Bioengineered Magnetoferritin Nanoprobes for Single-Dose Nuclear-Magnetic Resonance Tumor Imaging

Vertasile ferritin nanocages: Applications in detection and bioimaging

Food safety and human health remain significant concerns in the food industry. Detecting food contaminants and diagnosing diseases are critical aspects. Ferritin, an iron storage protein widely found in nature, offers unique advantages. Its hollow protein nanocage structure, distinct interfaces, hydrophobic or hydrophilic channels, and B-C loop regions recognized by transferrin receptor 1 make ferritin versatile for detecting heavy metals, free radicals, and bioimaging both in vitro and in vivo. This review summarizes ferritin's general characteristics, its specific properties as biosensors, and its applications in food safety and in vivo imaging. It emphasizes not only ferritin's role in detecting heavy metals like mercury and chemical hazards but also its potential in early diagnosing chronic diseases such as tumors, macrophages, and kidney diseases. Further research into ferritin promises advancements in enhancing food safety and improving human health diagnostics.

A New Age of Drug Delivery: A Comparative Perspective of Ferritin-Drug Conjugates (FDCs) and Antibody-Drug Conjugates (ADCs)

Ferritin-drug conjugates (FDCs) and antibody-drug conjugates (ADCs) respectively represent the innovative and traditional mainstream approaches in drug delivery systems, each offering unique advantages and challenges. This viewpoint delves into the evolving landscape of drug delivery technologies, specifically focusing on FDCs and ADCs. Each method exhibits unique advantages and inherent challenges, shaping their roles in therapeutic applications. The article provides a comparative analysis of two delivery systems, FDCs and ADCs, in terms of targeting accuracy, drug loading capacity, and the nature of the payload itself. This comparison offers valuable insights into the distinct advantages and disadvantages associated with each system, enabling a clearer understanding of their potential applications and limitations in therapeutic contexts. This analysis is crucial for optimizing the use of these delivery systems across varying medical contexts, offering a comprehensive overview of their impact on the field of drug delivery.

Current advance of nanotechnology in diagnosis and treatment for malignant tumors

Cancer remains a significant risk to human health. Nanomedicine is a new multidisciplinary field that is garnering a lot of interest and investigation. Nanomedicine shows great potential for cancer diagnosis and treatment. Specifically engineered nanoparticles can be employed as contrast agents in cancer diagnostics to enable high sensitivity and high-resolution tumor detection by imaging examinations. Novel approaches for tumor labeling and detection are also made possible by the use of nanoprobes and nanobiosensors. The achievement of targeted medication delivery in cancer therapy can be accomplished through the rational design and manufacture of nanodrug carriers. Nanoparticles have the capability to effectively transport medications or gene fragments to tumor tissues via passive or active targeting processes, thus enhancing treatment outcomes while minimizing harm to healthy tissues. Simultaneously, nanoparticles can be employed in the context of radiation sensitization and photothermal therapy to enhance the therapeutic efficacy of malignant tumors. This review presents a literature overview and summary of how nanotechnology is used in the diagnosis and treatment of malignant tumors. According to oncological diseases originating from different systems of the body and combining the pathophysiological features of cancers at different sites, we review the most recent developments in nanotechnology applications. Finally, we briefly discuss the prospects and challenges of nanotechnology in cancer.

Protein nanoparticles as drug delivery systems for cancer theranostics

Protein-based nanoparticles have garnered significant attention in theranostic applications due to their superior biocompatibility, exceptional biodegradability and ease of functionality. Compared to other nanocarriers, protein-based nanoparticles offer additional advantages, including biofunctionality and precise molecular recognition abilities, which make them highly effective in navigating complex biological environments. Moreover, proteins can serve as powerful tools with self-assembling structures and reagents that enhance cell penetration. And their derivation from abundant renewable sources and ability to degrade into harmless amino acids further enhance their suitability for biomedical applications. However, protein-based nanoparticles have so far not realized their full potential. In this review, we summarize recent advances in the use of protein nanoparticles in tumor diagnosis and treatment and outline typical methods for preparing protein nanoparticles. The review of protein nanoparticles may provide useful new insights into the development of biomaterial fabrication.

Pharmacological approaches for targeting lysosomes to induce ferroptotic cell death in cancer

Lysosomes are crucial organelles responsible for the degradation of cytosolic materials and bulky organelles, thereby facilitating nutrient recycling and cell survival. However, lysosome also acts as an executioner of cell death, including ferroptosis, a distinctive form of regulated cell death that hinges on iron-dependent phospholipid peroxidation. The initiation of ferroptosis necessitates three key components: substrates (membrane phospholipids enriched with polyunsaturated fatty acids), triggers (redox-active irons), and compromised defence mechanisms (GPX4-dependent and -independent antioxidant systems). Notably, iron assumes a pivotal role in ferroptotic cell death, particularly in the context of cancer, where iron and oncogenic signaling pathways reciprocally reinforce each other. Given the lysosomes' central role in iron metabolism, various strategies have been devised to harness lysosome-mediated iron metabolism to induce ferroptosis. These include the re-mobilization of iron from intracellular storage sites such as ferritin complex and mitochondria through ferritinophagy and mitophagy, respectively. Additionally, transcriptional regulation of lysosomal and autophagy genes by TFEB enhances lysosomal function. Moreover, the induction of lysosomal iron overload can lead to lysosomal membrane permeabilization and subsequent cell death. Extensive screening and individually studies have explored pharmacological interventions using clinically available drugs and phytochemical agents. Furthermore, a drug delivery system involving ferritin-coated nanoparticles has been specifically tailored to target cancer cells overexpressing TFRC. With the rapid advancements in understandings the mechanistic underpinnings of ferroptosis and iron metabolism, it is increasingly evident that lysosomes represent a promising target for inducing ferroptosis and combating cancer.

Ferritin-nanocaged aggregation-induced emission nanoaggregates for NIR-II fluorescence-guided noninvasive, controllable male contraception

Controllable contraception in male animals was demonstrated through the utilization of gold nanorods' photothermal effect to accomplish mild testicular hyperthermia. However, the challenges arising from testicular administration and the non-biodegradability of nanoparticles hinder further clinical implementation. Therefore, a straightforward, non-invasive, and enhanced contraception approach is required. This study explores the utilization of human heavy chain ferritin (HFn) nanocarriers loaded with aggregation-induced emission luminogens (AIEgens) for noninvasive, controllable male contraception guided by Near-Infrared-II (NIR-II) fluorescence imaging. The HFn-caged AIEgens (HFn@BBT) are delivered via intravenous injection and activated by near-infrared irradiation. Lower hyperthermia treatment induces partial damage to the testes and seminiferous tubules, reducing fertility indices by approximately 100% on the 7th day, which gradually recovers to 80% on the 60th day. Conversely, implementation of elevated hyperthermia therapy causes total destruction of both testes and seminiferous tubules, leading to a complete loss of fertility on the 60th day. Additionally, the use of AIEgens in NIR-II imaging offers improved fluorescence efficiency and penetration depth. The findings of this study hold significant promise for the advancement of safe and effective male contraceptive methods, addressing the need for noninvasive and controllable approaches to reproductive health and population control.

