SupraCells: Living Mammalian Cells Protected within Functional Modular Nanoparticle-Based Exoskeletons

Advances in Functionalized Biocomposites of Living Cells Combined with Metal-Organic Frameworks

Motivated by the remarkable innate characteristics of cells in living organisms, we have found that hybrid materials that combine bioorganisms with nanomaterials have significantly propelled advancements in industrial applications. However, the practical deployment of unmodified living entities is inherently limited due to their sensitivity to environmental fluctuations. To surmount these challenges, an efficacious strategy for the biomimetic mineralization of living organisms with nanomaterials has emerged, demonstrating extraordinary potential in biotechnology. Among them, innovative composites have been engineered by enveloping bioorganisms with a metal-organic framework (MOF) coating. This review systematically summarizes the latest developments in living cells/MOF-based composites, detailing the methodologies employed in structure fabrication and their diverse applications, such as bioentity preservation, sensing, catalysis, photoluminescence, and drug delivery. Moreover, the synergistic benefits arising from the individual compounds are elucidated. This review aspires to illuminate new prospects for fabricating living cells/MOF composites and concludes with a perspective on the prevailing challenges and impending opportunities for future research in this field.

Powering the Future Green Buildings: Multifunctional Ultraviolet-Shielding Transparent Wood

Indoor UV damage is a serious problem that is often ignored. Common glasses cannot filter UV rays well and have fragility and environmental issues. UV-shielding transparent wood (TW) holds promise, yet striking the right balance between blocking UV rays and allowing sufficient visible-light transmission poses a challenge. The pronounced capillary force, fueled by persistent moisture and extractives in wood, alongside the existence of multiphase interfaces, collectively hinder the uniform penetration of polymers and the effective dispersion of nanomaterials within the wood skeleton. Here, we incorporate high-pressure supercritical CO2 fluid-assisted impregnation (HSCFI) into fabricating UV-shielding TW. The supercritical CO2 pretreatment efficiently eliminates moisture and refines wood structure by extracting polar substances, resulting in a prominent 52.4% increase in average water permeability. Subsequently, this HSCFI method facilitates the infiltration of methyl methacrylate (MMA) monomer and Ce-ZnO nanorods (NRDs) into the refined anhydrous wood, leveraging the excellent solvency of supercritical CO2 for MMA. The impregnation rate of PMMA undergoes a substantial increase from 34.5 to 59.1%. With the robust UV-blocking capability of Ce-ZnO NRDs, thanks to dual-valence Ce doping widening the ZnO energy gap via the Burstein-Moss effect and their unique photoactive microstructure featuring a solid prism with a sharp hexahedral pyramidal tip, along with intrinsic physical scattering/reflection actions, Ce-ZnO NRDs@TW achieves an impressive 99.6% UVA radiation blockage (the highest for TW) and maintains high visible-light transmission (83.2%). Furthermore, Ce-ZnO NRDs@TW presents favorable energy-saving, sound absorption, and antifungal abilities, making it a promising candidate for future green buildings.

HP35 Protein in the Mesopore of MIL-101(Cr) MOF: A Model to Study Cotranslocational Unfolding

The immobilization of enzymes in metal-organic framework (MOF) cages is important in biotechnology. In this context, the mechanism of translocation of proteins through the cavities of the MOF and the roles played by confinement and MOF chemistry in giving rise to stable protein intermediates that are otherwise transiently populated in the physiological environment are important questions to be addressed. These unexplored aspects are examined with villin headpiece (HP35) as a model protein confined within a mesopore of MIL-101(Cr) using molecular dynamics simulations. At equilibrium, the protein is located farther from the center of the cavity and closer to the MOF surface. Molecular interactions with the MOF partially unfold helix-1 at its N-terminus. Umbrella sampling simulations inform the range of conformations that HP35 undertakes during translocation from one cavity to another and associated changes in free energy. Relative to its equilibrium state within the cavity, the free energy barrier for the unfolded protein at the cage window is estimated to be 16 kcal/mol. This study of MOF-based protein conformation can also be a general approach to observing intermediates in folding-unfolding pathways.

Ultrathin silica-tiling on living cells for chemobiotic catalysis

Harnessing the power of cell biocatalysis for sustainable chemical synthesis requires rational integration of living cells with the modern synthetic catalysts. Here, we develop silica-tiling strategy that constructs a hierarchical, inorganic, protocellular confined nanospace around the individual living cell to accommodate molecularly accessible abiotic catalytic sites. This empowers the living microorganisms for new-to-nature chemical synthesis without compromising the cellular regenerative process. Yeast cell, a widely used biocatalyst, is upgraded via highly controlled self-assembly of 2D-bilayer silica-based catalytic modules on cell surfaces, opening the avenues for diverse chemobiotic reactions. For example, combining [AuPt]-catalyzed NADH regeneration, light-induced [Pd]-catalyzed C-C cross-coupling or lipase-catalyzed esterification reactions-with the natural ketoreductase activity inside yeast cell. The conformal silica bilayer provides protection while allowing proximity to catalytic sites and preserving natural cell viability and proliferation. These living nanobiohybrids offer to bridge cell's natural biocatalytic capabilities with customizable heterogeneous metal catalysis, enabling programmable reaction sequences for sustainable chemical synthesis.

