Bioorthogonal catalytic patch

Advances in locally administered nucleic acid therapeutics

Nucleic acid drugs represent the latest generation of precision therapeutics, holding significant promise for the treatment of a wide range of intractable diseases. Delivery technology is crucial for the clinical application of nucleic acid drugs. However, extrahepatic delivery of nucleic acid drugs remains a significant challenge. Systemic administration often fails to achieve sufficient drug enrichment in target tissues. Localized administration has emerged as the predominant approach to facilitate extrahepatic delivery. While localized administration can significantly enhance drug accumulation at the injection sites, nucleic acid drugs still face biological barriers in reaching the target lesions. This review focuses on non-viral nucleic acid drug delivery techniques utilized in local administration for the treatment of extrahepatic diseases. First, the classification of nucleic acid drugs is described. Second, the current major non-viral delivery technologies for nucleic acid drugs are discussed. Third, the bio-barriers, administration approaches, and recent research advances in the local delivery of nucleic acid drugs for treating lung, brain, eye, skin, joint, and heart-related diseases are highlighted. Finally, the challenges associated with the localized therapeutic application of nucleic acid drugs are addressed.

Biomimetic hyaluronic acid-stabilized zinc oxide nanoparticles in acne treatment: A preclinical and clinical approach

Acne vulgaris is a common chronic inflammatory skin condition, often caused by C. acnes infection. While ZnO has shown promise as an antibacterial agent in acne treatment, concerns over toxicity and non-selective bacterial killing remain. In this study we developed a hyaluronic acid-stabilized nano‑zinc oxide (HA-ZnO) formulation aimed at enhancing the therapeutic efficacy and safety of ZnO for acne treatment. HA-ZnO was synthesized through biomimetic mineralization. HA-ZnO targeted acne-prone areas, especially sebaceous glands, without skin penetration. HA-ZnO demonstrated selective antibacterial activity against C. acnes, exhibiting a killing efficacy more than 16 times greater than that against S. epidermidis. The HA coating also improved ZnO's stability in acidic conditions, mitigating potential toxicity and side effects. Additionally, the sustained release of Zn2+ promoted cell proliferation and migration, reducing sebum secretion, and exerting anti-inflammatory effects, supporting scar-free acne repair and preventing recurrence. In preclinical models, HA-ZnO outperformed erythromycin ointment in treating acne, with no toxicity observed in zebrafish and HET-CAM. A clinical trial further confirmed its efficacy in reducing acne lesions and redness, with high safety. These results highlight HA-ZnO as a promising therapeutic strategy for acne, combining potent antibacterial and skin-repairing effects with enhanced safety.

Creation of Artificial Subcellular Organelles Using Compartmentalized Escherichia coli Bodies for Artificial Metalloenzyme-Mediated Abiotic Catalysis in Eukaryotic Cells

Artificial metalloenzymes (ArMs) stand out as excellent tools mediating intracellular abiotic transformations due to their multifaceted advantages, including their adaptability through directed evolution and availability as whole-cell catalysts. However, the applications of ArMs as exogenous agents in eukaryotic systems remain challenging due to issues with protein purification and delivery, metalloenzyme stability, and complex catalyst preparation. In this article, we present a method inspired by nature's endosymbiotic process, enabling the direct use of ArMs residing within the bacterial cells that express them as whole-cell-based catalytic platforms in eukaryotic cells. This approach utilizes HaloTag-SNAPTag fusion protein as the ArM scaffold, which undergoes liquid-liquid phase separation to form sanctuaries in Escherichia coli for different ArMs created from the same fusion protein. Such compartmentalized E. coli are then sterilized and granted cell permeability with polymer decoration so that they may enter eukaryotic cells and work as artificial subcellular organelles, mediating abiotic transformations using those well-protected ArMs residing within. We further demonstrate the potential of this strategy in therapeutic applications in proof-of-concept demonstrations, by showing that these encapsulated ArMs can be viable options for intracellular bacterial pathogen elimination and cancer therapy through prodrug activation in live cells and animals. Likely, this strategy will suggest a different pathway for expanding ArM applications in chemical biology and biomedicine.

Construction of In Situ Personalized Cancer Vaccines by Bioorthogonal Catalytic Microneedles for Augmented Melanoma Immunotherapy

In situ personalized tumor vaccines are produced directly at the primary tumor site by killing cancer cells and stimulating immune cells, they are effective against individuals and bypass the complexity and high cost of in vitro vaccine production. However, their clinical application is hindered by insufficient efficiency in inducing immunogenic cancer cell death (ICD) and systemic inflammation caused by immune adjuvants. Here, personalized cancer vaccines are constructed in situ for melanoma immunotherapy based on bioorthogonal catalytic microneedles, which enable the catalytic release of prodrugs at tumor sites and mediate strong ICD and an enhanced tumor immune response while avoiding systemic immune storms and toxic side effects. By incorporating TiO2 nanosheets supported Pd into swellable microneedles, the bioorthogonal microneedles are constructed to catalyze the depropargylation reaction of doxorubicin (DOX) prodrug and imiquimod (IMQ) prodrug in situ. The activated DOX at subcutaneous tumor sites induced strong ICD and released tumor-associated antigens. Concurrently, the activated IMQ acts as a Toll-like receptor (TLR7) agonist, enhancing the anti-tumor immune response. In vivo experiments demonstrate that this immunotherapy achieves ≈97% inhibition of primary tumors and effectively inhibits untreated distant tumors (≈94% inhibition) and lung metastasis (≈92% inhibition).

Enhancing melanoma therapy with hydrogel microneedles

Melanoma is highly invasive and resistant to conventional treatments, accounting for nearly 75% of skin cancer-related deaths globally. Traditional therapies, such as chemotherapy and immunotherapy, often exhibit limited efficacy and are associated with significant side effects due to systemic drug exposure. Microneedles (MNs), as an emerging drug delivery system, offer multiple advantages, including safety, painlessness, minimal invasiveness, and controlled drug release. Among these, hydrogel microneedles (HMNs) stand out due to their extracellular matrix-like structure and swelling-induced continuous hydrogel channels, which enable the direct delivery of therapeutic agents into the tumor microenvironment (TME). This approach enhances drug bioavailability while reducing systemic toxicity, establishing HMNs as a promising platform for melanoma treatment. This review highlights recent advancements in HMNs for melanoma therapy, focusing on their applications in biomarker extraction for early diagnosis and their role in supporting multimodal treatment strategies, such as chemotherapy, immunotherapy, phototherapy, targeted therapy, and combination therapy. Furthermore, the current matrix materials and fabrication techniques for HMNs are discussed. Finally, the limitations of HMNs in melanoma treatment are critically analyzed, and recommendations for future research and development are provided.

