

Additive manufacturing (AM) of magnetic materials has recently attracted increasing interest for various applications but is often limited by the high cost and supply chain risks of rare-earth-element (REE) magnetic precursors. Recent advances in nanomanufacturing have enabled the development of rare-earth-free (REF) magnetic materials, such as spinel ferrites, hexaferrites, MnAl, MnBi, Alnico, FePt, and iron oxides/nitrides, which offer promising alternatives for printing high-performance magnetic devices. This review provides a detailed overview of the latest developments in REF magnetic materials, covering both synthesis strategies of REF magnetic materials/nanomaterials and their integration into AM processes. We summarize the design and formulation of magnetic inks, emphasizing the unique properties of REF ferromagnetic and ferrimagnetic systems and their adaptability to AM techniques like direct ink writing, inkjet printing, aerosol jet printing, and screen printing. Key advancements in materials chemistry, ink rheology, and device performance are discussed, highlighting how the structure of REF magnetic materials impacts device functionalities. This review concludes with a perspective on the pressing challenges and emerging opportunities in AM of REF magnetic inks. Through this review, we aim to offer insights into the structure-processing-property relationship of REF magnetic inks and guide the design of next-generation printable magnetic systems in a scalable, cost-effective, and sustainable manner.

DOI: https://doi.org/10.1039/d4nr04035j
Nat Commun. 2025 Jan 02. 16(1): 328

Degradation bottlenecks and resource competition in transiently and stably engineered mammalian cells.

Jacopo Gabrielli, Roberto Di Blasi, Cleo Kontoravdi, Francesca Ceroni.

Degradation tags, otherwise known as degrons, are portable sequences that can be used to alter protein stability. Here, we report that degron-tagged proteins compete for cellular degradation resources in engineered mammalian cells leading to coupling of the degradation rates of otherwise independently expressed proteins when constitutively targeted human degrons are adopted. We show the effect of this competition to be dependent on the context of the degrons. By considering different proteins, degron position and cellular hosts, we highlight how the impact of the degron on both degradation strength and resource coupling changes, with identification of orthogonal combinations. By adopting inducible bacterial and plant degrons we also highlight how controlled uncoupling of synthetic construct degradation from the native machinery can be achieved. We then build a genomically integrated capacity monitor tagged with different degrons and confirm resource competition between genomic and transiently expressed DNA constructs. This work expands the characterisation of resource competition in engineered mammalian cells to protein degradation also including integrated systems, providing a framework for the optimisation of heterologous expression systems to advance applications in fundamental and applied biological research.

DOI: https://doi.org/10.1038/s41467-024-55311-w
ACS Appl Bio Mater. 2025 Jan 02.

Hemostasis Strategies and Recent Advances in Hydrogels for Managing Uncontrolled Hemorrhage.

Lijun Liu, Rui Jing, Lei Yao, Yanbo Wang, Lihua Mu, Yuan Hu.

  Hemorrhage continues to pose a significant challenge in various medical contexts, underscoring the need for advanced hemostatic materials. Hemostatic hydrogels have gained recognition as innovative tools for addressing uncontrollable bleeding, attributed to their distinctive features including biological compatibility, tunable mechanical properties, and exceptional hemostatic performance. This review provides a comprehensive overview of hemostatic hydrogels that offer rapid and effective bleeding control. Particularly, this review focuses on hemostatic hydrogel design and associated hemostatic mechanisms. Additionally, recent advancements in the application of these materials are discussed in detail, especially in clinical trials. Finally, the challenges and potential advancements of hemostatic hydrogels are analyzed and assessed. This review seeks to emphasize the role of hydrogels in biomedical applications for hemorrhage control and provide perspectives on the innovation of clinically applicable hemostatic materials.

Keywords:  bleeding control; clinical trials; hemostatic hydrogels; hemostatic mechanisms; uncontrolled hemorrhage

DOI:  https://doi.org/10.1021/acsabm.4c01221
ACS Cent Sci. 2024 Dec 25. 10(12): 2188-2199

Molecularly Designed and Nanoconfined Polymer Electronic Materials for Skin-like Electronics.

Yu-Qing Zheng, Zhenan Bao.

Stretchable electronics have seen substantial development in skin-like mechanical properties and functionality thanks to the advancements made in intrinsically stretchable polymer electronic materials. Nanoscale phase separation of polymer materials within an elastic matrix to form one-dimensional nanostructures, namely nanoconfinement, effectively reduces conformational disorders that have long impeded charge transport properties of conjugated polymers. Nanoconfinement results in enhanced charge transport and the addition of skin-like properties. In this Outlook, we highlight the current understanding of structure-property relationships for intrinsically stretchable electronic materials with a focus on the nanoconfinement strategy as a promising approach to incorporate skin-like properties and other functionalities without compromising charge transport. We outline emerging directions and challenges for intrinsically stretchable electronic materials with the aim of constructing skin-like electronic systems.

DOI: https://doi.org/10.1021/acscentsci.4c01541
J Biomed Mater Res A. 2025 Jan;113(1): e37837

In Situ Gelling Silk Fibroin/ECM Hydrogel With Sustained Oxygen Release for Neural Tissue Engineering Applications.