Juice Vesicles Bioreactors Technology for Constructing Advanced Carbon-Based Energy Storage

The construction of high-quality carbon-based energy materials through biotechnology has always been an eager goal of the scientific community. Herein, juice vesicles bioreactors (JVBs) bio-technology based on hesperidium (e.g., pomelo, waxberry, oranges) is first reported for preparation of carbon-based composites with controllable components, adjustable morphologies, and sizes. JVBs serve as miniature reaction vessels that enable sophisticated confined chemical reactions to take place, ultimately resulting in the formations of complex carbon composites. The newly developed approach is highly versatile and can be compatible with a wide range of materials including metals, alloys, and metal compounds. The growth and self-assembly mechanisms of carbon composites via JVBs are explained. For illustration, NiCo alloy nanoparticles are successfully in situ implanted into pomelo vesicles crosslinked carbon (PCC) by JVBs, and their applications as sulfur/carbon cathodes for lithium-sulfur batteries are explored. The well-designed PCC/NiCo-S electrode exhibits superior high-rate properties and enhanced long-term stability. Synergistic reinforcement mechanisms on transportation of ions/electrons of interface reactions and catalytic conversion of lithium polysulfides arising from metal alloy and carbon architecture are proposed with the aid of DFT calculations. The research provides a novel biosynthetic route to rational design and fabrication of carbon composites for advanced energy storage.

Construction of Mineralization Nanostructures in Polymers for Mechanical Enhancement and Functionalization

Mineralization capable of growing inorganic nanostructures efficiently, orderly, and spontaneously shows great potential for application in the construction of high-performance organic-inorganic composites. As a thermodynamically spontaneous solid-phase crystallization reaction involving dual organic and inorganic components, mineralization allows for the self-assembly of sophisticated and exclusive nanostructures within a polymer matrix. It results in a diversity of functions such as enhanced strength, toughness, electrical conductivity, selective permeability, and biocompatibility. While there are previous reviews discussing the progress of mineralization reactions, many of them overlook the significant benefits of interfacial regulation and functionalization that come from the incorporation of mineralized structures into polymers. Focusing on different means of assembly of mineralized nanostructures in polymer, the work analyzes their design principles and implementation strategies. Then, their different advantages and disadvantages are analyzed by combining nanostructures with organic substrates as well as involving the basis of different functionalizations. It is anticipated to provide insights and guidance for the future development of mineralized polymer composites and their application designs.

Putting Hybrid Nanomaterials to Work for Biomedical Applications

Hybrid nanomaterials have found use in many biomedical applications. This article provides a comprehensive review of the principles, techniques, and recent advancements in the design and fabrication of hybrid nanomaterials for biomedicine. We begin with an introduction to the general concept of material hybridization, followed by a discussion of how this approach leads to materials with additional functionality and enhanced performance. We then highlight hybrid nanomaterials in the forms of nanostructures, nanocomposites, metal-organic frameworks, and biohybrids, including their fabrication methods. We also showcase the use of hybrid nanomaterials to advance biomedical engineering in the context of nanomedicine, regenerative medicine, diagnostics, theranostics, and biomanufacturing. Finally, we offer perspectives on challenges and opportunities.

NH2-MIL-101(Fe)-mediated photo-Fenton reaction enhanced simultaneous removal of nitrogen and refractory organics in anammox process through interfacial electron transfer

In this study, H2O2 (0.1 ‰) and NH2-MIL-101(Fe)-driven (150 mg/L) photo-Fenton-coupled anammox were proposed to simultaneously improve the removal efficiency of nitrogen and humic acid. Long-term experiments showed that the total nitrogen removal efficiency was increased by the photo-Fenton reaction to 91.9 ± 1.5 % by altering the bioavailability of refractory organics. Correspondingly, the total organic carbon removal efficiency was significantly increased. Microbial community analyses indicated that Candidatus_Brocadia maintained high activity during photo-Fenton reaction and was the most abundant genus in the reactor. Dissimilatory nitrate reduction to ammonium process and denitrification process were enhanced, resulting in reduced NO3--N production. The establishment of electron transfer between microorganisms and NH2-MIL-101 (Fe) improved the charge separation efficiency of the quantum dots and increased the intracellular adenosine triphosphate content of anammox bacteria. These results indicated that photo-Fenton-anammox process promoted the removal of nitrogen and refractory organics in one reactor which had good economic value and application prospects.

Organismal Function Enhancement through Biomaterial Intervention

Living organisms in nature, such as magnetotactic bacteria and eggs, generate various organic-inorganic hybrid materials, providing unique functionalities. Inspired by such natural hybrid materials, researchers can reasonably integrate biomaterials with living organisms either internally or externally to enhance their inherent capabilities and generate new functionalities. Currently, the approaches to enhancing organismal function through biomaterial intervention have undergone rapid development, progressing from the cellular level to the subcellular or multicellular level. In this review, we will concentrate on three key strategies related to biomaterial-guided bioenhancement, including biointerface engineering, artificial organelles, and 3D multicellular immune niches. For biointerface engineering, excess of amino acid residues on the surfaces of cells or viruses enables the assembly of materials to form versatile artificial shells, facilitating vaccine engineering and biological camouflage. Artificial organelles refer to artificial subcellular reactors made of biomaterials that persist in the cytoplasm, which imparts cells with on-demand regulatory ability. Moreover, macroscale biomaterials with spatiotemporal regulation characters enable the local recruitment and aggregation of cells, denoting multicellular niche to enhance crosstalk between cells and antigens. Collectively, harnessing the programmable chemical and biological attributes of biomaterials for organismal function enhancement shows significant potential in forthcoming biomedical applications.

