Gadolinium metallofullerenol nanoparticles inhibit cancer metastasis through matrix metalloproteinase inhibition: imprisoning instead of poisoning cancer cells

Multifunctional Nanomaterials: Recent Advancements in Cancer Therapeutics and Vaccines

Nanotechnology has revolutionized cancer detection and treatment, overcoming limitations of conventional methods. Imaging, targeting, and therapy moieties can all be combined in multifunctional nanoparticle systems to deliver the imaging or treatment modalities to the tumor in a targeted manner. These nanostructures can be engineered to create smart drug delivery systems for effective distribution and combinatorial therapy. Nanostructures made of biomolecules are naturally multifunctional and have a variety of biological functions that can be investigated for use in cancer nanomedicine. The supramolecular characteristics of biomolecules can be carefully engineered to create smart drug delivery systems that enable effective drug distribution to specific areas of the body as well as combinatorial therapy in a single design. Nanotechnology has also increased the efficiency of cancer vaccines, highlighting the future of tumor immunotherapy. Nanomaterials are often used as anti-cancer drugs or anti-inflammatory drugs due to their biosafety potential and enhanced bioavailability. By delivering targeted antigens and adjuvants, nanomaterials can improve vaccination efficacy and safety, preventing rapid degradation and prolonging antigen retention in lymphoid and tumor cells. We examine both organic and inorganic multifunctional nanomaterials in this review, emphasizing particular multifunctional properties in the context of cancer targeting, therapy, and vaccinations.

Recent advances in endohedral metallofullerenes

Fullerenes are a collection of closed polycyclic polymers consisting exclusively of carbon atoms. Recent remarkable advancements in the fabrication of metal-fullerene nanocatalysts and polymeric fullerene layers have significantly expanded the potential applications of fullerenes in various domains, including electrocatalysis, transistors, energy storage devices, and superconductors. Notably, the interior of fullerenes provides an optimal environment for stabilizing a diverse range of metal ions or clusters through electron transfer, resulting in the formation of a novel class of hybrid molecules referred to as endohedral metallofullerenes (EMFs). The utilization of advanced synthetic methodologies and the progress achieved in separation techniques have played a pivotal role in expanding the diversity of the encapsulated metal constituents, consequently leading to distinctive structural, electronic, and physicochemical properties of novel EMFs that surpass conventional ones. Intriguing phenomena, including regioselective dimerization between EMFs, direct metal-metal bonding, and non-classical cage preferences, have been unveiled, offering valuable insights into the coordination interactions between metallic species and carbon. Of particular importance, the recent achievements in the comprehensive characterization of EMFs based on transition metals and actinide metals have generated a particular interest in the exploration of new metal clusters possessing long-desired bonding features within the realm of coordination chemistry. These clusters exhibit a remarkable affinity for coordinating with non-metal atoms such as carbon, nitrogen, oxygen, and sulfur, thus making them highly intriguing subjects of systematic investigations focusing on their electronic structures and physicochemical properties, ultimately leading to a deeper comprehension of their unparalleled bonding characteristics. Moreover, the versatility conferred by the encapsulated species endows EMFs with multifunctional properties, thereby unveiling potential applications in various fields including biomedicine, single-molecule magnets, and electronic devices.

Nano-scale dangers: Unravelling the impact of nanoplastics on human trophoblast invasion

Utilizing HTR-8/SVneo cells for in vitro modeling of human trophoblast invasion, we examined how different concentrations of 40 nm and 200 nm carboxylated polystyrene particles affect early-pregnancy trophoblast phenotype and function. We focused on migration and invasion, as critical processes in placental development. Our findings revealed disruptions in extravillous trophoblast mesenchymal phenotype and invasive behavior, following acute exposure to a higher concentration of the smaller sized particles. Specifically, differential uptake of the particles by trophoblast cells was observed, as well as cytotoxicity and concentration-dependent DNA damage after 72 h of exposure. In addition, a 24 h exposure to 100 μg/ml of 40 nm particles correlated with downregulated protein expression of α5 and α1 integrin subunits, N-cadherin, matrix metalloproteinase-2 and macrophage migration inhibitory factor, alongside upregulated protein expression of the epithelial marker E-cadherin. These changes likely contributed to the diminished migration of HTR-8/SVneo cells and the invasive potential of HTR-8/SVneo spheroids. Understanding these interactions is paramount for assessing the broader implications of nanoplastics on reproductive outcomes and maternal-fetal well-being and informing public health measures.

Fullerene Derivatives for Tumor Treatment: Mechanisms and Application

Fullerenes hold tremendous potential as alternatives to conventional chemotherapy or radiotherapy for tumor treatment due to their abilities to photodynamically kill tumor cells, destroy the tumor vasculature, inhibit tumor metastasis and activate anti-tumor immune responses, while protecting normal tissue through antioxidative effects. The symmetrical hollow molecular structures of fullerenes with abundant C=C bonds allow versatile chemical modification with diverse functional groups, metal clusters and biomacromolecules to synthesize a wide range of fullerene derivatives with increased water solubility, improved biocompatibility, enhanced photodynamic properties and stronger targeting abilities. This review introduces the anti-tumor mechanisms of fullerenes and summarizes the most recent works on the functionalization of fullerenes and the application of fullerene derivatives in tumor treatment. This review aims to serve as a valuable reference for further development and clinical application of anti-tumor fullerene derivatives.

