Facile Fabrication of Magnetic Microrobots Based on Spirulina Templates for Targeted Delivery and Synergistic Chemo-Photothermal Therapy

AlgaeSperm: Microalgae-Based Soft Magnetic Microrobots for Targeted Tumor Treatment

Magnetic microrobots are significant platforms for targeted drug delivery, among which sperm-inspired types have attracted much attention due to their flexible undulation. However, mass production of sperm-like soft magnetic microrobots with high-speed propulsion is still challenging due to the need of more reasonable structure design and facile fabrication. Herein, a novel strategy is proposed for large-scale preparation of microalgae-based soft microrobots with a fully magnetic head-to-tail structure, called AlgaeSperm with robust propulsion and chemo-photothermal performance. This approach deposited Pd@Au nanoparticles (NPs) inside chlorella cells, which are further coated with Fe3O4 NPs and polydopamine layers to form the magnetic heads. Then, flexible flagella are grafted via magnetic assembly of Fe3O4@PVP NPs to construct the final AlgaeSperm. Under precessing magnetic fields, the AlgaeSperms can achieve a forward velocity up to 2.3 body length/s, the highest among sperm-like magnetic microrobots to the best of the knowledge. Besides, their flexible maneuverability in a swarm is also verified. In vitro anti-cancer experiments are conducted after loading doxorubicin (DOX) to confirm their excellent targeted chemo-photothermal performance. This work offers a significant paradigm for constructing sperm-like soft magnetic microrobots with great potential for targeted tumor treatment.

Living Microalgae-Based Magnetic Microrobots for Calcium Overload and Photodynamic Synergetic Cancer Therapy

The combination of Ca2+ overload and reactive oxygen species (ROS) production for cancer therapy offers a superior solution to the lack of specificity in traditional antitumor strategies. However, current therapeutic platforms for this strategy are primarily based on non-targeting nanomaterials, leading to undesirable off-target side effects. Additionally, resistance to ROS and apoptosis induced by the hypoxic tumor microenvironment (TME) further limits therapeutic efficiency. Herein, a magnetic microrobot based on living Spirulina Platensis (SP), which is coated with a double layer of Fe3O4 nanoparticles (NPs) and CaCO3 NPs. The microrobots can accumulate in tumor regions under magnetic attraction, which produces a high-Ca2+ environment under the acidic TME and facilitates Ca2+ overload under ultrasound (US) stimulation. Meanwhile, sufficient oxygen (O2) production by photosynthesis helps alleviate hypoxia and promotes in situ ROS production by chlorophyll-mediated photodynamic therapy (PDT), which can coordinate with Ca2+ overload to induce cell apoptosis. With these unique properties, the SP-based microrobots offer a promising microrobotics-based strategy for in situ Ca2+ accumulation and ROS production, contributing to a precise and effective way for cancer treatment.

Microalgae-carrying nanomedicine for bioadhesive drug delivery for treating chemotherapy-induced intestinal injury

Gastrointestinal tract toxicity represents a serious adverse effect of chemotherapy, leading to reduced quality of life and survival. For instance, irinotecan (CPT-11) usually causes severe gastrointestinal toxicity, with a lack of effective therapeutic interventions, making treatment often unsustainable. Therefore, development of an effective and safe therapy is crucial for improving chemotherapy efficacy and the patients' quality of life. In this work, we developed a novel approach involving the helical-shaped cyanobacterium microalgae, Spirulina platensis (SP), to carry the bornyl acetate (BA)-loaded chitosan nanoparticles to enhance drug retention in the small intestine. We demonstrated the protection effect of BA against chemotherapy-induced intestinal injury using an epithelial cell model. In a mouse model, orally administered BA-ChNPs@SP accumulated in the small intestine and attenuated inflammation by reducing dsDNA release and oxidative stress. This was concomitant with the restoration of the intestinal barrier and modulation of the immune microenvironment. This work suggests the promise of the microalgae-carrying nanomedicine strategy for treatment of intestinal diseases, emphasizing its potential in addressing chemotherapy-induced gastrointestinal complications.

Application of photosensitive microalgae in targeted tumor therapy

Microalgae present a novel and multifaceted approach to cancer therapy by modulating the tumor-associated microbiome (TAM) and the tumor microenvironment (TME). Through their ability to restore gut microbiota balance, reduce inflammation, and enhance immune responses, microalgae contribute to improved cancer treatment outcomes. As photosynthetic microorganisms, microalgae exhibit inherent anti-tumor, antioxidant, and immune-regulating properties, making them valuable in photodynamic therapy and tumor imaging due to their capacity to generate reactive oxygen species. Additionally, microalgae serve as effective drug delivery vehicles, leveraging their biocompatibility and unique structural properties to target the TME more precisely. Microalgae-based microrobots further expand their therapeutic potential by autonomously navigating complex biological environments, offering a promising future for precision-targeted cancer treatments. We position microalgae as a multifunctional agent capable of modulating TAM, offering novel strategies to enhance TME and improve the efficacy of cancer therapies.

Magnetic Micro/nanorobots in Cancer Theranostics: From Designed Fabrication to Diverse Applications

Cancer poses a substantial threat and a serious challenge to public human health, driving the promotion of sophisticated technologies for cancer therapy. While conventional chemotherapy has bottlenecks such as low delivery efficiency, strong toxic side effects, and tumor enrichment barriers, magnetic micro/nanorobots (MNRs) emerge as promising therapeutic candidates that provide alternative strategies for cancer therapy. MNR is a kind of human-made machine that is micro- or nanosized, is reasonably designed, and performs command tasks through self-actuated or externally controlled propulsion mechanisms, which can be potentially applied in cancer theranostics. Here, this review first introduces the components that constitute a typical magnetic MNR, including the body part, the driving part, the control part, the function part, and the sensing part. Subsequently, this review elucidates representative fabrication methods to construct magnetic MNRs from top-down approaches to bottom-up approaches, covering injection molding, self-rolling, melt electrospinning writing, deposition, biotemplate method, lithography, assembling, 3D printing, and chemical synthesis. Furthermore, this review focuses on multiple applications of magnetic MNRs facing cancer diagnosis and treatment, encompassing imaging, quantification, drug release, synergy with typical therapies, cell manipulation, and surgical assistance. Then, this review systematically elaborates on the biocompatibility and biosafety of magnetic MNRs. Finally, the challenges faced by magnetic MNRs are discussed alongside future research directions. This review is intended to provide scientific guidance that may improve the comprehension and cognition of cancer theranostics through the platform of magnetic MNRs, promoting and prospering the practical application development of magnetic MNRs.

Advancements in Micro/Nanorobots in Medicine: Design, Actuation, and Transformative Application

In light of the ongoing technological transformation, embracing advancements that foster shared benefits is essential. Nanorobots, a breakthrough within nanotechnology, have demonstrated significant potential in fields such as medicine, where diagnostic and therapeutic applications are the primary focus areas. This review provides a comprehensive overview of nanotechnology, robots, and their evolving role in medical applications, particularly highlighting the use of nanorobots. Various design strategies and operational principles, including sensors, actuators, and nanocontrollers, are discussed based on prior research. Key nanorobot medical applications include biomedical imaging, biosensing, minimally invasive surgery, and targeted drug delivery, each utilizing advanced actuation technologies to enhance precision. The paper further examines recent progress in micro/nanorobot actuation and addresses important considerations for the future, including biocompatibility, control, navigation, delivery, targeting, safety, and ethical implications. This review offers a holistic perspective on how nanorobots can reshape medical practices, paving the way for precision medicine and improved patient outcomes.

Propulsion Mechanisms in Magnetic Microrobotics: From Single Microrobots to Swarms

Microrobots with different structures can exhibit multiple propulsion mechanisms under external magnetic fields. Swarms dynamically assembled by microrobots inherit the advantages of single microrobots, such as degradability and small dimensions, while also offering benefits like scalability and high flexibility. With control of magnetic fields, these swarms demonstrate diverse propulsion mechanisms and can perform precise actions in complex environments. Therefore, the relationship between single microrobots and their swarms is a significant area of study. This paper reviews the relationship between single microrobots and swarms by examining the structural design, control methods, propulsion mechanisms, and practical applications. At first, we introduce the structural design of microrobots, including materials and manufacturing methods. Then, we describe magnetic field generation systems, including gradient, rotating, and oscillating magnetic fields, and their characteristics. Next, we analyze the propulsion mechanisms of individual microrobots and the way microrobots dynamically assemble into a swarm under an external magnetic field, which illustrates the relationship between single microrobots and swarms. Finally, we discuss the application of different swarm propulsion mechanisms in water purification and targeted delivery, summarize current challenges and future work, and explore future directions.

Artificial Microglia Nanoplatform Loaded With Anti-RGMa in Acoustic/Magnetic Feld for Recanalization and Neuroprotection in Acute Ischemic Stroke

Ischemic stroke is a leading cause of death and disability worldwide, and the main goals of stroke treatment are to destroy the thrombus to recanalize blood vessels and protect tissue from ischemia/reperfusion injury. However, current recanalization therapies have serious limitations and there are few neuroprotection methods. Hence, an artificial nanoplatform loaded with anti-Repulsive Guidance Molecule a monoclonal antibody (anti-RGMa) and coated with microglia membrane (MiCM) is reported for stroke treatment, namely MiCM@PLGA/anti-RGMa/Fe3O4@PFH (MiCM-NPs). Tail vein injection of MiCM-NPs targeted the ischemia-damaged endothelial cells because of the MiCM, then superparamagnetic iron oxide (Fe3O4) and anti-RGMa are released after external low-intensity focused ultrasound (LIFU) exposure. The thrombus is destroyed by LIFU-induced "liquid-to-gas" phase transition and cavitation of perfluorohexane (PFH) as well as Fe3O4 movements induced by an external magnetic field. Anti-RGMa protected the ischemic region from ischemia/reperfusion injury. The nanoplatform enabled visualization of the thrombus by ultrasound/photoacoustic imaging when the clot is in an extracranial artery. Importantly, in vivo animal studies revealed good safety for MiCM-NPs treatment. In conclusion, this nanoplatform shows promise as an ischemic stroke treatment strategy combining targeted delivery, recanalization, and neuroprotection.

Biohybrid Micro/Nanorobots: Pioneering the Next Generation of Medical Technology

Biohybrid micro/nanorobots hold a great potential for advancing biomedical research. These tiny structures, designed to mimic biological organisms, offer a promising method for targeted drug delivery, tissue engineering, biosensing/imaging, and cancer therapy, among other applications. The integration of biology and robotics opens new possibilities for minimally invasive surgeries and personalized healthcare solutions. The key challenges in the development of biohybrid micro/nanorobots include ensuring biocompatibility, addressing manufacturing scalability, enhancing navigation and localization capabilities, maintaining stability in dynamic biological environments, navigating regulatory hurdles, and successfully translating these innovative technologies into clinical applications. Herein, the recent advancements, challenges, and future perspectives related to the biomedical applications of biohybrid micro/nanorobots are described. Indeed, this review sheds light on the cutting-edge developments in this field, providing researchers with an updated overview of the current potential of biohybrid micro/nanorobots in the realm of biomedical applications, and offering insights into their practical applications. Furthermore, it delves into recent advancements in the field of biohybrid micro/nanorobotics, providing a comprehensive analysis of the current state-of-the-art technologies and their future applications in the biomedical field.

Recent Advances in Micro- and Nanorobot-Assisted Colorimetric and Fluorescence Platforms for Biosensing Applications

Micro- and nanorobots (MNRs) have attracted significant interest owing to their promising applications in various fields, including environmental monitoring, biomedicine, and microengineering. This review explores advances in the synthetic routes used for the preparation of MNRs, focusing on both top-down and bottom-up approaches. Although the top-down approach dominates the field because of its versatility in design and functionality, bottom-up strategies that utilize template-assisted electrochemical deposition and bioconjugation present unique advantages in terms of biocompatibility. This review investigates the diverse propulsion mechanisms employed in MNRs, including magnetic, electric, light, and biological forces, which enable efficient navigation in various fluidic environments. The interplay between the synthesis and propulsion mechanisms of MNRs in the development of colorimetric and fluorescence detection platforms is emphasized. Additionally, we summarize the recent advancements in MNRs as sensing and biosensing platforms, particularly focusing on colorimetric and fluorescence-based detection systems. By utilizing the controlled motion of MNRs, dynamic changes in the fluorescent signals and colorimetric responses can be achieved, thereby enhancing the sensitivity and selectivity of biomolecular detection. This review highlights the transformative potential of MNRs in sensing applications and emphasizes their role in advancing diagnostic technologies through innovative motion-driven signal transduction mechanisms. Subsequently, we provide an overview of the primary challenges currently faced in MNR research, along with our perspective on the future applications of MNR-assisted colorimetric and fluorescence biosensing in chemical and biological sensing. Moreover, issues related to enhanced stability, biocompatibility, and integration with existing detection systems are discussed.

Recent advances in microalgae encapsulation techniques for biomedical applications

Microalgae are microorganisms that are rich in bioactive compounds, including pigments, proteins, lipids, and polysaccharides. These compounds can be utilized for a number of biomedical purposes, including drug delivery, wound healing, and tissue engineering. Nevertheless, encapsulating microalgae cells and microalgae bioactive metabolites is vital to protect them and prevent premature degradation. This also enables the development of intelligent controlled release strategies for the bioactive compounds. This review outlines the most employed encapsulation techniques for microalgae, with a particular focus on their biomedical applications. These include ionic gelation, oil-in-water emulsions, and spray drying. Such techniques have been widely explored, due to their ability to protect sensitive compounds from degradation, enhance their stability, extend their shelf life, mask undesirable tastes or odours, control the release of bioactive compounds, and enable targeted delivery to specific sites within the body or environment. Moreover, a patent landscape analysis is also provided, allowing an overview of the microalgae encapsulation technology development applied to a variety of fields, including pharmaceuticals, cosmetics, food, and agriculture.

Prospects of nano-theranostic approaches against breast and cervical cancer

The bottleneck on therapeutics and diagnostics is removed by an alternate approach known as theranostics which combines both therapeutics and diagnostics within a single platform. Due to this "all in one" nature of theranostics, it is now extensively applied in the medicinal field mainly in cancer treatment over the conventional therapy. Recently, FDA approval of lutetium 177 (177Lu) DOTATATE and 177Lu-PSMA-based radionuclide theranostics are clinically used and very few theranostics specific to breast cancer are in clinical trials. In this review, we are willing to draw special attention to the application of theranostics in the most relevant cancers in women, the breast and the cervical as these cancers affect women harshly but talked very silently due to the social restrictions and discriminations mainly in rural areas of developing and under developing countries. This approach not only combines therapeutics and diagnostics but targeting moieties can also be accommodated for the precise medication. Herein, our main objective is to enlighten the broader aspects of different kinds of theranostic devices based on radioisotopes, nanoparticles, graphene quantum dots, dendrimers and their fruitful application against breast and cervical cancer. The development of synthetic nano-theranostics was reported by accommodating therapeutic drugs, imaging probes and targeting ligands through conjugation or encapsulation. The imaging modalities like optical fluorescence, photosensitizers and radiotracers are used to get the diagnostic images through NIR, PET, MRI and CT/SPECT to detect the progress of cancer non-invasively and also at the same time targeting ligands such as antibodies, proteins and peptides in attachment with the theranostics enhances the therapeutic efficacy in addition to the clarity in diagnostics. The applications of theranostics from the last decade with their present scenario in clinics and future perspectives, as well as the pitfalls with the hurdles that still leave questions to rethink from the root are also been discussed in this review.

Light-Driven Microrobots for Targeted Drug Delivery

As a new micromanipulation tool with the advantages of small size, flexible movement and easy manipulation, light-driven microrobots have a wide range of prospects in biomedical fields such as drug targeting and cell manipulation. Recently, microrobots have been controlled in various ways, and light field has become a research hotspot by its advantages of noncontact manipulation, precise localization, fast response, and biocompatibility. It utilizes the force or deformation generated by the light field to precisely control the microrobot, and combines with the drug release technology to realize the targeted drug application. Therefore, this paper provides an overview of light-driven microrobots with drug targeting to provide new ideas for the manipulation of microrobots. Here, this paper briefly categorizes the driving mechanisms and materials of light-driven microrobots, which mainly include photothermal, photochemical, and biological. Then, typical designs of light-driven microrobots with different driving mechanisms and control strategies for multiple physical fields are summarized. Finally, the applications of microrobots in the fields of drug targeting and bioimaging are presented as well as the future prospects of light-driven microrobots in the biomedical field are demonstrated.

3D-printed microrobots for biomedical applications

Microrobots, which can perform tasks in difficult-to-reach parts of the human body under their own or external power supply, are potential tools for biomedical applications, such as drug delivery, microsurgery, imaging and monitoring, tissue engineering, and sensors and actuators. Compared with traditional fabrication methods for microrobots, recent improvements in 3D printers enable them to print high-precision microrobots, breaking through the limitations of traditional micromanufacturing technologies that require high skills for operators and greatly shortening the design-to-production cycle. Here, this review first introduces typical 3D printing technologies used in microrobot manufacturing. Then, the structures of microrobots with different functions and application scenarios are discussed. Next, we summarize the materials (body materials, propulsion materials and intelligent materials) used in 3D microrobot manufacturing to complete body construction and realize biomedical applications (e.g., drug delivery, imaging and monitoring). Finally, the challenges and future prospects of 3D printed microrobots in biomedical applications are discussed in terms of materials, manufacturing and advancement.

Microbe-material hybrids for therapeutic applications

As natural living substances, microorganisms have emerged as useful resources in medicine for creating microbe-material hybrids ranging from nano to macro dimensions. The engineering of microbe-involved nanomedicine capitalizes on the distinctive physiological attributes of microbes, particularly their intrinsic "living" properties such as hypoxia tendency and oxygen production capabilities. Exploiting these remarkable characteristics in combination with other functional materials or molecules enables synergistic enhancements that hold tremendous promise for improved drug delivery, site-specific therapy, and enhanced monitoring of treatment outcomes, presenting substantial opportunities for amplifying the efficacy of disease treatments. This comprehensive review outlines the microorganisms and microbial derivatives used in biomedicine and their specific advantages for therapeutic application. In addition, we delineate the fundamental strategies and mechanisms employed for constructing microbe-material hybrids. The diverse biomedical applications of the constructed microbe-material hybrids, encompassing bioimaging, anti-tumor, anti-bacteria, anti-inflammation and other diseases therapy are exhaustively illustrated. We also discuss the current challenges and prospects associated with the clinical translation of microbe-material hybrid platforms. Therefore, the unique versatility and potential exhibited by microbe-material hybrids position them as promising candidates for the development of next-generation nanomedicine and biomaterials with unique theranostic properties and functionalities.

Biomedical application of microalgal-biomaterials hybrid system

Microalgae are a group of microorganisms containing chlorophyll A, which are highly photosynthetic and rich in nutrients. And they can produce multiple bioactive substances (peptides, proteins, polysaccharides, and fatty acids) for biomedical applications. Despite the unique advantages of microalgae-based biotherapy, the insufficient treatment efficiency limits its further application. With the development of nanotechnology, the combination of microalgae and biomaterials can improve therapeutic efficacies, which has attracted increasing attention. In this microalgal-biomaterials hybrid system, biomaterials with excellent optical and magnetic properties play an important role in biological therapy. Microalgae, as a natural vehicle, can increase oxygen content and alleviate hypoxia in diseased areas, further enhancing therapeutic effects. In this review, the synergistic therapeutic effects of microalgal-biomaterials hybrid system in different diseases (cancer, myocardial infarction, ischemia stroke, chronic infection, and intestinal diseases) are comprehensively summarized.

Propulsion mechanisms of micro/nanorobots: a review

Micro/nanomotors (MNMs) are intelligent, efficient and promising micro/nanorobots (MNR) that can respond to external stimuli (e.g., chemical energy, temperature, light, pH, ultrasound, magnetic, biosignals, ions) and perform specific tasks. The MNR can adapt to different external stimuli and transform into various functional forms to match different application scenarios. So far, MNR have found extensive application in targeted therapy, drug delivery, tissue engineering, environmental remediation, and other fields. Despite the promise of MNR, there are few reviews that focus on them. To shed new light on the further development of the field, it is necessary to provide an overview of the current state of development of these MNR. Therefore, this paper reviews the research progress of MNR in terms of propulsion mechanisms, and points out the pros and cons of different stimulus types. Finally, this paper highlights the current challenges faced by MNR and proposes possible solutions to facilitate the practical application of MNR.

Nanomaterial-assisted oncolytic bacteria in solid tumor diagnosis and therapeutics

Cancer presents a formidable challenge in modern medicine due to the intratumoral heterogeneity and the dynamic microenvironmental niche. Natural or genetically engineered oncolytic bacteria have always been hailed by scientists for their intrinsic tumor-targeting and oncolytic capacities. However, the immunogenicity and low toxicity inevitably constrain their application in clinical practice. When nanomaterials, characterized by distinctive physicochemical properties, are integrated with oncolytic bacteria, they achieve mutually complementary advantages and construct efficient and safe nanobiohybrids. In this review, we initially analyze the merits and drawbacks of conventional tumor therapeutic approaches, followed by a detailed examination of the precise oncolysis mechanisms employed by oncolytic bacteria. Subsequently, we focus on harnessing nanomaterial-assisted oncolytic bacteria (NAOB) to augment the effectiveness of tumor therapy and utilizing them as nanotheranostic agents for imaging-guided tumor treatment. Finally, by summarizing and analyzing the current deficiencies of NAOB, this review provides some innovative directions for developing nanobiohybrids, intending to infuse novel research concepts into the realm of solid tumor therapy.

Sunflower Pollen-Morphology Mimicked Spiky Zinc Nanomotors as a Photosensitizer for Killing Bacteria and Cancer Cells

Photosensitizing agents have received increased attention from the medical community, owing to their higher photothermal efficiency, induction of hyperthermia, and sustained delivery of bioactive molecules to their targets. Micro/nanorobots can be used as ideal photosensitizing agents by utilizing various physical stimuli for the targeted killing of pathogens (e.g., bacteria) and cancer cells. Herein, we report sunflower-pollen-inspired spiky zinc oxide (s-ZnO)-based nanorobots that effectively kill bacteria and cancer cells under near-infrared (NIR) light irradiation. The as-fabricated s-ZnO was modified with a catechol-containing photothermal agent, polydopamine (PDA), to improve its NIR-responsive properties, followed by the addition of antimicrobial (e.g., tetracycline/TCN) and anticancer (e.g., doxorubicin/DOX) drugs. The fabricated s-ZnO/PDA@Drug nanobots exhibited unique locomotory behavior with an average speed ranging from 13 to 14 μm/s under 2.0 W/cm2 NIR light irradiation. Moreover, the s-ZnO/PDA@TCN nanobots exhibited superior antibacterial activity against E. coli and S. epidermidis under NIR irradiation. The s-ZnO/PDA@DOX nanobots also displayed sufficient reactive oxygen species (ROS) amplification in B16F10 melanoma cells and induced apoptosis under NIR light, indicating their therapeutic efficacy. We hope the sunflower pollen-inspired s-ZnO nanorobots have tremendous potential in biomedical engineering from the phototherapy perspective, with the hope to reduce pathogen infections.

Intelligent micro/nanorobots based on biotemplates

Intelligent micro/nanorobots based on natural materials as biotemplates are considered to be some of the most promising robots in the future in the microscopic field. Due to the advantages of biotemplates such as unique structure, abundant resources, environmental friendliness, easy removal, low price, easy access, and renewability, intelligent micro/nanorobots based on biotemplates can be endowed with both excellent biomaterial activity and unique structural morphology through biotemplates themselves and specific functions through artificial micro/nanotechnology. Thus, intelligent micro/nanorobots show excellent application potential in various fields from biomedical applications to environmental remediation. In this review, we introduce the advantages of using natural biological materials as biotemplates to build intelligent micro/nanorobots, and then, classify the micro/nanorobots according to different types of biotemplates, systematically detail their preparation strategies and summarize their application prospects. Finally, in order to further advance the development of intelligent micro/nanorobots, we discuss the current challenges and future prospects of biotemplates. Intelligent micro/nanorobots based on biotemplates are a perfect combination of natural biotemplates and micro/nanotechnology, which is an important trend for the future development of micro/nanorobots. We hope this review can provide useful references for developing more intelligent, efficient and safe micro/nanorobots in the future.

Development of a precision tumor bone metastasis model by a magnetic micro-living-motor system

An ideal bone metastasis animal model is critical and fundamental for mechanistic research and following development of new drug and treatment. Caudal artery (CA) injection allows bone metastasis in the hindlimb, while in-depth targeted and quantitative studies of bone metastasis require a new model to overcome its limitations. Here, we developed a targeted, quantitative, and highly consistent method for the modeling of bone metastasis with cell-based magnetic micro-living-motor (MLM) system created by effectively combining Fe3O4-PDA-Au with biosafety. The MLM system can achieve efficient migration, target site colonization and control tumorigenesis in bone precisely with the application of a magnetic field. In vivo, day 3 post cell injection, tumor bone metastasis signals were observed locally in the injected femur among 82.76% mice of the MLM group as compared to the 56.82% in the CA group, and the signal intensity was 45.1 and 95.9 times stronger than that in the left and right lower limbs of the CA group, respectively. Post-injection day 28, metastasis in vital organs was reduced by approximately 90% in the MLM group compared to the CA group. Our innovative use of the MLM system in the field of tumor modeling opens a new avenue for exploring the mechanisms of tumor bone metastasis, recurrence and drug resistance.

Magnetic Microrobots for In Vivo Cargo Delivery: A Review

Magnetic microrobots, with their small size and agile maneuverability, are well-suited for navigating the intricate and confined spaces within the human body. In vivo cargo delivery within the context of microrobotics involves the use of microrobots to transport and administer drugs and cells directly to the targeted regions within a living organism. The principal aim is to enhance the precision, efficiency, and safety of therapeutic interventions. Despite their potential, there is a shortage of comprehensive reviews on the use of magnetic microrobots for in vivo cargo delivery from both research and engineering perspectives, particularly those published after 2019. This review addresses this gap by disentangling recent advancements in magnetic microrobots for in vivo cargo delivery. It summarizes their actuation platforms, structural designs, cargo loading and release methods, tracking methods, navigation algorithms, and degradation and retrieval methods. Finally, it highlights potential research directions. This review aims to provide a comprehensive summary of the current landscape of magnetic microrobot technologies for in vivo cargo delivery. It highlights their present implementation methods, capabilities, and prospective research directions. The review also examines significant innovations and inherent challenges in biomedical applications.

Biohybrid Flexible Sperm-like Microrobot for Targeted Chemo-Photothermal Therapy

Magnetic micro/nanorobots are promising platforms for targeted drug delivery, and their construction with soft and flexible features has received extensive attention for practical applications. Despite significant efforts in this field, facile fabrication of magnetic microrobots with flexible structures and versatility in targeted therapy remains a big challenge. Herein, we proposed a novel universal strategy to fabricate a biohybrid flexible sperm-like microrobot (BFSM) based on a Chlorella (Ch.) cell and artificial flagella, which showed great potential for targeted chemo-photothermal therapy for the first time. In this approach, microspherical Ch. cells were utilized to construct the microrobotic heads, which were intracellularly deposited with core-shell Pd@Au, extracellularly magnetized with Fe3O4, and further loaded with anticancer drug. The magnetic heads with excellent photothermal and chemotherapeutic capability were further assembled with flexible polypyrrole nanowires via biotin-streptavidin bonding to construct the BFSMs. Based on the exquisite head-to-tail structures, the BFSMs could be effectively propelled under precessing magnetic fields and move back and forth without a U-turn. Moreover, in vitro chemo-photothermal tests were conducted to verify their performance of targeted drug delivery toward localized HeLa cells. Due to this superior versatility and facile fabrication, the BFSMs demonstrated great potential for targeted anticancer therapy.

Recent Advances in Microrobots Powered by Multi-Physics Field for Biomedical and Environmental Applications

Microrobots powered by multi-physics fields are becoming a hotspot for micro-nano manufacturing. Due to the small size of microrobots, they can easily enter small spaces that are difficult for ordinary robots to reach and perform a variety of special tasks. This gives microrobots a broad application prospect in many fields. This paper describes the materials, structures, and driving principles of microrobots in detail and analyzes the advantages and limitations of their driving methods in depth. In addition, the paper discusses the detailed categorization of the action forms of microrobots and explores their diversified motion modes and their applicable scenarios. Finally, the article highlights the wide range of applications of microrobots in the fields of biomedicine and environmental protection, emphasizing their great potential for solving real-world problems and advancing scientific progress.

A Survey of Recent Developments in Magnetic Microrobots for Micro-/Nano-Manipulation

Magnetically actuated microrobots have become a research hotspot in recent years due to their tiny size, untethered control, and rapid response capability. Moreover, an increasing number of researchers are applying them for micro-/nano-manipulation in the biomedical field. This survey provides a comprehensive overview of the recent developments in magnetic microrobots, focusing on materials, propulsion mechanisms, design strategies, fabrication techniques, and diverse micro-/nano-manipulation applications. The exploration of magnetic materials, biosafety considerations, and propulsion methods serves as a foundation for the diverse designs discussed in this review. The paper delves into the design categories, encompassing helical, surface, ciliary, scaffold, and biohybrid microrobots, with each demonstrating unique capabilities. Furthermore, various fabrication techniques, including direct laser writing, glancing angle deposition, biotemplating synthesis, template-assisted electrochemical deposition, and magnetic self-assembly, are examined owing to their contributions to the realization of magnetic microrobots. The potential impact of magnetic microrobots across multidisciplinary domains is presented through various application areas, such as drug delivery, minimally invasive surgery, cell manipulation, and environmental remediation. This review highlights a comprehensive summary of the current challenges, hurdles to overcome, and future directions in magnetic microrobot research across different fields.

Current status and future application of electrically controlled micro/nanorobots in biomedicine

Using micro/nanorobots (MNRs) for targeted therapy within the human body is an emerging research direction in biomedical science. These nanoscale to microscale miniature robots possess specificity and precision that are lacking in most traditional treatment modalities. Currently, research on electrically controlled micro/nanorobots is still in its early stages, with researchers primarily focusing on the fabrication and manipulation of these robots to meet complex clinical demands. This review aims to compare the fabrication, powering, and locomotion of various electrically controlled micro/nanorobots, and explore their advantages, disadvantages, and potential applications.

Ultrasound-propelled nanomotors for efficient cancer cell ferroptosis

Ferroptosis is a non-apoptotic form of cell death that is dependent on the accumulation of intracellular iron that causes elevation of toxic lipid peroxides. Therefore, it is crucial to improve the levels of intracellular iron and reactive oxygen species (ROS) in a short time. Here, we first propose ultrasound (US)-propelled Janus nanomotors (Au-FeOx/PEI/ICG, AFPI NMs) to accelerate cellular internalization and induce cancer cell ferroptosis. This nanomotor consists of a gold-iron oxide rod-like Janus nanomotor (Au-FeOx, AF NMs) and a photoactive indocyanine green (ICG) dye on the surface. It not only exhibits accelerating cellular internalization (∼4-fold) caused by its attractive US-driven propulsion but also shows good intracellular motion behavior. In addition, this Janus nanomotor shows excellent intracellular ROS generation performance due to the synergistic effect of the "Fenton or Fenton-like reaction" and the "photochemical reaction". As a result, the killing efficiency of actively moving nanomotors on cancer cells is 88% higher than that of stationary nanomotors. Unlike previous passive strategies, this work is a significant step toward accelerating cellular internalization and inducing cancer-cell ferroptosis in an active way. These novel US-propelled Janus nanomotors with strong propulsion, efficient cellular internalization and excellent ROS generation are suitable as a novel cell biology research tool.

Cell-Based Micro/Nano-Robots for Biomedical Applications: A Review

Micro/nano-robots are powerful tools for biomedical applications and are applied in disease diagnosis, tumor imaging, drug delivery, and targeted therapy. Among the various types of micro-robots, cell-based micro-robots exhibit unique properties because of their different cell sources. In combination with various actuation methods, particularly externally propelled methods, cell-based microrobots have enormous potential for biomedical applications. This review introduces recent progress and applications of cell-based micro/nano-robots. Different actuation methods for micro/nano-robots are summarized, and cell-based micro-robots with different cell templates are introduced. Furthermore, the review focuses on the combination of cell-based micro/nano-robots with precise control using different external fields. Potential challenges, further prospects, and clinical translations are also discussed.

Biohybrid Microalgae Robots: Design, Fabrication, Materials, and Applications

The integration of microorganisms and engineered artificial components has shown considerable promise for creating biohybrid microrobots. The unique features of microalgae make them attractive candidates as natural actuation materials for the design of biohybrid microrobotic systems. In this review, microalgae-based biohybrid microrobots are introduced for diverse biomedical and environmental applications. The distinct propulsion and phototaxis behaviors of green microalgae, as well as important properties from other photosynthetic microalga systems (blue-green algae and diatom) that are crucial to constructing powerful biohybrid microrobots, will be described first. Then the focus is on chemical and physical routes for functionalizing the algae surface with diverse reactive materials toward the fabrication of advanced biohybrid microalgae robots. Finally, representative applications of such algae-driven microrobots are presented, including drug delivery, imaging, and water decontamination, highlighting the distinct advantages of these active biohybrid robots, along with future prospects and challenges.

Preparation, Stimulus-Response Mechanisms and Applications of Micro/Nanorobots

Micro- and nanorobots are highly intelligent and efficient. They can perform various complex tasks as per the external stimuli. These robots can adapt to the required functional form, depending on the different stimuli, thus being able to meet the requirements of various application scenarios. So far, microrobots have been widely used in the fields of targeted therapy, drug delivery, tissue engineering, environmental remediation and so on. Although microbots are promising in some fields, few reviews have yet focused on them. It is therefore necessary to outline the current status of these microbots' development to provide some new insights into the further evolution of this field. This paper critically assesses the research progress of microbots with respect to their preparation methods, stimulus-response mechanisms and applications. It highlights the suitability of different preparation methods and stimulus types, while outlining the challenges experienced by microbots. Viable solutions are also proposed for the promotion of their practical use.

Applications of microalga-powered microrobots in targeted drug delivery

Over the past decade, researchers have proposed a new class of drug delivery systems, bio-hybrid micro-robots, designed with a variety of living cell-driven micro-robots that utilize the unique mobility of natural organisms (bacteria, cells, exosomes, etc.) to transport effective drugs. Microalgae are considered potential drug delivery carriers. Recent studies have shown that microalga-based drug delivery systems exhibit excellent biocompatibility. In addition, microalgae have a large surfactant area, phototaxis, oxygen production, and other characteristics, so they are used as a carrier for the treatment of bacterial infections, cancer, etc. This review summarizes the modification of microalgae including click chemistry and electrostatic adsorption, and can improve the drug loading efficiency through dehydration and hydration strategies. The prepared microalgal drug delivery system can be targeted to different organs by different dosing methods or using external forces. Finally, it summarizes its antibacterial (gastritis, periodontitis, skin wound inflammation, etc.) and antitumor applications.

Doxorubicin-Loaded Microrobots for Targeted Drug Delivery and Anticancer Therapy

Micro-sized magnetic particles (also known as microrobots [MRs]) have recently been shown to have potential applications for numerous biomedical applications like drug delivery, microengineering, and single cell manipulation. Interdisciplinary studies have demonstrated the ability of these tiny particles to actuate under the action of a controlled magnetic field that not only drive MRs in a desired trajectory but also precisely deliver therapeutic payload to the target site. Additionally, optimal concentrations of therapeutic molecules can also be delivered to the desired site which is cost-effective and safe especially in scenarios where drug dose-related side effects are a concern. In this study, MRs are used to deliver anticancer drugs (doxorubicin) to cancer cells and subsequent cell death is evaluated in different cell lines (liver, prostate, and ovarian cancer cells). Cytocompatibility studies show that MRs are well-tolerated and internalized by cancer cells. Doxorubicin (DOX) is chemically conjugated with MRs (DOX-MRs) and magnetically steered toward cancer cells using the magnetic controller. Time-lapsed video shows that cells shrink and eventually die when MRs are internalized by cells. Taken together, this study confirms that microrobots are promising couriers for targeted delivery of therapeutic biomolecules for cancer therapy and other non-invasive procedures that require precise control.

Biohybrid magnetic microrobots: An intriguing and promising platform in biomedicine

Biohybrid magnetic microrobots (BMMs) have emerged as an exciting class of microrobots and have been considered as a promising platform in biomedicine. Many microorganisms and body's own cells show intriguing properties, such as morphological characteristics, biosafety, and taxis abilities (e.g., chemotaxis, aerotaxis), which have made them attractive for the fabrication of microrobots. For remote controllability and sustainable actuation, magnetic components are usually incorporated onto these biological entities, and other functionalized non-biological components (e.g., therapeutic agents) are also included for specific applications. This review highlights the latest developments in BMMs with a focus on their biomedical applications. It starts by introducing the fundamental understanding of the propulsion system at the microscale in a magnetically driven manner, followed by a summary of diverse BMMs based on different microorganisms and body's own cells along with their relevant applications. Finally, the review discusses how BMMs contribute to the advancements of microrobots, the current challenges of using BMMs in practical clinical settings, and the future perspectives of this exciting field. STATEMENT OF SIGNIFICANCE: Biohybrid magnetic microrobots (BMMs), composed of biological entities and functional parts, hold great potential and serve as a novel and promising platform for biomedical applications such as targeted drug delivery. This review comprehensively summarizes the recent advancements in BMMs for biomedical applications, mainly focused on the representative propulsion modalities in a magnetically propelled manner and diverse designs of BMMs based on different biological entities, including microorganisms and body's own cells. We hope this review can provide ideas for the future design, development, and innovation of micro/nanorobots in the field of biomedicine.

Stimuli-Responsive Functional Micro-/Nanorobots: A Review

Stimuli-responsive functional micro-/nanorobots (srFM/Ns) are a class of intelligent, efficient, and promising microrobots that can react to external stimuli (such as temperature, light, ultrasound, pH, ion, and magnetic field) and perform designated tasks. Through adaptive transformation into the corresponding functional forms, they can perfectly match the demands depending on different applications, which manifest extremely important roles in targeted therapy, biological detection, tissue engineering, and other fields. Promising as srFM/Ns can be, few reviews have focused on them. It is therefore necessary to provide an overview of the current development of these intelligent srFM/Ns to provide clear inspiration for further development of this field. Hence, this review summarizes the current advances of stimuli-responsive functional microrobots regarding their response mechanism, the achieved functions, and their applications to highlight the pros and cons of different stimuli. Finally, we emphasize the existing challenges of srFM/Ns and propose possible strategies to help accelerate the study of this field and promote srFM/Ns toward actual applications.

Bubble-Based Microrobots with Rapid Circular Motions for Epithelial Pinning and Drug Delivery

Remotely powered microrobots are proposed as next-generation vehicles for drug delivery. However, most microrobots swim with linear trajectories and lack the capacity to robustly adhere to soft tissues. This limits their ability to navigate complex biological environments and sustainably release drugs at target sites. In this work, bubble-based microrobots with complex geometries are shown to efficiently swim with non-linear trajectories in a mouse bladder, robustly pin to the epithelium, and slowly release therapeutic drugs. The asymmetric fins on the exterior bodies of the microrobots induce a rapid rotational component to their swimming motions of up to ≈150 body lengths per second. Due to their fast speeds and sharp fins, the microrobots can mechanically pin themselves to the bladder epithelium and endure shear stresses commensurate with urination. Dexamethasone, a small molecule drug used for inflammatory diseases, is encapsulated within the polymeric bodies of the microrobots. The sustained release of the drug is shown to temper inflammation in a manner that surpasses the performance of free drug controls. This system provides a potential strategy to use microrobots to efficiently navigate large volumes, pin at soft tissue boundaries, and release drugs over several days for a range of diseases.