Synthetic Biohybrids of Red Blood Cells and Cascaded-Enzymes@ Metal-Organic Frameworks for Hyperuricemia Treatment

Hyperuricemia, caused by an imbalance between the rates of production and excretion of uric acid (UA), may greatly increase the mortality rates in patients with cardiovascular and cerebrovascular diseases. Herein, for fast-acting and long-lasting hyperuricemia treatment, armored red blood cell (RBC) biohybrids, integrated RBCs with proximal, cascaded-enzymes of urate oxidase (UOX) and catalase (CAT) encapsulated within ZIF-8 framework-based nanoparticles, have been fabricated based on a super-assembly approach. Each component is crucial for hyperuricemia treatment: 1) RBCs significantly increase the circulation time of nanoparticles; 2) ZIF-8 nanoparticles-based superstructure greatly enhances RBCs resistance against external stressors while preserving native RBC properties (such as oxygen carrying capability); 3) the ZIF-8 scaffold protects the encapsulated enzymes from enzymatic degradation; 4) no physical barrier exists for urate diffusion, and thus allow fast degradation of UA in blood and neutralizes the toxic by-product H2 O2 . In vivo results demonstrate that the biohybrids can effectively normalize the UA level of an acute hyperuricemia mouse model within 2 h and possess a longer elimination half-life (49.7 ± 4.9 h). They anticipate that their simple and general method that combines functional nanomaterials with living cell carriers will be a starting point for the development of innovative drug delivery systems.

MOFs Modulate Copper Trafficking in Tumor Cells for Bioorthogonal Therapy

In situ drug synthesis using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has attracted considerable attention in tumor therapy because of its satisfactory effectiveness and reduced side-effects. However, the exogenous addition of copper catalysts can cause cytotoxicity and has hampered biomedical applications in vivo. Here, we design and synthesize a metal-organic framework (MOF) to mimic copper chaperone, which can selectively modulate copper trafficking for bioorthogonal synthesis with no need of exogenous addition of copper catalysts. Like copper chaperones, the prepared ZIF-8 copper chaperone mimics specifically bind copper ions through the formation of coordination bonds. Moreover, the copper is unloaded under the acidic environment due to the dissipation of the coordination interactions between metal ions and ligands. In this way, the cancer cell-targeted copper chaperone mimics can selectively transport copper ions into cells. Regulation of intracellular copper trafficking may inspire constructing bioorthogonal catalysis system with reduced metal cytotoxicity in live cells.

Covalent-organic framework nanobionics for robust cytoprotection

We present a novel study introducing a durable and robust covalent-organic framework (COF) nanocoating, developed in situ on living cells. This COF nanocoating demonstrates remarkable resistance against a diverse range of lethal stressors, including high temperature, extreme pH, ultraviolet radiation, toxic metal ions, organic pollutants, and strong oxidative stress. Notably, the nanocoating exhibits exceptional cell survival enhancement under high temperature and strongly acidic conditions, an aspect yet unexplored in the case of metal-organic framework nanocoatings and other nanomaterials. Moreover, functionalization of the nanocoating with an exogenous enzyme catalase enables yeast fermentation and ethanol production even under strong oxidative stress. Our findings establish the durable and robust COF nanocoating as a reliable platform for safeguarding vulnerable microorganisms to allow their utilisation in a wide range of adverse environments.

Nanoarmor: cytoprotection for single living cells

Single cell modification or hybridization technology has become a popular direction in bioengineering in recent years, with applications in clean energy, environmental stewardship, and sustainable human development. Here, we draw attention to nanoarmor, a representative achievement of cytoprotection and functionalization technology. The fundamental principles of nanoarmor need to be studied with input from multiple disciplines, including biology, chemistry, and material science. In this review, we explain the role of nanoarmor and review progress in its applications. We also discuss three main challenges associated with its development: self-driving ability, heterojunction characteristics, and mineralization formation. Finally, we propose a preliminary classification system for nanoarmor.

Cytoprotective Metal-Phenolic Network Sporulation to Modulate Microalgal Mobility and Division

Synthetic cell exoskeletons created from abiotic materials have attracted interest in materials science and biotechnology, as they can regulate cell behavior and create new functionalities. Here, a facile strategy is reported to mimic microalgal sporulation with on-demand germination and locomotion via responsive metal-phenolic networks (MPNs). Specifically, MPNs with tunable thickness and composition are deposited on the surface of microalgae cells via one-step coordination, without any loss of cell viability or intrinsic cell photosynthetic properties. The MPN coating keeps the cells in a dormant state, but can be disassembled on-demand in response to environmental pH or chemical stimulus, thereby reviving the microalgae within 1 min. Moreover, the artificial sporulation of microalgae resulted in resistance to environmental stresses (e.g., metal ions and antibiotics) akin to the function of natural sporulation. This strategy can regulate the life cycle of complex cells, providing a synthetic strategy for designing hybrid microorganisms.

A Micrometric Transformer: Compositional Nanoshell Transformation of Fe3+ -Trimesic-Acid Complex with Concomitant Payload Release in Cell-in-Catalytic-Shell Nanobiohybrids

Nanoencapsulation of living cells within artificial shells is a powerful approach for augmenting the inherent capacity of cells and enabling the acquisition of extrinsic functions. However, the current state of the field requires the development of nanoshells that can dynamically sense and adapt to environmental changes by undergoing transformations in form and composition. This paper reports the compositional transformation of an enzyme-embedded nanoshell of Fe3+ -trimesic acid complex to an iron phosphate shell in phosphate-containing media. The cytocompatible transformation allows the nanoshells to release functional molecules without loss of activities and biorecognition, while preserving the initial shell properties, such as cytoprotection. Demonstrations include the lysis and killing of Escherichia coli by lysozyme, and the secretion of interleukin-2 by Jurkat T cells in response to paracrine stimulation by antibodies. This work on micrometric Transformers will benefit the creation of cell-in-shell nanobiohybrids that can interact with their surroundings in active and adaptive ways.