A High-Sensitivity Benchtop X-Ray Fluorescence Emission Tomography (XFET) System With a Full-Ring of X-Ray Imaging-Spectrometers and a Compound-Eye Collimation Aperture

The advent of metal-based drugs and metal nanoparticles as therapeutic agents in anti-tumor treatment has motivated the advancement of X-ray fluorescence computed tomography (XFCT) techniques. An XFCT imaging modality can detect, quantify, and image the biodistribution of metal elements using the X-ray fluorescence signal emitted upon X-ray irradiation. However, the majority of XFCT imaging systems and instrumentation developed so far rely on a single or a small number of detectors. This work introduces the first full-ring benchtop X-ray fluorescence emission tomography (XFET) system equipped with 24 solid-state detectors arranged in a hexagonal geometry and a 96-pinhole compound-eye collimator. We experimentally demonstrate the system's sensitivity and its capability of multi-element detection and quantification by performing imaging studies on an animal-sized phantom. In our preliminary studies, the phantom was irradiated with a pencil beam of X-rays produced using a low-powered polychromatic X-ray source (90kVp and 60W max power). This investigation shows a significant enhancement in the detection limit of gadolinium to as low as 0.1 mg/mL concentration. The results also illustrate the unique capabilities of the XFET system to simultaneously determine the spatial distribution and accurately quantify the concentrations of multiple metal elements.

Current advances in nanoformulations of therapeutic agents targeting tumor microenvironment to overcome drug resistance

The tumor microenvironment (TME) plays a pivotal role in cancer development and progression. In this line, revealing the precise mechanisms of the TME and associated signaling pathways of tumor resistance could pave the road for cancer prevention and efficient treatment. The use of nanomedicine could be a step forward in overcoming the barriers in tumor-targeted therapy. Novel delivery systems benefit from enhanced permeability and retention effect, decreasing tumor resistance, reducing tumor hypoxia, and targeting tumor-associated factors, including immune cells, endothelial cells, and fibroblasts. Emerging evidence also indicates the engagement of multiple dysregulated mediators in the TME, such as matrix metalloproteinase, vascular endothelial growth factor, cytokines/chemokines, Wnt/β-catenin, Notch, Hedgehog, and related inflammatory and apoptotic pathways. Hence, investigating novel multitargeted agents using a novel delivery system could be a promising strategy for regulating TME and drug resistance. In recent years, small molecules from natural sources have shown favorable anticancer responses by targeting TME components. Nanoformulations of natural compounds are promising therapeutic agents in simultaneously targeting multiple dysregulated factors and mediators of TME, reducing tumor resistance mechanisms, overcoming interstitial fluid pressure and pericyte coverage, and involvement of basement membrane. The novel nanoformulations employ a vascular normalization strategy, stromal/matrix normalization, and stress alleviation mechanisms to exert higher efficacy and lower side effects. Accordingly, the nanoformulations of anticancer monoclonal antibodies and conventional chemotherapeutic agents also improved their efficacy and lessened the pharmacokinetic limitations. Additionally, the coadministration of nanoformulations of natural compounds along with conventional chemotherapeutic agents, monoclonal antibodies, and nanomedicine-based radiotherapy exhibits encouraging results. This critical review evaluates the current body of knowledge in targeting TME components by nanoformulation-based delivery systems of natural small molecules, monoclonal antibodies, conventional chemotherapeutic agents, and combination therapies in both preclinical and clinical settings. Current challenges, pitfalls, limitations, and future perspectives are also discussed.

Fullerenes for the treatment of cancer: an emerging tool

Cancer is a most common cause of mortality globally. Available medicines possess severe side effects owing to their non-specific targeting. Hence, there is a need of an alternative in the healthcare system that should have high efficacy with the least side effects, also having the ability to achieve site-specific targeting and be reproducible. This is possible with the help of fullerenes. Fullerenes are having the unique physicochemical and photosensitizer properties. This article discusses the synthesis, functionalization, mechanism, various properties, and applications of C60 fullerenes in the treatment of cancer. The review article also addresses the various factors influencing the activity of fullerenes including the environmental conditions, toxicity profile, and future prospective.

Nano-bio interactions: A major principle in the dynamic biological processes of nano-assemblies

Controllable nano-assembly with stimuli-responsive groups is emerging as a powerful strategy to generate theranostic nanosystems that meet unique requirements in modern medicine. However, this prospective field is still in a proof-of-concept stage due to the gaps in our understanding of complex-(nano-assemblies)-complex-(biosystems) interactions. Indeed, stimuli-responsive assembly-disassembly is, in and of itself, a process of nano-bio interactions, the key steps for biological fate and functional activity of nano-assemblies. To provide a comprehensive understanding of these interactions in this review, we first propose a 4W1H principle (Where, When, What, Which and How) to delineate the relevant dynamic biological processes, behaviour and fate of nano-assemblies. We further summarize several key parameters that govern effective nano-bio interactions. The effects of these kinetic parameters on ADMET processes (absorption, distribution, metabolism, excretion and transformation) are then discussed. Furthermore, we provide an overview of the challenges facing the evaluation of nano-bio interactions of assembled nanodrugs. We finally conclude with future perspectives on safe-by-design and application-driven-design of nano-assemblies. This review will highlight the dynamic biological and physicochemical parameters of nano-bio interactions and bridge discrete concepts to build a full spectrum understanding of the biological outcomes of nano-assemblies. These principles are expected to pave the way for future development and clinical translation of precise, safe and effective nanomedicines with intelligent theranostic features.

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Metallofullerenols in biomedical applications

Metallofullerenols (MFs) are functionalized endohedral fullerenes connecting at least three levels of organization of matter: atomic, molecular, and supramolecular, resulting in their unique activity at the nanoscale. Biomedical applications of MFs started from gadolinium-containing contrasting agents, but today their potential medical applications go far beyond diagnostics and magnetic resonance imaging. In many cases, preclinical studies have shown a great therapeutic value of MFs, and here we provide an overview of interactions of MFs with high-energy radiation and with reactive oxygen species generated during radiation as a ground for potential applications in modern therapy of cancer patients. We also present the current knowledge on interactions of MFs with proteins and with other components of cells and tissues. Due to their antioxidant properties, as well as their ability to regulate the expression of genes involved in apoptosis, angiogenesis, and stimulation of the immune response, MFs can contribute to inhibition of tumor growth and protection of normal cells. MFs with enclosed gadolinium act as inhibitors of tumor growth in targeted therapy along with imaging techniques, but we hope that the data gathered in this review will help to accelerate further progress in the implementation of MFs, also the ones containing rare earth metals other than gadolinium, in a broad range of bioapplications covering not only diagnostics and bioimaging but also radiation therapy and cancer treatment by not-cytotoxic agents.

