A Motor-Based Carbonaceous Nanocalabash Catalyst for Deep-Layered Bioorthogonal Chemistry

Recent Advances in the Design and Application of Asymmetric Carbon-Based Materials

Asymmetric carbon-based materials (ACBMs) have received significant attention in scientific research due to their unique structures and properties. Through the introduction of heterogeneous atoms and the construction of asymmetric ordered/disordered structures, ACBMs are optimized in terms of electrical conductivity, pore structure, and chemical composition and exhibit multiple properties such as hydrophilicity, hydrophobicity, optical characteristics, and magnetic behavior. Here, the recent research progress of ACBMs is reviewed, focusing on the potential of these materials for electrochemical, catalysis, and biomedical applications and their unique advantages over conventional symmetric carbon-based materials. Meanwhile, a variety of construction strategies of asymmetric structures, including template method, nanoemulsion assembly method, and self-assembly method, are described in detail. In addition, the contradictions between material synthesis and application are pointed out, such as the limitations of synthesis methods and morphology modulation means, as well as the trade-off between property improvement and production costs. Finally, the future development path of ACBMs is envisioned, emphasizing the importance of the close integration of theory and practice, and looking forward to promoting the research and development of a new generation of high-performance materials through the in-depth understanding of the design principles and action mechanisms of ACBMs.

Photothermal-Driven α-Amylase-Modified Polydopamine Pot-Like Nanomotors for Enhancing Penetration and Elimination of Drug-Resistant Biofilms

Biological enzyme-functionalized antibacterial nanoparticles, which can degrade biofilm and kill bacteria under mild reaction conditions, have attracted much attention for the elimination of deep-seated bacterial infections. However, the poor diffusion and penetration capabilities of recently developed biological enzyme-functionalized antibacterial nanoparticles in biofilm severely impair the eradication efficacy of deep-seated bacteria. Herein, a photothermal-driven nanomotor (denoted as APPNM) is developed for enhancing the elimination of drug-resistant biofilms and the eradication of deep-seated bacteria. The nanomotor contained a pot-like polydopamine (PDA) nanostructure and its outer surface is chemically immobilized with a layer of α-amylases. Under exposure to 808 nm near-infrared (NIR) laser irradiation, the self-propelled nanomotors, integrating the α-amylases to destroy the compact structure of biofilms, can penetrate deeply into biofilms and effectively eliminate them. Subsequently, they can accumulate on the surface of bacteria using the inherent bio-adhesion property of PDA, thereby completely eradicating deep-seated bacteria by photothermal effect. These synergistic effects enable them to exhibit superior antibiofilm effects and produce remarkable therapeutic efficacy with accelerated wound healing in vivo. With excellent biocompatibility, the as-developed nanomotors have great potential to be applied for treating biofilm-related infections.

Photothermal Cavitation-Driven Micromotor to Penetrate Cell Membrane

Photothermally driven micro/nanomotors efficiently convert light into mechanical motion, making them highly attractive for biomedical applications due to their exceptional biocompatibility and safety. However, one mystery of the photothermally driven micro/nanomotor is the wide range of reported light intensities applied, ranging from 1 W cm-2 to over 105 W cm-2. To address this mystery, we systematically investigated the propulsion of a carbon microbottle-based micromotor under three illumination conditions: continuous laser, pulsed laser, and scanning laser, where a new cavitation-driven mechanism is identified. Using a high-speed camera, we find that the instantaneous deposition of laser energy on the micromotors can lead to transient and localized evaporation of the solvent, creating cavitation bubbles to drive micromotors with ultrafast speed, where instantaneous velocity over 1 m s-1 is observed. Through precise modulation of the scanning orientation and intensity of the laser, directional propulsion and targeted explosions of the microbottles are achieved, where the instant force is strong enough to penetrate live cell membranes. Finally, the cavitation-driven micromotors are exploited as gene transfection tools, where targeted cytoplasmic transfection is demonstrated.