Heat sensitive E-helix cut ferritin nanocages for facile and high-efficiency loading of doxorubicin

Ferritin possesses a stable and uniform cage structure, along with tumor-targeting properties and excellent biocompatibility, making it a promising drug delivery vehicle. However, the current ferritin drug loading strategy involves complex steps and harsh reaction conditions, resulting in low yield and recovery of drug loading, which limits the clinical application prospects of ferritin nanomedicine. In this study, we utilized the high-efficiency heat-sensitivity of the multiple channel switch structures of the E-helix-cut ferritin mutant (Ecut-HFn) and Cu2+ assistance to achieve high-efficiency loading of chemotherapeutic drugs in a one-step process at low temperatures. This method features mild reaction conditions (45 °C), high loading efficiency (about 110 doxorubicin (Dox) per Ecut-HFn), and improved protein and Dox recovery rates (with protein recovery rate around 94 % and Dox recovery rate reaching up to 45 %). The prepared ferritin-Dox particles (Ecut-HFn-Cu-Dox) exhibit a uniform size distribution, good stability, and retain the natural tumor targeting ability of ferritin. Overall, this temperature-controlled drug loading strategy utilizing heat-sensitivity ferritin mutants is energy-saving, environmentally friendly, efficient, and easy to operate, offering a new perspective for scaling up the industrial production of ferritin drug carriers.

A novel view of ferritin in cancer

Since its discovery more than 85 years ago, ferritin has principally been known as an iron storage protein. However, new roles, beyond iron storage, are being uncovered. Novel processes involving ferritin such as ferritinophagy and ferroptosis and as a cellular iron delivery protein not only expand our thinking on the range of contributions of this protein but present an opportunity to target these pathways in cancers. The key question we focus on within this review is whether ferritin modulation represents a useful approach for treating cancers. We discussed novel functions and processes of this protein in cancers. We are not limiting this review to cell intrinsic modulation of ferritin in cancers, but also focus on its utility in the trojan horse approach in cancer therapeutics. The novel functions of ferritin as discussed herein realize the multiple roles of ferritin in cell biology that can be probed for therapeutic opportunities and further research.

Nanozymes and nanoflower: Physiochemical properties, mechanism and biomedical applications

Natural enzymes possess several drawbacks which limits their application in industries, wastewater remediation and biomedical field. Therefore, in recent years researchers have developed enzyme mimicking nanomaterials and enzymatic hybrid nanoflower which are alternatives of enzyme. Nanozymes and organic inorganic hybrid nanoflower have been developed which mimics natural enzymes functionalities such as diverse enzyme mimicking activities, enhanced catalytic activities, low cost, ease of preparation, stability and biocompatibility. Nanozymes include metal and metal oxide nanoparticles mimicking oxidases, peroxidases, superoxide dismutase and catalases while enzymatic and non-enzymatic biomolecules were used for preparing hybrid nanoflower. In this review nanozymes and hybrid nanoflower have been compared in terms of physiochemical properties, common synthetic routes, mechanism of action, modification, green synthesis and application in the field of disease diagnosis, imaging, environmental remediation and disease treatment. We also address the current challenges facing nanozyme and hybrid nanoflower research and the possible way to fulfil their potential in future.

Transferrin receptor 1 targeted nanomedicine for brain tumor therapy

Achieving effective drug delivery to traverse the blood-brain barrier (BBB) and target tumor cells remains the greatest challenge for brain tumor therapy. Importantly, the overexpressed membrane receptors on the brain endothelial cells, especially transferrin receptor 1 (TfR1), which mediate their ligands/antibodies to overcome the BBB by transcytosis, have been emerging as promising targets for brain tumor therapy. By employing ligands (e.g., transferrin, H-ferritin), antibodies or targeting peptides of TfR1 or aptamers, various functional nano-formulations have been developed in the last decade. These agents showed great potential for the treatment of brain diseases due to their ideal size, high loading capacity, controlled drug release and suitable pharmacokinetics. Herein, we summarize the latest advances on TfR1-targeted nanomedicine for brain tumor therapy. Moreover, we also discuss the strategies of improving stability, targeting ability and accumulation of nano-formulations in brain tumors for better outcomes. In this review, we hope to provide inspiration for the rational design of TfR1-targeted nanomedicine against brain tumors.

A clinically translatable kit for MRI/NMI dual-modality nanoprobes based on anchoring group-mediated radiolabeling

Magnetic resonance imaging (MRI)/nuclear medicine imaging (NMI) dual-modality imaging based on radiolabeled nanoparticles has been increasingly exploited for accurate diagnosis of tumor and cardiovascular diseases by virtue of high spatial resolution and high sensitivity. However, significant challenges exist in pursuing truly clinical applications, including massive preparation and rapid radiolabeling of nanoparticles. Herein, we report a clinically translatable kit for the convenient construction of MRI/NMI nanoprobes relying on the flow-synthesis and anchoring group-mediated radiolabeling (LAGMERAL) of iron oxide nanoparticles. First, homogeneous iron oxide nanoparticles with excellent performance were successfully obtained on a large scale by flow synthesis, followed by the surface anchoring of diphosphonate-polyethylene glycol (DP-PEG) to simultaneously render the underlying nanoparticles biocompatible and competent in robust labeling of radioactive metal ions. Moreover, to enable convenient and safe usage in clinics, the DP-PEG modified nanoparticle solution was freeze-dried and sterilized to make a radiolabeling kit followed by careful evaluations of its in vitro and in vivo performance and applicability. The results showed that ^99mTc labeled nanoprobes are effectively obtained with a labeling yield of over 95% in 30 minutes after simply injecting Na[^99mTcO₄] solution into the kit. In addition, the Fe₃O₄ nanoparticles sealed in the kit can well stand long-term storage even for 300 days without deteriorating the colloidal stability and radiolabeling yield. Upon intravenous injection of the as-prepared radiolabeled nanoprobes, high-resolution vascular images of mice were obtained by vascular SPECT imaging and magnetic resonance angiography, demonstrating the promising clinical translational value of our radiolabeling kit.

Synthesis of Amorphous/Crystalline Hetero-Phase Nanozymes With Peroxidase-Like Activity by Coordination-Driven Self-Assembly for Biosensors

Nanozymes and amorphous nanomaterials attract great attention owing to their extraordinary properties. However, the requirements for special synthesis conditions become the bottleneck of their development. Herein, a new strategy involving the DNA-based coordination-driven self-assembly is reported for the synthesis of a novel amorphous/crystalline hetero-phase nanozyme (Fe-DNA). For the synthesis of both nanozymes and amorphous materials, this strategy is simple and controllable, avoiding the traditionally employed harsh conditions. Benefitting from the amorphous structure and the superior physicochemical properties, the synthesized Fe-DNA nanozyme is subsequently found to exhibit a smaller Michaelis constant value for hydrogen peroxide (H₂ O₂ ) (0.81 mm) than that of horseradish peroxidase (HRP) (3.70 mm), demonstrating the stronger affinity of the Fe-DNA nanozyme toward H₂ O₂ . The Fe-DNA nanozyme also shows significant peroxidase-like activity but only negligible oxidase-like activity, a characteristic which releases the corresponding assay system from oxygen interference, thereby improving the performance of the nanozyme-based sensing platform. In addition, compared with other nanozymes, the novel Fe-DNA nanozyme is degradable via phosphate; thus, mitigating potential environmental threat. This work provides novel amorphous/crystalline hetero-phase nanozymes and opens a new avenue for the design of amorphous nanomaterials and nanozymes.

