Red Blood Cell Membrane-Coated Ultrasmall NaGdF4 Nanoprobes for High-Resolution 3D Magnetic Resonance Angiography

Ultrasmall catechol-PEG-anchored ferrite nanoparticles for highly sensitive magnetic resonance angiography

Highly sensitive iron oxide nanoparticles with stable, safe and efficient surface functionalization, as potential substitutes for gadolinium-based contrast agents (GBCAs) with increasing biosafety concerns, exhibit great potential for high-performance magnetic resonance angiography (MRA). Herein, we developed ultrasmall catechol-PEG-anchored ferrite nanoparticles (PEG-UMFNPs) for highly sensitive MRA. The obtained nanoprobe has a high T1 relaxivity value (7.2 mM-1 s-1) due to its ultrasmall size and Mn doping. It has a suitable hydrodynamic size of 20 nm, which prevents rapid vascular extravasation and renal clearance and prolongs its blood circulation time. In vivo MRA at 3.0 T using the nanoprobe shows that the arteries and veins of rats, even blood vessels as small as 0.32 mm, are distinctly visible, and the contrast enhancement can last for at least 1 h. In addition, due to the outstanding contrast enhancement and long circulation time, the stenosis and recanalization process of the rat's carotid artery can be continuously monitored with a single injection of the nanoprobe. Our study indicates that PEG-UMFNPs are outstanding MR imaging nanoprobes that can be used to diagnose vascular diseases without the biosafety issues of GBCAs.

Recent advances in nanomaterial-driven strategies for diagnosis and therapy of vascular anomalies

Nanotechnology has demonstrated immense potential in various fields, especially in biomedical field. Among these domains, the development of nanotechnology for diagnosing and treating vascular anomalies has garnered significant attention. Vascular anomalies refer to structural and functional anomalies within the vascular system, which can result in conditions such as vascular malformations and tumors. These anomalies can significantly impact the quality of life of patients and pose significant health concerns. Nanoscale contrast agents have been developed for targeted imaging of blood vessels, enabling more precise identification and characterization of vascular anomalies. These contrast agents can be designed to bind specifically to abnormal blood vessels, providing healthcare professionals with a clearer view of the affected areas. More importantly, nanotechnology also offers promising solutions for targeted therapeutic interventions. Nanoparticles can be engineered to deliver drugs directly to the site of vascular anomalies, maximizing therapeutic effects while minimizing side effects on healthy tissues. Meanwhile, by incorporating functional components into nanoparticles, such as photosensitizers, nanotechnology enables innovative treatment modalities such as photothermal therapy and photodynamic therapy. This review focuses on the applications and potential of nanotechnology in the imaging and therapy of vascular anomalies, as well as discusses the present challenges and future directions.

The Art of Nanoparticle Design: Unconventional Morphologies for Advancing Luminescent Technologies

The advanced design of rare-earth-doped (RE-doped) fluoride nanoparticles has expanded their applications ranging from anticounterfeiting luminescence and contactless temperature measurement to photodynamic therapy. Several recent studies have focused on developing rare morphologies of RE-doped nanoparticles. Distinct physical morphologies of RE-doped fluoride materials set them apart from contemporary nanoparticles. Every unusual structure holds the potential to dramatically improve the physical performance of nanoparticles, resulting in a remarkable revolution and a wide range of applications. This comprehensive review serves as a guide offering insights into various uniquely structured nanoparticles, including hollow, dumbbell-shaped, and peasecod-like forms. It aims to cater to both novices and experts interested in exploring the morphological transformations of nanoparticles. Discovering new energy transfer pathways and enhancing the optical application performance have been long-term challenges for which new solutions can be found in old papers. In the future, nanoparticle morphology design is expected to involve more refined microphysical methods and chemically-induced syntheses. Targeted modification of nanoparticle morphology and the aggregation of nanoparticles of various shapes can provide the advantages of different structures and enhance the universality of nanoparticles.