Exploring New Bioorthogonal Catalysts: Scaffold Diversity in Catalysis for Chemical Biology

Bioorthogonal catalysis has revolutionized the field of chemical biology by enabling selective and controlled chemical transformations within living systems. Research has converged on the development of innovative catalyst scaffolds, seeking to broaden the scope of bioorthogonal reactions, boost their efficiency, and surpass the limitations of conventional catalysts. This review provides a comprehensive overview of the latest advancements in bioorthogonal catalyst research based on different scaffold materials. Through an in-depth analysis of fabrication strategies and applications of bioorthogonal catalysts, this review discusses the design principles, mechanisms of action, and applications of these novel catalysts in chemical biology. Current challenges and future directions in exploring the scaffold diversity are also highlighted. The integration of diverse catalyst scaffolds offers exciting prospects for precise manipulation of biomolecules and the development of innovative therapeutic strategies in chemical biology. In addition, the review fills in the gaps in previous reviews, such as in fully summarizing the presented scaffold materials applied in bioorthogonal catalysts, emphasizing the potential impact on advancing bioorthogonal chemistry, and offering prospects for future development in this field.

Influence of the neck length of urease-powered flask-like colloidal motors on their kinematic behavior

Enzyme-powered synthetic colloidal motors hold promising potential for in vivo medical applications because of their unique features such as self-propulsion, sub-micrometer size, fuel bioavailability, and structural and functional versatility. However, the key parameters influencing the propulsion efficiency of enzyme-powered colloidal motors still remain unclear. Here, we report the effect of the neck length of urease-powered pentosan flask-like colloidal motors on their kinematic behavior resembling the role of bacterial flagella. The sub-micrometer-sized and streamlined pentosan flask-like colloidal motors with variable neck lengths are synthesized through a facile interfacial dynamic assembly and polymerization strategy. The urease molecules are loaded through vacuum infusion technology and thus the urease-triggered catalytic reaction can propel the pentosan flask-like colloidal motors to move autonomously in the urea solution. The self-propelled speed of these pentosan flask-like colloidal motors significantly increases with the elongating neck lengths. The mechanism of the relationship between the neck length and self-propelled motion is that a longer neck can provide a larger self-propelled force due to the larger force area and stabilize the rotation because of the increased rotational friction. This research can provide guidance for the design of biomedical colloidal motors.

Cu-MOF-based targeted nanomedicine utilizing biorthogonally catalyzed chemotherapy and chemodynamic therapy with spatiotemporal orchestration to treat hepatocellular carcinoma

A nanomedicine was developed using a Cu-based metal-organic framework (MOF) to co-deliver Cu(I) and prodrugs for targeted biorthogonally catalyzed chemotherapy and chemodynamic therapy of hepatocellular carcinoma.

In-situ activation of biomimetic single-site bioorthogonal nanozyme for tumor-specific combination therapy

Copper-catalyzed click chemistry offers creative strategies for activation of therapeutics without disrupting biological processes. Despite tremendous efforts, current copper catalysts face fundamental challenges in achieving high efficiency, atom economy, and tissue-specific selectivity. Herein, we develop a facile "mix-and-match synthetic strategy" to fabricate a biomimetic single-site copper-bipyridine-based cerium metal-organic framework (Cu/Ce-MOF@M) for efficient and tumor cell-specific bioorthogonal catalysis. This elegant methodology achieves isolated single-Cu-site within the MOF architecture, resulting in exceptionally high catalytic performance. Cu/Ce-MOF@M favors a 32.1-fold higher catalytic activity than the widely used MOF-supported copper nanoparticles at single-particle level, as first evidenced by single-molecule fluorescence microscopy. Furthermore, with cancer cell-membrane camouflage, Cu/Ce-MOF@M demonstrates preferential tropism for its parent cells. Simultaneously, the single-site CuII species within Cu/Ce-MOF@M are reduced by upregulated glutathione in cancerous cells to CuI for catalyzing the click reaction, enabling homotypic cancer cell-activated in situ drug synthesis. Additionally, Cu/Ce-MOF@M exhibits oxidase and peroxidase mimicking activities, further enhancing catalytic cancer therapy. This study guides the reasonable design of highly active heterogeneous transition-metal catalysts for targeted bioorthogonal reactions.