Ferritin - a multifaceted protein scaffold for biotherapeutics

The ferritin nanocage is an endogenous protein that exists in almost all mammals. Its hollow spherical structure that naturally stores iron ions has been diversely exploited by researchers in biotherapeutics. Ferritin has excellent biosafety profiles, and the nanosized particles exhibit rapid dispersion and controlled/sustained release pharmacokinetics. Moreover, the large surface-to-volume ratio and the disassembly/reassembly behavior of the 24 monomer subunits into a sphere allow diverse modifications by chemical and genetic methods on the surface and inner cage of ferritin. Here, we critically review ferritin and its applications. We (i) introduce the application of ferritin in drug delivery; (ii) present an overview of the use of ferritin in imaging and diagnosis for biomedical purposes; (iii) discuss ferritin-based vaccines; and (iv) review ferritin-based agents currently in clinical trials. Although there are no currently approved drugs based on ferritin, this multifunctional protein scaffold shows immense potential in drug development in diverse categories, and ferritin-based drugs have recently entered phase I clinical trials. This golden shortlist of recent developments will be of immediate benefit and interest to researchers studying ferritin and other protein-based biotherapeutics.

Application Perspectives of Nanomedicine in Cancer Treatment

Cancer is a disease that seriously threatens human health. Based on the improvement of traditional treatment methods and the development of new treatment modes, the pattern of cancer treatment is constantly being optimized. Nanomedicine plays an important role in these evolving tumor treatment modalities. In this article, we outline the applications of nanomedicine in three important tumor-related fields: chemotherapy, gene therapy, and immunotherapy. According to the current common problems, such as poor targeting of first-line chemotherapy drugs, easy destruction of nucleic acid drugs, and common immune-related adverse events in immunotherapy, we discuss how nanomedicine can be combined with these treatment modalities, provide typical examples, and summarize the advantages brought by the application of nanomedicine.

Potential of Ferritin-Based Platforms for Tumor Immunotherapy

Ferritin is an iron storage protein that plays a key role in iron homeostasis and cellular antioxidant activity. Ferritin has many advantages as a tumor immunotherapy platform, including a small particle size that allows for penetration into tumor-draining lymph nodes or tumor tissue, a unique structure consisting of 24 self-assembled subunits, cavities that can encapsulate drugs, natural targeting functions, and a modifiable outer surface. In this review, we summarize related research applying ferritin as a tumor immune vaccine or a nanocarrier for immunomodulator drugs based on different targeting mechanisms (including dendritic cells, tumor-associated macrophages, tumor-associated fibroblasts, and tumor cells). In addition, a ferritin-based tumor vaccine expected to protect against a wide range of coronaviruses by targeting multiple variants of SARS-CoV-2 has entered phase I clinical trials, and its efficacy is described in this review. Although ferritin is already on the road to transformation, there are still many difficulties to overcome. Therefore, three barriers (drug loading, modification sites, and animal models) are also discussed in this paper. Notwithstanding, the ferritin-based nanoplatform has great potential for tumor immunotherapy, with greater possibility of clinical transformation.

Advancements in cell membrane camouflaged nanoparticles: A bioinspired platform for cancer therapy

The idea of employing natural cell membranes as a coating medium for nanoparticles (NPs) endows man-made vectors with natural capabilities and benefits. In addition to retaining the physicochemical characteristics of the NPs, the biomimetic NPs also have the functionality of source cell membranes. It has emerged as a promising approach to enhancing the properties of NPs for drug delivery, immune evasion, imaging, cancer-targeting, and phototherapy sensitivity. Several studies have been reported with a multitude of approaches to reengineering the surface of NPs using biological membranes. Owing to their low immunogenicity and intriguing biomimetic properties, cell-membrane-based biohybrid delivery systems have recently gained a lot of interest as therapeutic delivery systems. This review summarises different kinds of biomimetic NPs reported so far, their fabrication aspects, and their application in the biomedical field. Finally, it briefs on the latest advances available in this biohybrid concept.

Nanotechnology for Cardiovascular Diseases

Cardiovascular diseases have become the major killers in today's world, among which coronary artery diseases (CADs) make the greatest contributions to morbidity and mortality. Although state-of-the-art technologies have increased our knowledge of the cardiovascular system, the current diagnosis and treatment modalities for CADs still have limitations. As an emerging cross-disciplinary approach, nanotechnology has shown great potential for clinical use. In this review, recent advances in nanotechnology in the diagnosis of CADs will first be elucidated. Both the sensitivity and specificity of biosensors for biomarker detection and molecular imaging strategies, such as magnetic resonance imaging, optical imaging, nuclear scintigraphy, and multimodal imaging strategies, have been greatly increased with the assistance of nanomaterials. Second, various nanomaterials, such as liposomes, polymers (PLGA), inorganic nanoparticles (AuNPs, MnO₂, etc.), natural nanoparticles (HDL, HA), and biomimetic nanoparticles (cell-membrane coating) will be discussed as engineered as drug (chemicals, proteins, peptides, and nucleic acids) carriers targeting pathological sites based on their optimal physicochemical properties and surface modification potential. Finally, some of these nanomaterials themselves are regarded as pharmaceuticals for the treatment of atherosclerosis because of their intrinsic antioxidative/anti-inflammatory and photoelectric/photothermal characteristics in a complex plaque microenvironment. In summary, novel nanotechnology-based research in the process of clinical transformation could continue to expand the horizon of nanoscale technologies in the diagnosis and therapy of CADs in the foreseeable future.

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Nanotechnology represents new viable approaches for diagnosis and treatment of cardiovascular diseases, the leading cause of morbidity and mortality worldwide

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Nanotechnology-assisted biosensing and molecular imaging can improve the sensitivity and specificity in the diagnosis of cardiovascular diseases

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Nanomaterials enable targeted drug delivery or directly exert therapeutic action for cardiovascular system, based on their physicochemical properties and surface modification

Nanomedicine Strategies to Circumvent Intratumor Extracellular Matrix Barriers for Cancer Therapy

The dense and heterogeneous physical network of the extracellular matrix (ECM) in tumors represents a formidable barrier that limits intratumor drug delivery and the therapeutic efficacy of many anticancer therapies. Here, the two major nanomedicine strategies to circumvent intratumor ECM barriers: regulating the physiochemical properties of nanomedicines and remodeling the components and structure of the ECM are summarized. Nanomedicines can be rationally regulated by optimizing physiochemical properties or designed with biomimetic features to promote ECM permeation capability. Meanwhile, they can also be designed to remodel the ECM by modulating signaling pathways or destroying the components and architecture of the ECM via chemical, biological, or physical treatments. These efforts produce profound improvements in intratumor drug delivery and anticancer efficacy. Moreover, to aid in their anticancer efficacy, feasible approaches for improving ECM-circumventing nanomedicines are proposed.