Biorhythm-mimicking growth hormone patch

Timing dosing throughout the day impacts the therapeutic efficacy and side effects of medications. Thus, optimizing release profiles to synchronize drug concentrations with natural rhythms is critical for optimal therapeutic benefits. However, existing delivery systems are still inefficient in delivering drugs in a biorhythm-mimicking fashion. Here we describe a biorhythm-inspired growth hormone transdermal microneedle patch with multistage drug release that mimics the natural rhythm of human growth hormone secretion at night. Programmed drug release is achieved by combining a 'burst-release' module with several 'delayed-release' modules. Compared with the subcutaneous daily injections currently used in clinics, the patch exhibits enhanced efficacy in terms of longitudinal bone growth and bone quality, leading to bone length increases of ~10 mm and ~5 mm in healthy rats and growth hormone gene knockout mice, respectively. Our findings reveal that the biorhythm-mimicking release pattern significantly enhances growth hormone bioavailability and effectively regulates the growth-related biological process, thus boosting the secretion of insulin-like growth factor-1 and ultimately promoting bone growth.

Dendritic Platinum Nanoparticles Shielded by Pt-S PEGylation as Intracellular Reactors for Bioorthogonal Uncaging Chemistry

Beyond their classical role as cytotoxics, Platinum (Pt) coordination complexes recently joined the selected group of transition metals capable of performing bioorthogonal reactions in living environments. To minimize their reactivity towards nucleophiles, which limit their catalytic performance, we investigated the use of Pt(0) with different forms, sizes and surface functionalization. We report herein the development of PEGylated Pt nanodendrites with the capacity to activate prodyes and prodrugs in cell culture and in vivo. Their dendritic morphology together with their surface shielding through Pt-S-bonded PEGylation synergistically contributed to create catalytic nanoreactors compatible with the highly-crowded and reductive environment of the cell cytoplasm, thereby facilitating in situ bioorthogonal drug uncaging in cancer cells in 2D and 3D culture, including in microfluidic systems, and xenografted in zebrafish.

A Spatially Distributed Microneedle System for Bioorthogonal T Cell-Guided Cancer Therapy

Chimeric antigen receptor (CAR)-T cell therapy represents a promising strategy for cancer treatment. However, the diversity of solid tumor antigens and the poor infiltration of CAR-T cells significantly hinder the efficacy of CAR-T therapies against tumors. Here, a spatially distributed microneedle system (SDMNS) is developed that leverages bioorthogonal reactions to activate and guide endogenous T cells to tumors for effective destruction. The SDMNS consists of two dissolving microneedles, each loaded with complementary bioorthogonal groups and applied separately to lymph nodes and tumor sites. One microneedle loaded with two dibenzocyclooctyne (DBCO)-modified antibodies activates T cells and labels them with bioorthogonal groups in lymph nodes. The other microneedle, containing N-azidoacetylmannosamine-tetraacylated (Ac4ManNAz) for glycometabolic labeling of tumor cells, and the T cell chemotactic factor IP10, is applied directly to the tumor site. The in vivo studies demonstrate that SDMNS effectively directs the migration and infiltration of endogenous activated T cells into the tumors. Through a bioorthogonal click reaction, DBCO-modified T cells conjugate with azide (N3)-modified tumor cells, eliciting robust antitumor immune responses and durable immune memory. The SDMNS offers a novel strategy to overcomes tumor heterogeneity by facilitating the directed migration of endogenous T cells.

Bioorthogonal catalytic microvesicle-mediated prodrug activation against liver cancer

OBJECTIVE

Exploring the role and mechanism of a novel bioorthogonal system using transition metals as catalysts in the treatment of hepatocellular carcinoma (HCC).

METHODS

Initially, a catalytic ruthenium (Ru) complex and the substrate alloc-RH 110 were synthesized, followed by the identification of their structures utilizing mass spectrometry and nuclear magnetic resonance (NMR) techniques. The catalytic efficacy of the Ru complex was then assessed using a fluorescence spectrophotometer. Subsequently, employing HepG2 cells as the cellular source, cell-derived vesicles encapsulating the Ru complexes, designated as EVs@Ru, were prepared. The EVs@Ru were characterized by measuring their particle size and Zeta potential, observing morphological features under transmission electron microscopy (TEM), and detecting specific protein expressions via Western blot analysis. Drug loading within the EVs@Ru was quantified using inductively coupled plasma mass spectrometry (ICP-MS), and their catalytic efficiency was evaluated. In vitro, the low-activity prodrug alloc-DOX was synthesized and its toxicity, along with the drug concentration in EVs@Ru, was determined. Further, the catalytic cytotoxicity of alloc-DOX against HepG2 cells encapsulated in EVs@Ru was analyzed through microscopic observation, CCK-8 assays, and apoptosis experiments. For in vivo studies, a tumor-bearing mouse model was established using human liver cancer HepG2 cells to observe the antitumor effects. Finally, the primary organs of each group of tumor-bearing mice were assessed for in vivo safety.

RESULTS

ESI-MS and 1H NMR confirmed the accurate structure of Ru complexes and alloc-RH 110. The Ru complexes achieved full catalytic conversion of alloc-RH 110 within 24 hours. EVs and EVs@Ru exhibited particle sizes of ∼116.85 nm and ∼281.88 nm, respectively, with Zeta potentials of ∼-20.86 mV and ∼-25.89 mV, both appearing quasi-circular under TEM. WB analysis verified the presence of vesicle-specific marker proteins in both, confirming their cell-derived nature. ICP-MS determined a drug loading of 21.90 μg/mL for EVs@Ru, with an encapsulation efficiency of ∼24.86%. Fluorescence spectrophotometry demonstrated 100% catalytic efficiency for EVs@Ru. Synthetic alloc-DOX validated by 1H NMR and ESI-MS matched literature data. MTT and CCK-8 assays confirmed low toxicity for alloc-DOX and Ru complexes, setting the experimental drug concentration at 4μM. In vitro, the EVs@Ru+alloc-DOX group exhibited potent HepG2 cell killing and apoptosis. In vivo, this group significantly inhibited tumor growth in tumor-bearing mice, with no observed toxicity to vital organs, indicating good biosafety.

CONCLUSION

The integration of bio-derived microvesicles (MVs) with transition metal catalysts has resulted in a biologically orthogonal system for efficient Ru complex delivery to tumor sites. This system facilitates controlled release of the Ru complexes, enabling tumor cell elimination. This innovative strategy holds great promise for enhancing tumor immunity and targeted therapeutic approaches.

Programmable production of bioactive extracellular vesicles in vivo to treat myocardial infarction

Current myocardial infarction (MI) treatment strategies remain challenged in suboptimal pharmacokinetics and potential adverse effects. Here we present a bioelectronic interface capable of producing on-demand abundant bioactive extracellular vesicles (EVs) near the MI area for in-situ localized treatment. The technology, termed electroactive patch for wirelessly and controllable EV generation (ePOWER), leverages wireless bioelectronic patch to stimulate embedded electrosensitive macrophages, actively modulating the biosynthesis of EVs and enabling EV production with high programmability to be delivered directly to the MI area. ~2400% more bioactive EVs were produced per cell under our ePOWER system. When surgically implanted, we demonstrate the therapeutic potential of in-situ EV production system to alleviate MI symptoms and improve cardiac function. This programmable ePOWER technology enables in-situ production of therapeutically rich EVs, thus reducing the need for exogenous cell expansion platforms and dedicated delivery, holding promise as a therapeutic all-in-one platform to treat various diseases.