Catalytic Biomaterials-Activated In Situ Chemical Reactions: Strategic Modulation and Enhanced Disease Treatment

Chemical reactions underpin biological processes, and imbalances in critical biochemical pathways within organisms can lead to the onset of severe diseases. Within this context, the emerging field of "Nanocatalytic Medicine" leverages nanomaterials as catalysts to modulate fundamental chemical reactions specific to the microenvironments of diseases. This approach is designed to facilitate the targeted synthesis and localized accumulation of therapeutic agents, thus enhancing treatment efficacy and precision while simultaneously reducing systemic side effects. The effectiveness of these nanocatalytic strategies critically hinges on a profound understanding of chemical kinetics and the intricate interplay of reactions within particular pathological microenvironments to ensure targeted and effective catalytic actions. This review methodically explores in situ catalytic reactions and their associated biomaterials, emphasizing regulatory strategies that control therapeutic responses. Furthermore, the discussion encapsulates the crucial elements-reactants, catalysts, and reaction conditions/environments-necessary for optimizing the thermodynamics and kinetics of these reactions, while rigorously addressing both the biochemical and biophysical dimensions of the disease microenvironments to enhance therapeutic outcomes. It seeks to clarify the mechanisms underpinning catalytic biomaterials and evaluate their potential to revolutionize treatment strategies across various pathological conditions.

Dynamic Covalent Prodrug Nanonetworks via Reaction-Induced Self-Assembly for Periodontitis Treatment

Periodontitis is characterized by dysbiotic biofilms, gingival inflammation, and bone resorption, highlighting the urgent need for a comprehensive approach to drug combination therapy. In this study, we introduce dynamic covalent nanonetworks (dcNNWs) synthesized through a one-pot, four-component reaction-induced self-assembly method using polyamines, 2-formylphenylboronic acid, epigallocatechin gallate, and alendronate. The formation of iminoboronate bonds drives the creation of dcNNWs, allowing controlled release in the periodontitis microenvironment. The inclusion of catechol and bisphosphonate imparts exceptional bioadhesive properties to the dcNNWs, enhancing their efficacy in preventing pathogenic bacterial biofilm formation and eliminating mature biofilms. Moreover, the dcNNWs efficiently absorb pathogen-associated molecular patterns and scavenge excess reactive oxygen species, regulating the local immune response and demonstrating anti-inflammatory effects. Additionally, the released polyphenol and alendronate from the dcNNWs alleviated inflammation and enhanced osteogenesis significantly. The detailed synergistic effects of dcNNWs in biofilm eradication, anti-inflammation, and bone remodeling, with minimal impact on healthy tissues, are confirmed in a rat model of periodontitis. With a facile synthesis process, excellent synergistic effects in periodontitis treatment, and biocompatibility, our dcNNWs present a promising and translational solution for the effective management of periodontitis.

Bioorthogonal chemistry-based prodrug strategies for enhanced biosafety in tumor treatments: current progress and challenges

Cancer is a significant global health challenge, and while chemotherapy remains a widely used treatment, its non-specific toxicity and broad distribution can lead to systemic side effects and limit its effectiveness against tumors. Therefore, the development of safer chemotherapy alternatives is crucial. Prodrugs hold great promise, as they remain inactive until they reach the cancer site, where they are selectively activated by enzymes or specific factors, thereby reducing side effects and improving targeting. However, subtle differences in the microenvironments between tumors and normal tissue may still result in unintended cytotoxicity. Bioorthogonal reactions, known for their selectivity and precision without interfering with natural biochemical processes, are gaining attention. When combined with prodrug strategies, these reactions offer the potential to create highly effective chemotherapy drugs. This review examines the safety and efficacy of prodrug strategies utilizing various bioorthogonal reactions in cancer treatment.