Anchoring Group Mediated Radiolabeling for Achieving Robust Nanoimaging Probes

Radiolabeling counts for much in the functionalization of inorganic nanoparticles (NPs) because it endows NPs with high-sensitive imaging capacities apart from providing accurate pharmacokinetic information on the labeled particles, which makes the development of relevant radiolabeling chemistry highly desirable. Herein, a novel Ligand Anchoring Group MEdiated RAdioLabeling (LAGMERAL) method is reported, in which a polyethylene glycol (PEG) ligand with a diphosphonate (DP) terminal group plays a key role. It offers possibilities to radiolabel NPs through the spare coordination sites of the DP anchoring group. Through X-ray absorption spectroscopy studies, the coordination states of the foreign metal ions on the particle surface are investigated. In addition, radioactive Fe₃ O₄ NPs are prepared by colabeling the particles with ¹²⁵ I at the outskirt of the particles through a phenolic hydroxyl moiety of the PEG ligand, and ^99m Tc at the root of the ligand, respectively. In this way, the stabilities of these types of radiolabeling are compared both in vitro and in vivo to show the advantages of the LAGMERAL method. The outstanding stability of probe and simplicity of the labeling process make the current approach universal for creating advanced NPs with different combinations of functionalities of the inorganic NPs and radioactive properties of the metal radioisotopes.

The Impact of Redox, Hydrolysis and Dehydration Chemistry on the Structural and Magnetic Properties of Magnetoferritin Prepared in Variable Thermal Conditions

Ferritin, a spherically shaped protein complex, is responsible for iron storage in bacteria, plants, animals, and humans. Various ferritin iron core compositions in organisms are associated with specific living requirements, health state, and different biochemical roles of ferritin isomers. Magnetoferritin, a synthetic ferritin derivative, serves as an artificial model system of unusual iron phase structures found in humans. We present the results of a complex structural study of magnetoferritins prepared by controlled in vitro synthesis. Using various complementary methods, it was observed that manipulation of the synthesis technology can improve the physicochemical parameters of the system, which is useful in applications. Thus, a higher synthesis temperature leads to an increase in magnetization due to the formation of the magnetite phase. An increase in the iron loading factor has a more pronounced impact on the protein shell structure in comparison with the pH of the aqueous medium. On the other hand, a higher loading factor at physiological temperature enhances the formation of an amorphous phase instead of magnetite crystallization. It was confirmed that the iron-overloading effect alone (observed during pathological events) cannot contribute to the formation of magnetite.

Iron, Copper, and Zinc Homeostasis: Physiology, Physiopathology, and Nanomediated Applications

Understanding of how the human organism functions has preoccupied researchers in medicine for a very long time. While most of the mechanisms are well understood and detailed thoroughly, medicine has yet much to discover. Iron (Fe), Copper (Cu), and Zinc (Zn) are elements on which organisms, ranging from simple bacteria all the way to complex ones such as mammals, rely on these divalent ions. Compounded by the continuously evolving biotechnologies, these ions are still relevant today. This review article aims at recapping the mechanisms involved in Fe, Cu, and Zn homeostasis. By applying the knowledge and expanding on future research areas, this article aims to shine new light of existing illness. Thanks to the expanding field of nanotechnology, genetic disorders such as hemochromatosis and thalassemia can be managed today. Nanoparticles (NPs) improve delivery of ions and confer targeting capabilities, with the potential for use in treatment and diagnosis. Iron deficiency, cancer, and sepsis are persisting major issues. While targeted delivery using Fe NPs can be used as food fortifiers, chemotherapeutic agents against cancer cells and microbes have been developed using both Fe and Cu NPs. A fast and accurate means of diagnosis is a major impacting factor on outcome of patients, especially when critically ill. Good quality imaging and bed side diagnostic tools are possible using NPs, which may positively impact outcome.

Cargo loading within ferritin nanocages in preparation for tumor-targeted delivery

Ferritins are spherical iron storage proteins within cells, composed of 24 subunits of two types, heavy-chain ferritin (HFn) and light-chain ferritin. Ferritins auto-assemble naturally into hollow nanocages with an outer diameter of 12 nm and an interior cavity 8 nm in diameter. Since the intrinsic tumor-targeting property of human HFn was first reported in 2012, HFn has been extensively explored for tumor-targeted delivery of anticancer drugs and diagnostic molecules, including radioisotopes and fluorophores, as well as inorganic nanoparticles (NPs) and chemotherapeutic drugs. This protocol provides four detailed procedures describing how to load four types of cargoes within HFn nanocages that are capable of accurately controlling cargo loading: synthesis of inorganic metal nanoparticles within the cavity of a wild-type human HFn nanocage (Procedure 1, requires ~5 h); loading of doxorubicin into the cavity of a wild-type human HFn nanocage (Procedure 2, requires ~3 d); loading Gd3+ into the cavity of a genetically engineered human HFn nanocage (Procedure 3, requires ~20 h); and loading 64Cu2+ radioisotope into the cavity of a genetically engineered human HFn nanocage (Procedure 4, requires ~3 h). Subsequent use of these HFn-based formulations is advantageous as they have intrinsic tumor-targeting capability and lack immunogenicity. Human HFn generated as described in this protocol can therefore be used to deliver therapeutic drugs and diagnostic signals as multifunctional nanomedicines.

Ferritin: A Multifunctional Nanoplatform for Biological Detection, Imaging Diagnosis, and Drug Delivery

