Bioengineered Carboxymethylcellulose-Peptide Hybrid Nanozyme Cascade for Targeted Intracellular Biocatalytic-Magnetothermal Therapy of Brain Cancer Cells

Peptide nanozymes: An emerging direction for functional enzyme mimics

The abundance of molecules on early Earth likely enabled a wide range of prebiotic chemistry, with peptides playing a key role in the development of early life forms and the evolution of metabolic pathways. Among peptides, those with enzyme-like activities occupy a unique position between peptides and enzymes, combining both structural flexibility and catalytic functionality. However, their full potential remains largely untapped. Further exploration of these enzyme-like peptides at the nanoscale could provide valuable insights into modern nanotechnology, biomedicine, and even the origins of life. Hence, this review introduces the groundbreaking concept of "peptide nanozymes (PepNzymes)", which includes single peptides exhibiting enzyme-like activities, peptide-based nanostructures with enzyme-like activities, and peptide-based nanozymes, thus enabling the investigation of biological phenomena at nanoscale dimensions. Through the rational design of enzyme-like peptides or their assembly with nanostructures and nanozymes, researchers have found or created PepNzymes capable of catalyzing a wide range of reactions. By scrutinizing the interactions between the structures and enzyme-like activities of PepNzymes, we have gained valuable insights into the underlying mechanisms governing enzyme-like activities. Generally, PepNzymes play a crucial role in biological processes by facilitating small-scale enzyme-like reactions, speeding up molecular oxidation-reduction, cleavage, and synthesis reactions, leveraging the functional properties of peptides, and creating a stable microenvironment, among other functions. These discoveries make PepNzymes useful for diagnostics, cellular imaging, antimicrobial therapy, tissue engineering, anti-tumor treatments, and more while pointing out opportunities. Overall, this research provides a significant journey of PepNzymes' potential in various biomedical applications, pushing them towards new advancements.

Nanozymes-Mediated Cascade Reaction System for Tumor-Specific Diagnosis and Targeted Therapy

Cascade reactions are described as efficient and versatile tools, and organized catalytic cascades can significantly improve the efficiency of chemical interworking between nanozymes. They have attracted great interest in many fields such as chromogenic detection, biosensing, tumor diagnosis, and therapy. However, how to selectively kill tumor cells by enzymatic reactions without harming normal cells, as well as exploring two or more enzyme-engineered nanoreactors for cascading catalytic reactions, remain great challenges in the field of targeted and specific cancer diagnostics and therapy. The latest research advances in nanozyme-catalyzed cascade processes for cancer diagnosis and therapy are described in this article. Here, various sensing strategies are summarized, for tumor-specific diagnostics. Targeting mechanisms for tumor treatment using cascade nanozymes are classified and analyzed, "elements" and "dimensions" of cascade nanozymes, types, designs of structure, and assembly modes of highly active and specific cascade nanozymes, as well as a variety of new strategies of tumor targeting based on the cascade reaction of nanozymes. Finally, the integrated application of the cascade nanozymes systems in tumor-targeted and specific diagnostic therapy is summarized, which will lay the foundation for the design of more rational, efficient, and specific tumor diagnostic and therapeutic modalities in the future.

Metal nanozymes modulation of reactive oxygen species as promising strategies for cancer therapy

Nanozymes, nanostructured materials emulating natural enzyme activities, exhibit potential in catalyzing reactive oxygen species (ROS) production for cancer treatment. By facilitating oxidative reactions, elevating ROS levels, and influencing the tumor microenvironment (TME), nanozymes foster the eradication of cancer cells. Noteworthy are their superior stability, ease of preservation, and cost-effectiveness compared to natural enzymes, rendering them invaluable for medical applications. This comprehensive review intricately explores the interplay between ROS and tumor therapy, with a focused examination of metal-based nanozyme strategies mitigating tumor hypoxia. It provides nuanced insights into diverse catalytic processes, mechanisms, and surface modifications of various metal nanozymes, shedding light on their role in intra-tumoral ROS generation and applications in antioxidant therapy. The review concludes by delineating specific potential prospects and challenges associated with the burgeoning use of metal nanozymes in future tumor therapies.