Smart Bioorthogonal Nanozymes: From Rational Design to Appropriate Bioapplications

Bioorthogonal chemistry has provided an elaborate arsenal to manipulate native biological processes in living systems. As the great advancement of nanotechnology in recent years, bioorthogonal nanozymes are innovated to tackle the challenges that emerged in practical biomedical applications. Bioorthogonal nanozymes are uniquely positioned owing to their advantages of high customizability and tunability, as well as good adaptability to biological systems, which bring exciting opportunities for biomedical applications. More intriguingly, the great advancement in nanotechnology offers an exciting opportunity for innovating bioorthogonal catalytic materials. In this comprehensive review, the significant progresses of bioorthogonal nanozymes are discussed with both spatiotemporal controllability and high performance in living systems, and highlight their design principles and recent rapid applications. The remaining challenges and future perspectives are then outlined along this thriving field. It is expected that this review will inspire and promote the design of novel bioorthogonal nanozymes, and facilitate their clinical translation.

On-Demand Activatable and Integrated Bioorthogonal Nanocatalyst against Biofilm-Associated Infections

Bioorthogonal chemistry has emerged as a powerful tool for manipulating biological processes. However, difficulties in controlling the exact location and on-demand catalytic synthesis limit its application in biological systems. Herein, this work constructs an activatable bioorthogonal system integrating a shielded catalyst and prodrug molecules to combat biofilm-associated infections. The catalytic species is activated in response to the hyaluronidase (HAase) secreted by the bacteria and the acidic pH of the biofilm, which is accompanied by the release of prodrugs, to achieve the bioorthogonal catalytic synthesis of antibacterial molecules in situ. Moreover, the system can produce reactive oxygen species (ROS) to disperse bacterial biofilms, enabling the antibacterial molecules to penetrate the biofilm and eliminate the bacteria within it. This study promotes the design of efficient and safe bioorthogonal catalysts and the development of bioorthogonal chemistry-mediated antibacterial strategies.

Enhanced Bacterial Cuproptosis-Like Death via Reversal of Hypoxia Microenvironment for Biofilm Infection Treatment

A recently emerging cell death pathway, known as copper-induced cell death, has demonstrated significant potential for treating infections. Existing research suggests that cells utilizing aerobic respiration, as opposed to those reliant on glycolysis, exhibit greater sensitivity to copper-induced death. Herein, a MnO2-loaded copper metal-organic frameworks platform is developed denoted as MCM, to enhance bacterial cuproptosis-like death via the remodeling of bacterial respiratory metabolism. The reversal of hypoxic microenvironments induced a cascade of responses, encompassing the reactivation of suppressed immune responses and the promotion of osteogenesis and angiogenesis. Initially, MCM catalyzed O2 production, alleviating hypoxia within the biofilm and inducing a transition in bacterial respiration mode from glycolysis to aerobic respiration. Subsequently, the sensitized bacteria, characterized by enhanced tricarboxylic acid cycle activity, underwent cuproptosis-like death owing to increased copper concentrations and aggregated intracellular dihydrolipoamide S-acetyltransferase (DLAT). The disruption of hypoxia also stimulated suppressed dendritic cells and macrophages, thereby strengthening their antimicrobial activity through chemotaxis and phagocytosis. Moreover, the nutritional effects of copper elements, coupled with hypoxia alleviation, synergistically facilitated the regeneration of bones and blood vessels. Overall, reshaping the infection microenvironment to enhance cuproptosis-like cell death presents a promising avenue for eradicating biofilms.

Rotary FoF1-ATP Synthase-Driven Flasklike Pentosan Colloidal Motors with ATP Synthesis and Storage

We report the hierarchical assembly of a chloroplast-derived rotary FoF1-ATPase motor-propelled flasklike pentosan colloidal motor (FPCM) with the ability of the synthesis, storage, and triggered release of biological energy currency ATP. These streamlined and submicrometer-sized hollow flasklike pentosan colloidal motors are prepared by combining a soft-template-based hydrothermal polymerization with a vacuum infusion of chloroplast-derived proteoliposomes containing rotary FoF1-ATPase motors. The generation of proton motive force across the proteoliposomes by injecting an acidic buffer solution promotes the rotation of FoF1-ATPase motors to drive the self-propelled motion of FPCMs, accompanying the inner ATP synthesis and storage. These rotary FoF1-ATPase motor-powered FPCMs exhibit a chemotactic behavior by migrating from their neck opening to their round bottom along a proton gradient of the external environment (negative chemotaxis). Such rotary biomolecular motor-driven flasklike pentosan colloidal motors with ATP synthesis and on-demand release make them promising candidates for engineering novel intelligent nanocarriers to actively regulate cellular metabolism.