Ferritins are spherical iron storage proteins within cells that are composed of a combination of 24 subunits of two types, heavy-chain ferritin (HFn) and light-chain ferritin (LFn). They autoassemble naturally into a spherical hollow nanocage with an outer diameter of 12 nm and an interior cavity that is 8 nm in diameter. In recent years, with the constantly emerging safety issues and the concerns about unfavorable uniformity and indefinite in vivo behavior of traditional nanomedicines, the characteristics of native ferritin nanocages, such as the unique nanocage structure, excellent safety profile, and definite in vivo behavior, make ferritin-based formulations uniquely attractive for nanomedicine development. To date, a variety of cargo molecules, including therapeutic drugs (e.g., cisplatin, carboplatin, paclitaxel, curcumin, atropine, quercetin, gefitinib, daunomycin, epirubicin, doxorubicin, etc.), imaging agents (e.g., fluorescence dyes, radioisotopes, and MRI contrast agents), nucleic acids (e.g., siRNA and miRNA), and metal nanoparticles (e.g., Fe₃O₄, CeO₂, AuPd, CuS, CoPt, FeCo, Ag, etc.) have been loaded into the interior cavity of ferritin nanocages for a broad range of biomedical applications from in vitro biosensing to targeted delivery of cargo molecules in living systems with the aid of modified targeting ligands either genetically or chemically. We reported that human HFn could selectively deliver a large amount of cargo into tumors in vivo via transferrin receptor 1 (TfR1)-mediated tumor-cell-specific targeting followed by rapid internalization. By the use of the intrinsic tumor-targeting property and unique nanocage structure of human HFn, a broad variety of cargo-loaded HFn formulations have been developed for biological analysis, imaging diagnosis, and medicine development. In view of the intrinsic tumor-targeting property, unique nanocage structure, lack of immunogenicity, and definite in vivo behavior, human HFn holds promise to promote therapeutic drugs, diagnostic imaging agents, and targeting moieties into multifunctional nanomedicines.Since the report of the intrinsic tumor-targeting property of human HFn, we have extensively explored human HFn as an ideal nanocarrier for tumor-targeted delivery of anticancer drugs, MRI contrast agents, inorganic nanoparticles, and radioisotopes. In particular, by the use of genetic tools, we also have genetically engineered human HFn nanocages to recognize a broader range of disease biomarkers. In this Account, we systematically review human ferritins from characterizing their tumor-binding property and understanding their mechanism and kinetics for cargo loading to exploring their biomedical applications. We finally discuss the prospect of ferritin-based formulations to become next-generation nanomedicines. We expect that ferritin formulations with unique physicochemical characteristics and intrinsic tumor-targeting property will attract broad interest in fundamental drug research and offer new opportunities for nanomedicine development.

Ferritin nanocage: A promising and designable multi-module platform for constructing dynamic nanoassembly-based drug nanocarrier

Ferritin has been widely recognized as an ideal drug delivery vehicle owing to its unique cage-like structure. Coupled with intrinsic targeting ability and excellent biosafety, ferritin-based drug delivery system, recently coined as ferritin drug carrier (FDC), has sparked great interest among researchers and shown promising application potential in the biomedical field. However, the flexibility and accuracy of traditional FDCs are limited when facing with complex disease microenvironments. To meet the fast-growing requirements for precision medicine, ferritin can serve as a designable multi-module platform to fabricate smarter FDC, which we introduce here as dynamic nanoassembly-based ferritin drug carrier (DNFDC). Compared to conventional FDC, DNFDCs directly integrate required functions into their nanostructure, which can achieve dynamic transformation upon stimuli to specifically activate and exert therapeutic functions at targeted sites. In this review, we summarize the superior characteristics of ferritin that contribute to the on-demand design of DNFDC and outline the current advances in DNFDC. Moreover, the potential research directions and challenges are also discussed here. Hopefully, this review may inspire the future development of DNFDC.

Ferritin nanocages for early theranostics of tumors via inflammation-enhanced active targeting

Engineered nanocarriers have been widely developed for tumor theranostics. However, the delivery of imaging probes or therapeutic drugs to the tumor pre-formation site for early and accurate detection and therapy remains a major challenge. Here, by using tailor-functionalized human H-ferritin (HFn), we developed a triple-modality nanoprobe IRdye800-M-HFn and achieved the early imaging of tumor cells before the formation of solid tumor tissues. Then, we developed an HFn-doxorubicin (Dox) drug delivery system by loading Dox into the HFn protein cage and achieved early-stage tumor therapy. The intravenous injection of HFn nanoprobes enabled the imaging of tumor cells as early as two days after tumor implantation, and the triple-modality imaging techniques, namely, near-infrared fluorescence molecular imaging (NIR-FMI), magnetic resonance imaging (MRI), and photoacoustic imaging (PAI), ensured the accuracy of detection. Further exploration indicated that HFn could specifically penetrate into pre-solid tumor sites by tumor-associated inflammation-mediated blood vessel leakage, followed by effective accumulation in tumor cells by the specific targeting property of HFn to transferrin receptor 1. Thus, the HFn-Dox drug delivery system delivered Dox into the tumor pre-formation site and effectively killed tumor cells at early stage. IRDye800-M-HFn nanoprobes and HFn-Dox provide promising strategies for early-stage tumor diagnosis and constructive implications for early-stage tumor treatment.

Artificially engineered antiferromagnetic nanoprobes for ultra-sensitive histopathological level magnetic resonance imaging

Histopathological level imaging in a non-invasive manner is important for clinical diagnosis, which has been a tremendous challenge for current imaging modalities. Recent development of ultra-high-field (UHF) magnetic resonance imaging (MRI) represents a large step toward this goal. Nevertheless, there is a lack of proper contrast agents that can provide superior imaging sensitivity at UHF for disease detection, because conventional contrast agents generally induce T2 decaying effects that are too strong and thus limit the imaging performance. Herein, by rationally engineering the size, spin alignment, and magnetic moment of the nanoparticles, we develop an UHF MRI-tailored ultra-sensitive antiferromagnetic nanoparticle probe (AFNP), which possesses exceptionally small magnetisation to minimize T2 decaying effect. Under the applied magnetic field of 9 T with mice dedicated hardware, the nanoprobe exhibits the ultralow r2/r1 value (~1.93), enabling the sensitive detection of microscopic primary tumours (<0.60 mm) and micrometastases (down to 0.20 mm) in mice. The sensitivity and accuracy of AFNP-enhanced UHF MRI are comparable to those of the histopathological examination, enabling the development of non-invasive visualization of previously undetectable biological entities critical to medical diagnosis and therapy.

Apoferritin-Engineered Nanoprobe for Tumor-Targeted Triple-NIR Imaging and Phototherapy

Considering that pathological hallmarks are directly related to structural and chemical information of tumor, noninvasive, real-time, spatially resolved quantitative chemical imaging is significant for treatment decisions. The discovery of the transparency window of biological tissues and the advancement of near-infrared technology provide exciting prospects for in vivo imaging. Herein, an engineering apoferritin-conjugated cypate nanoprobe is fabricated for near-infrared photoacoustic imaging and fluorescence imaging in the first and second window. As the analogue of indocyanine green, dicarboxylic cypate is directly conjugated with the apoferritin molecules for forming assembly nanoprobes. Resulting from the intrinsic targeting and optical capacity of the nanoprobes, the triple near-infrared imaging can perform multimeasurements of the target analyte in real-time. This imaging methodology not only provides the structural background information of the tumor, each pixel also contains quantitative in situ information of the tumor. In particular, part of the absorbed light energy is released as heat energy in the near-infrared photoacoustic imaging process. The constructed triple near-infrared nanoprobes therefore naturally navigate the photothermal treatment plan of tumor and finally realize the efficient assistance of tumor photothermal ablation. The tumor metabolomics reveal that the nanoprobe-assisted tumor ablation has a potential mechanism toward glutamine- and phenylalanine-related metabolism perturbation and the disordered oxidative stress state. The tumor-specific bioconjugate nanoprobes hold great potential as a versatile theranostic platform for tumor imaging and therapy.