Mahyar Haki, Nadia Shafaei, Mohammad Moeini.

  In situ gelling, cell-laden hydrogels hold promise for regenerating tissue lesions with irregular shapes located in complex and hard-to-reach anatomical sites. A notable example is the regeneration of neural tissue lost due to cerebral cavitation. However, hypoxia-induced cell necrosis during the vascularization period imposes a significant challenge to the success of this approach. Oxygen-releasing hydrogels have been developed to address this issue, but they suffer from fast oxygen release over a short period, limiting their efficacy. This study develops an in situ gelling hydrogel system based on silk fibroin (SF) and decellularized brain extracellular matrix (dECM) with sustained oxygen release and tunable gelation time. Calcium peroxide nanoparticles (CPO NPs) served as the oxygen generating material, which were encapsulated within SF microparticles before incorporation into the SF-dECM hydrogel, aiming to regulate the oxygen release rate. The total CPO content of the hydrogels was only 2%-4% w/w. Characterization of hydrogels containing various SF concentrations (2%, 4% or 6% w/v) and microparticle loadings (10%, 15% or 20% w/w) demonstrated that SF concentration in the hydrogel matrix significantly affects the swelling, resorption rate and mechanical properties, while microparticle loading has a milder effect. On the other hand, microparticle loading strongly affected the oxygen release profile. High SF concentration in the hydrogel matrix (6% w/v) led to slow resorption rate and high stiffness, likely unsuitable for intended application. Low SF concentration (2% w/v), on the other hand, led to a high swelling ratio and a less sustained oxygen release. Among 4% w/v SF hydrogels, increased microparticle loading led to a slower resorption rate, increased stiffness and enhanced oxygen release. However, cell viability was reduced at 20% w/w microparticle loading, likely due to decreased cell attachment. The 4% w/v SF hydrogels containing 10% w/w SF-CPO microparticles exhibited relatively low swelling ratio (12.8% ± 2.4%), appropriate resorption rate (70.16% ± 10.75% remaining weight after 28 days) and compressive modulus (36.9 ± 1.7 kPa) and sustained oxygen release for over 2 weeks. This sample also showed the highest viability under hypoxic conditions among tested hydrogel samples (87.6% ± 15.9%). Overall, the developed hydrogels in this study showed promise for potential application in brain tissue engineering.

Keywords:  calcium peroxide; decellularized extracellular matrix; in situ gelling hydrogel; neural tissue engineering; silk fibroin; sustained oxygen release

DOI:  https://doi.org/10.1002/jbm.a.37837
Eng Biol. 2024 Dec;8(4): 69-73

Supercharging engineering biology with automation.

Sébastien Lambertucci, Faye Deakin.

  Breakthroughs in engineering biology will solve the challenges facing humanity, by harnessing life itself. Standing in the way of these breakthroughs are the technical challenges of collecting the requisite data. Data variability and reproducibility problems, mean the odds are stacked against emerging biotechs. Automation has long been known to solve both problems; Let a robot do the pipetting and get reproducible data with less hands-on time. Although transitioning to automation has clear benefits, it can introduce additional complexity if done incorrectly. Analytik Jena UK has focused on supporting this transition to automation. We have found the combining of industry expertise with the biology know-how at the bench is paramount. Great automation should empower the scientist. Scientists should be trained on how to harness their automation. Through industry-customer relationships, we have successfully automated platforms for building DNA to antibody development. Through this partnership, we can enable a smooth translation of engineering biology to scalable industrial solutions. In this communication we have highlighted some successful examples where translating engineering biology workflows onto automation has proven beneficial, paving the way to industry ready solutions.

Keywords:  automation; genetic engineering; industry; innovation; optimisation; scale‐up strategies; synthetic biology

DOI:  https://doi.org/10.1049/enb2.12036
Theranostics. 2025 ;15(2): 460-493

Advancements in GelMA bioactive hydrogels: Strategies for infection control and bone tissue regeneration.

Lei Huang, Ziyao Guo, Xiaoxia Yang, Yinchun Zhang, Yiyun Liang, Xiaxue Chen, Xiaoling Qiu, Xuan Chen.

  Infectious bone defects present a significant clinical challenge, characterized by infection, inflammation, and subsequent bone tissue destruction. Traditional treatments, including antibiotic therapy, surgical debridement, and bone grafting, often fail to address these defects effectively. However, recent advancements in biomaterials research have introduced innovative solutions for managing infectious bone defects. GelMA, a three-dimensional network of hydrophilic polymers that can absorb and retain substantial amounts of water, has attracted considerable attention in the fields of materials science and biomedical engineering. Its distinctive properties, such as biocompatibility, responsiveness to stimuli, and customisable mechanical characteristics make GelMA an exemplary scaffold material for bone tissue engineering. This review aims to thoroughly explore the current literature on antibacterial and osteogenic strategies using GelMA hydrogels for the restoration of infected bones. It discusses their fabrication methods, biocompatibility, antibacterial effectiveness, and bioactivity. We conclude by discussing the existing challenges and future research directions in this field, with the hope of inspiring further innovations in the synthesis, modification, and application of GelMA-based hydrogels for infection control and bone tissue regeneration.