Exoskeleton Partial-Coated Stem Cells for Infarcted Myocardium Restoring

The integration of abiotic materials with live cells has emerged as an exciting strategy for the control of cellular functions. Exoskeletons consisting ofmetal-organic frameworks are generated to produce partial-coated bone marrow stem cells (BMSCs) to overcome low cell survival leading to disappointing effects for cell-based cardiac therapy. Partially coated exoskeletons can promote the survival of suspended BMSCs by integrating the support of exoskeletons and unimpaired cellular properties. In addition, partial exoskeletons exhibit protective effects against detrimental environmental conditions, including reactive oxygen species, pH changes, and osmotic pressure. The partial-coated cells exhibit increased intercellular adhesion forces to aggregate and adhere, promoting cell survival and preventing cell escape during cell therapy. The exoskeletons interact with cell surface receptors integrin α5β1, leading to augmented biological functions with profitable gene expression alteration, such as Vegfa, Cxcl12, and Adm. The partial-coated BMSCs display enhanced cell retention in infarcted myocardium through non-invasive intravenous injections. The repair of myocardial infarction has been achieved with improved cardiac function, myocardial angiogenesis, proliferation, and inhibition of cell apoptosis. This discovery advances the elucidation of potential molecular and cellular mechanisms for cell-exoskeleton interactions and benefits the rational design and manufacture of next-generation nanobiohybrids.

Catalytic metal-nucleotide coordinative cytoskeleton on algae cell towards photosynthetic hydrogen production under air

A metal-nucleotide coordinative cytoskeleton with ascorbate oxidase-like catalytic behavior was constructed on an individual algae cell wall, which endows the engineered cells with the capability of self-generating a localized hypoxic microenvironment around the cell surface, and thus allows the functionality switching from photosynthetic oxygen production to efficient hydrogen evolution for over one month.

An Alternative Thinking in Tumor Therapeutics: Living Yeast Armored with Silicate

A hybrid platform, constructed via the surface "armoring" of living yeasts by a manganese silicate compound (MS@Yeast), is investigated for combinational cancer treatment. The intrinsic characteristics of living yeasts, in both acidophilic and anaerobic conditions, empower the hybrid platform with activated selected colonization in tumors. While silicate particles are delivered in a targeting manner, yeast fermentation occurs at the cancerous region, inducing both alcohol and CO2. The excessive content of alcohol causes the hemangiectasis of tumor tissue, facilitating the penetration of therapeutics into central tumors and subsequent endocytosis. The catalytic Mn2+ ions, released from silicate particles, react with CO2 to induce forceful oxidative stress in tumor cells, ablating the primary tumors. More interestingly, the debris of sacrificed tumor cells and yeasts triggers considerable antitumor immune responses, rejecting both rechallenged and metastatic tumors. The integration of biologically active microorganisms and functional materials, illustrated in this study, provides distinctive perspectives in the exploration of potential therapeutics for tackling cancer.

Material-engineered bioartificial microorganisms enabling efficient scavenging of waterborne viruses

Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to scavenge pathogenic waterborne viruses, we engineer Paramecium caudatum (Para), single-celled microorganisms, with a semiartificial and specific virus-scavenging organelle (VSO). Fe3O4 magnetic nanoparticles modified with a virus-capture antibody (MNPs@Ab) are integrated into the vacuoles of Para during feeding to produce VSOs, which persist inside Para without impairing their swimming ability. Compared with natural Para, which has no capture specificity and shows inefficient inactivation, the VSO-engineered Para (E-Para) specifically gathers waterborne viruses and confines them inside the VSOs, where the captured viruses are completely deactivated because the peroxidase-like nano-Fe3O4 produces virus-killing hydroxyl radicals (•OH) within acidic environment of VSO. After treatment, magnetized E-Para is readily recycled and reused, avoiding further contamination. Materials-based artificial organelles convert natural Para into a living virus scavenger, facilitating waterborne virus clearance without extra energy consumption.

DNA-Guided Extracellular-Vesicle Metallization with High Catalytic Activity for Accurate Diagnosis of Pulmonary Nodules

Sensitive and specific analysis of extracellular vesicles (EVs) offers a promising minimally invasive way to identify malignant pulmonary nodules from benign lesions. However, accurate analysis of EVs is subject to free target proteins in blood samples, which compromises the clinical diagnosis value of EVs. Here a DNA-guided extracellular-vesicle metallization (DEVM) strategy is described for ultrasensitive and specific analysis of EV protein biomarkers and classification of pulmonary nodules. The facile DEVM process mainly includes the incorporation of DNA labeled with cholesterol and thiol groups into EV membranes and subsequent deposition of Au3+ and Pt4+ to allow the DNA-functionalized EVs to be encapsulated with AuPt nanoshells. It is found that the synthesized AuPt-metallized EVs possess extrinsic peroxidase-like activity. Utilizing the feature of the catalytic metal nanoshells just growth on the EV membranes, the DEVM method enables multiparametric recognition of target proteins and EV membranes and can produce an amplified colorimetric signal, avoiding the interference of free proteins. By profiling four surface proteins of EVs from 48 patients with pulmonary nodules, the highest area under the receiver operating characteristic curve (0.9983) is obtained. Therefore, this work provides a feasible EVs analysis tool for accurate pulmonary nodules management.

Nanoparticle-Decorated Biomimetic Extracellular Matrix for Cell Nanoencapsulation and Regulation

Cell encapsulation has been studied for various applications ranging from cell transplantation to biological production. However, current encapsulation technologies focus on cell protection rather than cell regulation that is essential to most if not all cell-based applications. Here we report a method for cell nanoencapsulation and regulation using an ultrathin biomimetic extracellular matrix as a cell nanocapsule to carry nanoparticles (CN2 ). This method allows high-capacity nanoparticle retention at the vicinity of cell surfaces. The encapsulated cells maintain high viability and normal metabolism. When gold nanoparticles (AuNPs) are used as a model to decorate the nanocapsule, light irradiation transiently increases the temperature, leading to the activation of the heat shock protein 70 (HSP70) promoter and the regulation of reporter gene expression. As the biomimetic nanocapsule can be decorated with any or multiple NPs, CN2 is a promising platform for advancing cell-based applications.