Peptide-Functionalized Inorganic Oxide Nanomaterials for Solid Cancer Imaging and Therapy

The diagnosis and treatment of solid tumors have undergone significant advancements marked by a trend toward increased specificity and integration of imaging and therapeutic functions. The multifaceted nature of inorganic oxide nanomaterials (IONs), which boast optical, magnetic, ultrasonic, and biochemical modulatory properties, makes them ideal building blocks for developing multifunctional nanoplatforms. A promising class of materials that have emerged in this context are peptide-functionalized inorganic oxide nanomaterials (PFIONs), which have demonstrated excellent performance in multifunctional imaging and therapy, making them potential candidates for advancing solid tumor diagnosis and treatment. Owing to the functionalities of peptides in tumor targeting, penetration, responsiveness, and therapy, well-designed PFIONs can specifically accumulate and release therapeutic or imaging agents at the solid tumor sites, enabling precise imaging and effective treatment. This review provides an overview of the recent advances in the use of PFIONs for the imaging and treatment of solid tumors, highlighting the superiority of imaging and therapeutic integration as well as synergistic treatment. Moreover, the review discusses the challenges and prospects of PFIONs in depth, aiming to promote the intersection of the interdisciplinary to facilitate their clinical translation and the development of personalized diagnostic and therapeutic systems by optimizing the material systems.

Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

Neuromodulation by nanozymes and ultrasound during Alzheimer's disease management

Alzheimer's disease (AD) is a neurodegenerative disorder with complex pathogenesis and effective clinical treatment strategies for this disease remain elusive. Interestingly, nanomedicines are under extensive investigation for AD management. Currently, existing redox molecules show highly bioactive property but suffer from instability and high production costs, limiting clinical application for neurological diseases. Compared with natural enzymes, artificial enzymes show high stability, long-lasting catalytic activity, and versatile enzyme-like properties. Further, the selectivity and performance of artificial enzymes can be modulated for neuroinflammation treatments through external stimuli. In this review, we focus on the latest developments of metal, metal oxide, carbon-based and polymer based nanozymes and their catalytic mechanisms. Recent developments in nanozymes for diagnosing and treating AD are emphasized, especially focusing on their potential to regulate pathogenic factors and target sites. Various applications of nanozymes with different stimuli-responsive features were discussed, particularly focusing on nanozymes for treating oxidative stress-related neurological diseases. Noninvasiveness and focused application to deep body regions makes ultrasound (US) an attractive trigger mechanism for nanomedicine. Since a complete cure for AD remains distant, this review outlines the potential of US responsive nanozymes to develop future therapeutic approaches for this chronic neurodegenerative disease and its emergence in AD management.

Co-based Nanozymatic Profiling: Advances Spanning Chemistry, Biomedical, and Environmental Sciences

Nanozymes, next-generation enzyme-mimicking nanomaterials, have entered an era of rational design; among them, Co-based nanozymes have emerged as captivating players over times. Co-based nanozymes have been developed and have garnered significant attention over the past five years. Their extraordinary properties, including regulatable enzymatic activity, stability, and multifunctionality stemming from magnetic properties, photothermal conversion effects, cavitation effects, and relaxation efficiency, have made Co-based nanozymes a rising star. This review presents the first comprehensive profiling of the Co-based nanozymes in the chemistry, biology, and environmental sciences. The review begins by scrutinizing the various synthetic methods employed for Co-based nanozyme fabrication, such as template and sol-gel methods, highlighting their distinctive merits from a chemical standpoint. Furthermore, a detailed exploration of their wide-ranging applications in biosensing and biomedical therapeutics, as well as their contributions to environmental monitoring and remediation is provided. Notably, drawing inspiration from state-of-the-art techniques such as omics, a comprehensive analysis of Co-based nanozymes is undertaken, employing analogous statistical methodologies to provide valuable guidance. To conclude, a comprehensive outlook on the challenges and prospects for Co-based nanozymes is presented, spanning from microscopic physicochemical mechanisms to macroscopic clinical translational applications.

Applications of Bioengineered Polymer in the Field of Nano-Based Drug Delivery

The most favored route of drug administration is oral administration; however, several factors, including poor solubility, low bioavailability, and degradation, in the severe gastrointestinal environment frequently compromise the effectiveness of drugs taken orally. Bioengineered polymers have been developed to overcome these difficulties and enhance the delivery of therapeutic agents. Polymeric nanoparticles, including carbon dots, fullerenes, and quantum dots, have emerged as crucial components in this context. They provide a novel way to deliver various therapeutic materials, including proteins, vaccine antigens, and medications, precisely to the locations where they are supposed to have an effect. The promise of this integrated strategy, which combines nanoparticles with bioengineered polymers, is to address the drawbacks of conventional oral medication delivery such as poor solubility, low bioavailability, and early degradation. In recent years, we have seen substantially increased interest in bioengineered polymers because of their distinctive qualities, such as biocompatibility, biodegradability, and flexible physicochemical characteristics. The different bioengineered polymers, such as chitosan, alginate, and poly(lactic-co-glycolic acid), can shield medications or antigens from degradation in unfavorable conditions and aid in the administration of drugs orally through mucosal delivery with lower cytotoxicity, thus used in targeted drug delivery. Future research in this area should focus on optimizing the physicochemical properties of these polymers to improve their performance as drug delivery carriers.