In Vivo Self-Assembly of PROTACs by Bioorthogonal Chemistry for Precision Cancer Therapy

Proteolysis targeting chimeras (PROTACs) hold immense promise for targeted protein degradation; however, challenges such as off-target effects, poor drug-likeness properties, and the "hook effect" remain. This study introduces Nano-Click-formed PROTACs (Nano-CLIPTACs) for precise tumor protein degradation in vivo. Traditional PROTACs with high molecular weight were first divided into two smaller druglike precursors capable of self-assembling to form functional PROTACs through a bioorthogonal reaction. Then, optimal CLIPTACs precursors (W4 and Z2) were encapsulated individually into cyclic RGDfC-peptide-modified liposomes to prepare Nano-CLIPTACs, enabling tumor-targeted delivery and subsequent in situ self-assembly to form PROTACs WZ42 within tumor cells. The degradation abilities of Nano-CLIPTACs in vitro and in vivo were further verified using a key oncology target, anaplastic lymphoma kinase (ALK), validating the safety, efficacy and "anti-hook effect" of this strategy. Overall, Nano-CLIPTACs represent a critical step towards the clinical translation of PROTACs technology for precise targeted anti-cancer therapies.

Biomineralized Nanocomposite-Integrated Microneedle Patch for Combined Brachytherapy and Photothermal Therapy in Postoperative Melanoma Recurrence and Infectious Wound Healing

In the surgical management of malignant melanoma, incomplete tumor resection and large-area cutaneous defects are major contributors to high locoregional recurrence and uncontrolled wound infections, resulting in poor prognosis and prolonged recovery times for patients. Herein, a versatile nanocomposite microneedle patch (referred to as GM-Ag2S/Ca32P) is designed to simultaneously eliminate residual tumor post-surgery and promote the healing of infectious wounds. This microneedle patch effectively penetrates subcutaneous tissues, delivering therapeutic payloads to infiltrating tumor cells and bacteria. The Ag2S/Ca32P nanocomposites encapsulated within the microneedle patch decompose in the acidic microenvironment of tumors and bacterial biofilms, releasing radioactive 32P and Ag2S nanodots, which enhance tumor eradication and bacteria killing through synergistic brachytherapy and photothermal therapy (PTT). Moreover, the nanocomposite microneedle patch promotes scar-free wound healing by reducing inflammation, and promoting granulation tissue formation, collagen deposition, and angiogenesis, thanks to localized hyperthermia, radiation, and the swelling and biodegradation of the microneedle matrices. This microneedle patch-based postoperative adjuvant therapy offers a comprehensive strategy for addressing melanoma recurrence and infectious wound healing, with promising potential for clinical application in postsurgical management.

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.

Nanobiohybrid Oncolytic Bacteria with Optimized Intratumoral Distribution for Combined Sono-Photodynamic/Immunotherapy

"Living therapeutic carriers" present a promising avenue for cancer research, but it is still challenging to achieve uniform and durable distribution of payloads throughout the solid tumor owing to the tumor microenvironment heterogeneity. Herein, a living drug sprinkle biohybrid (YB1-HCNs) was constructed by hitching acid/enzyme-triggered detachable nanoparticles (HCNs) backpack on the surface of metabolic oligosaccharide-engineered oncolytic bacteria YB1. Along with the process of tumor penetration by bacterial hypoxia navigation, YB1-HCNs responsively and continuously release HCNs, achieving a uniform distribution of loaded agents throughout the tumor. Upon successive irradiation of laser and ultrasound (US), the HCNs can separately generate type II and type I ROS for superior sono-photodynamic therapy (SPDT), which enables HCNs to synergize with YB1 for a satisfactory therapeutic effect in both superficial normoxic and deep hypoxic regions of the tumor. After a single dose, this efficient combination realized 98.3% primary tumor inhibition rate and prolonged survival of mice for 90 days with no recurrence, further inducing a powerful immunological memory effect to completely suppress tumor rechallenge in cured mice. Such a bacterial hybridization vector enables optimization of the spatial distribution of YB1 and HCNs, providing an innovative strategy to maximize therapeutic outcomes and evoke durable antitumor immunity.

Nanoparticle-enabled In Situ drug potency activation for enhanced tumor-specific therapy

Cancer treatment faces significant challenges including inadequate tumor specificity, drug resistance, and severe side effects, often resulting in unsatisfactory patient outcomes. Nanomedicines offer a transformative platform for tumor-targeted drug delivery and antitumor potency activation, providing an indispensable strategy for overcoming the severe damage to normal tissues caused by the inherent "always-on" cytotoxicity of conventional therapeutic agents. This review focuses on the emerging concept of "nanoparticle-enabled in situ drug potency activation", where inactive or minimally toxic agents are selectively activated within tumors to enhance the therapeutic efficacy and minimize the adverse effects. We systematically analyzed literature from PubMed and Web of Science databases spanning the last two decades, emphasizing experimental evidence supporting this in situ drug potency activation concept. Key strategies including stimuli-responsive prodrug nanoparticles, metal-induced activation, and bioorthogonal reactions are critically evaluated for their potential to overcome limitations in current cancer therapies. The findings highlight the potential of in situ potency activation as a promising alternative to conventional therapeutics, with far-reaching implications for advancing effective and safe cancer treatments.

Microneedles at the Forefront of Next Generation Theranostics

Theranostics, combining therapeutic and diagnostic functions, marks a revolutionary advancement in modern medicine, with microneedle technology at its forefront. This review explores the substantial developments and multifaceted applications of microneedles, which have evolved from basic transdermal drug delivery devices to sophisticated diagnostic and therapeutic platforms. Microneedles enhance access to biomarkers via interstitial fluid, enabling real-time monitoring of physiological conditions, such as glucose and hormone levels, thus facilitating continuous health tracking. The evolution of microneedle design from solid to dissolvable forms broadens their utility from mere drug delivery to complex sensing and therapeutic applications, including insulin delivery for diabetes management, vaccination, and gene therapy. This paper delves into the integration of microneedles with wearable technologies, highlighting their role in closed-loop systems that combine real-time monitoring with dynamic, precise therapeutic delivery. By addressing gaps in the literature regarding their integrated diagnostic and treatment capabilities, this review underscores the pivotal role of microneedles in personalizing medicine. It concludes with a visionary perspective on the future trajectory of microneedle technology, emphasizing its potential to revolutionize therapeutic strategies through enhanced efficacy, safety, and patient compliance.

Bottom-up approaches to prepare ultrathin TiO2 nanosheets

Atomically thin two-dimensional (2D) materials are promising platforms to explore the unusual physical and chemical properties in surface chemistry, various catalysis, and devices. Most 2D materials derive from inherently layer-structured compounds through top-down exfoliation, but it is usually challenging to directly prepare ultrathin nanosheets of non-layered materials. TiO2 contains at least 8 non-layered polymorphs, and some of them have found wide applications in heterogeneous catalysis, photocatalysis, solar cells, lithium-ion batteries, etc. In this review, we summarize typical bottom-up wet-chemistry synthetic systems of atomically thin TiO2 nanosheets. The synthesis protocols are discussed in groups of different phases, and the growth mechanisms are classified into three approaches of strong ligand confinement, layered intermediate, and templated synthesis.