Chemical and Biophysical Signatures of the Protein Corona in Nanomedicine

An inconvenient hurdle in the practice of nanomedicine is the protein corona, a spontaneous collection of biomolecular species by nanoparticles in living systems. The protein corona is dynamic in composition and may entail improved water suspendability and compromised delivery and targeting to the nanoparticles. How much of this nonspecific protein ensemble is determined by the chemistry of the nanoparticle core and its surface functionalization, and how much of this entity is dictated by the biological environments that vary spatiotemporally in vivo? How do we "live with" and exploit the protein corona without significantly sacrificing the efficacy of nanomedicines in diagnosing and curing human diseases? This article discusses the chemical and biophysical signatures of the protein corona and ponders challenges ahead for the field of nanomedicine.

The Molecular Mechanism of Human Voltage-Dependent Anion Channel 1 Blockade by the Metallofullerenol Gd@C82(OH)22: An In Silico Study

The endohedral metallofullerenol Gd@C₈₂(OH)₂₂ has been identified as a possible antineoplastic agent that can inhibit both the growth and metastasis of cancer cells. Despite these potentially important effects, our understanding of the interactions between Gd@C₈₂(OH)₂₂ and biomacromolecules remains incomplete. Here, we study the interaction between Gd@C₈₂(OH)₂₂ and the human voltage-dependent anion channel 1 (hVDAC1), the most abundant porin embedded in the mitochondrial outer membrane (MOM), and a potential druggable target for novel anticancer therapeutics. Using in silico approaches, we observe that Gd@C₈₂(OH)₂₂ molecules can permeate and form stable interactions with the pore of hVDAC1. Further, this penetration can occur from either side of the MOM to elicit blockage of the pore. The binding between Gd@C₈₂(OH)₂₂ and hVDAC1 is largely driven by long-range electrostatic interactions. Analysis of the binding free energies indicates that it is thermodynamically more favorable for Gd@C₈₂(OH)₂₂ to bind to the hVDAC1 pore when it enters the channel from inside the membrane rather than from the cytoplasmic side of the protein. Multiple factors contribute to the preferential penetration, including the surface electrostatic landscape of hVDAC1 and the unique physicochemical properties of Gd@C₈₂(OH)₂₂. Our findings provide insights into the potential molecular interactions of macromolecular biological systems with the Gd@C₈₂(OH)₂₂ nanodrug.

Bioinspired Heteromultivalent Chitosan-α-Fe₂O₃/Gadofullerene Hybrid Composite for Enhanced Antibiotic-Resistant Bacterial Pneumonia

Herein, we have designed and developed a heteromultivalent chitosan base α-Fe₂O₃/Gadofullerene (GdF) hybrid composite through a simple chemical precipitation method. Unlike other methods, the addition of external stabilizing agents to generate GdF nanoparticles (NPs) was not necessary herein. The prepared chitosan-α-Fe₂O₃/GdF hybrid nanocomposites were characterized using UV, FT-IR, XRD and morphological microscopic analyses. The results showed that α-Fe₂O₃ and GdF hybrid nanocomposites were successfully grown on the surface of chitosan. The FT-IR vibration peaks showed the formation of Fe₂O₃ NPs, and the vibration peak for Fe-O was 568 cm^-1. The broad absorption peak observed in the range of 250-350 nm and a sharp absorption peak at 219 nm represents the UV absorption of the synthesized hybrid composites. XRD pattern showed sharp peaks of crystallinity and purity of α-Fe₂O₃ nanoparticles. Finally, the synthesized chitosan-α-Fe₂O₃/GdF hybrid composites were screened for their antibacterial resistance against the Escherichia coli, Pseudomonas aeruginosa, Bacilus subtilis, and Staphylococcus aereus. In addition, in vitro biocompatibility results exhibited that developed hybrid samples have provided high cell compatibility with fibroblast (L929) cell line. The in vivo bio inspired nanotherapeutics have the potential action to effective inhibition ability on antibiotic-resistant P. aeruginosa, which has been main factor of inducing pneumonia. In conclusion, we expect biomimicking systems combined with the effective antibacterial agent could be the suitable next generation therapeutic potential factors for prevention and treatment of antibiotic-resistant pneumonia.

Antitumor Activity and Potential Mechanism of Novel Fullerene Derivative Nanoparticles

The development of novel nanoparticles as a new generation therapeutic drug platform is an active field of chemistry and cancer research. In recent years, fullerene nanoparticles have received extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity, which makes them have broad application prospects in the field of cancer therapy. Therefore, understanding the anti-tumor mechanism of fullerene nanoparticles is of great significance for the design and development of anti-tumor drugs with low toxicity and high targeting. This review has focused on various anti-tumor mechanisms of fullerene derivatives and discusses their toxicity and their distribution in organisms. Finally, the review points out some urgent problems that need solution before fullerene derivatives as a new generation of anti-tumor nano-drug platform enter clinical research.

Matrix metalloproteinase inhibitors (MMPIs) as attractive therapeutic targets: Recent progress and current challenges

Matrix metalloproteinase (MMP) plays an essential role in many physiological and pathological processes. An increase in MMP activity contributes to excessive degradation and remodeling of the extracellular matrix (ECM), which has been correlated with invasion and metastasis of tumors. Matrix metalloproteinase inhibitor (MMPI) has been developed as an attractive therapeutic target for decades, suggesting inspiring therapeutic effects in preclinical studies. However, achieving specificity remains an important challenge in the development of MMPIs, limiting their clinical application and bringing about the risk of biosafety. Nanomaterials can be used as alternative candidates for MMPI design, providing a new strategy for this problem. This report reviewed the research about MMPIs, summarized their MMPs activity regulation mechanisms, and discussed their failures in clinical trials. Furthermore, we outlined several schemes of MMPIs screening and design. Finally, we reviewed the therapeutic application prospects of MMPIs and discussed the remaining challenges and solutions, which may offer new insights for the development of MMPIs studies.