Glyconanofluorides as Immunotracers with a Tunable Core Composition for Sensitive Hotspot Magnetic Resonance Imaging of Inflammatory Activity

Nature-inspired nanosized formulations based on an imageable, small-sized inorganic core scaffold, on which biomolecules are assembled to form nanobiomimetics, hold great promise for both early diagnostics and developed therapeutics. Nevertheless, the fabrication of nanobiomimetics that allow noninvasive background-free mapping of pathological events with improved sensitivity, enhanced specificity, and multiplexed capabilities remains a major challenge. Here, we introduce paramagnetic glyconanofluorides as small-sized (<10 nm) glycomimetics for immunotargeting and sensitive noninvasive in vivo19F magnetic resonance imaging (MRI) mapping of inflammation. A very short T1 relaxation time (70 ms) of the fluorides was achieved by doping the nanofluorides' solid crystal core with paramagnetic Sm3+, resulting in a significant 8-fold enhancement in their 19F MRI sensitivity, allowing faster acquisition and improved detectability levels. The fabricated nanosized glycomimetics exhibit significantly enhanced uptake within activated immune cells, providing background-free in vivo mapping of inflammatory activity, demonstrated in both locally induced inflammation and clinically related neuropathology animal models. Fabricating two types of nanofluorides, each with a distinct chemical shift, allowed us to exploit the color-like features of 19F MRI to map, in real time, immune specificity and preferred targetability of the paramagnetic glyconanofluorides, demonstrating the approach's potential extension to noninvasive multitarget imaging scenarios that are not yet applicable for nanobiomimetics based on other nanocrystal cores.

Biomimetic magnetofluorescent ferritin nanoclusters for magnetic resonance and fluorescence-dual modal imaging and targeted tumor therapy

Multiple imaging by combining magnetic resonance (MR) and fluorescence imaging into a single nanosystem displays distinctive merits, which is desirable for precise in vivo imaging. In this work, we proposed a new tumor-targeting dual-modal diagnosis strategy by designing and fabricating a biocompatible nano-erythrocyte and successfully delivering it into in vivo tumors. The novel nano-contrast agent (CMR) was prepared by encapsulating human heavy-chain ferritin (HFn) nanoparticles with Cy5.5 binding and mineralized iron oxide nanoparticles (Fe3O4 NPs) into erythrocyte membranes (RBCs). We demonstrated that the as-prepared CMR displayed excellent biocompatibility with low hepatotoxicity and long blood circulation time. More importantly, by functionalizing the CMR with different types of targeting moieties, the nanosystem could precisely target both subcutaneous and orthotopic tumors, and exhibited excellent MR and fluorescence dual-model imaging ability. Moreover, we demonstrated that the CMR was able to modulate the tumor microenvironment to achieve an efficient antitumor effect.

In vivo guiding inorganic nanozymes for biosensing and therapeutic potential in cancer, inflammation and microbial infections

Researchers have recently introduced some artificial enzymes based on nanomaterials that show significant catalytic activity relative to native enzymes called nanozyme. These nanozymes show superior performance than conventional catalysts and are considered as fascinating candidates for introducing the next generation of biomaterials in various industrial and biomedical fields. Recently, nanozymes have received a great deal of attention in biomedical applications due to their potential properties such as long-term stability, low cost, mass production capability, and controllable catalytic activity. Due to the intrinsic catalytic activity of nanoparticles (NPs) as nanozymes and their ability to be regulated in biomedical processes, this review paper focuses on the in vivo applications of nanozymes in biosensing and therapeutic activities. Despite the challenges and benefits of each approach, this paper attempts to provide an appropriate motivation for the classification of different nanozymes followed by their application in biomedical activities including in vivo biosensing and therapeutic potential in cancer, inflammation and microbial infections. Finally, some ongoing challenges and future perspective of nanozymes in biomedical application were surveyed. In conclusion, this paper may provide useful information regarding the development of nanozymes as promising platforms in biomedical settings due to expedited diagnosis, the advancement of multifactorial therapies and their pronounced stability.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Raman Imaging: An Impending Approach Towards Cancer Diagnosis

In accordance with the recent studies, Raman spectroscopy is well experimented as a highly sensitive analytical and imaging technique in biomedical research, mainly for various disease diagnosis including cancer. In comparison with other imaging modalities, Raman spectroscopy facilitate numerous assistances owing to its low background signal, immense spatial resolution, high chemical specificity, multiplexing capability, excellent photo stability and non-invasive detection capability. In cancer diagnosis Raman imaging intervened as a promising investigative tool to provide molecular level information to differentiate the cancerous vs non-cancerous cells, tissues and even in body fluids. Anciently, spontaneous Raman scattering is very feeble due to its low signal intensity and long acquisition time but new advanced techniques like coherent Raman scattering (CRS) and surface enhanced Raman scattering (SERS) gradually superseded these issues. So, the present review focuses on the recent developments and applications of Raman spectroscopy-based imaging techniques for cancer diagnosis.

Ultra-small gold nanoparticles self-assembled by gadolinium ions for enhanced photothermal/photodynamic liver cancer therapy

Gold nanomaterials are widely used in biomedical research as drug delivery systems, imaging agents and therapeutic materials owing to their unique physicochemical properties and high biocompatibility. In this study, we prepared ultra-small gold nanoparticles (AuNPs) and induced them with gadolinium ions to form a spherical self-assembly. The nanoparticles were coupled with matrix metalloproteinase-2 (MMP-2) and loaded with the photosensitive drug IR820 for photothermal/photodynamic combination therapy of liver cancer. The formed nanoprobes were metabolised in vivo via degradation under dual-mode real-time imaging because of their acid response degradation characteristics. In addition, the nanoprobe showed excellent tumour-targeting ability due to the presence of surface-modified MMP-2. In vivo treatment experiments revealed that the nanoprobes achieved enhanced photodynamic/photothermal combination therapy under laser irradiation and significantly inhibited tumour growth. Therefore, the nanoprobes have great potential for anti-tumour therapy guided by dual-mode real-time imaging of liver cancer.

Polypeptide-Based Theranostics with Tumor-Microenvironment-Activatable Cascade Reaction for Chemo-ferroptosis Combination Therapy

Nanoengineering of polymer-based therapeutic carriers is promising for precise cancer treatment. Herein, we report the fabrication of polypeptide vehicles encapsulated with anticancer drug of cisplatin (Pt drug) and Fe₃O₄ nanoparticles (denoted as Pt&Fe₃O₄@PP) as theranostics for T₂-weighted magnetic resonance imaging (MRI)-guided chemo-ferroptosis combination therapy. The number of Fe₃O₄ nanoparticles per polypeptide vehicle is well controlled by adjusting the added amount of Fe₃O₄ nanoparticles. The tumor microenvironment can trigger the release of Pt drug and Fe^2/3+, which could induce the intracellular cascade reaction to generate sufficient ^•OH for ferroptosis therapy. Moreover, the released Pt drug can cause the apoptosis of tumor cells. Meanwhile, the encapsulated Fe₃O₄ nanoparticles can also be used for T₂-weighted MRI of tumor. Both in vitro and in vivo results indicate that the reported Pt&Fe₃O₄@PP can efficiently inhibit cancer cell growth without causing significant systemic toxicity. Importantly, polypeptide vehicles could significantly reduce the side effect of free Pt drug in vivo and therefore improve the drug delivery efficacy. Our findings suggest that polypeptide-based theranostics with tumor-microenvironment-activatable cascade reaction have great potential in biomedical applications.