Berberine mediated fluorescent gold nanoclusters in biomimetic erythrocyte ghosts as a nanocarrier for enhanced photodynamic treatment

Photodynamic therapy (PDT) is a well-established cancer treatment method that employs light to generate reactive oxygen species (ROS) causing oxidative damage to cancer cells. Nevertheless, PDT encounters challenges due to its oxygen-dependent nature, which makes it less effective in hypoxic tumor environments. To address this issue, we have developed a novel nanocomposite known as AuNC@BBR@Ghost. This nanocomposite combines the advantageous features of erythrocyte ghost membranes, the photoresponsive properties of gold nanoclusters (AuNC) and the anticancer characteristics of Berberine (BBR) for cancer treatment. Our synthesized AuNC efficiently produce ROS, with a 25% increase in efficiency when exposed to near-infrared (NIR) irradiation. By harnessing the oxygen-carrying capacity of erythrocyte ghost cells, AuNC@BBR@Ghost demonstrates a significant improvement in ROS generation, achieving an 80% efficiency. Furthermore, the AuNC exhibit tunable emission wavelengths due to their excellent fluorescent properties. In normoxic conditions, treatment of A549 lung carcinoma cells with AuNC@BBR@Ghost followed by exposure to 808 nm NIR irradiation results in a notable increase in intracellular ROS levels, accelerating cell death. In hypoxic conditions, when A549 cells were treated with AuNC@BBR@Ghost, the erythrocyte ghost acted as an oxygen supplement due to the residual hemoglobin, alleviating hypoxia and enhancing the nanocomposite's sensitivity to PDT treatment. Thus, the AuNC@BBR@Ghost nanocomposite achieves an improved effect by combining the advantageous properties of its individual components, resulting in enhanced ROS generation and adaptability to hypoxic conditions. This innovative approach successfully overcomes PDT's limitations, making AuNC@BBR@Ghost a promising nanotheranostic agent with significant potential for advanced cancer therapy.

MRI-Based Interstitial Fluid Velocity Analysis for Drug Delivery Efficiency Evaluation in Tumor

There are many flow behaviors in solid tumors, including intravascular, bloodstream, and interstitial convection. Studies have shown that tumor interstitial fluid (TIF) is an important part of tumor microenvironment regulation and affects drug delivery and metabolism between tumor cells. Magnetic resonance imaging (MRI) is suitable for detecting the flow rates of liquids in tissues. Clinical phase contrast PC-MRI technology has been designed to observe the blood flow in large vessels such as arteries and veins; however, it is not sensitive enough to deal with slow flow velocity. Our previously developed vertical plane echo PC-MRI technology, the Velocity Mapping sequence, improved the signal-to-noise ratio (SNR) for measuring slow interstitial fluid rate. In this study, this sequence was used to determine the TIF flow rate in MDA-MB-231 human breast tumor cells used in BALB/c nude male mice. Two different sizes of contrast agents were intravenously injected, and the relationship between their distribution and the TIF flow rate was studied for the first time. Combining the results of clinical scanning showed that small-molecule DTPA-Gd (diethylenetriaminepentaacetic acid-gadolinium) was distributed immediately around the tumor margin after the injection. This distribution was positively correlated to the high flow rate area of the TIF before administration. In contrast, nanoparticles NaGdF4-PEG (polyethylene glycol) entered the tumor and reached their peak at 3 h. Drug distribution was negatively correlated with the high-flow-rate region of the TIF. Investigation of the TIF velocity can help better understand the fluid behavior in tumors and its role in drug delivery.

Progress of cell membrane-derived biomimetic nanovesicles for cancer phototherapy

In recent years, considerable attention has been given to phototherapy, including photothermal and photodynamic therapy to kill tumor cells by producing heat or reactive oxygen species (ROS). It has the high merits of noninvasiveness and limited drug resistance. To fully utilize this therapy, an extraordinary nanovehicle is required to target phototherapeutic agents in the tumor cells. Nanovesicles embody an ideal strategy for drug delivery applications. Cell membrane-derived biomimetic nanovesicles represent a developing type of nanocarrier. Combining this technique with cancer phototherapy could enable a novel strategy. Herein, efforts are made to describe a comprehensive overview of cell membrane-derived biomimetic nanovesicles for cancer phototherapy. The description in this review is mainly based on representative examples of exosome-derived biomimetic nanomedicine research, ranging from their comparison with traditional nanocarriers to extensive applications in cancer phototherapy. Additionally, the challenges and future prospectives for translating these for clinical application are discussed.