Metallic Nanocarriers for Therapeutic Peptides: Emerging Solutions Addressing the Delivery Challenges in Brain Ailments

Peptides and proteins have recently emerged as efficient therapeutic alternatives to conventional therapies. Although they emerged a few decades back, extensive exploration of various ailments or disorders began recently. The drawbacks of current chemotherapies and irradiation treatments, such as drug resistance and damage to healthy tissues, have enabled the rise of peptides in the quest for better prospects. The chemical tunability and smaller size make them easy to design selectively for target tissues. Other remarkable properties include antifungal, antiviral, anti-inflammatory, protection from hemorrhage stroke, and as therapeutic agents for gastric disorders and Alzheimer and Parkinson diseases. Despite these unmatched properties, their practical applicability is often hindered due to their weak susceptibility to enzymatic digestion, serum degradation, liver metabolism, kidney clearance, and immunogenic reactions. Several methods are adapted to increase the half-life of peptides, such as chemical modifications, fusing with Fc fragment, change in amino acid composition, and carrier-based delivery. Among these, nanocarrier-mediated encapsulation not only increases the half-life of the peptides in vivo but also aids in the targeted delivery. Despite its structural complexity, they also efficiently deliver therapeutic molecules across the blood-brain barrier. Here, in this review, we tried to emphasize the possible potentiality of metallic nanoparticles to be used as an efficient peptide delivery system against brain tumors and neurodegenerative disorders. SIGNIFICANCE STATEMENT: In this review, we have emphasized the various therapeutic applications of peptides/proteins, including antimicrobial, anticancer, anti-inflammatory, and neurodegenerative diseases. We also focused on these peptides' challenges under physiological conditions after administration. We highlighted the importance and potentiality of metallic nanocarriers in the ability to cross the blood-brain barrier, increasing the stability and half-life of peptides, their efficiency in targeting the delivery, and their diagnostic applications.

Bio-functionalized nanocolloids of ZnS quantum dot/amine-rich polypeptides for bioimaging cancer cells with antibacterial activity: "seeing is believing"

Among almost 200 types of cancers, glioma is considered one of the most common forms of malignant tumors located in the central nervous system (CNS). Glioblastoma (GBM), one of the deadliest types of brain cancer, remains one of the challenges faced by oncologists. Thus, smartly designed nanomaterials biofunctionalized with polypeptides can offer disruptive strategies relying on the earliest possible diagnosis ("seeing is believing") combined with more efficient therapies for fighting cancer cells. To worsen this scenario, bacteria infections very often pose a serious challenge to cancer-immunodeficient patients under chemotherapy. Thus, in this research, we report for the first time the design and synthesis of novel nanoconjugates composed of photoluminescent ZnS quantum dots (ZnS QDs), which were directly surface biofunctionalized with epsilon-poly-l-lysine (εPL), acting as an amine-rich cell-penetrating peptide (CPP) and antimicrobial peptide agent (AMP). These nanoconjugates (named ZnS@CPP-AMP) were produced through a one-step facile, eco-friendly, and biocompatible colloidal aqueous process to be applied as a proof of concept as nanoprobes for bioimaging GBM cancer cells (U87-MG) associated with synergic antibacterial activity. They were characterized regarding their physicochemical and optical properties associated with the biological activity. The results demonstrated that chemically stable aqueous colloidal nanoconjugates were effectively formed, resembling core-shell (inorganic, ZnS, organic, εPL) nanostructures with positively surface-charged features due to the cationic nature of the amine-rich polypeptide. More importantly, they demonstrated photoluminescent activity, cytocompatibility in vitro, and no significant intracellular reactive oxygen species (ROS) generation. These ZnS@CPP-AMP nanocolloids behaved as fluorescent nanoprobes for bioimaging GBM cancer cells, where the polycationic nature of the εPL biomolecule may have enhanced the cellular uptake. Additionally, they displayed mild antibacterial growth inhibition due to electrostatic interactions with bacterial membranes. Thus, it can be envisioned that these novel photoluminescent colloidal nanoconjugates offer novel nanoplatforms that can be specifically targeted with biomolecules for bioimaging to diagnose highly lethal cancers, such as GBM, and as an adjuvant in antibacterial therapy.