Nanobiohybrids: Synthesis strategies and environmental applications from micropollutants sensing and removal to global warming mitigation

Micropollutants contamination and global warming are critical environmental issues that require urgent attention due to natural and anthropogenic activities posing serious threats to human health and ecosystems. However, traditional technologies (such as adsorption, precipitation, biodegradation, and membrane separation et al.) are facing challenges of low utilization efficiency of oxidants, poor selectivity, and complex in-situ monitoring operations. To address these technical bottlenecks, nanobiohybrids, synthesized by interfacing the nanomaterials and biosystems, have recently emerged as eco-friendly technologies. In this review, we summarize the synthesis approaches of nanobiohybrids and their utilization as emerging environmental technologies for addressing environmental problems. Studies demonstrate that enzymes, cells, and living plants can be integrated with a wide range of nanomaterials including reticular frameworks, semiconductor nanoparticles and single-walled carbon nanotubes. Moreover, nanobiohybrids demonstrate excellent performance for micropollutant removal, carbon dioxide conversion, and sensing of toxic metal ions and organic micropollutants. Therefore, nanobiohybrids are expected to be environmental friendly, efficient, and cost-effective techniques for addressing environmental micropollutants issues and mitigating global warming, benefiting both humans and ecosystems alike.

Polymerization in living organisms

Vital biomacromolecules, such as RNA, DNA, polysaccharides and proteins, are synthesized inside cells via the polymerization of small biomolecules to support and multiply life. The study of polymerization reactions in living organisms is an emerging field in which the high diversity and efficiency of chemistry as well as the flexibility and ingeniousness of physiological environment are incisively and vividly embodied. Efforts have been made to design and develop in situ intra/extracellular polymerization reactions. Many important research areas, including cell surface engineering, biocompatible polymerization, cell behavior regulation, living cell imaging, targeted bacteriostasis and precise tumor therapy, have witnessed the elegant demeanour of polymerization reactions in living organisms. In this review, recent advances in polymerization in living organisms are summarized and presented according to different polymerization methods. The inspiration from biomacromolecule synthesis in nature highlights the feasibility and uniqueness of triggering living polymerization for cell-based biological applications. A series of examples of polymerization reactions in living organisms are discussed, along with their designs, mechanisms of action, and corresponding applications. The current challenges and prospects in this lifeful field are also proposed.

Engineering Cyborg Bacteria Through Intracellular Hydrogelation

Natural and artificial cells are two common chassis in synthetic biology. Natural cells can perform complex tasks through synthetic genetic constructs, but their autonomous replication often causes safety concerns for biomedical applications. In contrast, artificial cells based on nonreplicating materials, albeit possessing reduced biochemical complexity, provide more defined and controllable functions. Here, for the first time, the authors create hybrid material-cell entities termed Cyborg Cells. To create Cyborg Cells, a synthetic polymer network is assembled inside each bacterium, rendering them incapable of dividing. Cyborg Cells preserve essential functions, including cellular metabolism, motility, protein synthesis, and compatibility with genetic circuits. Cyborg Cells also acquire new abilities to resist stressors that otherwise kill natural cells. Finally, the authors demonstrate the therapeutic potential by showing invasion into cancer cells. This work establishes a new paradigm in cellular bioengineering by exploiting a combination of intracellular man-made polymers and their interaction with the protein networks of living cells.

A Semiconductor Biohybrid System for Photo-Synergetic Enhancement of Biological Hydrogen Production

CdS nanoparticles were introduced on E. coli cells to construct a hydrogen generating biohybrid system via the biointerface of tannic acid-Fe complex. This hybrid system promotes good biological activity in a high salinity environment. Under light illumination, the as-synthesized biohybrid system achieves a 32.44 % enhancement of hydrogen production in seawater through a synergistic effect.

Biohybrid materials: Structure design and biomedical applications

Biohybrid materials are proceeded by integrating living cells and non-living materials to endow materials with biomimetic properties and functionalities by supporting cell proliferation and even enhancing cell functions. Due to the outstanding biocompatibility and programmability, biohybrid materials provide some promising strategies to overcome current problems in the biomedical field. Here, we review the concept and unique features of biohybrid materials by comparing them with conventional materials. We emphasize the structure design of biohybrid materials and discuss the structure-function relationships. We also enumerate the application aspects of biohybrid materials in biomedical frontiers. We believe this review will bring various opportunities to promote the communication between cell biology, material sciences, and medical engineering.

Donors for nerve transplantation in craniofacial soft tissue injuries

Neural tissue is an important soft tissue; for instance, craniofacial nerves govern several aspects of human behavior, including the expression of speech, emotion transmission, sensation, and motor function. Therefore, nerve repair to promote functional recovery after craniofacial soft tissue injuries is indispensable. However, the repair and regeneration of craniofacial nerves are challenging due to their intricate anatomical and physiological characteristics. Currently, nerve transplantation is an irreplaceable treatment for segmental nerve defects. With the development of emerging technologies, transplantation donors have become more diverse. The present article reviews the traditional and emerging alternative materials aimed at advancing cutting-edge research on craniofacial nerve repair and facilitating the transition from the laboratory to the clinic. It also provides a reference for donor selection for nerve repair after clinical craniofacial soft tissue injuries. We found that autografts are still widely accepted as the first options for segmental nerve defects. However, allogeneic composite functional units have a strong advantage for nerve transplantation for nerve defects accompanied by several tissue damages or loss. As an alternative to autografts, decellularized tissue has attracted increasing attention because of its low immunogenicity. Nerve conduits have been developed from traditional autologous tissue to composite conduits based on various synthetic materials, with developments in tissue engineering technology. Nerve conduits have great potential to replace traditional donors because their structures are more consistent with the physiological microenvironment and show self-regulation performance with improvements in 3D technology. New materials, such as hydrogels and nanomaterials, have attracted increasing attention in the biomedical field. Their biocompatibility and stimuli-responsiveness have been gradually explored by researchers in the regeneration and regulation of neural networks.