Bioorthogonal Janus microparticles for photothermal and chemo-therapy

Bioorthogonal chemistry, recognized as a highly efficient tool in chemical biology, has shown significant value in cancer treatment. The primary objective is to develop efficient delivery strategies to achieve enhanced bioorthogonal drug treatment for tumors. Here, Janus microparticles (JMs) loaded with cyclooctene-modified doxorubicin prodrug (TCO-DOX) and tetrazine-modified indocyanine green (Tz-ICG) triggers are reported. Besides activating TCO-DOX, Tz-ICG is also a photothermal agent used in photothermal therapy (PTT), enabling the simultaneous use of biorthogonal chemotherapy and PTT. Additionally, the DOX could be significantly reduced in systemic toxicity with the modification of cyclooctene. Thus, the developed drug-carrying JMs system exhibits effective tumor cell killing in vitro and effectively inhibits tumor local progress and distant lung metastasis after postoperative treatment with good safety. These results demonstrate that the prepared JMs provide a paradigm for bioorthogonal prodrug activation and localized delivery, and hold great promise for cancer therapy as well as other related applications.

Microneedles as transdermal drug delivery system for enhancing skin disease treatment

Microneedles (MNs) serve as a revolutionary paradigm in transdermal drug delivery, heralding a viable resolution to the formidable barriers presented by the cutaneous interface. This review examines MNs as an advanced approach to enhancing dermatological pathology management. It explores the complex dermis structure and highlights the limitations of traditional transdermal methods, emphasizing MNs' advantage in bypassing the stratum corneum to deliver drugs directly to the subdermal matrix. The discourse outlines the diverse typologies of MNs, including solid, coated, hollow, hydrogel, and dissolvable versions. Each type is characterized by its unique applications and benefits. The treatise details the deployment of MNs in the alleviation of cutaneous cancers, the administration of inflammatory dermatoses such as psoriasis and atopic dermatitis, and their utility in wound management. Additionally, the paper contemplates the prospects of MNs within the realm of aesthetic dermatology and the burgeoning market traction of cosmetic MN formulations. The review summarizes the scientific and commercial challenges to the clinical adoption of MN therapeutics, including dosage calibration, pharmacodynamics, biocompatibility, patient compliance, sterilization, mass production, and regulatory oversight. It emphasizes the need for ongoing research, innovation, and regulatory harmonization to overcome these obstacles and fully realize MNs' potential in treating skin diseases and improving patient welfare.

Local Release of Copper Manganese Oxide Using HA Microneedle for Improving the Efficacy of Drug-Resistant Wound Inflammation

The production of bacterial toxins and excessive accumulation of reactive oxygen species (ROS) can induce localized oxidative stress, triggering an exaggerated immune response that impedes wound healing and culminates in chronic wounds. To address this issue, a microneedle (MN) system loaded with copper-manganese oxide (CMO) is developed to modulate the hyperimmune response in wounds. CMO@MN exhibits excellent antimicrobial and anti-inflammatory properties by effectively killing bacteria, scavenging ROS, and modulating macrophage polarization through their multiple enzymatic activities and photothermal properties. RNA sequencing revealed that CMO@MN improved the therapeutic effect on the infected skin of mice by balancing the ratio of M1/M2 macrophages and promoting cell migration and angiogenesis through the regulation of relevant pathways. Overall, this CMO@MN patch skillfully balances the complex issues between the immune response and wound healing and has potential applications in the treatment of other serious bacterial infections.

Precise Clearance of Intracellular MRSA via Internally and Externally Mediated Bioorthogonal Activation of Micro/Nano Hydrogel Microspheres

Traditional high-dose antibiotic treatments of intracellular methicillin-resistant staphylococcus aureus (MRSA) are highly inefficient and associated with a high rate of infection relapse. As an effective antibacterial technology, sonodynamic therapy (SDT) may be able to break the dilemma. However, indiscriminate reactive oxygen species (ROS) release leads to potential side effects. This study incorporates Staphylococcal Protein A antibody-modified Cu2+/tetracarboxyphenylporphyrin nanoparticles (Cu(II)NS-SPA) into hydrogel microspheres (HAMA@Cu(II)NS-SPA) to achieve precise eradication of intracellular bacteria. This eradication is under bioorthogonal activation mediated by bacillithiol (BSH) (internally) and ultrasound (US) (externally). To specify, the US responsiveness of Cu(II)NS-SPA is restored when it is reduced to Cu(I)NS-SPA by the BSH secreted characteristically by intracellular MRSA, thus forming a bioorthogonal activation with the external US, which confines ROS production within the infected MΦ. Under external US activation at 2 W cm-2, over 95% of intracellular MRSA can be cleared. In vivo, a single injection of HAMA@Cu(II)NS-SPA achieves up to two weeks of antibacterial sonodynamic therapy, reducing pro-inflammatory factor expression by 90%, and peri-implant bone trabeculae numbers exceed the control group by five times. In summary, these micro/nano hydrogel microspheres mediated by internal and external bioorthogonal activation can precisely eliminate intracellular MRSA, effectively treating multi-drug resistant intracellular bacterial infections.

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.

Microorganism microneedle micro-engine depth drug delivery

As a transdermal drug delivery method, microneedles offer minimal invasiveness, painlessness, and precise in-situ treatment. However, current microneedles rely on passive diffusion, leading to uncontrollable drug penetration. To overcome this, we developed a pneumatic microneedle patch that uses live Enterobacter aerogenes as microengines to actively control drug delivery. These microbes generate gas, driving drugs into deeper tissues, with adjustable glucose concentration allowing precise control over the process. Our results showed that this microorganism-powered system increases drug delivery depth by over 200%, reaching up to 1000 μm below the skin. In a psoriasis animal model, the technology effectively delivered calcitriol into subcutaneous tissues, offering rapid symptom relief. This innovation addresses the limitations of conventional microneedles, enhancing drug efficiency, transdermal permeability, and introducing a creative paradigm for on-demand controlled drug delivery.

A novel shockwave-driven nanomotor composite microneedle transdermal delivery system for the localized treatment of osteoporosis: a basic science study

BACKGROUND

Clinical protocols in osteoporosis treatment could not meet the requirement of increasing local bone mineral density. A local delivery system was brought in to fix this dilemma. The high-energy extracorporeal shock wave (ESW) can travel into the deep tissues with little heat loss. Hence, ESW-driven nanoparticles could be used for local treatment of osteoporosis.

MATERIALS AND METHODS

An ESW-actuated nanomotor (NM) sealed into microneedles (MNs) (ESW-NM-MN) was constructed for localized osteoporosis protection. The NM was made of calcium phosphate nanoparticles with a high Young's modulus, which allows it to absorb ESW energy efficiently and convert it into kinetic energy for solid tissue penetration. Zoledronic (ZOL), as an alternative phosphorus source, forms the backbone of the NM (ZOL-NM), leading to bone targeting and ESW-mediated drug release.

RESULTS

After the ZOL-NM is sealed into hyaluronic acid (HA)-made microneedles, the soluble MN tips could break through the stratum corneum, injecting the ZOL-NM into the skin. As soon as the ESW was applied, the ZOL-NM would absorb the ESW energy to move from the outer layer of skin into the deep tissue and be fragmented to release ZOL and Ca 2+ for anti-osteoclastogenesis and pro-osteogenesis. In vivo , the ZOL-NM increases localized bone parameters and reduces fracture risk, indicating its potential value in osteoporotic healing and other biomedical fields.