Molecular imaging of tumour-associated pathological biomarkers with smart nanoprobe: From "Seeing" to "Measuring"

Although the extraordinary progress has been made in molecular biology, the prevention of cancer remains arduous. Most solid tumours exhibit both spatial and temporal heterogeneity, which is difficult to be mimicked in vitro. Additionally, the complex biochemical and immune features of tumour microenvironment significantly affect the tumour development. Molecular imaging aims at the exploitation of tumour-associated molecules as specific targets of customized molecular probe, thereby generating image contrast of tumour markers, and offering opportunities to non-invasively evaluate the pathological characteristics of tumours in vivo. Particularly, there are no "standard markers" as control in clinical imaging diagnosis of individuals, so the tumour pathological characteristics-responsive nanoprobe-based quantitative molecular imaging, which is able to visualize and determine the accurate content values of heterogeneous distribution of pathological molecules in solid tumours, can provide criteria for cancer diagnosis. In this context, a variety of "smart" quantitative molecular imaging nanoprobes have been designed, in order to provide feasible approaches to quantitatively visualize the tumour-associated pathological molecules in vivo. This review summarizes the recent achievements in the designs of these nanoprobes, and highlights the state-of-the-art technologies in quantitative imaging of tumour-associated pathological molecules.

Hypersensitive MR angiography based on interlocking stratagem for diagnosis of cardiac-cerebral vascular diseases

Magnetic resonance (MR) angiography is one of the main diagnostic approaches for cardiac-cerebral vascular diseases. Nevertheless, the non-contrast-enhanced MR angiography suffers from its intrinsic problems derived from the blood flow-dependency, while the clinical Gd-chelating contrast agents are limited by their rapid vascular extravasation. Herein, we report a hypersensitive MR angiography strategy based on interlocking stratagem of zwitterionic Gd-chelate contrast agents (PAA-Gd). The longitudinal molar relaxivity of PAA-Gd was 4.6-times higher than that of individual Gd-chelates as well as appropriate blood half-life (73.8 min) and low immunogenicity, enabling sophisticated micro-vessels angiography with a resolution at the order of hundred micrometers. A series of animal models of cardiac-cerebrovascular diseases have been built for imaging studies on a 7.0 T MRI scanner, while the clinical translation potential of PAA-Gd has been evaluated on swine on a 3.0 T clinical MRI scanner. The current studies offer a promising strategy for precise diagnosis of vascular diseases.

Cell membrane-based nanomaterials for theranostics of central nervous system diseases

Central nervous system (CNS) diseases have been widely acknowledged as one of the major healthy concerns globally, which lead to serious impacts on human health. There will be about 135 million CNS diseases cases worldwide by mid-century, and CNS diseases will become the second leading cause of death after the cardiovascular disease by 2040. Most CNS diseases lack of effective diagnostic and therapeutic strategies with one of the reasons that the biological barrier extremely hampers the delivery of theranostic agents. In recent years, nanotechnology-based drug delivery is a quite promising way for CNS diseases due to excellent properties. Among them, cell membrane-based nanomaterials with natural bio-surface, high biocompatibility and biosafety, are of great significance in both the diagnosis and treatment of different CNS diseases. In this review, the state of art of the fabrication of cell membranes-based nanomaterials is introduced. The characteristics of different CNS diseases, and the application of cell membranes-based nanomaterials in the theranostics are summarized. In addition, the future prospects and limitations of cell membrane nanotechnology are anticipated. Through summarizing the state of art of the fabrication, giving examples of CNS diseases, and highlighting the applications in theranostics, the current review provides designing methods and ideas for subsequent cell membrane nanomaterials.

Fabrication of magnetic nanoprobes for ultrahigh-field magnetic resonance imaging

Ultrahigh-field magnetic resonance imaging (UHF-MRI) has been attracting tremendous attention in biomedical imaging owing to its high signal-to-noise ratio, superior spatial resolution, and fast imaging speed. However, at UHF-MRI, there is a lack of proper imaging probes that can impart superior imaging sensitivity of disease lesions because conventional contrast agents generally produce pronounced susceptibility artifacts and induce very strong T₂ decay effects, thus hindering satisfactory imaging performance. This review focused on the recent development of high-performance nanoprobes that can improve the sensitivity and specificity of UHF-MRI. Firstly, the contrast enhancement mechanism of nanoprobes at UHF-MRI has been elucidated. In particular, the strategies for modulating nanoprobe performance, including size effects, metal alloying and magnetic-dopant effects, surface effects, and stimuli-response regulation, have been comprehensively discussed. Furthermore, we illustrate the remarkable advances in the design of UHF-MRI nanoprobes for medical diagnosis, such as early-stage primary tumor and metastasis imaging, angiography, and dynamic monitoring of biosignaling factors in vivo. Finally, we provide a summary and outlook on the development of cutting-edge UHF-MRI nanoprobes for advanced biomedical imaging.