Multiscale Functional Metal Architectures by Antibody-Guided Metallization of Specific Protein Assemblies in Ex Vivo Multicellular Organisms

Biological systems consist of hierarchical protein structures, each of which has unique 3D geometries optimized for specific functions. In the past decades, the growth of inorganic materials on specific proteins has attracted considerable attention. However, the use of specific proteins as templates has only been demonstrated in relatively simple organisms, such as viruses, limiting the range of structures that can be used as scaffolds. This study proposes a method for synthesizing metallic structures that resemble the 3D assemblies of specific proteins in mammalian cells and animal tissues. Using 1.4 nm nanogold-conjugated antibodies, specific proteins within cells and ex vivo tissues are labeled, and then the nanogold acts as nucleation sites for growth of metal particles. As proof of concept, various metal particles are grown using microtubules in cells as templates. The metal-containing cells are applied as catalysts and show catalytic stability in liquid-phase reactions due to the rigid support provided by the microtubules. Finally, this method is used to produce metal structures that replicate the specific protein assemblies of neurons in the mouse brain or the extracellular matrices in the mouse kidney and heart. This new biotemplating approach can facilitate the conversion of specific protein structures into metallic forms in ex vivo multicellular organisms.

Cell-in-Catalytic-Shell Nanoarchitectonics: Catalytic Empowerment of Individual Living Cells by Single-Cell Nanoencapsulation

Cell-in-shell biohybrid structures, synthesized by encapsulating individual living cells with exogenous materials, have emerged as exciting functional entities for engineered living materials, with emergent properties outside the scope of biochemical modifications. Artificial exoskeletons have, to date, provided physicochemical shelters to the cells inside in the first stage of technological development, and further advances in the field demand catalytically empowered, cellular hybrid systems that augment the biological functions of cells and even introduce completely new functions to the cells. This work describes a facile and generalizable strategy for empowering living cells with extrinsic catalytic capability through nanoencapsulation of living cells with a supramolecular metal-organic complex of Fe³⁺ and benzene-1,3,5-tricarboxylic acid (BTC). A series of enzymes are embedded in situ, without loss of catalytic activity, in the Fe³⁺ -BTC shells, not to mention the superior characteristics of cytocompatible and rapid shell-forming processes. The nanoshell enhances the catalytic efficiency of multienzymatic cascade reactions by confining reaction intermediates to its internal voids and the nanoencapsulated cells acquire exogenous biochemical functions, including enzymatic cleavage of lethal octyl-β-d-glucopyranoside into d-glucose, with autonomous cytoprotection. The system will provide a versatile, nanoarchitectonic tool for interfacing biological cells with functional materials, especially for catalytic bioempowerment of living cells.

Magnetic-Powered Janus Cell Robots Loaded with Oncolytic Adenovirus for Active and Targeted Virotherapy of Bladder Cancer

A unique robotic medical platform is designed by utilizing cell robots as the active "Trojan horse" of oncolytic adenovirus (OA), capable of tumor-selective binding and killing. The OA-loaded cell robots are fabricated by entirely modifying OA-infected 293T cells with cyclic arginine-glycine-aspartic acid tripeptide (cRGD) to specifically bind with bladder cancer cells, followed by asymmetric immobilization of Fe₃ O₄ nanoparticles (NPs) on the cell surface. OA can replicate in host cells and induce cytolysis to release the virus progeny to the surrounding tumor sites for sustainable infection and oncolysis. The asymmetric coating of magnetic NPs bestows the cell robots with effective movement in various media and wireless manipulation with directional migration in a microfluidic device and bladder mold under magnetic control, further enabling steerable movement and prolonged retention of cell robots in the mouse bladder. The biorecognition of cRGD and robust, controllable propulsion of cell robots work synergistically to greatly enhance their tissue penetration and anticancer efficacy in the 3D cancer spheroid and orthotopic mouse bladder tumor model. Overall, this study integrates cell-based microrobots with virotherapy to generate an attractive robotic system with tumor specificity, expanding the operation scope of cell robots in biomedical community.

Layer-by-Layer Assembly of a Polysaccharide "Armor" on the Cell Surface Enabling the Prophylaxis of Virus Infection

Airborne pathogens, such as the world-spreading severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), cause global epidemics via transmission through the respiratory pathway. It is of great urgency to develop adequate interventions that can protect individuals against future pandemics. This study presents a nasal spray that forms a polysaccharide "armor" on the cell surface through the layer-by-layer self-assembly (LBL) method to minimize the risk of virus infection. The nasal spray has two separate components: chitosan and alginate. Harnessing the electrostatic interaction, inhaling the two polysaccharides alternatively enables the assembly of a barrier that reduces virus uptake into the cells. The results showed that this approach has no obvious cellular injury and endows cells with the ability to resist the infection of adenovirus and SARS-CoV-2 pseudovirus. Such a method can be a potential preventive strategy for protecting the respiratory tract against multiple viruses, especially the upcoming SARS-CoV-2 variants.