Mild Acid-Responsive "Nanoenzyme Capsule" Remodeling of the Tumor Microenvironment to Increase Tumor Penetration

Dense extracellular matrix (ECM) severely impedes the spread of drugs in solid tumors and induces hypoxia, reducing chemotherapy efficiency. Different proteolytic enzymes, such as collagenase (Col) or bromelain, can directly attach to the surface of nanoparticles and improve their diffusion, but the method of ligation may also impair the enzymatic activity due to conformational changes or blockage of the active site. Herein, a "nanoenzyme capsule" was constructed by combining collagenase nanocapsules (Col-nc) with heavy-chain ferritin (HFn) nanocages encapsulating the chemotherapy drug doxorubicin (DOX) to enhance tumor penetration of the nanoparticles by hydrolyzing collagen from the ECM. Col-nc could protect the activity of the enzyme before reaching the site of action while being degraded under mildly acidic conditions in tumors, and the released proteolytic enzyme could digest collagen. In addition, HFn as a carrier could effectively load DOX and had a self-targeting ability, enabling the nanoparticles to internalize into cancer cells more effectively. From in vivo and in vitro studies, we found that collagen was effectively degraded by Col-nc/HFn(DOX) to increase the accumulation and penetration of nanoparticles in the solid tumor site and could alleviate hypoxia inside the tumor to enhance the antitumor effects of DOX. Therefore, the strategy of increasing nanoparticle penetration in this system is expected to provide a potential approach for the clinical treatment of solid tumors.

Ligand-Installed Nanocarriers toward Precision Therapy

Development of drug-delivery systems that selectively target neoplastic cells has been a major goal of nanomedicine. One major strategy for achieving this milestone is to install ligands on the surface of nanocarriers to enhance delivery to target tissues, as well as to enhance internalization of nanocarriers by target cells, which improves accuracy, efficacy, and ultimately enhances patient outcomes. Herein, recent advances regarding the development of ligand-installed nanocarriers are introduced and the effect of their design on biological performance is discussed. Besides academic achievements, progress on ligand-installed nanocarriers in clinical trials is presented, along with the challenges faced by these formulations. Lastly, the future perspectives of ligand-installed nanocarriers are discussed, with particular emphasis on their potential for emerging precision therapies.

Nanozymes: A New Disease Imaging Strategy

Nanozymes are nanomaterials with intrinsic enzyme-like properties. They can specifically catalyze substrates of natural enzymes under physiological condition with similar catalytic mechanism and kinetics. Compared to natural enzymes, nanozymes exhibit the unique advantages including high catalytic activity, low cost, high stability, easy mass production, and tunable activity. In addition, as a new type of artificial enzymes, nanozymes not only have the enzyme-like catalytic activity, but also exhibit the unique physicochemical properties of nanomaterials, such as photothermal properties, superparamagnetism, and fluorescence, etc. By combining the unique physicochemical properties and enzyme-like catalytic activities, nanozymes have been widely developed for in vitro detection and in vivo disease monitoring and treatment. Here we mainly summarized the applications of nanozymes for disease imaging and detection to explore their potential application in disease diagnosis and precision medicine.

Protein-based nanoplatforms for tumor imaging and therapy

Cancer is one of the leading causes of death all over the world. The development of nanoplatform provides a promising strategy for the diagnosis and treatment of cancer. As the foundation of the nanoplatform, the composition of nanocarrier decides the basic properties. Protein exists in all kinds of life and participates in any life activities, having great potentials to serve as a nanocarrier because of its excellent biocompatibility, abundance of functional groups, and inherent biological activity. As a result, protein-based nanoplatforms have evoked extensive interests for tumor imaging and therapy. This review presents the latest progresses on the advancement of protein-based nanoplatforms, introducing the most common protein nanocarriers (such as human/bovine serum albumin, ferritin, human transferrin) thoroughly including their physiochemical properties and specific applications. Also, other kinds of protein are briefly involved. Finally, the prospects and challenges of the development of protein-based nanoplatforms are summarized. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Fenozyme Protects the Integrity of the Blood-Brain Barrier against Experimental Cerebral Malaria

Cerebral malaria is a lethal complication of malaria infection characterized by central nervous system dysfunction and is often not effectively treated by antimalarial combination therapies. It has been shown that the sequestration of the parasite-infected red blood cells that interact with cerebral vessel endothelial cells and the damage of the blood-brain barrier (BBB) play critical roles in the pathogenesis. In this study, we developed a ferritin nanozyme (Fenozyme) composed of recombinant human ferritin (HFn) protein shells that specifically target BBB endothelial cells (BBB ECs) and the inner Fe₃O₄ nanozyme core that exhibits reactive oxygen species-scavenging catalase-like activity. In the experimental cerebral malaria (ECM) mouse model, administration of the Fenozyme, but not HFn, markedly ameliorated the damage of BBB induced by the parasite and improved the survival rate of infected mice significantly. Further investigations found that Fenozyme, as well as HFn, was able to polarize the macrophages in the liver to the M1 phenotype and promote the elimination of malaria in the blood. Thus, the catalase-like activity of the Fenozyme is required for its therapeutic effect in the mouse model. Moreover, the Fenozyme significantly alleviated the brain inflammation and memory impairment in ECM mice that had been treated with artemether, indicating that combining Fenozyme with an antimalarial drug is a novel strategy for the treatment of cerebral malaria.

Recent Trends of the Bio-Inspired Nanoparticles in Cancer Theranostics

In recent years, various nanomaterials have emerged as an exciting tool in cancer theranostic applications due to their multifunctional property and intrinsic molecular property aiding effective diagnosis, imaging, and successful therapy. However, chemically synthesized nanoparticles have several issues related to the cost, toxicity and effectiveness. In this context, bio-inspired nanoparticles (NPs) held edges over conventionally synthesized nanoparticles due to their low cost, easy synthesis and low toxicity. In this present review article, a detailed overview of the cancer theranostics applications of various bio-inspired has been provided. This includes the recent examples of liposomes, lipid nanoparticles, protein nanoparticles, inorganic nanoparticles, and viral nanoparticles. Finally, challenges and the future scopes of these NPs in cancer therapy and diagnostics applications are highlighted.

