Twin-bioengine self-adaptive micro/nanorobots using enzyme actuation and macrophage relay for gastrointestinal inflammation therapy

Optoelectronic-Coupled-Driven Microrobot for Biological Cargo Transport in Conductive Isosmotic Glucose Solution

Electric field-driven micro/nanorobots, as micro/nanodevices with autonomous motion capability, have emerged as promising candidates for targeted cargo delivery in biomedical applications due to their advantages of label-free operation, selectivity, and controllability. In biological systems, many biological cargos need to be operated in conductive isosmotic solutions to ensure their viability. However, in the conductive solution, electric field-driven micro/nanorobots exhibit significantly reduced propulsion performance, despite retaining the capability to manipulate cargos by the dielectrophoretic force. This limitation restricts the wider applicability of electric field-driven micro/nanorobots in biomedical fields. This paper presents a novel optoelectronic-coupled-driven α-Fe2O3@aTiO2/Au microrobot, which exhibits significantly improved mobility and enables biological cargo transportation in the conductive isosmotic glucose solution. Benefiting from the flowerlike surface structure and composite photocatalytic material, the proposed microrobot exhibits enhanced photocatalytic capability, enabling efficient propulsion in glucose solution under light irradiation. In addition, the motion behavior of the microrobot under light, electric, and optoelectronic-coupled fields is investigated. It is found that the speed of the microrobot could exceed 300 μm/s under coupled fields, which is more than ten times faster than that of previously reported electric field-driven micro/nanorobots. Due to the magnetic property, the proposed microrobot can be precisely navigated under the guidance of an external uniform magnetic field. Furthermore, the proposed microrobot can achieve the transportation of various biological cargos in a conductive isosmotic glucose solution. The proposed microrobot opens a new avenue for targeted delivery and holds great potential for applications in the biological and pharmaceutical fields.

Micro/nanomotors for active inflammatory disease therapy

Inflammation is a carefully orchestrated response of the immune system to repair injured tissues and clear various damage factors. However, dysregulated inflammation can eventually contribute to the development and progression of various inflammatory diseases. Although anti-inflammatory drugs have demonstrated certain therapeutic efficacy in clinical settings, significant limitations still persist, highlighting the necessity for the development of improved approaches to address complex inflammatory conditions. Micro/nanomotors (MNMs) have shown significant promise for applications in the biomedical field due to their micro/nano-scale sizes and autonomous movement. Unlike traditional nanoparticles, which exhibit passive diffusion in biological fluids, MNMs can convert external energy into a driving force for self-propulsion. This capability not only enhances the tissue penetration depth and retention rates but also facilitates interaction with inflammatory lesions. Recent efforts have suggested that MNMs for inflammatory disease therapy could provide an efficient therapeutic effect. Herein, we mainly introduce the recent advances in inflammatory disease therapy based on MNMs. We conclude by discussing both the obstacles and potential opportunities for MNMs innovations in addressing inflammation.

Magnetite Micro/Nanorobots for Efficient Targeted Alleviation of Inflammatory Bowel Disease

Millions of people worldwide have inflammatory bowel disease (IBD). Self-driven micro/nanorobots (MNRs) are efficient in the treatment of IBD. However, their lack of controllability regarding direction of motion in the organism and their inability to achieve continuous navigation limits their further application. In this study, polydopamine is wrapped around the magnetite surface, loaded with an anti-inflammatory drug resveratrol, and wrapped with pH-responsive sodium alginate to obtain magnetic MNRs. MNRs can be driven by magnetic fields to achieve directional movement and targeted transportation. In addition, MNRs can effectively remove reactive oxygen species from the inflammation site, repair intestinal damage, inhibit the cellular pathway of pro-inflammatory factors, such as MAPK and NF-κB pathways, and restore intestinal flora, thereby relieving IBDs. MNRs are safe and effective for in vivo treatment of IBD and have proven to be a promising therapeutic platform. This MNRs therapeutic strategy provides new insights into comprehensive IBD therapy.