CONCLUSION

The ESW-mediated transdermal delivery platform (ESW-NM-MN) could be used as a new strategy to improve local bone mineral density and protect local prone-fracture areas.

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.

Acid-Responsive Polymer Micelles for Targeted Delivery and Bioorthogonal Activation of Prodrug through Ru Catalyst in Tumor Cells

Bioorthogonal reactions present a promising strategy for minimizing off-target toxicity in cancer chemotherapy, yet a dependable nanoplatform is urgently required. Here, we have fabricated an acid-responsive polymer micelle for the specific delivery and activation of the prodrug within tumor cells through Ru catalyst-mediated bioorthogonal reactions. The decomposition of micelles, triggered by the cleavage of the hydrazone bond in the acidic lysosomal environment, facilitated the concurrent release of Alloc-DOX and the Ru catalyst within the cells. Subsequently, the uncaging process of Alloc-DOX was demonstrated to be induced by the high levels of glutathione within tumor cells. Notably, the limited glutathione inside normal cells prevented the conversion of Alloc-DOX into active DOX, thereby minimizing the toxicity toward normal cells. In tumor-bearing mice, this nanoplatform exhibited enhanced efficacy in tumor suppression while minimizing off-target toxicity. Our study provides an innovative approach for in situ drug activation that combines safety and effectiveness in cancer chemotherapy.

A Versatile Cryomicroneedle Patch for Traceable Photodynamic Therapy

Photodynamic therapy (PDT) continues to encounter multifarious hurdles, stemming from the ineffectual preservation and delivery system of photosensitizers, the dearth of imaging navigation, and the antioxidant/hypoxic tumor microenvironment. Herein, a versatile cryomicroneedle patch (denoted as CMN-CCPH) is developed for traceable PDT. The therapeutic efficacy is further amplified by catalase (CAT)-induced oxygen (O2) generation and Cu2+-mediated glutathione (GSH) depletion. The CMN-CCPH is composed of cryomicroneedle (CMN) as the vehicle and CAT-biomineralized copper phosphate nanoflowers (CCP NFs) loaded with hematoporphyrin monomethyl ether (HMME) as the payload. Importantly, the bioactive function of HMME and CAT can be optimally maintained under the protection of CCPH and CMN for a duration surpassing 60 days, leading to bolstered bioavailability and notable enhancements in PDT efficacy. The in vivo visualization of HMME and oxyhemoglobin saturation (sO2) monitored by fluorescence (FL)/photoacoustic (PA) duplex real-time imaging unveils the noteworthy implications of CMN-delivered CCPH for intratumoral enrichment of HMME and O2 with reduced systemic toxicity. This versatile CMN patch demonstrates distinct effectiveness in neoplasm elimination, underscoring its promising clinical prospects.

Regioselective epitaxial growth of metallic heterostructures

Constructing regioselective architectures in heterostructures is important for many applications; however, the targeted design of regioselective architectures is challenging due to the sophisticated processes, impurity pollution and an unclear growth mechanism. Here we successfully realized a one-pot kinetically controlled synthetic framework for constructing regioselective architectures in metallic heterostructures. The key objective was to simultaneously consider the reduction rates of metal precursors and the lattice matching relationship at heterogeneous interfaces. More importantly, this synthetic method also provided phase- and morphology-independent behaviours as foundations for choosing substrate materials, including phase regulation from Pd20Sb7 hexagonal nanoplates (HPs) to Pd8Sb3 HPs, and morphology regulation from Pd20Sb7 HPs to Pd20Sb7 rhombohedra and Pd20Sb7 nanoparticles. Consequently, the activity of regioselective epitaxially grown Pt on Pd20Sb7 HPs was greatly enhanced towards the ethanol oxidation reaction; its activity was 57 times greater than that of commercial Pt/C, and the catalyst showed increased stability (decreasing by 16.3% after 2,000 cycles) and selectivity (72.4%) compared with those of commercial Pt/C (56.0%, 18.2%). This work paves the way for the design of unconventional well-defined heterostructures for use in various applications.

Bio-inspired biorthogonal compartmental microparticles for tumor chemotherapy and photothermal therapy

Microcarrier is a promising drug delivery system demonstrating significant value in treating cancers. One of the main goals is to devise microcarriers with ingenious structures and functions to achieve better therapeutic efficacy in tumors. Here, inspired by the nucleus-cytoplasm structure of cells and the material exchange reaction between them, we develop a type of biorthogonal compartmental microparticles (BCMs) from microfluidics that can separately load and sequentially release cyclooctene-modified doxorubicin prodrug (TCO-DOX) and tetrazine-modified indocyanine green (Tz-ICG) for tumor therapy. The Tz-ICG works not only as an activator for TCO-DOX but also as a photothermal agent, allowing for the combination of bioorthogonal chemotherapy and photothermal therapy (PTT). Besides, the modification of DOX with cyclooctene significantly decreases the systemic toxicity of DOX. As a result, the developed BCMs demonstrate efficient in vitro tumor cell eradication and exhibit notable tumor growth inhibition with favorable safety. These findings illustrate that the formulated BCMs establish a platform for bioorthogonal prodrug activation and localized delivery, holding significant potential for cancer therapy and related applications.

Research Progress of Hydrogel Microneedles in Wound Management

Microneedles are a novel drug delivery system that offers advantages such as safety, painlessness, minimally invasive administration, simplicity of use, and controllable drug delivery. As a type of polymer microneedle with a three-dimensional network structure, hydrogel microneedles (HMNs) possess excellent biocompatibility and biodegradability and encapsulate various therapeutic drugs while maintaining drug activity, thus attracting significant attention. Recently, they have been widely employed to promote wound healing and have demonstrated favorable therapeutic effects. Although there are reviews about HMNs, few of them focus on wound management. Herein, we present a comprehensive overview of the design and preparation methods of HMNs, with a particular emphasis on their application status in wound healing, including acute wound healing, infected wound healing, diabetic wound healing, and scarless wound healing. Finally, we examine the advantages and limitations of HMNs in wound management and provide suggestions for future research directions.

Nitric Oxide-Activated Bioorthogonal Codelivery Nanoassembly for In Situ Synthesis of Photothermal Agent for Precise and Safe Anticancer Treatment

The development of bioorthogonal activation in drug release represents a promising avenue for precise and safe anticancer treatment. However, two significant limitations currently hinder their clinical application: i) the necessity for separate administration of the drug precursor and its corresponding activator, leading to poor drug accumulation and potential side effects; ii) the reliance on exogenous metal or organic activators for triggering bioorthogonal activation, which often exhibit low efficiency and systemic toxicity when extending to living animals. To overcome these limitations, a nitric oxide (NO)-mediated bioorthogonal codelivery nanoassembly, termed TTB-NH2@PArg, which comprises a precursor molecular (TTB-NH2) and amphipathic polyarginine (PArg) is developed. In TTB-NH2@PArg, PArg serves as both self-assembled nanocarrier for TTB-NH2 and a NO generator. In tumor microenvironment (TME), the TME-specific generation of NO acts as a gas activator, triggering in situ bioorthogonal bond formation that transforms TTB-NH2 into TTB-AZO. This tumor-specific generation of TTB-AZO not only serves as a potential photothermal agent for effective tumor inhibition but also induces fluorescence change that enables real-time monitoring of bioorthogonal activation. This study presents a drug codelivery approach that enables precise and safe control of bioorthogonal activation for anticancer treatment, improving cancer therapy efficacy while minimizing side effects.