Killing Two Birds with One Stone: Biomineralized Bacteria Tolerate Adverse Environments and Absorb Hexavalent Chromium

Heavy metal ions in contaminated water, such as hexavalent chromium, are harmful to humans. Bacterial biosorption is an ideal method for the treatment of hexavalent chromium. However, hexavalent chromium in solution causes bacteria to produce reactive oxygen species, which leads to bacterial death and affects biosorption. We developed a microfluidics-based biomimetic mineralization method to encapsulate bacteria (e.g., Escherichia coli and Bacillus subtilis) with zeolitic imidazolate framework-8 (ZIF-8), thus allowing the bacteria to form a continuous and homogeneous shell. The artificial shells endowed bacteria with the ability to tolerate harsh environments, which was significant during the treatment of contaminated water. The adsorption of hexavalent chromium was a two-step process: first the fast physical adsorption of ZIF-8 and biosorption by bacteria (up to 30-50% adsorption in 1 day), followed by secondary biosorption after decomposition of the system. The maximum adsorption of hexavalent chromium by the encapsulated bacteria reached 90%. The microfluidic device developed in this study provides a simple method to encapsulate bacteria mildly and enable cell survival in extreme environments, offering the possibility of future microbial applications in environmental and other fields.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Reticular Nanoscience: Bottom-Up Assembly Nanotechnology

The chemistry of metal-organic and covalent organic frameworks (MOFs and COFs) is perhaps the most diverse and inclusive among the chemical sciences, and yet it can be radically expanded by blending it with nanotechnology. The result is reticular nanoscience, an area of reticular chemistry that has an immense potential in virtually any technological field. In this perspective, we explore the extension of such an interdisciplinary reach by surveying the explored and unexplored possibilities that framework nanoparticles can offer. We localize these unique nanosized reticular materials at the juncture between the molecular and the macroscopic worlds, and describe the resulting synthetic and analytical chemistry, which is fundamentally different from conventional frameworks. Such differences are mirrored in the properties that reticular nanoparticles exhibit, which we described while referring to the present state-of-the-art and future promising applications in medicine, catalysis, energy-related applications, and sensors. Finally, the bottom-up approach of reticular nanoscience, inspired by nature, is brought to its full extension by introducing the concept of augmented reticular chemistry. Its approach departs from a single-particle scale to reach higher mesoscopic and even macroscopic dimensions, where framework nanoparticles become building units themselves and the resulting supermaterials approach new levels of sophistication of structures and properties.

Cell-based biocomposite engineering directed by polymers

Biological cells such as bacterial, fungal, and mammalian cells always exploit sophisticated chemistries and exquisite micro- and nano-structures to execute life activities, providing numerous templates for engineering bioactive and biomorphic materials, devices, and systems. To transform biological cells into functional biocomposites, polymer-directed cell surface engineering and intracellular functionalization have been developed over the past two decades. Polymeric materials can be easily adopted by various cells through polymer grafting or in situ hydrogelation and can successfully bridge cells with other functional materials as interfacial layers, thus achieving the manufacture of advanced biocomposites through bioaugmentation of living cells and transformation of cells into templated materials. This review article summarizes the recent progress in the design and construction of cell-based biocomposites by polymer-directed strategies. Furthermore, the applications of cell-based biocomposites in broad fields such as cell research, biomedicine, and bioenergy are discussed. Last, we provide personal perspectives on challenges and future trends in this interdisciplinary area.

Cell-Selective Encapsulation within Metal-Organic Framework Shells via Precursor-Functionalized Aptamer Identification for Whole-Cell Cancer Vaccine

Single-cell encapsulation is an emerging technology to endow cells with various functions, of which developing new applications in vivo is in high demand. Currently, metal-organic frameworks (MOFs) that are used as nanometric shells to coat living cells, however, have not realized cell-selective encapsulation. Here, a biocompatible and selective cell encapsulation strategy based on precursor-functionalized nucleolin aptamer and in situ MOF mineralization on the aptamer-identified cancer cell surface are developed. After MOF coating, the encapsulated cancer cells undergo immunogenic cell death, which is found associated with the changed cell stiffness (indicated by Young's modulus). The immunogenic dead cancer cells are used as whole-cell cancer vaccines (WCCVs), forming the integral WCCV-in-shell structure with enhanced immunogenicity ascribing from the surface-exposed calreticulin to promote dendritic cell recruitment, antigen presentation, and T-cell activation. The major activation pathways in the immune response are identified including tumor necrosis factor signaling pathway, cytokine-cytokine receptor interaction, and Toll-like receptor signaling pathway, suggesting the potential adjuvant effect of the MOF shells. After vaccination, WCCV-in-shell shows much better tumor immunoprophylaxis than either the imperfectly coated cancer cells or the traditional WCCV. This strategy is promising for the universal and facile development of novel whole-cell vaccines.

Nanocell hybrids for green chemistry

Global concerns about reducing or minimizing the costs associated with toxic waste materials have driven the continuing development of green-cell-based biosynthesis methods. Inspired by the hybridization phenomenon of living organisms, recent interest has arisen in nanocell hybrids that possess multiple new functions. They have potential to propel biosynthesis into a new generation of green chemistry. This review article discusses the development of applications for nanocell hybrids in the areas of sustainable energy, clean environment, and green catalysis. Continuing advances in these hybrids will require combining knowledge from the fields of biology, physics, chemistry, material science, and engineering.

Robust and Long-Term Cellular Protein and Enzymatic Activity Preservation in Biomineralized Mammalian Cells

Preservation of evolved biological structure and function in robust engineering materials is of interest for storage of biological samples before diagnosis and development of vaccines, sensors, and enzymatic reactors and has the potential to avoid cryopreservation and its associated cold-chain issues. Here, we demonstrate that "freezing cells in amorphous silica" is a powerful technique for long-term preservation of whole mammalian cell proteomic structure and function at room temperature. Biomimetic silicification employs the crowded protein microenvironment of mammalian cells as a catalytic framework to proximally transform monomeric silicic acid into silicates forming a nanoscopic silica shell over all biomolecular interfaces. Silicification followed by dehydration preserves and passivates proteomic information within a nanoscale thin silica coating that exhibits size selective permeability (<3.6 nm), preventing protein leaching and protease degradation of cellular contents, while providing access of small molecular constituents for cellular enzymatic reaction. Exposure of dehydrated silicified cells to mild etchant or prolonged hydrolysis removes the silica, completely rerevealing biomolecular components and restoring their accessibility and functionality.