Nanomedicine-based drug delivery towards tumor biological and immunological microenvironment

The complex tumor microenvironment is a most important factor in cancer development. The biological microenvironment is composed of a variety of barriers including the extracellular matrix and associated cells such as endothelia cells, pericytes, and cancer-associated fibroblasts. Different strategies can be utilized to enhance nanoparticle-based drug delivery and distribution into tumor tissues addressing the extracellular matrix or cellular components. In addition to the biological microenvironment, the immunological conditions around the tumor tissue can be very complicated and cancer cells have various ways of evading immune surveillance. Nanoparticle drug delivery systems can enhance cancer immunotherapy by tuning the immunological response and memory of various immune cells such as T cells, B cells, macrophages, and dendritic cells. In this review, the main components in the tumor biological and immunological environment are discussed. The focus is on recent advances in nanoparticle-based drug delivery systems towards targets within the tumor microenvironment to improve cancer chemotherapy and immunotherapy.

Harnessing nanomedicine to overcome the immunosuppressive tumor microenvironment

Cancer immunotherapy has received extensive attention due to its ability to activate the innate or adaptive immune systems of patients to combat tumors. Despite a few clinical successes, further endeavors are still needed to tackle unresolved issues, including limited response rates, development of resistance, and immune-related toxicities. Accumulating evidence has pinpointed the tumor microenvironment (TME) as one of the major obstacles in cancer immunotherapy due to its detrimental impacts on tumor-infiltrating immune cells. Nanomedicine has been battling with the TME in the past several decades, and the experience obtained could be exploited to improve current paradigms of immunotherapy. Here, we discuss the metabolic features of the TME and its influence on different types of immune cells. The recent progress in nanoenabled cancer immunotherapy has been summarized with a highlight on the modulation of immune cells, tumor stroma, cytokines and enzymes to reverse the immunosuppressive TME.

Metal-derived nanoparticles in tumor theranostics: Potential and limitations

Initially, metal derived nanoparticles have been used exclusively as contrasting agents in magnetic resonance imaging. Today, green routes of chemical synthesis together with numerous modifications of the core and surface gave rise to a plethora of biomedical applications of metal derived nanoparticles including tumor imaging, diagnostics, and therapy. These materials are an emerging class of tools for tumor theranostics. Nevertheless, the spectrum of clinically approved metal nanoparticles remains narrow, as the safety, specificity and efficiency still have to be improved. In this review we summarize the major directions for development and biomedical applications of metal based nanoparticles and analyze their effects on tumor cells and microenvironment. We discuss the advantages and possible limitations of metal nanoparticle-based tumor theranostics, as well as the potential strategies to improve the in vivo performance of these unique materials.

Gd-metallofullerenol drug delivery system mediated macrophage polarization enhances the efficiency of chemotherapy

Treatment of solid tumors by chemotherapy is usually failed in clinical because of its low effectiveness and side effects. Stimulation of immune system in vivo to fight cancer has been proved to be a pleasant complementary to systemic chemotherapy. Herein, we have developed a combination cancer therapy strategy by using polymer nanoparticles to deliver Gd-metallofullerenol and doxorubicin simultaneously. The Gd-metallofullerenol provoked the Th1 immune response by regulating the M1 macrophage polarization and the doxorubicin realized direct tumor cells killing by its cytotoxic effect. Also, the Gd-metallofullerenol as part of component in delivery system enhances the encapsulation efficiency of doxorubicin in polymer cargo for potential passive tumor target. The biocompatible and reliable method by combining nanoparticle-induced immune modulation and chemotherapy triggers systemic antitumor immune responses for the synergistic inhibition of tumor growth in vivo. The integration of Gd-metallofullerenol and doxorubicin with potentially complementary functions in one nanoplatform may provide new opportunities to improve cancer treatments.

Potential of Matrix Metalloproteinase Inhibitors for the Treatment of Local Tissue Damage Induced by a Type P-I Snake Venom Metalloproteinase

Snake bite envenoming is a public health problem that was recently included in the list of neglected tropical diseases of the World Health Organization. In the search of new therapies for the treatment of local tissue damage induced by snake venom metalloproteinases (SVMPs), we tested the inhibitory activity of peptidomimetic compounds designed as inhibitors of matrix metalloproteinases on the activities of the SVMP Batx-I, from Bothrops atrox venom. The evaluated compounds show great potential for the inhibition of Batx-I proteolytic, hemorrhagic and edema-forming activities, especially the compound CP471474, a peptidomimetic including a hydroxamate zinc binding group. Molecular dynamics simulations suggest that binding of this compound to the enzyme is mediated by the electrostatic interaction between the hydroxamate group and the zinc cofactor, as well as contacts, mainly hydrophobic, between the side chain of the compound and amino acids located in the substrate binding subsites S1 and S1′. These results show that CP471474 constitutes a promising compound for the development of co-adjuvants to neutralize local tissue damage induced by snake venom metalloproteinases.

A Safe-by-Design Strategy towards Safer Nanomaterials in Nanomedicines

The marriage of nanotechnology and medicine offers new opportunities to fight against human diseases. Benefiting from their unique optical, thermal, magnetic, or redox properties, a wide range of nanomaterials have shown potential in applications such as diagnosis, drug delivery, or tissue repair and regeneration. Despite the considerable success achieved over the past decades, the newly emerging nanomedicines still suffer from an incomplete understanding of their safety risks, and of the relationships between their physicochemical characteristics and safety profiles. Herein, the most important categories of nanomaterials with clinical potential and their toxicological mechanisms are summarized, and then, based on this available information, an overview of the principles in developing safe-by-design nanomaterials for medical applications and of the recent progress in this field is provided. These principles may serve as a starting point to guide the development of more effective safe-by-design strategies and to help identify the major knowledge and skill gaps.