Nanozymes: From New Concepts, Mechanisms, and Standards to Applications

Nanozymes are nanomaterials with intrinsic enzyme-like characteristics that have been booming over the past decade because of their capability to address the limitations of natural enzymes such as low stability, high cost, and difficult storage. Along with the rapid development and ever-deepening understanding of nanoscience and nanotechnology, nanozymes hold promise to serve as direct surrogates of traditional enzymes by mimicking and further engineering the active centers of natural enzymes. In 2007, we reported the first evidence that Fe₃O₄ nanoparticles (NPs) have intrinsic peroxidase-mimicking activity, and since that time, hundreds of nanomaterials have been found to mimic the catalytic activity of peroxidase, oxidase, catalase, haloperoxidase, glutathione peroxidase, uricase, methane monooxygenase, hydrolase, and superoxide dismutase. Uniquely, a broad variety of nanomaterials have been reported to simultaneously exhibit dual- or multienzyme mimetic activity. For example, Fe₃O₄ NPs show pH-dependent peroxidase-like and catalase-like activities; Prussian blue NPs simultaneously possess peroxidase-, catalase-, and superoxide dismutase-like activity; and Mn₃O₄ NPs mimic all three cellular antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxidase. Taking advantage of the physiochemical properties of nanomaterials, nanozymes have shown a broad range of applications from in vitro detection to replacing specific enzymes in living systems. With the emergence of the new concept of "nanozymology", nanozymes have now become an emerging new field connecting nanotechnology and biology. Since the landmark paper on nanozymes was published in 2007, we have extensively explored their catalytic mechanism, established the corresponding standards to quantitatively determine their catalytic activities, and opened up a broad range of applications from biological detection and environmental monitoring to disease diagnosis and biomedicine development. Here we mainly focus on our progress in the systematic design and construction of functionally specific nanozymes, the standardization of nanozyme research, and the exploration of their applications for replacing natural enzymes in living systems. We also show that, by combining the unique physicochemical properties and enzyme-like catalytic activities, nanozymes can offer a variety of multifunctional platforms with a broad of applications from in vitro detection to in vivo monitoring and therapy. For instance, targeting antibody-conjugated ferromagnetic nanozymes simultaneously provide three functions: target capture, magnetic separation, and nanozyme color development for target detection. We finally will address the prospect of nanozyme research to become "nanozymology". We expect that nanozymes with unique physicochemical properties and intrinsic enzyme-mimicking catalytic properties will attract broad interest in both fundamental research and practical applications and offer new opportunities for traditional enzymology.

Ferritin variants: inspirations for rationally designing protein nanocarriers

Ferritin, a natural iron storage protein, is endowed with a unique structure, the ability to self-assemble and excellent physicochemical properties. Beyond these, genetic manipulation can easily tune the structure and functions of ferritin nanocages, which further expands the biomedical applications of ferritin. Here, we focus on human H-ferritin, a recently discovered ligand of transferrin receptor 1, to review its derived variants and related structures and properties. We hope this review will provide new insights into how to rationally design versatile protein cage nanocarriers for effective disease treatment.

Magnetoferritin: Process, Prospects, and Their Biomedical Applications

Ferritin is a spherical iron storage protein composed of 24 subunits and an iron core. Using biomimetic mineralization, magnetic iron oxide can be synthesized in the cavity of ferritin to form magnetoferritin (MFt). MFt, also known as a superparamagnetic protein, is a novel magnetic nanomaterial with good biocompatibility and flexibility for biomedical applications. Recently, it has been demonstrated that MFt had tumor targetability and a peroxidase-like catalytic activity. Thus, MFt, with its many unique properties, provides a powerful platform for tumor diagnosis and therapy. In this review, we discuss the biomimetic synthesis and biomedical applications of MFt.

Zwitterionic Gadolinium(III)-Complexed Dendrimer-Entrapped Gold Nanoparticles for Enhanced Computed Tomography/Magnetic Resonance Imaging of Lung Cancer Metastasis

Design of dual mode or multimode contrast agents or nanoplatforms with antifouling properties is crucial for improved cancer diagnosis since the antifouling materials are able to escape the clearance of the reticuloendothelial system with improved pharmacokinetics. Herein, we present the creation of zwitterionic gadolinium(III) (Gd(III))-complexed dendrimer-entrapped gold nanoparticles (Au DEN) for enhanced dual mode computed tomography (CT)/magnetic resonance (MR) imaging of lung cancer metastasis. In the present work, poly(amidoamine) (PAMAM) dendrimers of generation 5 were partially decorated with carboxybetanie acrylamide (CBAA), 2-methacryloyloxyethyl phosphorylcholine (MPC), and 1,3-propane sultone (1,3-PS), respectively at different degrees, then used to entrap Au NPs within their interiors, and finally acetylated to cover their remaining amine termini. Through protein resistance, macrophage cellular uptake, and pharmacokinetics assays, we show that zwitterionic Au DEN modified with 1,3-PS exhibit the best antifouling property with the longest half-decay time (37.07 h) when compared to the CBAA- and MPC-modified Au DEN. Furthermore, with the optimized zwitterion type, we then prepared zwitterionic Gd(III)-loaded Au DEN modified with arginine-glycine-aspartic acid peptide for targeted dual mode CT/MR imaging of a lung cancer metastasis model. We disclose that the designed multifunctional Au DEN having an Au core size of 2.7 nm and a surface potential of 7.6 ± 0.9 mV display a good X-ray attenuation property, relatively high r₁ relaxivity (13.17 mM s^-1), acceptable cytocompatibility, and targeting specificity to α_vβ₃ integrin-expressing cancer cells and enable effective dual mode CT/MR imaging of a lung cancer metastasis model in vivo. The developed multifunctional zwitterion-functionalized Au DEN may be potentially adopted as an effective nanoprobe for enhanced dual-modal CT/MR imaging of other cancer types.

Emerging blood–brain-barrier-crossing nanotechnology for brain cancer theranostics

The advancements, perspectives, and challenges in blood–brain-barrier (BBB)-crossing nanotechnology for effective brain tumor delivery and highly efficient brain cancer theranostics.

Self-Assembly of Ferritin: Structure, Biological Function and Potential Applications in Nanotechnology

Protein cages are normally formed by the self-assembly of multiple protein subunits and ferritin is a typical example of a protein cage structure. Ferritin is a ubiquitous multi-subunit iron storage protein formed by 24 polypeptide chains that self-assemble into a hollow, roughly spherical protein cage. Ferritin has external and internal diameters of approximately 12 nm and 8 nm, respectively. Functionally, ferritin performs iron sequestration and is highly conserved in evolution. The interior cavity of ferritin provides a unique reaction vessel to carry out reactions separated from the exterior environment. In nature, the cavity is utilized for sequestration of iron and bio-mineralization as a mechanism to render iron inert and safe from the external environment. Material scientists have been inspired by this system and exploited a range of ferritin superfamily proteins as supramolecular templates to encapsulate different carrier molecules ranging from cancer drugs to therapeutic proteins, in addition to using ferritin proteins as well-defined building blocks for fabrication. Besides the interior cavity, the exterior surface and sub-unit interface of ferritin can be modified without affecting ferritin assembly.