Janus micro/nanomotors for enhanced disease treatment through their deep penetration capability

Nanotherapeutic systems have provided an innovative means for the treatment of a wide range of diseases in modern medicine. However, the limited penetration of nanoparticles into focal tissues still greatly hampered their clinical application. With their unique two-sided structure and superior motility, Janus micro/nanomotors are expected to significantly improve the penetration of nanocarriers into organisms, thereby enhancing the therapeutic effects of diseases. This review introduces Janus micro/nanomotors with different morphologies and focuses on their propulsion mechanisms, including chemical field-driven, external physical field-driven, biologically-driven, and hybrid-driven mechanisms. We explore the research progress of Janus micro/nanomotors in various disease treatment areas (including cancer, cardiovascular diseases, neurological diseases, bacterial/fungal infections, and chronic inflammatory diseases) and elucidate the implementation strategies of Janus micro/nanomotors in facilitating disease therapies. Finally, we discuss the biosafety and biocompatibility of Janus micro/nanomotor, while exploring current challenges and opportunities in the field. We look forward to the Janus micro/nanomotor therapeutic platform demonstrating surprising therapeutic effects in the clinical treatment of diseases. STATEMENT OF SIGNIFICANCE: Micro/nanomotors are the highly promising nanotherapeutic systems due to their self-propelled motion capability. Janus micro/nanomotors possess an asymmetric structure with different physical or chemical properties on both sides. The flexibility of this bifunctional surface allows them to hold promise for improving the penetration of nanotherapeutic systems and enhancing therapeutic efficacy for complex diseases. This review focuses on the latest advancements in Janus micro/nanomotors for enhanced disease treatment, including the structural types and driving mechanisms, the enhancement effect to cope with different disease treatments, the biocompatibility and safety, the current challenges and possible solutions. These insights inform the design of deep-penetrating nanotherapeutic systems and the strategies of enhanced disease treatment.

Living material-derived intelligent micro/nanorobots

Living materials, which include various types of cells, organelles, and biological components from animals, plants, and microorganisms, have become central to recent investigations in micro and nanorobotics. Living material-derived intelligent micro/nanorobots (LMNRs) are self-propelled devices that combine living materials with synthetic materials. By harnessing energy from external physical fields or biological sources, LMNRs can move autonomously and perform various biomedical functions, such as drug delivery, crossing biological barriers, medical imaging, and disease treatment. This review, from a biomimetic strategy perspective, summarized the latest advances in the design and biomedical applications of LMNRs. It provided a comprehensive overview of the living materials used to construct LMNRs, including mammalian cells, plants, and microorganisms while highlighting their biological properties and functions. Lastly, the review discussed the major challenges in this field and offered suggestions for future research that may help facilitate the clinical application of LMNRs in the near future.

Micro- and Nanomotors: Engineered Tools for Targeted and Efficient Biomedicine

Over the past two decades, nanotechnology has made significant progress toward the development and applications of micromotors (MMs) and nanomotors (NMs). Characterized by their capability to self-propel and swim in fluids, they have emerged as promising tools in various fields, particularly in biomedicine. This Review presents an overview of the current state of MMs and NMs, their motion in viscous media and complex environments, their interaction with biological barriers, and potential therapeutical applications. We identify the choice of appropriate administration routes to reach their target location as a key aspect of the success of MMs and NMs in biomedical applications. Looking ahead, we envision NMs playing a key role in treating diverse medical disorders, as recent proof-of-concept in vivo studies demonstrate their distinct capabilities and versatility. However, addressing regulatory, scalability, biocompatibility, and safety concerns remains imperative for the successful translation of NMs into clinical trials and industrial-scale production. This work provides a guideline for researchers, guiding them through the current landscape, challenges, and prospects of using MMs and NMs in biomedicine, thereby encouraging their responsible development and positioning in the future of nanomedicine. Furthermore, we outline critical areas for further research, including studies on biocompatibility, safety, and methods to overcome physical obstacles.

Translational nanorobotics breaking through biological membranes

In the dynamic realm of translational nanorobotics, the endeavor to develop nanorobots carrying therapeutics in rational in vivo applications necessitates a profound understanding of the biological landscape of the human body and its complexity. Within this landscape, biological membranes stand as critical barriers to the successful delivery of therapeutic cargo to the target site. Their crossing is not only a challenge for nanorobotics but also a pivotal criterion for the clinical success of therapeutic-carrying nanorobots. Nevertheless, despite their urgency, strategies for membrane crossing in translational nanorobotics remain relatively underrepresented in the scientific literature, signaling an opportunity for further research and innovation. This review focuses on nanorobots with various propulsion mechanisms from chemical and physical to hybrid mechanisms, and it identifies and describes four essential biological membranes that represent the barriers needed to be crossed in the therapeutic journey of nanorobots in in vivo applications. First is the entry point into the blood stream, which is the skin or mucosa or intravenous injection; next is the exit from the bloodstream across the endothelium to the target site; further is the entry to the cell through the plasma membrane and, finally, the escape from the lysosome, which otherwise destroys the cargo. The review also discusses design challenges inherent in translating nanorobot technologies to real-world applications and provides a critical overview of documented membrane crossings. The aim is to underscore the need for further interdisciplinary collaborations between chemists, materials scientists and chemical biologists in this vital domain of translational nanorobotics that has the potential to revolutionize the field of precision medicine.

Breaking Through Physiological Barriers: Nanorobotic Strategies for Active Drug Delivery

Self-propelled micro/nanomotors (MNMs) represent a groundbreaking advancement in precision drug delivery, offering potential solutions to persistent challenges such as systemic toxicity, limited bioavailability, and nonspecific distribution. By transforming various energy sources into mechanical motion, MNMs are able to autonomously navigate through complex physiological environments, facilitating targeted delivery of therapeutic agents to previously inaccessible regions. However, to achieve efficient in vivo drug delivery, biomedical MNMs must demonstrate their ability to overcome crucial physiological barriers encompassing mucosal surfaces, blood flow dynamics, vascular endothelium, and cellular membrane. This review provides a comprehensive overview of the latest strategies developed to address these obstacles while also analyzing the broader challenges and opportunities associated with clinical translation. Our objective is to establish a solid foundation for future research in medical MNMs by focusing on enhancing drug delivery efficiency and advancing precision medicine, ultimately paving the way for practical theragnostic applications and wider clinical adoption.

Positive Chemotactic Flasklike Colloidal Motors Propelled by Rotary FoF1-ATP Synthases

Living microorganisms can perform directed migration for foraging in response to a chemoattractant gradient. We report a biomimetic strategy that rotary FoF1-ATPase (adenosine triphosphatase)-propelled flasklike colloidal motors exhibit positive chemotaxis resembling the chemotactic behavior of bacteria. The streamlined flasklike colloidal particles are fabricated through polymerization, expansion, surface rupture, and re-polymerizing nanoemulsions composed of triblock copolymers and ribose. The as-synthesized particles enable the incorporation of thylakoid vesicles into the cavity, ensuring a geometric asymmetric nanoarchitecture. The chemical gradient in the neck channel across flasklike colloidal motors facilitates autonomous movement at a speed of 1.19 μm/s in a ΔpH value of 4. Computer simulations reveal the self-actuated flasklike colloidal motors driven by self-diffusiophoretic force. These flasklike colloidal motors display positive directional motion along an adenosine diphosphate (ADP) concentration gradient during adenosine triphosphate (ATP) synthesis. The positive chemotaxis is ascribed that the phosphorylation reaction occurring inside colloidal motors generates 2 distinct phoretic torques at the bottom and the opening owing to the diffusion of ADP, thereby a continuous reorientation motion. Such a biophysical strategy that nanosized rotary protein molecular motors propel the directional movement of a flasklike colloidal motor holds promise for designing new types of biomedical swimming nanobots.

Miniature Robots for Battling Bacterial Infection

Micro/nanorobots have shown great promise for minimally invasive bacterial infection therapy. However, bacterial infections usually form biofilms inside the body by aggregation and adhesion, preventing antibiotic penetration and increasing the likelihood of recurrence. Moreover, a substantial portion of the infection happens in those hard-to-access regions, making delivery of antibiotics to infected sites or tissues difficult and exacerbating the challenge of addressing bacterial infections. Micro/nanorobots feature exceptional mobility and controllability, are able to deliver drugs to specific sites (targeted delivery), and enhance drug penetration. In particular, the emergence of bioinspired microrobot surface design strategies have provided effective alternatives for treating infections, thereby preventing the possible development of bacterial resistance. In this paper, we review the recent advances in design, mechanism, and actuation modalities of micro/nanorobots with exceptional antimicrobial features, highlighting active therapy strategies for bacterial infections and derived complications at various organs, from the laboratory bench to in vivo applications. The current challenges and future research directions in this field are summarized. Those breakthroughs in micro/nanorobots offer a huge potential for clinical translation for bacterial infection therapy.

Micro/nanorobots for gastrointestinal tract

The application of micro/nanomotors (MNMs) in the gastrointestinal tract has become a Frontier in the treatment of gastrointestinal diseases. These miniature robots can enter the gastrointestinal tract through oral administration, achieving precise drug delivery and therapy. They can traverse mucosal layers and tissue barriers, directly targeting tumors or other lesion sites, thereby enhancing the bioavailability and therapeutic effects of drugs. Through the application of nanotechnology, these MNMs are able to accomplish targeted medication release, regulating drug release in response to either external stimuli or the local biological milieu. This results in reduced side effects and increased therapeutic efficacy. This review summarizes the primary classifications and power sources of current MNMs, as well as their applications in the gastrointestinal tract, providing inspiration and direction for the treatment of gastrointestinal diseases with MNMs.

Oral administration microrobots for drug delivery

Oral administration is the most simple, noninvasive, convenient treatment. With the increasing demands on the targeted drug delivery, the traditional oral treatment now is facing some challenges: 1) biologics how to implement the oral treatment and ensure the bioavailability is not lower than the subcutaneous injections; 2) How to achieve targeted therapy of some drugs in the gastrointestinal tract? Based on these two issues, drug delivery microrobots have shown great application prospect in oral drug delivery due to their characteristics of flexible locomotion or driven ability. Therefore, this paper summarizes various drug delivery microrobots developed in recent years and divides them into four categories according to different driving modes: magnetic-controlled drug delivery microrobots, anchored drug delivery microrobots, self-propelled drug delivery microrobots and biohybrid drug delivery microrobots. As oral drug delivery microrobots involve disciplines such as materials science, mechanical engineering, medicine, and control systems, this paper begins by introducing the gastrointestinal barriers that oral drug delivery must overcome. Subsequently, it provides an overview of typical materials involved in the design process of oral drug delivery microrobots. To enhance readers' understanding of the working principles and design process of oral drug delivery microrobots, we present a guideline for designing such microrobots. Furthermore, the current development status of various types of oral drug delivery microrobots is reviewed, summarizing their respective advantages and limitations. Finally, considering the significant concerns regarding safety and clinical translation, we discuss the challenges and prospections of clinical translation for various oral drug delivery microrobots presented in this paper, providing corresponding suggestions for addressing some existing challenges.

Toward Practical Applications of Engineered Living Materials with Advanced Fabrication Techniques

Engineered Living Materials (ELMs) are materials composed of or incorporating living cells as essential functional units. These materials can be created using bottom-up approaches, where engineered cells spontaneously form well-defined aggregates. Alternatively, top-down methods employ advanced materials science techniques to integrate cells with various kinds of materials, creating hybrids where cells and materials are intricately combined. ELMs blend synthetic biology with materials science, allowing for dynamic responses to environmental stimuli such as stress, pH, humidity, temperature, and light. These materials exhibit unique "living" properties, including self-healing, self-replication, and environmental adaptability, making them highly suitable for a wide range of applications in medicine, environmental conservation, and manufacturing. Their inherent biocompatibility and ability to undergo genetic modifications allow for customized functionalities and prolonged sustainability. This review highlights the transformative impact of ELMs over recent decades, particularly in healthcare and environmental protection. We discuss current preparation methods, including the use of endogenous and exogenous scaffolds, living assembly, 3D bioprinting, and electrospinning. Emphasis is placed on ongoing research and technological advancements necessary to enhance the safety, functionality, and practical applicability of ELMs in real-world contexts.

Biorobotic Drug Delivery for Biomedical Applications

Despite extensive efforts, current drug-delivery systems face biological barriers and difficulties in bench-to-clinical use. Biomedical robotic systems have emerged as a new strategy for drug delivery because of their innovative diminutive engines. These motors enable the biorobots to move independently rather than relying on body fluids. The main components of biorobots are engines controlled by external stimuli, chemical reactions, and biological responses. Many biorobot designs are inspired by blood cells or microorganisms that possess innate swimming abilities and can incorporate living materials into their structures. This review explores the mechanisms of biorobot locomotion, achievements in robotic drug delivery, obstacles, and the perspectives of translational research.

Design strategies, advances and future perspectives of colon-targeted delivery systems for the treatment of inflammatory bowel disease

Inflammatory bowel diseases (IBD) significantly contribute to high mortality globally and negatively affect patients' qualifications of life. The gastrointestinal tract has unique anatomical characteristics and physiological environment limitations. Moreover, certain natural or synthetic anti-inflammatory drugs are associated with poor targeting, low drug accumulation at the lesion site, and other side effects, hindering them from exerting their therapeutic effects. Colon-targeted drug delivery systems represent attractive alternatives as novel carriers for IBD treatment. This review mainly discusses the treatment status of IBD, obstacles to drug delivery, design strategies of colon-targeted delivery systems, and perspectives on the existing complementary therapies. Moreover, based on recent reports, we summarized the therapeutic mechanism of colon-targeted drug delivery. Finally, we addressed the challenges and future directions to facilitate the exploitation of advanced nanomedicine for IBD therapy.

Catalase-Powered Nanobots for Overcoming the Mucus Barrier

Biological barriers present a significant obstacle to treatment, especially when drugs are administered locally to increase their concentrations at the target site while minimizing unintended off-target effects. Among these barriers, mucus presents a challenge, as it serves as a protective layer in the respiratory, urogenital, and gastrointestinal tracts. Its role is to shield the underlying epithelial cells from pathogens and toxic compounds but also impedes the efficient delivery of drugs. Despite the exploration of mucolytic agents to improve drug delivery, overcoming this protective barrier remains a significant hurdle. In our study, we investigate an alternative approach involving the use of catalase-powered nanobots. We use an in vitro model that simulates intestinal mucus secretion to demonstrate the dual functionality of our nanobots. This includes their ability to disrupt mucus, which we confirmed through in vitro and ex vivo validation, as well as their self-propulsion to overcome the mucus barrier, resulting in a 60-fold increase compared with passive nanoparticles. Therefore, our findings highlight the potential utility of catalase-powered nanobots as carriers for therapeutic agents since they could enhance drug delivery efficiency by penetrating the mucus barrier.

A Gas Therapy Strategy for Intestinal Flora Regulation and Colitis Treatment by Nanogel-Based Multistage NO Delivery Microcapsules

Current approaches to treating inflammatory bowel disease focus on the suppression of overactive immune responses, the removal of reactive intestinal oxygen species, and regulation of the intestinal flora. However, owing to the complex structure of the gastrointestinal tract and the influence of mucus, current small-molecule and biologic-based drugs for treating colitis cannot effectively act at the site of colon inflammation, and as a result, they tend to exhibit low efficacies and toxic side effects. In this study, nanogel-based multistage NO delivery microcapsules are developed to achieve NO release at the inflammation site by targeting the inflammatory tissues using the nanogel. Surprisingly, oral administration of the microcapsules suppresses the growth of pathogenic bacteria and increases the abundance of probiotic bacteria. Metabolomics further show that an increased abundance of intestinal probiotics promotes the production of metabolites, including short-chain fatty acids and indole derivatives, which modulate the intestinal immunity and restore the intestinal barrier via the interleukin-17 and PI3K-Akt signaling pathways. This work reveals that the developed gas therapy strategy based on multistage NO delivery microcapsules modulates the intestinal microbial balance, thereby reducing inflammation and promoting intestinal barrier repair, ultimately providing a new therapeutic approach for the clinical management of colitis.

Engineered platelet cell motors for boosted cancer radiosensitization

Design of engineered cells to target and deliver nanodrugs to the hard-to-reach regions has become an exciting research area. However, the limited penetration and retention of cell-based carriers in tumor tissue restricted their therapeutic efficiency. Inspired by the enhanced delivery behavior of mobile micro/nanomotors, herein, urease-powered platelet cell motors (PLT@Au@Urease) capable of active locomotion, tumor targeting, and radiosensitizers delivery were designed for boosting radiosensitization. The engineered platelet cell motors were constructed by in situ synthesis and loading of radiosensitizers gold nanoparticles in platelets, and then conjugation with urease as the engine. Under physiological concentration of urea, thrust around PLT@Au@Urease motors can be generated via the biocatalytic reactions of urease, leading to rapid tumor cell targeting and enhanced cellular uptake of radiosensitizers. Encouragingly, in comparison with engineered PLT without propulsion capability (PLT@Au), the self-propelled PLT@Au@Urease motors could significantly increase intracellular ROS level and exacerbate nuclear DNA damage induced by γ-radiation, resulting in a remarkably high sensitization enhancement rate (1.89) than that of PLT@Au (1.08). In vivo experiments with 4 T1-bearing mice demonstrated that PLT@Au@Urease in combination with radiation therapy possessed good antitumor performance. Such an intelligent cell motor would provide a promising approach to enhance radiosensitization and broaden the applications of cell motor-based delivery systems.

Understanding yeast shells: structure, properties and applications

Background and purpose

The employment of yeasts for biomedical purposes has become increasingly frequent for the delivery of prophylactic and therapeutic products. Its structural components, such as β-glucans, mannan, and chitin, can be explored as immunostimulators that show safety and low toxicity. Besides, this system minimizes antigen degradation after administration, facilitating the delivery to the target cells.

Review approach

This review sought to present molecules derived from yeast, called yeast shells (YS), and their applications as carrier vehicles for drugs, proteins, and nucleic acids for immunotherapy purposes. Furthermore, due to the diversity of information regarding the production and immunostimulation of these compounds, a survey of the protocols and immune response profiles generated was presented.

Key results

The use of YS has allowed the development of strategies that combine efficiency and effectiveness in antigen delivery. The capsular structure can be recognized and phagocytized by dendritic cells and macrophages. In addition, the combination with different molecules, such as nanoparticles or even additional adjuvants, improves the cargo loading, enhancing the system. Activation by specific immune pathways can also be achieved by different administration routes.

Conclusion

Yeast derivatives combined in different ways can increase immunostimulation, enhancing the delivery of medicines and vaccine antigens. These aspects, combined with the simplicity of the production steps, make these strategies more accessible to be applied in the prevention and treatment of various diseases.

Dual-Fuel Propelled Nanomotors with Two-Stage Permeation for Deep Bacterial Infection in the Treatment of Pulpitis

Bacterial infection-induced inflammatory response could cause irreversible death of pulp tissue in the absence of timely and effective therapy. Given that, the narrow structure of root canal limits the therapeutic effects of passive diffusion-drugs, considerable attention has been drawn to the development of nanomotors, which have high tissue penetration abilities but generally face the problem of insufficient fuel concentration. To address this drawback, dual-fuel propelled nanomotors (DPNMs) by encapsulating L-arginine (L-Arg), calcium peroxide (CaO2 ) in metal-organic framework is developed. Under pathological environment, L-Arg could release nitric oxide (NO) by reacting with reactive oxygen species (ROS) to provide the driving force for movement. Remarkably, the depleted ROS could be supplemented through the reaction between CaO2 with acids abundant in the inflammatory microenvironment. Owing to high diffusivity, NO achieves further tissue penetration based on the first-stage propulsion of nanomotors, thereby removing deep-seated bacterial infection. Results indicate that the nanomotors effectively eliminate bacterial infection based on antibacterial activity of NO, thereby blocking inflammatory response and oxidative damage, forming reparative dentine layer to avoid further exposure and infection. Thus, this work provides a propagable strategy to overcome fuel shortage and facilitates the therapy of deep lesions.

Urease-Powered Micromotors with Spatially Selective Distribution of Enzymes for Capturing and Sensing Exosomes

Enzyme-catalyzed micro/nanomotors (MNMs) exhibit tremendous potential for biological isolation and sensing, because of their biocompatibility, versatility, and ready access to biofuel. However, flow field generated by enzyme-catalyzed reactions might significantly hinder performance of surface-linked functional moieties, e.g., the binding interaction between MNMs and target cargos. Herein, we develop enzymatic micromotors with spatially selective distribution of urease to enable the independent operation of various modules and facilitate the capture and sensing of exosomes. When urease is modified into the motors' cavity, the flow field from enzyme catalysis has little effect on the exterior surface of the motors. The active motion and encapsulating urease internally result in enhancement of ∼35% and 18% in binding efficiency of target cargos, e.g., exosomes as an example here, compared to their static counterparts and moving micromotors with urease modified externally, respectively. Once exosomes are trapped, they can be transferred to a clean environment by the motors for Raman signal detection and/or identification using the surface Raman enhancement scattering (SERS) effect of coated gold nanoshell. The biocatalytic micromotors, achieving spatial separation between driving module and function module, offer considerable promise for future design of multifunctional MNMs in biomedicine and diagnostics.

Macrophage-Based Microrobots for Anticancer Therapy: Recent Progress and Future Perspectives

Macrophages, which are part of the mononuclear phagocytic system, possess sensory receptors that enable them to target cancer cells. In addition, they are able to engulf large amounts of particles through phagocytosis, suggesting a potential "Trojan horse" drug delivery approach to tumors by facilitating the engulfment of drug-hidden particles by macrophages. Recent research has focused on the development of macrophage-based microrobots for anticancer therapy, showing promising results and potential for clinical applications. In this review, we summarize the recent development of macrophage-based microrobot research for anticancer therapy. First, we discuss the types of macrophage cells used in the development of these microrobots, the common payloads they carry, and various targeting strategies utilized to guide the microrobots to cancer sites, such as biological, chemical, acoustic, and magnetic actuations. Subsequently, we analyze the applications of these microrobots in different cancer treatment modalities, including photothermal therapy, chemotherapy, immunotherapy, and various synergistic combination therapies. Finally, we present future outlooks for the development of macrophage-based microrobots.

Construction of micro-nano robots: living cells and functionalized biological cell membranes

Micro-nano robots have emerged as a promising research field with vast potential applications in biomedicine. The motor is the key component of micro-nano robot research, and the design of the motor is crucial. Among the most commonly used motors are those derived from living cells such as bacteria with flagella, sperm, and algal cells. Additionally, scientists have developed numerous self-adaptive biomimetic motors with biological functions, primarily cell membrane functionalized micromotors. This novel type of motor exhibits remarkable performance in complex media. This paper provides a comprehensive review of the structure and performance of micro-nano robots that utilize living cells and functionalized biological cell membranes. We also discuss potential practical applications of these mirco-nano robots as well as potential challenges that may arise in future development.

Selective organ targeting nanoparticles: from design to clinical translation

Targeting nanoparticle is a very promising therapeutic approach that can precisely target specific sites to treat diseases. Research on nanoscale drug delivery systems has made great progress in the past few years, making targeting nanoparticles a promising prospect. However, selective targeting nanoparticles designed for specific organs still face several challenges, one of which is the unknown fate of nanoparticles in vivo. This review starts with the in vivo journey of nanoparticles and describes the biological barriers and some targeting strategies for nanoparticles to target specific organs. Then, through the collection of literature in recent years, the design of selective targeting nanoparticles for various organs is illustrated, which provides a reference strategy for people to study the design of selective organ targeting nanoparticles. Ultimately, the prospect and challenge of selective organ targeting nanoparticles are discussed by collecting the data of clinical trials and marketed drugs.

Recent progress of micro/nanomotors to overcome physiological barriers in the gastrointestinal tract

Oral administration is a convenient administration route for gastrointestinal disease therapy with good patient compliance. But the nonspecific distribution of the oral drugs may cause serious side effects. In recent years, oral drug delivery systems (ODDS) have been applied to deliver the drugs to the gastrointestinal disease sites with decreased side effects. However, the delivery efficiency of ODDS is tremendously limited by physiological barriers in the gastrointestinal sites, such as the long and complex gastrointestinal tract, mucus layer, and epithelial barrier. Micro/nanomotors (MNMs) are micro/nanoscale devices that transfer various energy sources into autonomous motion. The outstanding motion characteristics of MNMs inspired the development of targeted drug delivery, especially the oral drug delivery. However, a comprehensive review of oral MNMs for the gastrointestinal diseases therapy is still lacking. Herein, the physiological barriers of ODDS were comprehensively reviewed. Afterward, the applications of MNMs in ODDS for overcoming the physiological barriers in the past 5 years were highlighted. Finally, future perspectives and challenges of MNMs in ODDS are discussed as well. This review will provide inspiration and direction of MNMs for the therapy of gastrointestinal diseases, pushing forward the clinical application of MNMs in oral drug delivery.

Engineered Living Materials for Advanced Diseases Therapy

Natural living materials serving as biotherapeutics exhibit great potential for treating various diseases owing to their immunoactivity, tissue targeting, and other biological activities. In this review, the recent developments in engineered living materials, including mammalian cells, bacteria, viruses, fungi, microalgae, plants, and their active derivatives that are used for treating various diseases are summarized. Further, the future perspectives and challenges of such engineered living material-based biotherapeutics are discussed to provide considerations for future advances in biomedical applications.

Biocompatible smart micro/nanorobots for active gastrointestinal tract drug delivery

INTRODUCTION

Oral delivery is the most commonly used route of drug administration owing to good patient compliance. However, the gastrointestinal (GI) tract contains multiple physiological barriers that limit the absorption efficiency of conventional passive delivery systems resulting in a low drug concentration reaching the diseased sites. Micro/nanorobots can convert energy to self-propulsive force, providing a novel platform to actively overcome GI tract barriers for noninvasive drug delivery and treatment.

AREAS COVERED

In this review, we first describe the microenvironments and barriers in the different compartments of the GI tract. Afterward, the applications of micro/nanorobots to overcome GI tract barriers for active drug delivery are highlighted and discussed. Finally, we summarize and discuss the challenges and future prospects of micro/nanorobots for further clinical applications.

EXPERT OPINION

Micro/nanorobots with the ability to autonomously propel themselves and to load, transport, and release payloads on demand are ideal carriers for active oral drug delivery. Although there are many challenges to be addressed, micro/nanorobots have great potential to introduce a new era of drug delivery for precision therapy.

Repairing gastric ulcer with hyaluronic acid/extracellular matrix composite through promoting M2-type polarization of macrophages

The treatment of gastric ulcer and perforation using synthetic and biomaterials has been a clinical challenge. In this work, a drug-carrying layer of hyaluronic acid was combined with a gastric submucosal decellularized extracellular matrix called gHECM. The regulation of macrophage polarization by the extracellular matrix's components was then investigated. This work proclaims how gHECM responds to inflammation and aids in the regeneration of the gastric lining by altering the phenotype of surrounding macrophages and stimulating the body's whole immune response. In a nutshell, gHECM promotes tissue regeneration by changing the phenotype of macrophages around the site of injury. In particular, gHECM reduces the production of pro-inflammatory cytokines, decreases the percentage of M1 macrophages, and further encourages differentiation of macrophage subpopulation to the M2 phenotype and the release of anti-inflammatory cytokines, which could block the NF-κB pathway. Activated macrophages are capable of immediately delivering through spatial barriers, modulating the peripheral immune system, influencing the inflammatory microenvironment, and ultimately promoting the recovery of inflammation and healing of ulcers. They contribute to the secreted cytokines that act on local tissues or enhance the chemotactic ability of macrophages through paracrine secretion. In this study, we focused on the immunological regulatory network of macrophage polarization to further develop the mechanisms behind this process. Nevertheless, the signaling pathways involved in this process need to be further explored and identified. We think that our research will encourage more investigation into how the decellularized matrix affects immune modulation and will help the decellularized matrix perform better as a new class of natural biomaterials for tissue engineering.

In vivo applications of micro/nanorobots

Untethered robots in the size range of micro/nano-scale offer unprecedented access to hard-to-reach areas of the body. In these challenging environments, autonomous task completion capabilities of micro/nanorobots have been the subject of research in recent years. However, most of the studies have presented preliminary in vitro results that can significantly differ under in vivo settings. Here, we focus on the studies conducted with animal models to reveal the current status of micro/nanorobotic applications in real-world conditions. By a categorization based on target locations, we highlight the main strategies employed in organs and other body parts. We also discuss key challenges that require interest before the successful translation of micro/nanorobots to the clinic.