In situ silver nanoparticle coating of virions for quantification at single virus level

In situ labelling and encapsulation of biological entities, such as of single viruses, may provide a versatile approach to modulate their functionality and facilitate their detection at single particle level. Here, we introduce a novel virus metallization approach based on in situ coating of viruses in solution with silver nanoparticles (AgNP) in a two-step synthetic process, i.e. surface activation with a tannic acid - Sn(II) coordination complex, which subsequently induces silver ion (I) reduction. The metalic coating on the virus surface opens the opportunity for electrochemical quantification of the AgNP-tagged viruses by nano-impact electrochemistry on a microelectrode with single particle sensitivity, i.e. enable the detection of particles oherwise undetectable. We show that the silver coating of the virus particles impacting the electrode can be oxidized to produce distinct current peaks the frequency of which show a linear correlation with the virus count. The proof of the concept was done with inactivated Influenza A (H3N2) viruses resulting in their quantitation down to the femtomolar concentrations (ca. 5 × 10⁷ particles per mL) using 50 s counting sequences.

Multi-layered ZIF-coated cells for the release of bioactive molecules in hostile environments

Metal-organic framework (MOF) coatings on cells enhance viability in cytotoxic environments. Here, we show how protective multi-layered MOF bio-composite shells on a model cell system (yeast) enhance the proliferation of...

The chemistry behind room temperature synthesis of hafnium and cerium UiO-66 derivatives

RT formation of Hf and Ce UiO-66 derivatives is investigated using a one-step method where the linker and metal salt are simply combined, and a two-step method where the inorganic component is pre-heated to form metal clusters.

Multifunctional Metal-Organic Framework Exoskeletons Protect Biohybrid Sperm Microrobots for Active Drug Delivery from the Surrounding Threats

Utilizing spermatozoa as the engine unit of robotic systems at a microscale has brought revolutionized inspirations and strategies to the biomedical community. However, the motility of sperms is impaired by the surrounding threats. For example, the antisperm antibody (AsA) can specifically bind with surface antigens on the sperm membrane and adversely affect their propulsion, hindering the operation of sperm-based microrobots in practical environments. In the present work, we report a biohybrid sperm microrobot by encapsulating sperm cells within metal-organic frameworks (MOFs) and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) (ZIFSpermbot), capable of active drug delivery and cytoprotection from the biological threats of AsA. ZIF-8 NPs can be facilely coated on the sperm membrane through complexation with tannic acid. Such cell surface engineering has a negligible impact on sperm motility under optimized conditions. The selective permeability of the resulting porous ZIF-8 wrappings protects ZIFSpermbots from the specific binding of AsA, enabling the preservation of intrinsic propulsion of the sperm engine. Besides, ZIF-8 wrappings sustainably release zinc ions and attenuate the oxidative damage generated in sperm cells, allowing the maintenance of sperm movement. Combining the effective protection of sperm propulsion with the drug-loading capacity of ZIF-8 NPs provides new applicability to ZIFSpermbots in risky surroundings with AsA, exhibiting rapid migration in a microfluidic device for active drug delivery with enhanced therapeutic efficacy due to their retained effective propulsion. Imparting bioengine-based microrobots with multifunctional wrappings holds great promise for designing adaptive cell robots that endure harsh environments toward locally extended and diverse operations, facilitating their use in practical and clinical applications.

Mechanistically Scoping Cell-Free and Cell-Dependent Artificial Scaffolds in Rebuilding Skeletal and Dental Hard Tissues

Rebuilding mineralized tissues in skeletal and dental systems remains costly and challenging. Despite numerous demands and heavy clinical burden over the world, sources of autografts, allografts, and xenografts are far limited, along with massive risks including viral infections, ethic crisis, and so on. Per such dilemma, artificial scaffolds have emerged to provide efficient alternatives. To date, cell-free biomimetic mineralization (BM) and cell-dependent scaffolds have both demonstrated promising capabilities of regenerating mineralized tissues. However, BM and cell-dependent scaffolds have distinctive mechanisms for mineral genesis, which makes them methodically, synthetically, and functionally disparate. Herein, these two strategies in regenerative dentistry and orthopedics are systematically summarized at the level of mechanisms. For BM, methodological and theoretical advances are focused upon; and meanwhile, for cell-dependent scaffolds, it is demonstrated how scaffolds orchestrate osteogenic cell fate. The summary of the experimental advances and clinical progress will endow researchers with mechanistic understandings of artificial scaffolds in rebuilding hard tissues, by which better clinical choices and research directions may be approached.

Engineered osteoclasts as living treatment materials for heterotopic ossification therapy

Osteoclasts (OCs), the only cells capable of remodeling bone, can demineralize calcium minerals biologically. Naive OCs have limitations for the removal of ectopic calcification, such as in heterotopic ossification (HO), due to their restricted activity, migration and poor adhesion to sites of ectopic calcification. HO is the formation of pathological mature bone within extraskeletal soft tissues, and there are currently no reliable methods for removing these unexpected calcified plaques. In the present study, we develop a chemical approach to modify OCs with tetracycline (TC) to produce engineered OCs (TC-OCs) with an enhanced capacity for targeting and adhering to ectopic calcified tissue due to a broad affinity for calcium minerals. Unlike naive OCs, TC-OCs are able to effectively remove HO both in vitro and in vivo. This achievement indicates that HO can be reversed using modified OCs and holds promise for engineering cells as "living treatment agents" for cell therapy.