Keywords:  GelMA hydrogels; antimicrobial materials; bone tissue regeneration; infected bone tissue regeneration; infection control

DOI:  https://doi.org/10.7150/thno.103725
Mater Horiz. 2025 Jan 03.

Ultra-stretchable, self-recoverable, notch-insensitive, self-healable and adhesive hydrogel enabled by synergetic hydrogen and dipole-dipole crosslinking.

Wanting Yuan, Yi He, Qianqian Liang, Hongyi Lv, Ziqi Wang, Haitao Wu, Jinrong Wu, Lijuan Zhao, Yi Wang.

Hydrogels are promising materials for wearable electronics, artificial skins and biomedical engineering, but their limited stretchability, self-recovery and crack resistance restrict their performance in demanding applications. Despite efforts to enhance these properties using micelle cross-links, nanofillers and dynamic interactions, it remains a challenge to fabricate hydrogels that combine high stretchability, self-healing and strong adhesion. Herein, we report a novel hydrogel synthesized via the copolymerization of acrylamide (AM), maleic acid (MA) and acrylonitrile (AN), designed to address these limitations. The resulting hydrogel forms a dual physical crosslinking network enabled by dynamic hydrogen bonds and dipole-dipole interactions. This hierarchical structure allows polymer chains to undergo progressive deformation, leading to ultrahigh stretchability exceeding 9000% and excellent fatigue resistance under cyclic strains of up to 3000%. Furthermore, the hydrogel exhibits outstanding notch-insensitivity (fracture energy: >10 kJ m-2), notable adhesive properties and superior self-healing capabilities. The incorporation of LiCl imparts conductivity to the hydrogel, making it suitable for wearable strain sensors that can accurately monitor human motion. These results demonstrate the successful development of an ultra-stretchable, self-recoverable, notch-insensitive, self-healable and adhesive hydrogel with significant potential for advanced applications in wearable electronics and healthcare monitoring devices. This work represents a significant step forward in the design of multifunctional hydrogels, offering new pathways for the development of next-generation soft materials with enhanced mechanical and functional properties.

DOI: https://doi.org/10.1039/d4mh01462f
Metab Eng Commun. 2024 Dec;19 e00255

Genetically encoded biosensors for the circular plastics bioeconomy.

Micaela Chacón, Neil Dixon.

  Current plastic production and consumption routes are unsustainable due to impact upon climate change and pollution, and therefore reform across the entire value chain is required. Biotechnology offers solutions for production from renewable feedstocks, and to aid end of life recycling/upcycling of plastics. Biology sequence/design space is complex requiring high-throughput analytical methods to facilitate the iterative optimisation, design-build, test-learn (DBTL), cycle of Synthetic Biology. Furthermore, genetic regulatory tools can enable harmonisation between biotechnological demands and the physiological constraints of the selected production host. Genetically encoded biosensors offer a solution for both requirements to facilitate the circular plastic bioeconomy. In this review we present a summary of biosensors developed to date reported to be responsive to plastic precursors/monomers. In addition, we provide a summary of the demonstrated and prospective applications of these biosensors for the construction and deconstruction of plastics. Collectively, this review provides a valuable resource of biosensor tools and enabled applications to support the development of the circular plastics bioeconomy.

Keywords:  Biotechnology; Degradation; Genetic biosensors; Monomer synthesis; Plastic

DOI:  https://doi.org/10.1016/j.mec.2024.e00255
ACS Appl Bio Mater. 2025 Jan 01.

Coating of Threads with Fluorescent Curli Fibers for pH Sensing.

Dalia Jane Saldanha, Noémie-Manuelle Dorval Courchesne.

  Threads coated with bioresponsive materials hold promise for innovative wearable diagnostics. However, most thread coatings reported so far cannot be easily customized for different analytes and frequently incorporate non-biodegradable components. Most optically active thread coatings rely on dyes, which often exhibit irreversible responses. In this work, we propose a biosensing coating for threads using curli fibers. Curli fibers are self-assembling fibers of the protein CsgA that can be genetically engineered to sense rapidly evolving diagnostic targets. We first established a simple electrostatic-mediated absorption protocol for coating anionic cotton threads with anionic curli fibers using an intervening cationic chitosan layer. We applied this protocol to two types of pH-sensing curli fibers, displaying either fluorescent pHuji or mCitrine proteins. This process ensures extensive curli coating over the entire thread surface using only water-based solvents. The resulting protein-coated threads are moderately hydrophobic, stretchable, and can monitor pH changes in real time through fluorescence. The coatings are also stable and functional on the surface for over 25 cycles of use, highlighting their potential for reusable practical applications. This straightforward and adaptable protocol can be extended to coat threads with diverse sensing and responsive capabilities for intelligent clothing.

Keywords:  curli fibers; electrostatic assembly; pH sensing; recombinant proteins; thread sensors

DOI:  https://doi.org/10.1021/acsabm.4c01073