Fabrication of magneticα-Fe2O3/Fe3O4heterostructure nanorods via the urea hydrolysis-calcination process and their biocompatibility with LO2and HepG2cells

β-FeOOH nanorods were prepared via the urea hydrolysis process with the average length of 289.1 nm and average diameter of 61.2 nm, while magneticα-Fe2O3/Fe3O4heterostructure nanorods were prepared via the urea calcination process withβ-FeOOH nanorods as precursor, and the optimum conditions were the calcination temperature of 400 °C, the calcination time of 2 h, theβ-FeOOH/urea mass ratio of 1:6. The average length, diameter, and the saturation magnetization of the heterostructure nanorods prepared under the optimum conditions were 328.8 nm, 63.4 nm and 42 emu·g-1, respectively. The Prussian blue test demonstrated that the heterostructure nanorods could be taken up by HepG2 cells, and cytotoxicity tests proved that the heterostructure nanorods had no significant effect on the viabilities of LO2 and HepG2 cells within 72 h in the range of 100-1600μg·ml-1. Therefore, magneticα-Fe2O3/Fe3O4heterostructure nanorods had better biocompatibility with LO2 and HepG2 cells.

Nanozymes with Peroxidase-like Activity for Ferroptosis-Driven Biocatalytic Nanotherapeutics of Glioblastoma Cancer: 2D and 3D Spheroids Models

Glioblastoma (GBM) is the most common primary brain cancer in adults. Despite the remarkable advancements in recent years in the realm of cancer diagnosis and therapy, regrettably, GBM remains the most lethal form of brain cancer. In this view, the fascinating area of nanotechnology has emerged as an innovative strategy for developing novel nanomaterials for cancer nanomedicine, such as artificial enzymes, termed nanozymes, with intrinsic enzyme-like activities. Therefore, this study reports for the first time the design, synthesis, and extensive characterization of innovative colloidal nanostructures made of cobalt-doped iron oxide nanoparticles chemically stabilized by a carboxymethylcellulose capping ligand (i.e., Co-MION), creating a peroxidase-like (POD) nanozyme for biocatalytically killing GBM cancer cells. These nanoconjugates were produced using a strictly green aqueous process under mild conditions to create non-toxic bioengineered nanotherapeutics against GBM cells. The nanozyme (Co-MION) showed a magnetite inorganic crystalline core with a uniform spherical morphology (diameter, 2R = 6-7 nm) stabilized by the CMC biopolymer, producing a hydrodynamic diameter (H_D) of 41-52 nm and a negatively charged surface (ZP~-50 mV). Thus, we created supramolecular water-dispersible colloidal nanostructures composed of an inorganic core (Cox-MION) and a surrounding biopolymer shell (CMC). The nanozymes confirmed the cytotoxicity evaluated by an MTT bioassay using a 2D culture in vitro of U87 brain cancer cells, which was concentration-dependent and boosted by increasing the cobalt-doping content in the nanosystems. Additionally, the results confirmed that the lethality of U87 brain cancer cells was predominantly caused by the production of toxic cell-damaging reactive oxygen species (ROS) through the in situ generation of hydroxyl radicals (·OH) by the peroxidase-like activity displayed by nanozymes. Thus, the nanozymes induced apoptosis (i.e., programmed cell death) and ferroptosis (i.e., lipid peroxidation) pathways by intracellular biocatalytic enzyme-like activity. More importantly, based on the 3D spheroids model, these nanozymes inhibited tumor growth and remarkably reduced the malignant tumor volume after the nanotherapeutic treatment (ΔV~40%). The kinetics of the anticancer activity of these novel nanotherapeutic agents decreased with the time of incubation of the GBM 3D models, indicating a similar trend commonly observed in tumor microenvironments (TMEs). Furthermore, the results demonstrated that the 2D in vitro model overestimated the relative efficiency of the anticancer agents (i.e., nanozymes and the DOX drug) compared to the 3D spheroid models. These findings are notable as they evidenced that the 3D spheroid model resembles more precisely the TME of "real" brain cancer tumors in patients than 2D cell cultures. Thus, based on our groundwork, 3D tumor spheroid models might be able to offer transitional systems between conventional 2D cell cultures and complex biological in vivo models for evaluating anticancer agents more precisely. These nanotherapeutics offer a wide avenue of opportunities to develop innovative nanomedicines for fighting against cancerous tumors and reducing the frequency of severe side effects in conventionally applied chemotherapy-based treatments.