Functional Metallofullerene Materials and Their Applications in Nanomedicine, Magnetics, and Electronics

Endohedral metallofullerenes exhibit combined properties from carbon cages as well as internal metal moieties and have great potential in a wide range of applications as molecule materials. Along with the breakthrough of mass production of metallofullerenes, their applied research has been greatly developed with more and more new functions and practical applications. For gadolinium metallofullerenes, their water-soluble derivatives have been demonstrated with antitumor activity and unprecedented tumor vascular-targeting therapy. Metallofullerene water-soluble derivatives also can be applied to treat reactive oxygen species (ROS)-induced diseases due to their high antioxidative activity. For magnetic metallofullerenes, the internal electron spin and metal species bring about spin sensitivity, molecular magnets, and spin quantum qubits, which have many promising applications. Metallofullerenes are significant candidates for fabricating useful electronic devices because of their various electronic structures. This Review provides a summary of the metallofullerene studies reported recently, in the fields of tumor inhibition, tumor vascular-targeting therapies, antioxidative activity, spin probes, single-molecule magnets, spin qubits, and electronic devices. This is not an exhaustive summary and there are many other important study results regarding metallofullerenes. All of this research has revealed the irreplaceable role of metallofullerene materials.

The pharmaceutical multi-activity of metallofullerenol invigorates cancer therapy

Currently, cancer continues to afflict humanity. The direct destruction and killing of tumor cells by surgery, radiation and chemotherapy gives rise to many side effects and compromised efficacy. Encouragingly, the rapid development of nanotechnology offers attractive opportunities to revolutionize the current situation of cancer therapy. Metallofullerenol Gd@C82(OH)22, in contrast to chemotherapeutics that directly kill tumor cells, demonstrates anti-tumor behavior with high efficiency and low toxicity by modulating the tumor microenvironment. Furthermore, Gd@C82(OH)22 has been recently reported to specifically target cancer stem cells. In this review, we give a concise introduction to the development of the fullerene family and then report the anti-tumor activity of Gd@C82(OH)22 based on its unique physicochemical characteristics, followed by a comprehensive summary of the anti-tumor biological mechanisms which target different components of the tumor microenvironment as well as the biodistribution and toxicity of Gd@C82(OH)22. Finally, we describe Gd@C82(OH)22 as a "particulate medicine" to highlight its distinctions from conventional "molecular medicine", with considerable emphasis on the advantages of nanomedicine. The in-depth investigation of Gd@C82(OH)22 undoubtedly provides a constructive reference for the development of other nanomedicines, especially in the fullerene family. The application of nanotechnology in the medical field definitely provides a promising and favorable future for improving the current status of cancer therapy.

Precision Nanomedicine Development Based on Specific Opsonization of Human Cancer Patient-Personalized Protein Coronas

When a nanomedicine is administrated into the human body, biomolecules in biological fluids, particularly proteins, form a layer on the surface of the nanoparticle known as a "personalized protein corona". An understanding of the formation and behavior of the personalized protein corona not only benefits the nanotherapy treatment efficacy but also can aid in disease diagnosis. Here we used Gd@C₈₂(OH)₂₂ nanoparticles, a nanomedicine effective against several types of cancer, as a model nanomedicine to investigate the natural protein fingerprint of the personalized protein corona formed in 10 human lung squamous cell carcinoma patients. Our analysis revealed a specific biomarker, complement component C1q, in lung cancer personalized protein coronas, abundantly bound to Gd@C₈₂(OH)₂₂ NPs. This binding altered the secondary structure of C1q protein and led to the activation of an innate immune response, which could be exploited for cancer immune therapy. On the basis of this finding, we provide a new strategy for the development of precision nanomedicine derived from opsonization of a unique protein fingerprint within patients. This approach overcomes the common pitfall of protein corona formation and exploits the corona proteins to generate a precision nanomedicine and diagnostic tool.

A Novel Drug Design Strategy: An Inspiration from Encaging Tumor by Metallofullerenol Gd@C82(OH)22

Cancer remains a major threat to human health worldwide. Cytotoxicity has imposed restrictions on the conventional cytotoxic drug-based chemotherapy. The rapidly-developing nanomedicine has shown great promise in revolutionizing chemotherapy with improved efficiency and reduced toxicity. Gd@C₈₂(OH)₂₂, a novel endohedral metallofullerenol, was first reported by our research group to suppress tumor growth and metastasis efficiently without obvious toxicity. Gd@C₈₂(OH)₂₂ imprisons tumors by facilitating the formation of surrounding fibrous layers which is different from chemotherapeutics that poison tumor cells. In this review, the authors first reported the antineoplastic activity of metallofullerenol Gd@C₈₂(OH)₂₂ followed by further discussions on its new anti-cancer molecular mechanism—tumor encaging. On this basis, the unparalleled advantages of nanomedicine in the future drug design are discussed. The unique interaction modes of Gd@C₈₂(OH)₂₂ with specific targeted biomolecules may shed light on a new avenue for drug design. Depending on the surface characteristics of target biomolecules, nanomedicine, just like a transformable and dynamic key, can self-assemble into suitable shapes to match several locks for the thermodynamic stability, suggesting the target-tailoring ability of nanomedicine.