In situ bioorthogonal-modulation of m6A RNA methylation in macrophages for efficient eradication of intracellular bacteria

N6-Methyladenosine (m6A) methylation plays a critical role in controlling the RNA fate. Emerging evidence has demonstrated that aberrant m6A methylation in immune cells such as macrophages could alter cell homeostasis and function, which can be a promising target for disease treatment. Despite tremendous progress in regulating the level of m6A methylation, the current methods suffer from the time-consuming operation and annoying off-target effect, which hampers the in situ manipulation of m6A methylation. Here, a bioorthogonal in situ modulation strategy of m6A methylation was proposed. Well-designed covalent organic framework (COF) dots (CIDM) could deprotect the agonist prodrug of m6A methyltransferase, resulting in a considerable hypermethylation of m6A modification. Simultaneously, the bioorthogonal catalyst CIDM showed oxidase (OXD)-mimic activity that further promoted the level of m6A methylation. Ultimately, the potential therapeutic effect of bioorthogonal controllable regulation of m6A methylation was demonstrated through intracellular bacteria eradication. The remarkable antimicrobial outcomes indicate that upregulating m6A methylation in macrophages could reprogram them into the M1 phenotype with high bactericidal activity. We believe that our bioorthogonal chemistry-controlled epigenetics regulatory strategy will provide a unique insight into the development of controllable m6A methylation.

Grooved Microneedle Patch Augments Adoptive T Cell Therapy Against Solid Tumors via Diverting Regulatory T Cells

The efficacy of adoptive T cell therapy (ACT) for the treatment of solid tumors remains challenging. In addition to the poor infiltration of effector T (Teff) cells limited by the physical barrier surrounding the solid tumor, another major obstacle is the extensive infiltration of regulatory T (Treg) cells, a major immunosuppressive immune cell subset, in the tumor microenvironment. Here, this work develops a grooved microneedle patch for augmenting ACT, aiming to simultaneously overcome physical and immunosuppressive barriers. The microneedles are engineered through an ice-templated method to generate the grooved structure for sufficient T-cell loading. In addition, with the surface modification of chemokine CCL22, the MNs could not only directly deliver tumor-specific T cells into solid tumors through physical penetration, but also specifically divert Treg cells from the tumor microenvironment to the surface of the microneedles via a cytokine concentration gradient, leading to an increase in the ratio of Teff cells/Treg cells in a mouse melanoma model. Consequently, this local delivery strategy of both T cell receptor T cells and chimeric antigen receptor T cells via the CCL22-modified grooved microneedles as a local niche could significantly enhance the antitumor efficacy and reduce the on-target off-tumor toxicity of ACT.

A Hemoglobin Bionics-Based System for Combating Antibiotic Resistance in Chronic Diabetic Wounds via Iron Homeostasis Regulation

Owing to the increased tissue iron accumulation in patients with diabetes, microorganisms may activate high expression of iron-involved metabolic pathways, leading to the exacerbation of bacterial infections and disruption of systemic glucose metabolism. Therefore, an on-demand transdermal dosing approach that utilizes iron homeostasis regulation to combat antimicrobial resistance is a promising strategy to address the challenges associated with low administration bioavailability and high antibiotic resistance in treating infected diabetic wounds. Here, it is aimed to propose an effective therapy based on hemoglobin bionics to induce disturbances in bacterial iron homeostasis. The preferred "iron cargo" is synthesized by protoporphyrin IX chelated with dopamine and gallium (PDGa), and is delivered via a glucose/pH-responsive microneedle bandage (PDGa@GMB). The PDGa@GMB downregulates the expression levels of the iron uptake regulator (Fur) and the peroxide response regulator (perR) in Staphylococcus aureus, leading to iron nutrient starvation and oxidative stress, ultimately suppressing iron-dependent bacterial activities. Consequently, PDGa@GMB demonstrates insusceptibility to genetic resistance while maintaining sustainable antimicrobial effects (>90%) against resistant strains of both S. aureus and E. coli, and accelerates tissue recovery (<20 d). Overall, PDGa@GMB not only counteracts antibiotic resistance but also holds tremendous potential in mediating microbial-host crosstalk, synergistically attenuating pathogen virulence and pathogenicity.

Transdermal microarrayed electroporation for enhanced cancer immunotherapy based on DNA vaccination

Despite the tremendous clinical potential of nucleic acid-based vaccines, their efficacy to induce therapeutic immune response has been limited by the lack of efficient local gene delivery techniques in the human body. In this study, we develop a hydrogel-based organic electronic device (μEPO) for both transdermal delivery of nucleic acids and in vivo microarrayed cell electroporation, which is specifically oriented toward one-step transfection of DNAs in subcutaneous antigen-presenting cells (APCs) for cancer immunotherapy. The μEPO device contains an array of microneedle-shaped electrodes with pre-encapsulated dry DNAs. Upon a pressurized contact with skin tissue, the electrodes are rehydrated, electrically triggered to release DNAs, and then electroporate nearby cells, which can achieve in vivo transfection of more than 50% of the cells in the epidermal and upper dermal layer. As a proof-of-concept, the μEPO technique is employed to facilitate transdermal delivery of neoantigen genes to activate antigen-specific immune response for enhanced cancer immunotherapy based on a DNA vaccination strategy. In an ovalbumin (OVA) cancer vaccine model, we show that high-efficiency transdermal transfection of APCs with OVA-DNAs induces robust cellular and humoral immune responses, including antigen presentation and generation of IFN-γ+ cytotoxic T lymphocytes with a more than 10-fold dose sparing over existing intramuscular injection (IM) approach, and effectively inhibits tumor growth in rodent animals.

Reactive Microneedle Patches with Antibacterial and Dead Bacteria-Trapping Abilities for Skin Infection Treatment

Bacterial skin infections are highly prevalent and pose a significant public health threat. Current strategies are primarily focused on the inhibition of bacterial activation while disregarding the excessive inflammation induced by dead bacteria remaining in the body and the effect of the acidic microenvironment during therapy. In this study, a novel dual-functional MgB2 microparticles integrated microneedle (MgB2 MN) patch is presented to kill bacteria and eliminate dead bacteria for skin infection management. The MgB2 microparticles not only can produce a local alkaline microenvironment to promote the proliferation and migration of fibroblasts and keratinocytes, but also achieve >5 log bacterial inactivation. Besides, the MgB2 microparticles effectively mitigate dead bacteria-induced inflammation through interaction with lipopolysaccharide (LPS). With the incorporation of these MgB2 microparticles, the resultant MgB2 MN patches effectively kill bacteria and capture dead bacteria, thereby mitigating these bacteria-induced inflammation. Therefore, the MgB2 MN patches show good therapeutic efficacy in managing animal bacterial skin infections, including abscesses and wounds. These results indicate that reactive metal borides-integrated microneedle patches hold great promise for the treatment of clinical skin infections.