Advances of medical nanorobots for future cancer treatments

Early detection and diagnosis of many cancers is very challenging. Late stage detection of a cancer always leads to high mortality rates. It is imperative to develop novel and more sensitive and effective diagnosis and therapeutic methods for cancer treatments. The development of new cancer treatments has become a crucial aspect of medical advancements. Nanobots, as one of the most promising applications of nanomedicines, are at the forefront of multidisciplinary research. With the progress of nanotechnology, nanobots enable the assembly and deployment of functional molecular/nanosized machines and are increasingly being utilized in cancer diagnosis and therapeutic treatment. In recent years, various practical applications of nanobots for cancer treatments have transitioned from theory to practice, from in vitro experiments to in vivo applications. In this paper, we review and analyze the recent advancements of nanobots in cancer treatments, with a particular emphasis on their key fundamental features and their applications in drug delivery, tumor sensing and diagnosis, targeted therapy, minimally invasive surgery, and other comprehensive treatments. At the same time, we discuss the challenges and the potential research opportunities for nanobots in revolutionizing cancer treatments. In the future, medical nanobots are expected to become more sophisticated and capable of performing multiple medical functions and tasks, ultimately becoming true nanosubmarines in the bloodstream.

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.

GOx-Powered Janus Platelet Nanomotors for Targeted Delivery of Thrombolytic Drugs in Treating Thrombotic Diseases

Low efficiency of targeting and delivery toward the thrombus site poses challenges to using thrombolytic drugs. Inspired by the biomimetic system of platelet membranes (PMs) and glucose oxidase (GOx) modification technologies, we develop a novel GOx-powered Janus nanomotor by asymmetrically attaching the GOx to polymeric nanomotors coated with the PMs. Then the PM-coated nanomotors were conjugated with urokinase plasminogen activators (uPAs) on their surfaces. The PM-camouflaged design conferred excellent biocompatibility to the nanomotors and improved their targeting ability to thrombus. The Janus distribution of GOx also allows the uneven decomposition of glucose in biofluids to produce a chemophoretic motion, increasing the drug delivery efficiency of nanomotors. In addition, these nanomotors are located at the lesion site due to the mutual adhesion and aggregation of platelet membranes. Furthermore, thrombolysis effects of nanomotors are enhanced in static and dynamic thrombus as well as in mouse models. It is believed that the novel PM-coated enzyme-powered nanomotors represent a great value for thrombolysis treatment.

Nanoparticles from Microalgae and Their Biomedical Applications

Over the years, microalgae have been a source of useful compounds mainly used as food and dietary supplements. Recently, microalgae have been used as a source of metabolites that can participate in the synthesis of several nanoparticles through inexpensive and environmentally friendly routes alternative to chemical synthesis. Notably, the occurrence of global health threats focused attention on the microalgae application in the medicinal field. In this review, we report the influence of secondary metabolites from marine and freshwater microalgae and cyanobacteria on the synthesis of nanoparticles that were applied as therapeutics. In addition, the use of isolated compounds on the surface of nanoparticles to combat diseases has also been addressed. Although studies have proven the beneficial effect of high-value bioproducts on microalgae and their potential in medicine, there is still room for understanding their exact role in the human body and translating lab-based research into clinical trials.

Engineered photoresponsive biohybrids for tumor therapy

Engineered biohybrids have recently emerged as innovative biomimetic platforms for cancer therapeutic applications. Particularly, engineered photoresponsive biohybrids hold tremendous potential against tumors due to their intriguing biomimetic properties, photoresponsive ability, and enhanced biotherapeutic functions. In this review, the design principles of engineered photoresponsive biohybrids and their latest progresses for tumor therapy are summarized. Representative engineered photoresponsive biohybrids are highlighted including biomolecules-associated, cell membrane-based, eukaryotic cell-based, bacteria-based, and algae-based photoresponsive biohybrids. Representative tumor therapeutic modalities of the engineered photoresponsive biohybrids are presented, including photothermal therapy, photodynamic therapy, synergistic therapy, and tumor therapy combined with tissue regeneration. Moreover, the challenges and future perspectives of these photoresponsive biohybrids for clinical practice are discussed.

Applications and Future Prospects of Micro/Nanorobots Utilizing Diverse Biological Carriers

Targeted drug delivery using micro-nano robots (MNRs) is a rapidly advancing and promising field in biomedical research. MNRs enable precise delivery of drugs, addressing a wide range of healthcare needs. However, the application of MNRs in vivo is limited by power issues and specificity in different scenarios. Additionally, the controllability and biological safety of MNRs must be considered. To overcome these challenges, researchers have developed bio-hybrid micro-nano motors that offer improved accuracy, effectiveness, and safety for targeted therapies. These bio-hybrid micro-nano motors/robots (BMNRs) use a variety of biological carriers, blending the benefits of artificial materials with the unique features of different biological carriers to create tailored functions for specific needs. This review aims to give an overview of the current progress and application of MNRs with various biocarriers, while exploring the characteristics, advantages, and potential hurdles for future development of these bio-carrier MNRs.

Recent advances in stimuli-responsive nano-heterojunctions for tumor therapy

Stimuli-responsive catalytic therapy based on nano-catalysts has attracted much attention in the field of biomedicine for tumor therapy, due to its excellent and unique properties. However, the complex tumor microenvironment conditions and the rapid charge recombination in the catalyst limit catalytic therapy's effectiveness and further development. Effective heterojunction nanomaterials are constructed to address these problems to improve catalytic performance. Specifically, on the one hand, the band gap of the material is adjusted through the heterojunction structure to promote the charge separation efficiency under exogenous stimulation and further improve the catalytic capacity. On the other hand, the construction of a heterojunction structure can not only preserve the function of the original catalyst but also achieve significantly enhanced synergistic therapy ability. This review summarized the construction and functions of stimuli-responsive heterojunction nanomaterials under the excitation of X-rays, visible-near infrared light, and ultrasound in recent years, and further introduces their application in cancer therapy. Hopefully, the summary of stimuli-responsive heterojunction nanomaterials' applications will help researchers promote the development of nanomaterials in cancer therapy.

A review on microrobots driven by optical and magnetic fields

Due to their small sizes, microrobots are advantageous for accessing hard-to-reach spaces for delivery and measurement. However, their small sizes also bring challenges in on-board powering, thus usually requiring actuation by external energy. Microrobots actuated by external energy have been applied to the fields of physics, biology, medical science, and engineering. Among these actuation sources, light and magnetic fields show advantages in high precision and high biocompatibility. This paper reviews the recent advances in the design, actuation, and applications of microrobots driven by light and magnetic fields. For light-driven microrobots, we summarized the uses of optical tweezers, optoelectronic tweezers, and heat-mediated optical manipulation techniques. For magnetically driven microrobots, we summarized the uses of torque-driven microrobots, force-driven microrobots, and shape-deformable microrobots. Then, we compared the two types of field-driven microrobots and reviewed their advantages and disadvantages. The paper concludes with an outlook for the joint use of optical and magnetic field actuation in microrobots.

Intelligent Micro-/Nanorobots for Cancer Theragnostic

Cancer is one of the most intractable diseases owing to its high mortality rate and lack of effective diagnostic and treatment tools. Advancements in micro-/nanorobot (MNR)-assisted sensing, imaging, and therapeutics offer unprecedented opportunities to develop MNR-based cancer theragnostic platforms. Unlike ordinary nanoparticles, which exhibit Brownian motion in biofluids, MNRs overcome viscous resistance in an ultralow Reynolds number (Re << 1) environment by effective self-propulsion. This unique locomotion property has motivated the advanced design and functionalization of MNRs as a basis for next-generation cancer-therapy platforms, which offer the potential for precise distribution and improved permeation of therapeutic agents. Enhanced barrier penetration, imaging-guided operation, and biosensing are additionally studied to enable the promising cancer-related applications of MNRs. Herein, the recent advances in MNR-based cancer therapy are comprehensively addresses, including actuation engines, diagnostics, medical imaging, and targeted drug delivery; promising research opportunities that can have a profound impact on cancer therapy over the next decade is highlighted.

3D-printed microrobots from design to translation

Microrobots have attracted the attention of scientists owing to their unique features to accomplish tasks in hard-to-reach sites in the human body. Microrobots can be precisely actuated and maneuvered individually or in a swarm for cargo delivery, sampling, surgery, and imaging applications. In addition, microrobots have found applications in the environmental sector (e.g., water treatment). Besides, recent advancements of three-dimensional (3D) printers have enabled the high-resolution fabrication of microrobots with a faster design-production turnaround time for users with limited micromanufacturing skills. Here, the latest end applications of 3D printed microrobots are reviewed (ranging from environmental to biomedical applications) along with a brief discussion over the feasible actuation methods (e.g., on- and off-board), and practical 3D printing technologies for microrobot fabrication. In addition, as a future perspective, we discussed the potential advantages of integration of microrobots with smart materials, and conceivable benefits of implementation of artificial intelligence (AI), as well as physical intelligence (PI). Moreover, in order to facilitate bench-to-bedside translation of microrobots, current challenges impeding clinical translation of microrobots are elaborated, including entry obstacles (e.g., immune system attacks) and cumbersome standard test procedures to ensure biocompatibility.

Microbots have attracted attention due to an ability to reach places and perform tasks which are not possible with conventional techniques in a wide range of applications. Here, the authors review the recent work in the field on the fabrication, application and actuation of 3D printed microbots offering a view of the direction of future microbot research.

Multifunctional Gold Helix Phototheranostic Biohybrid That Enables Targeted Image-Guided Photothermal Therapy in Breast Cancer

The preparation of multifunctional smart theranostic systems is commonly achieved through complicated strategies, limiting their biomedical applications. Spirulina platensis (SP) microalgae, as a natural helix with some of the intrinsic theranostic functionalities (e.g., fluorescent and photosensitizer pigments), not only facilitates the fabrication process but also guarantees their biosafety for clinical applications. Herein, the helical architecture of gold nanoparticles (AuNPs) based on a SP biotemplate was engineered as a safe, biodegradable, and tumor-targeted biohybrid for imaging-guided photothermal therapy (PTT) to combat triple-negative breast cancer. The quasi-spherical AuNPs were embedded throughout the SP cell (Au-SP) with minimally involved reagents, only by controlling the original morphological stability of SP through pH adjustment of the synthesis media. SP thiolation increased the localization of AuNPs selectively on the cell wall without using a reducing agent (Au-TSP). SP autofluorescence, along with the high X-ray absorption of AuNPs, was employed for dual-modal fluorescence and computed tomography (FL/CT) imaging. Furthermore, the theranostic efficacy of Au-SP was improved through a targeting process with folic acid (Au-SP@CF). High tumor inhibition effects were obtained by the excellent photothermal performance of Au-SP@CF in both in vitro and in vivo analyses. Of particular note, a comparison of the photothermal effect of Au-SP@CF with the naked SP and calcined form of Au-SP@CF not only indicated the key role of the helical architecture of AuNPs in achieving a high photothermal effect but also led to the formation of new gold microspiral biohybrids (Au-MS) over the calcination process. In short, well-controllable immobilization of AuNPs, appropriate biodegradability, good hemocompatibility, long-term biosafety, accurate imaging, high tumor suppression, and low tumor metastasis effects under laser irradiation are an array of intriguing attributes, making the proposed biohybrid a promising theranostic system for FL/CT-imaging-guided PTT.

MoSBOTs: Magnetically Driven Biotemplated MoS2 -Based Microrobots for Biomedical Applications

2D layered molybdenum disulfide (MoS₂ ) nanomaterials are a promising platform for biomedical applications, particularly due to its high biocompatibility characteristics, mechanical and electrical properties, and flexible functionalization. Additionally, the bandgap of MoS₂ can be engineered to absorb light over a wide range of wavelengths, which can then be transformed into local heat for applications in photothermal tissue ablation and regeneration. However, limitations such as poor stability of aqueous dispersions and low accumulation in affected tissues impair the full realization of MoS₂ for biomedical applications. To overcome such challenges, herein, multifunctional MoS₂ -based magnetic helical microrobots (MoSBOTs) using cyanobacterium Spirulina platensis are proposed as biotemplate for therapeutic and biorecognition applications. The cytocompatible microrobots combine remote magnetic navigation with MoS₂ photothermal activity under near-infrared irradiation. The resulting photoabsorbent features of the MoSBOTs are exploited for targeted photothermal ablation of cancer cells and on-the-fly biorecognition in minimally invasive oncotherapy applications. The proposed multi-therapeutic MoSBOTs hold considerable potential for a myriad of cancer treatment and diagnostic-related applications, circumventing current challenges of ablative procedures.

How Microalgae is Effective in Oxygen Deficiency Aggravated Diseases? A Comprehensive Review of Literature

Hypoxia can aggravate the conditions of many oxygen-deficiency-aggravated diseases (ODAD), such as cancer, ischemic heart disease, and chronic wounds. Photosynthetic microalgae can alleviate the hepatotoxicity of the local microenvironment by producing oxygen. In addition, microalgae extracts have antitumor, anti-inflammatory, antibacterial, and antioxidant effects. These properties make them attractive candidates for developing methods to treat ODAD. Although researchers have exploited the advantages of microalgae and developed a variety of microalgae-based biomaterials to treat ODAD, a comprehensive review of this topic has not been presented previously. Therefore, in this review, we summarize the development and progress made in the field of developing microalgae-based biomaterials toward the treatment of ODAD. The challenges and prospects of this field are also discussed.