Positron Emission Tomography/Magnetic Resonance Imaging of Glioblastoma Using a Functionalized Gadofullerene Nanoparticle

Water-soluble gadofullerene nanomaterials have been extensively investigated as magnetic resonance imaging (MRI) contrast agents, radical scavengers, sensitizers for photodynamic therapy, and inherent antineoplastic agents. Most recently, an alanine-modified gadofullerene nanoparticle (Gd@C₈₂-Ala) with excellent anticancer activity has been reported; however, the absolute tumor uptake of Gd@C₈₂-Ala is still far from being satisfactory, and its dynamic pharmacokinetics and long-term metabolic behaviors remain to be elucidated. Herein, Gd@C₈₂-Ala was chemically modified with eight-arm polyethylene glycol amine to improve its biocompatibility and provide the active sites for the attachment of a tumor-homing ligand (cRGD) and positron emission tomography (PET) isotopes (i.e., ⁶⁴Cu or ⁸⁹Zr). The physical and chemical properties (e.g., size, surface functionalization condition, radiochemical stability, etc.) of functionalized Gd@C₈₂-Ala were properly characterized. Also, its glioblastoma cell targeting capacity was evaluated in vitro by flow cytometry, confocal fluorescence microscopy, and dynamic cellular interaction assays. Because of the presence of gadolinium ions, the gadofullerene conjugates can act simultaneously as T₁* MRI contrast agents and PET probes. Thus, the pharmacokinetic behavior of functionalized Gd@C₈₂-Ala was investigated by PET/MRI, which combines the merits of high resolution and excellent sensitivity. The functionalized Gd@C₈₂-Ala-PEG-cRGD-NOTA-⁶⁴Cu (NOTA stands for 1,4,7-triazacyclononane-triacetic acid) demonstrated much higher accumulation in U87-MG tumor than its counterpart without cRGD attachment from in vivo PET observation, consistent with observation at the cellular level. In addition, Gd@C₈₂-Ala-PEG-Df-⁸⁹Zr (Df stands for desferrioxamine) was employed to investigate the metabolic behavior of gadofullerene conjugates in vivo for up to 30 days. It was estimated that nearly 70% of Gd@C₈₂-Ala-PEG-Df-⁸⁹Zr was excreted from the test subjects primarily through renal pathways within 24 h. With proper surface engineering, functionalized Gd@C₈₂-Ala nanoparticles can show an improved accumulation in glioblastoma. Pharmacokinetic studies also confirmed the safety of this nanoplatform, which can be used as an image-guidable therapeutic agent for glioblastoma.

Photo-triggered gadofullerene: enhanced cancer therapy by combining tumor vascular disruption and stimulation of anti-tumor immune responses

Efficient treatment of primary tumor and preventing cancer metastasis present intriguing alternatives to cancer therapy. Herein, for the first time, we reported the photo-triggered nano-gadofullerene (Gd@C₈₂-Ala, abbreviated Gd-Ala) induced malignant tumor vascular disruption by shortening the light interval between Gd-Ala administration and light illumination, where oxygen in blood vessels was employed efficiently to produce cytotoxic reactive oxygen species (ROS). The produced ROS could not only destroy the tumor cells but also devastate the vascular endothelial cells corresponding to the loss of intercellular junctions and vessels disruption. Notably, the irradiated Gd-Ala could enhance dendritic cells (DCs) maturation, which further secreted tumor necrosis factor-α (TNF-α) and interleukin-12 (IL)-12, and then activated T lymphocytes by up-regulation of cluster of differentiation CD4⁺ and CD8⁺ T lymphocytes. Furthermore, the down-regulation of matrix metalloprotein 2 (MMP2) and MMP9 also reduce the rate of tumor metastasis. This work explored a new biomedical application of gadofullerene, thereby providing a smart carbon nanomaterial candidate for tumor ablation and inhibition of cancer metastasis.

Application of nanotechnology to target and exploit tumour associated proteases

Proteases are hydrolytic enzymes fundamental for a variety of physiological processes, but the loss of their regulation leads to aberrant functions that promote onset and progression of many diseases including cancer. Proteases have been implicated in almost every hallmark of cancer and whilst widely investigated for tumour therapy, clinical adoption of protease inhibitors as drugs remains a challenge due to issues such as off-target toxicity and inability to achieve therapeutic doses at the disease site. Now, nanotechnology-based solutions and strategies are emerging to circumvent these issues. In this review, preclinical advances in approaches to enhance the delivery of protease drugs and the exploitation of tumour-derived protease activities to promote targeting of nanomedicine formulations is examined. Whilst this field is still in its infancy, innovations to date suggest that nanomedicine approaches to protease targeting or inhibition may hold much therapeutic and diagnostic potential.

Gd-Metallofullerenol nanoparticles cause intracellular accumulation of PDGFR-α and morphology alteration of fibroblasts

Gadolinium-metallofullerenols (Gd@C82(OH)22) are a promising agent for cancer therapy and have shown beneficial effects in regulating the tumor microenvironment with low toxicity. However, the underlying mechanism by which Gd@C82(OH)22 interacts with fibroblasts remains unclear. In order to explore the critical role that activated fibroblasts play in tumorigenesis and fibrosis, we investigated the regulatory effect of Gd@C82(OH)22 in fibroblast activation and oncogenic transformation, and found that the PDGFR-α is an essential molecule in modulating the morphology and functional changes in fibroblasts after Gd@C82(OH)22 treatment. Apart from increasing the PDGFR-α protein level, Gd@C82(OH)22 nanoparticles also significantly increased the protein level of Rab5, which is required for regulating PDGFR-α endosomal recycling. The Rab5-mediated recycling of PDGFR-α maybe attributed to the Gd@C82(OH)22 regulated inhibition of fibroblast activation. Overall, our work demonstrated that Gd@C82(OH)22 nanoparticles can attenuate the PDGF-stimulated phosphorylation of PDGFR-α in fibroblasts and suppress the fibroblast activation by interrupting endosomal recycling. These findings may be contributed to the collagen accumulation for encaging cancer.