Poly(d-amino acid) Nanoparticles Target Staphylococcal Growth and Biofilm Disassembly by Interfering with Peptidoglycan Synthesis

d-Amino acids are signals for biofilm disassembly. However, unexpected metabolic pathways severely attenuate the utilization of d-amino acids in biofilm disassembly, resulting in unsatisfactory efficiency. Herein, three-dimensional poly(d-amino acid) nanoparticles (NPs), which possess the ability to block intracellular metabolism, are constructed with the aim of disassembling the biofilms. The obtained poly(α-N-acryloyl-d-phenylalanine)-block-poly(β-N-acryloyl-d-aminoalanine NPs (denoted as FA NPs) present α-amino groups and α-carboxyl groups of d-aminoalanine on their surface, which guarantees that FA NPs can effectively insert into bacterial peptidoglycan (PG) via the mediation of PG binding protein 4 (PBP4). Subsequently, the FA NPs trigger the detachment of amyloid-like fibers that connect to the PG and reduce the number of polysaccharides and proteins in extracellular polymeric substances (EPS). Finally, FA NPs damage the structural stability of EPS and lead to the disassembly of the biofilm. Based on this feature, FA NPs significantly enhance the killing efficacy of encapsulated sitafloxacin sesquihydrate (Sita) by facilitating the penetration of Sita within the biofilm, achieving complete elimination of Staphylococcal biofilm in mice. Therefore, this study strongly demonstrates that FA NPs can effectively improve biofilm disassembly efficacy and provide great potential for bacterial biofilm infection treatment.

Photothermal-driven micro/nanomotors: From structural design to potential applications

Micro/nanomotors (MNMs) that accomplish autonomous movement by transforming external energy into mechanical work are attractive cargo delivery vehicles. Among various propulsion mechanisms of MNMs, photothermal propulsion has gained considerable attention because of their unique advantages, such as remote, flexible, accurate, biocompatible, short response time, etc. Moreover, besides as a propulsion source, the light has been extensively investigated as an excitation source in bioimaging, photothermal therapy (PTT), photodynamic therapy (PDT) and so on. Furthermore, the geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility. Hence, this review article provides a comprehensive overview of structural design principles and construction strategies of photothermal-driven MNMs, and their emerging nanobiomedical applications. Finally, we further provide an outlook towards prospects and challenges during the development of photothermal-driven MNMs in the future. STATEMENT OF SIGNIFICANCE: Photothermal-driven micro/nanomotors (MNMs) that are regarded as functional cargo delivery tools have gained considerable attention because of unique advantages in propulsion mechanisms, such as remote, flexible, accurate and fully biocompatible light manipulation and extremely short light response time. The geometric topology and morphology of MNMs have a tremendous impact on improving their performance in motion behavior under NIR light propulsion, environmental suitability and functional versatility of MNMs. There are no reports about the review focusing on photothermal-driven MNMs up to now. Herein, we systematically review the latest progress of photothermal-driven MNMs including design principle, fabrication strategy of various MNMs with different structures and nanobiomedical applications. Moreover, the summary and outlook on the development prospects and challenges of photothermal-driven MNMs are proposed, hoping to provide new ideas for the future design of photothermal-driven MNMs with efficient propulsion, multiple functions and high biocompatibility.

Target-Specific Bioorthogonal Reactions for Precise Biomedical Applications

Bioorthogonal chemistry is a promising toolbox for dissecting biological processes in the native environment. Recently, bioorthogonal reactions have attracted considerable attention in the medical field for treating diseases, since this approach may lead to improved drug efficacy and reduced side effects via in situ drug synthesis. For precise biomedical applications, it is a prerequisite that the reactions should occur in the right locations and on the appropriate therapeutic targets. In this minireview, we highlight the design and development of targeted bioorthogonal reactions for precise medical treatment. First, we compile recent strategies for achieving target-specific bioorthogonal reactions. Further, we emphasize their application for the precise treatment of different therapeutic targets. Finally, a perspective is provided on the challenges and future directions of this emerging field for safe, efficient, and translatable disease treatment.

Progress in controllable bioorthogonal catalysis for prodrug activation

Bioorthogonal catalysis, a class of catalytic reactions that are mediated by abiotic metals and proceed in biological environments without interfering with native biochemical reactions, has gained ever-increasing momentum in prodrug delivery over the past few decades. Albeit great progress has been attained in developing new bioorthogonal catalytic reactions and optimizing the catalytic performance of transition metal catalysts (TMCs), the use of TMCs to activate chemotherapeutics at the site of interest in vivo remains a challenging endeavor. To translate the bioorthogonal catalysis-mediated prodrug activation paradigm from flasks to animals, TMCs with targeting capability and stimulus-responsive behavior have been well-designed to perform chemical transformations in a controlled manner within highly complex biochemical systems, rendering on-demand drug activation to mitigate off-target toxicity. Here, we review the recent advances in the development of controllable bioorthogonal catalysis systems, with an emphasis on different strategies for engineering TMCs to achieve precise control over prodrug activation. Furthermore, we outline the envisaged challenges and discuss future directions of controllable bioorthogonal catalysis for disease therapy.

Inorganic nanoparticles as scaffolds for bioorthogonal catalysts

Bioorthogonal transition metal catalysts (TMCs) transform therapeutically inactive molecules (pro-drugs) into active drug compounds. Inorganic nanoscaffolds protect and solubilize catalysts while offering a flexible design space for decoration with targeting elements and stimuli-responsive activity. These "drug factories" can activate pro-drugs in situ, localizing treatment to the disease site and minimizing off-target effects. Inorganic nanoscaffolds provide structurally diverse scaffolds for encapsulating TMCs. This ability to define the catalyst environment can be employed to enhance the stability and selectivity of the TMC, providing access to enzyme-like bioorthogonal processes. The use of inorganic nanomaterials as scaffolds TMCs and the use of these bioorthogonal nanozymes in vitro and in vivo applications will be discussed in this review.

A biotin-guided near-infrared fluorescent probe for imaging hydrogen sulfide and differentiating cancer cells

Imaging cancer specific biomarkers with near-infrared (NIR) fluorescent probes can help inaccurate diagnosis. Hydrogen sulfide (H₂S) has been reported to be involved in many physiological and pathological processes and is considered as one of the key gasotransmitters during the development of cancer. To achieve specific H₂S detection in cancer cells, we reported a biotin-guided NIR fluorescent sensor P1 targeting a cancer cell surface biomarker, based on the H₂S-specific thiolysis of the NBD-amine-hemicyanine conjugate. The probe showed a fast turn-on signal at 754 nm upon H₂S activation and good selectivity towards H₂S over millimolar levels of other biothiols. We successfully employed P1 to image endogenous H₂S and demonstrated its tumor-targeting ability in live cells. P1 could differentiate multiple cancer cells with various levels of H₂S from normal cells, indicating its potential for cancer imaging.

Bioorthogonal nanozymes: an emerging strategy for disease therapy

Transition metal catalysts (TMCs), capable of performing bioorthogonal reactions, have been engineered to trigger the formation of bioactive molecules in a controlled manner for biomedical applications. However, the widespread use of TMCs based biorthogonal reactions in vivo is still largely limited owing to their toxicity, poor stability, and insufficient targeting properties. The emergence of nanozymes (nanomaterials with enzyme-like activity), especially bioorthogonal nanozymes that combine the bioorthogonal catalytic activity of TMCs, the physicochemical properties of nanomaterials, and the enzymatic properties of classical nanozymes potentially provide opportunities to address these challenges. Thus, they can be used as multifunctional catalytic platforms for disease treatment and will be far-reaching. In this review, we first briefly recall the classical TMC-based bioorthogonal reactions. Furthermore, this review highlights the diverse strategies for manufacturing bioorthogonal nanozymes and their potential for therapeutic applications, with the goal of facilitating bioorthogonal catalysis in the clinic. Finally, we present challenges and the prospects of bioorthogonal nanozymes in bioorthogonal chemistry.