Development of Biocompatible Cu(I)-Microdevices for Bioorthogonal Uncaging and Click Reactions

Transition-metal-catalyzed bioorthogonal reactions emerged a decade ago as a novel strategy to implement spatiotemporal control over enzymatic functions and pharmacological interventions. The use of this methodology in experimental therapy is driven by the ambition of improving the tolerability and PK properties of clinically-used therapeutic agents. The preclinical potential of bioorthogonal catalysis has been validated in vitro and in vivo with the in situ generation of a broad range of drugs, including cytotoxic agents, anti-inflammatory drugs and anxiolytics. In this article, we report our investigations towards the preparation of solid-supported Cu(I)-microdevices and their application in bioorthogonal uncaging and click reactions. A range of ligand-functionalized polymeric devices and off-on Cu(I)-sensitive sensors were developed and tested under conditions compatible with life. Last, we present a preliminary exploration of their use for the synthesis of PROTACs through CuAAC assembly of two heterofunctional mating units.

Critical learning from industrial catalysis for nanocatalytic medicine

Systematical and critical learning from industrial catalysis will bring inspiration for emerging nanocatalytic medicine, but the relevant knowledge is quite limited so far. In this review, we briefly summarize representative catalytic reactions and corresponding catalysts in industry, and then distinguish the similarities and differences in catalytic reactions between industrial and medical applications in support of critical learning, deep understanding, and rational designing of appropriate catalysts and catalytic reactions for various medical applications. Finally, we summarize/outlook the present and potential translation from industrial catalysis to nanocatalytic medicine. This review is expected to display a clear picture of nanocatalytic medicine evolution.

Recent advances in hydrogel microneedle-based biofluid extraction and detection in food and agriculture

Microneedle (MN) technology has been extensively studied for its advantages of minimal invasiveness and user-friendliness. Notably, hydrogel microneedles (HMNs) have garnered considerable attention for biofluid extraction due to its high swelling properties and biocompatibility. This review provides a comprehensive overview of definition, materials, and fabrication methods associated with HMNs. The extraction mechanisms and optimization strategies for enhancing extraction efficiency are summarized. Moreover, particular emphasis is placed on HMN-based biofluid extraction and detection in the domains of food and agriculture, encompassing the detection of small molecules, nucleic acids, and other relevant analytes. Finally, current challenges and possible solutions associated with HMN-based biofluid extraction are discussed.

Nanoparticle-Catalyzed Transamination under Tumor Microenvironment Conditions: A Novel Tool to Disrupt the Pool of Amino Acids and GSSG in Cancer Cells

Catalytic cancer therapy targets cancer cells by exploiting the specific characteristics of the tumor microenvironment (TME). TME-based catalytic strategies rely on the use of molecules already present in the TME. Amino groups seem to be a suitable target, given the abundance of proteins and peptides in biological environments. Here we show that catalytic CuFe2O4 nanoparticles are able to foster transaminations with different amino acids and pyruvate, another key molecule present in the TME. We observed a significant in cellulo decrease in glutamine and alanine levels up to 48 h after treatment. In addition, we found that di- and tripeptides also undergo catalytic transamination, thereby extending the range of the effects to other molecules such as glutathione disulfide (GSSG). Mechanistic calculations for GSSG transamination revealed the formation of an imine between the oxo group of pyruvate and the free -NH2 group of GSSG. Our results highlight transamination as alternative to the existing toolbox of catalytic therapies.

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

Self-Heating Multistage Microneedle Patch for Topical Therapy of Skin Cancer

Topical therapy is a favored route for treating skin cancers, but remain many challenges, such as low delivery efficiency, limited tumor tissue penetration, and unsatisfactory blood circulation. Here, a self-heating microneedle (MN) patch with multilevel structures, including a dissolvable base for rapid drug release, a degradable tip for sustained drug release, and a self-heating substrate is described. The thermally enhanced drug release performance is validated through both in vitro and in vivo experiments. High tumor therapeutic efficacy can be achieved due to the rapid release of 5-fluorouracil, while the sustained release of thymoquinone endows the MN patch with long-term tumor inhibition ability. It is further demonstrated the feasibility of such an MN patch for in vivo topical therapy of cutaneous squamous cell carcinoma with high efficacy, low side effects, and long-term inhibition of recurrence. This self-heating MN patch holds great promise for potential clinical applications, especially for the treatment of skin cancers.

Enzyme-Mediated Bioorthogonal Cascade Catalytic Reaction for Metabolism Intervention and Enhanced Ferroptosis on Neuroblastoma

It remains a tremendous challenge to explore effective therapeutic modalities against neuroblastoma, a lethal cancer of the sympathetic nervous system with poor prognosis and disappointing treatment outcomes. Considering the limitations of conventional treatment modalities and the intrinsic vulnerability of neuroblastoma, we herein develop a pioneering sequential catalytic therapeutic system that utilizes lactate oxidase (LOx)/horseradish peroxidase (HRP)-loaded amorphous zinc metal-organic framework, named LOx/HRP-aZIF, in combination with a 3-indole-acetic acid (IAA) prodrug. On the basis of abnormal lactate accumulation that occurs in the tumor microenvironment, the cascade reaction of LOx and HRP consumes endogenous glutathione and a reduced form of nicotinamide adenine dinucleotide to achieve the first stage of killing cancer cells via antioxidative incapacitation and electron transport chain interference. Furthermore, the generation of reactive oxygen species induced by HRP and IAA through bioorthogonal catalysis promotes ferritin degradation and lipid peroxidation, ultimately provoking self-enhanced ferroptosis with positive feedback by initiating an endogenous Fenton reaction. This work highlights the superiority of the natural enzyme-dependent cascade and bioorthogonal catalytic reaction, offering a paradigm for synergistically enzyme-based metabolism-ferroptosis anticancer therapy.

Single-Atom Catalysts Mediated Bioorthogonal Modulation of N6-Methyladenosine Methylation for Boosting Cancer Immunotherapy

Bioorthogonal reactions provide a powerful tool to manipulate biological processes in their native environment. However, the transition-metal catalysts (TMCs) for bioorthogonal catalysis are limited to low atomic utilization and moderate catalytic efficiency, resulting in unsatisfactory performance in a complex physiological environment. Herein, sulfur-doped Fe single-atom catalysts with atomically dispersed and uniform active sites are fabricated to serve as potent bioorthogonal catalysts (denoted as Fe-SA), which provide a powerful tool for in situ manipulation of cellular biological processes. As a proof of concept, the N6-methyladensoine (m6A) methylation in macrophages is selectively regulated by the mannose-modified Fe-SA nanocatalysts (denoted as Fe-SA@Man NCs) for potent cancer immunotherapy. Particularly, the agonist prodrug of m6A writer METTL3/14 complex protein (pro-MPCH) can be activated in situ by tumor-associated macrophage (TAM)-targeting Fe-SA@Man, which can upregulate METTL3/14 complex protein expression and then reprogram TAMs for tumor killing by hypermethylation of m6A modification. Additionally, we find the NCs exhibit an oxidase (OXD)-like activity that further boosts the upregulation of m6A methylation and the polarization of macrophages via producing reactive oxygen species (ROS). Ultimately, the reprogrammed M1 macrophages can elicit immune responses and inhibit tumor proliferation. Our study not only sheds light on the design of single-atom catalysts for potent bioorthogonal catalysis but also provides new insights into the spatiotemporal modulation of m6A RNA methylation for the treatment of various diseases.

Controlled Bio-Orthogonal Catalysis Using Nanozyme-Protein Complexes via Modulation of Electrostatic Interactions

Bio-orthogonal chemistry provides a powerful tool for drug delivery systems due to its ability to generate therapeutic agents in situ, minimizing off-target effects. Bio-orthogonal transition metal catalysts (TMCs) with stimuli-responsive properties offer possibilities for controllable catalysis due to their spatial-, temporal-, and dosage-controllable properties. In this paper, we fabricated a stimuli-responsive bio-orthogonal catalysis system based on an enhanced green fluorescent protein (EGFP)-nanozyme (NZ) complex (EGFP-NZ). Regulation of the catalytic properties of the EGFP-NZ complex was directly achieved by modulating the ionic strength of the solution. The dielectric screening introduced by salt ions allows the dissociation of the EGFP-NZ complex, increasing the access of substrate to the active site of the NZs and concomitantly increasing nanozyme activity. The change in catalytic rate of the NZ/EGFP = 1:1 complex was positively correlated with salt concentration from 0 mM to 150 mM.

Self-Metallized Whole Cell Vaccines Prepared by Microfluidics for Bioorthogonally Catalyzed Antitumor Immunotherapy

Tumor whole cell, carrying a complete set of tumor-associated antigens and tumor-specific antigens, has shown great potential in the construction of tumor vaccines but is hindered by the complex engineering means and limited efficacy to cause immunity. Herein, we provided a strategy for the self-mineralization of autologous tumor cells with palladium ions in microfluidic droplets, which endowed the engineered cells with both immune and catalytic functions, to establish a bioorthogonally catalytic tumor whole-cell vaccine. This vaccine showed strong inhibition both in the occurrence and recurrence of tumor by invoking the immediate antitumor immunity and building a long-term immunity.

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

Immunotherapy harnesses the inherent immune system in the body to generate systemic antitumor immunity, offering a promising modality for defending against cancer. However, tumor immunosuppression and evasion seriously restrict the immune response rates in clinical settings. Catalytic nanomedicines can transform tumoral substances/metabolites into therapeutic products in situ, offering unique advantages in antitumor immunotherapy. Through catalytic reactions, both tumor eradication and immune regulation can be simultaneously achieved, favoring the development of systemic antitumor immunity. In recent years, with advancements in catalytic chemistry and nanotechnology, catalytic nanomedicines based on nanozymes, photocatalysts, sonocatalysts, Fenton catalysts, electrocatalysts, piezocatalysts, thermocatalysts and radiocatalysts have been rapidly developed with vast applications in cancer immunotherapy. This review provides an introduction to the fabrication of catalytic nanomedicines with an emphasis on their structures and engineering strategies. Furthermore, the catalytic substrates and state-of-the-art applications of nanocatalysts in cancer immunotherapy have also been outlined and discussed. The relationships between nanostructures and immune regulating performance of catalytic nanomedicines are highlighted to provide a deep understanding of their working mechanisms in the tumor microenvironment. Finally, the challenges and development trends are revealed, aiming to provide new insights for the future development of nanocatalysts in catalytic immunotherapy.

Bacterial Flagellum-Drug Nanoconjugates for Carrier-Free Immunochemotherapy

The combination of immunotherapy and chemotherapy to ablate tumors has attracted substantial attention due to the ability to simultaneously elicit antitumor immune responses and trigger direct tumor cell death. However, conventional combinational strategies mainly focus on the employment of drug carriers to deliver immunomodulators, chemotherapeutics, or their combinations, always suffering from complicated preparation and carrier-relevant side effects. Here, the fabrication of bacterial flagellum-drug nanoconjugates (FDNCs) for carrier-free immunochemotherapy is described. FDNCs are simply prepared by attaching chemotherapeutics to amine residues of flagellin through an acid-sensitive and traceless cis-aconityl linker. By virtue of native nanofibrous structure and immunogenicity, bacterial flagella not only show long-term tumor retention and highly efficient cell internalization, but also provoke robust systemic antitumor immune responses. Meanwhile, conjugated chemotherapeutics exhibit an acid-mediated release profile and durable intratumoral exposure, which can induce potent tumor cell inhibition via direct killing. More importantly, this combination is able to augment immunoactivation effects associated with chemotherapy-enabled immunogenic tumor cell death to further enhance antitumor efficacy. By leveraging the innate response of the immune system to pathogens, the conjugation of therapeutic agents with self-adjuvant bacterial flagella provides an alternative approach to develop carrier-free nanotherapeutics for tumor immunochemotherapy.

The Necessity to Investigate In Vivo Fate of Nanoparticle-Loaded Dissolving Microneedles

Transdermal drug delivery systems are rapidly gaining prominence and have found widespread application in the treatment of numerous diseases. However, they encounter the challenge of a low transdermal absorption rate. Microneedles can overcome the stratum corneum barrier to enhance the transdermal absorption rate. Among various types of microneedles, nanoparticle-loaded dissolving microneedles (DMNs) present a unique combination of advantages, leveraging the strengths of DMNs (high payload, good mechanical properties, and easy fabrication) and nanocarriers (satisfactory solubilization capacity and a controlled release profile). Consequently, they hold considerable clinical application potential in the precision medicine era. Despite this promise, no nanoparticle-loaded DMN products have been approved thus far. The lack of understanding regarding their in vivo fate represents a critical bottleneck impeding the clinical translation of relevant products. This review aims to elucidate the current research status of the in vivo fate of nanoparticle-loaded DMNs and elaborate the necessity to investigate the in vivo fate of nanoparticle-loaded DMNs from diverse aspects. Furthermore, it offers insights into potential entry points for research into the in vivo fate of nanoparticle-loaded DMNs, aiming to foster further advancements in this field.

Exploration of the Delivery of Oncolytic Newcastle Disease Virus by Gelatin Methacryloyl Microneedles

Oncolytic Newcastle disease virus is a new type of cancer immunotherapy drug. This paper proposes a scheme for delivering oncolytic viruses using hydrogel microneedles. Gelatin methacryloyl (GelMA) was synthesized by chemical grafting, and GelMA microneedles encapsulating oncolytic Newcastle disease virus (NDV) were prepared by micro-molding and photocrosslinking. The release and expression of NDV were tested by immunofluorescence and hemagglutination experiments. The experiments proved that GelMA was successfully synthesized and had hydrogel characteristics. NDV was evenly dispersed in the allantoic fluid without agglomeration, showing a characteristic virus morphology. NDV particle size was 257.4 ± 1.4 nm, zeta potential was -13.8 ± 0.5 mV, virus titer TCID50 was 107.5/mL, and PFU was 2 × 107/mL, which had a selective killing effect on human liver cancer cells in a dose and time-dependent manner. The NDV@GelMA microneedles were arranged in an orderly cone array, with uniform height and complete needle shape. The distribution of virus-like particles was observed on the surface. GelMA microneedles could successfully penetrate 5% agarose gel and nude mouse skin. Optimal preparation conditions were freeze-drying. We successfully prepared GelMA hydrogel microneedles containing NDV, which could effectively encapsulate NDV but did not detect the release of NDV.