Carbon-Based Nanomaterials for Cancer Therapy via Targeting Tumor Microenvironment

Cancer remains one of the major health problems all over the world and conventional therapeutic approaches have failed to attain an effective cure. Tumor microenvironments (TME) present a unique challenge in tumor therapy due to their complex structures and multiple components, which also serve as the soil for tumor growth, development, invasion, and migration. The complex TME includes immune cells, fibrous collagen structures, and tortuous blood vessels, in which conventional therapeutic approaches are rendered useless. State-of-the-art nanotechnologies have potential to cope with the threats of malignant tumors. With unique physiochemical properties, carbon nanomaterials (CNMs), including graphene, fullerenes, carbon nanotubes, and carbon quantum dots, offer opportunities to resolve the hurdles, by targeting not only cancer cells but also the TME. This review summarizes the progress about CNM-based cancer therapy strategies, which mainly focuses on both the treatment for cancer cells and TME-targeted modulation. In the last, the challenges for TME-based therapy via CNMs are discussed, which will be important in guiding current basic research to clinical translation in the future.

Biomedical applications of carbon nanomaterials: Drug and gene delivery potentials

One of the major components in the development of nanomedicines is the choice of the right biomaterial, which notably determines the subsequent biological responses. The popularity of carbon nanomaterials (CNMs) has been on the rise due to their numerous applications in the fields of drug delivery, bioimaging, tissue engineering, and biosensing. Owing to their considerably high surface area, multifunctional surface chemistry, and excellent optical activity, novel functionalized CNMs possess efficient drug-loading capacity, biocompatibility, and lack of immunogenicity. Over the past few decades, several advances have been made on the functionalization of CNMs to minimize their health concerns and enhance their biosafety. Recent evidence has also implied that CNMs can be functionalized with bioactive peptides, proteins, nucleic acids, and drugs to achieve composites with remarkably low toxicity and high pharmaceutical efficiency. This review focuses on the three main classes of CNMs, including fullerenes, graphenes, and carbon nanotubes, and their recent biomedical applications.

Small size fullerenol nanoparticles suppress lung metastasis of breast cancer cell by disrupting actin dynamics

BACKGROUND

Tumor metastasis is the primary cause of mortality in cancer patients. Migratory breast cancer cells in lymphatic and blood vessels seek new sites and form metastatic colonies in the lung and bone, and then these cancer cells often wreak considerable havoc. With advances in nanotechnology, nanomaterials and nanotechnologies are widely applied in tumor therapy. In this paper, small size fullerenol nanoparticles, which are separated by isoelectric focusing electrophoresis (IFE) for discrepancy of isoelectric point (pI), are used in the study of tumor metastasis.

RESULTS

In this study, the commendable inhibition of tumor metastasis was uncovered by intravenous injection of purified fullerenol fraction with special surface charge and functional groups, which was separated by IFE for discrepancy of pI. By investigating the actin dynamics in several cancer cell lines, we found these small size fullerenol nanoparticles disturbed actin dynamics. Young's modulus detection and cell migration assays revealed that fullerenol lowered stiffness and restrained migration of breast cancer cells. Filopodia, the main supporting structures of actin bundles, are important for cell motility and adhesion. Scanning electron microscopy showed that fullerenol reduced the number and length of filopodia. Simultaneously, the inhibition of integrin to form clusters on filopodias, which was likely induced by reorganizing of actin cytoskeleton, impacted cancer cell adhesion and motility.

CONCLUSIONS

With intravenous injection of these fullerenol nanoparticles, tumor metastasis is well inhibited in vivo. The underlying mechanism most likely to be attributed to the effect of fullerenol nanoparticles on disturbing actin dynamics. With the disordered actin fiber, cell function is varied, including decreased cell stiffness, reduced filopodia formation, and inactivated integrin.

Induction of Apoptosis and Inhibition of Invasion in Gastric Cancer Cells by Titanium Dioxide Nanoparticles

Objectives

Nanoparticles induce oxidative stress in cells and damage them through the cell membrane and DNA damage, eventually resulting in cell death. This study aimed to evaluate the effect of titanium dioxide (TiO₂) nanoparticles on apoptosis induction and invasion of gastric cancer cell line, MKN-45.

Methods

We used the MTT assay to assess proliferation of MKN-45 gastric cancer cells after exposure to different forms of TiO₂ nanoparticles including amorph, brookite, anatase, and rutile coated with polyethylene glycol (PEG) and bovine serum albumin (BSA). Ethidium bromide and acridine orange staining were used to visualize cancer cell apoptosis, and the wound healing assay technique (migration test) was used to assay cancer cell invasion.

Results

Viability and proliferation of cancer cells in the presence of various forms of TiO₂ nanoparticles were reduced (p ≤ 0.050). This reduction in cell proliferation and viability was directly related to concentration and duration of exposure to nanoparticles. Induction of cell death was seen in all groups (p ≤ 0.050). Increased cell invasion was seen in PEG-amorph TiO₂ group compared to the control group. Cell invasion was decreased only in the brookite BSA group (p ≤ 0.050).

Conclusions

Various forms of TiO₂ nanoparticles reduced cell proliferation and induced apoptosis in cancer cells. Some forms of TiO₂ nanoparticles such as brookite BSA also inhibited cell invasion. PEG-amorph TiO₂ nanoparticles increased cell invasion. These differences seem to be due to the effects of different configurations of TiO₂ nanoparticles. TiO₂ may provide a new strategy for cancer treatment and more studies are needed.

Three-dimensional ultrastructural imaging reveals the nanoscale architecture of mammalian cells

Knowledge of the interactions between nanomaterials and large-size mammalian cells, including cellular uptake, intracellular localization and translocation, has greatly advanced nanomedicine and nanotoxicology. Imaging techniques that can locate nanomaterials within the structures of intact large-size cells at nanoscale resolution play crucial roles in acquiring this knowledge. Here, the quantitative imaging of intracellular nanomaterials in three dimensions was performed by combining dual-energy contrast X-ray microscopy and an iterative tomographic algorithm termed equally sloped tomography (EST). Macrophages with a size of ∼20 µm that had been exposed to the potential antitumour agent [Gd@C82(OH)22] n were investigated. Large numbers of nanoparticles (NPs) aggregated within the cell and were mainly located in phagosomes. No NPs were observed in the nucleus. Imaging of the nanomedicine within whole cells advanced the understanding of the high-efficiency antitumour activity and the low toxicity of this agent. This imaging technique can be used to probe nanomaterials within intact large-size cells at nanometre resolution uniformly in three dimensions and may greatly benefit the fields of nanomedicine and nanotoxicology.

Gd@C82(OH)22 harnesses inflammatory regeneration for osteogenesis of mesenchymal stem cells through JNK/STAT3 signaling pathway

Gd@C₈₂(OH)₂₂ dose-dependently manipulates osteogenesis of MSCs in inflammatory microenvironment, which is capable for bone tissue engineering as an immunomodulatory nanoparticle.

Molecular targets in aortic aneurysm for establishing novel management paradigms

Aortic aneurysm (AA) is a lethal disease and presents a large challenge for surgeons in the clinic. Although surgical management remains the major choice of AA, operative mortality remains high. With advances in understanding of the mechanisms of AAs, molecular targets, such as matrix metalloproteinases (MMPs), D-dimer, and inflammation markers, including C-reactive protein, interleukins and phagocytes, are important in the pathology of development of AA. These markers may become important for improving the diagnostic quality and provide more therapeutic choices for treatment of AA. Although these new markers require long-term trials before they can be translated into the clinic, they can still be helpful in determining new directions. The main aim of this review is to discuss the current findings of molecular targets in progression of AA and discuss the potential application of these new targets for managing this disease.

Molecular mechanism of Gd@C82(OH)22 increasing collagen expression: Implication for encaging tumor

Gadolinium-containing fullerenol Gd@C₈₂(OH)₂₂ has demonstrated low-toxicity and highly therapeutic efficacy in inhibiting tumor growth and metastasis through new strategy of encaging cancer, however, little is known about the mechanisms how this nanoparticle regulates fibroblast cells to prison (instead of poison) cancer cells. Here, we report that Gd@C₈₂(OH)₂₂ promote the binding activity of tumor necrosis factor (TNFα) to tumor necrosis factor receptors 2 (TNFR2), activate TNFR2/p38 MAPK signaling pathway to increase cellular collagen expression in fibrosarcoma cells and human primary lung cancer associated fibroblasts isolated from patients. We also employ molecular dynamics simulations to study the atomic-scale mechanisms that dictate how Gd@C₈₂(OH)₂₂ mediates interactions between TNFα and TNFRs. Our data suggest that Gd@C₈₂(OH)₂₂ might enhance the association between TNFα and TNFR2 through a "bridge-like" mode of interaction; by contrast, the fullerenol appears to inhibit TNFα-TNFR1 association by binding to two of the receptor's cysteine-rich domains. In concert, our results uncover a sequential, systemic process by which Gd@C₈₂(OH)₂₂ acts to prison tumor cells, providing new insights into principles of designs of cancer therapeutics.

Metallofullerenol Inhibits Cellular Iron Uptake by Inducing Transferrin Tetramerization

Herein, A549 tumor cell proliferation was confirmed to be positively dependent on the concentration of Fe³⁺ or transferrin (Tf). Gd@C₈₂ (OH)₂₂ or C₆₀ (OH)₂₂ effectively inhibited the iron uptake and the subsequent proliferation of A549 cells. The conformational changes of Tf mixed with FeCl₃ , GdCl₃ , C₆₀ (OH)₂₂ or Gd@C₈₂ (OH)₂₂ were obtained by SAXS. The results demonstrate that Tf homodimers can be decomposed into monomers in the presence of FeCl₃ , GdCl₃ or C₆₀ (OH)₂₂ , but associated into tetramers in the presence of Gd@C₈₂ (OH)₂₂ . The larger change of SAXS shapes between Tf+C₆₀ (OH)₂₂ and Tf+FeCl₃ implies that C₆₀ (OH)₂₂ is bound to Tf, blocking the iron-binding site. The larger deviation of the SAXS shape from a possible crystal structure of Tf tetramer implies that Gd@C₈₂ (OH)₂₂ is bound to the Tf tetramer, thus disturbing iron transport. This study well explains the inhibition mechanism of Gd@C₈₂ (OH)₂₂ and C₆₀ (OH)₂₂ on the iron uptake and the proliferation of A549 tumor cells and highlights the specific interactions of a nanomedicine with the target biomolecules in cancer therapy.

Fullerenol inhibits the cross-talk between bone marrow-derived mesenchymal stem cells and tumor cells by regulating MAPK signaling

The interaction between bone marrow-derived mesenchymal stem cells (BDMSCs) and tumor cells promotes tumor proliferation and metastasis. We found that 4T1 breast cancer cells induced malignant differentiation of BDMSCs and that BDMSCs also affected the growth and metastasis of 4T1 cells. However, when the interaction between BDMSCs and 4T1 cells was attenuated or blocked by C₆₀(OH)₂₂ nanoparticles, tumor growth and metastasis were significantly suppressed. The suppression of metastasis depended on the activation of MAPK signals in the BDMSCs, whereas the underlying pathways were related to a broad range of extracellular responses and were modulated by the secretion of multiple cytokines. Interestingly, C₆₀(OH)₂₂ regulated the malignantly differentiated BDMSCs via the Erk- and p38-MAPK and its downstream NF-κB signal pathway, but in normal BDMSCs regulation occurred only through Erk- and p38-MAPK and not by NF-κB activation. This study may provide a novel mechanism for C₆₀(OH)₂₂ nanoparticles as an anti-tumor drug.

Diverse Applications of Nanomedicine

The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic.