Multifunctional imaging probe based on gadofulleride nanoplatform

A Review on the Design of Carbon-Based Nanomaterials as MRI Contrast Agents

The administration of magnetic resonance imaging (MRI) contrast agents (CAs) has been conducted since 1988 by clinicians to enhance the clarity and interpretability of MR images. CAs based on gadolinium chelates are the clinical standard used worldwide for the diagnosis of various pathologies, such as the detection of brain lesions, the visualization of blood vessels, and the assessment of soft tissue disorders. However, due to ongoing concerns associated with the safety of gadolinium-based contrast agents, considerable efforts have been directed towards developing contrast agents with better relaxivities, reduced toxicity, and eventually combined therapeutic modalities. In this context, grafting (or encapsulating) paramagnetic metals or chelates onto (within) carbon-based nanoparticles is a straightforward approach enabling the production of contrast agents with high relaxivities while providing extensive tuneability regarding the functionalization of the nanoparticles. Here, we provide an overview of the parameters defining the efficacy of lanthanide-based contrast agents and the subsequent developments in the field of nanoparticular-based contrast agents incorporating paramagnetic species.

Progress in Antiviral Fullerene Research

Unlike traditional small molecule drugs, fullerene is an all-carbon nanomolecule with a spherical cage structure. Fullerene exhibits high levels of antiviral activity, inhibiting virus replication in vitro and in vivo. In this review, we systematically summarize the latest research regarding the different types of fullerenes investigated in antiviral studies. We discuss the unique structural advantage of fullerenes, present diverse modification strategies based on the addition of various functional groups, assess the effect of structural differences on antiviral activity, and describe the possible antiviral mechanism. Finally, we discuss the prospective development of fullerenes as antiviral drugs.

A mesoporous polydopamine nanoparticle enables highly efficient manganese encapsulation for enhanced MRI-guided photothermal therapy

Theranostic agents based on magnetic resonance imaging (MRI) and photothermal therapy (PTT) play an important role in tumor therapy. However, the available theranostic agents are facing great challenges such as biocompatibility, MRI contrast effect and photothermal conversion efficiency (η). In this work, mesoporous polydopamine nanoparticles (MPDAPs/Mn) were prepared on MRI and PTT combined theranostic nanoplatforms, of which the high loading manganese ions and specific surface areas enable good MRI contrast and excellent photothermal conversion efficiency, respectively. The MPDAPs/Mn have uniform morphology, good stability and biocompatibility. Meanwhile, in vitro and in vivo studies have confirmed their superior T₁-weighted MRI effect and photothermal conversion efficiency. Furthermore, MPDAPs/Mn have excellent antitumor efficacy in HeLa tumor-bearing mice. Therefore, this developed MPDAPs/Mn theranostic nanoplatform could be a promising candidate for MRI-guided photothermal cancer therapy.

Gadolinium-containing carbon nanomaterials for magnetic resonance imaging: Trends and challenges

Gadolinium-containing carbon nanomaterials are a new class of contrast agent for magnetic resonance imaging. They are characterized by a superior proton relaxivity to any current commercial gadolinium contrast agent and offer the possibility to design multifunctional contrasts. Intense efforts have been made to develop these nanomaterials because of their potential for better results than the available gadolinium contrast agents. The aim of the present work is to provide a review of the advances in research on gadolinium-containing carbon nanomaterials and their advantages over conventional gadolinium contrast agents. Due to their enhanced proton relaxivity, they can provide a reliable imaging contrast for cells, tissues or organs with much smaller doses than currently used in clinical practice, thus leading to reduced toxicity (as shown by cytotoxicity and biodistribution studies). Their active targeting capability allows for improved MRI of molecular or cellular targets, overcoming the limited labelling capability of available contrast agents (restricted to physiological irregularities during pathological conditions). Their potential of multifunctionality encompasses multimodal imaging and the combination of imaging and therapy.

Novel Hybrid Dextran-Gadolinium Nanoparticles as High-relaxivity T1 Magnetic Resonance Imaging Contrast Agent for Mapping the Sentinel Lymph Node

OBJECTIVES

To assess the applicability of a novel hybrid dextran-gadolinium nanoparticles (NPs) as high-relaxivity T1 magnetic resonance imaging (MRI) contrast agent for mapping the sentinel lymph node (SLN).

METHODS

Dextran-bis-acrylamide-polyacrylic acid (Dex-MBA-PAA) NPs were synthesized through a self-assembly assisted approach and complexed with multiple chelated gadolinium (Gd) (III) ions. After their characterization was validated, they were used to mapping SLNs by MRI in Wistar rats, and their biosafety was evaluated.

RESULTS

Dextran-MBA-polyacrylic acid-Gd NPs have suitable particle size and much higher longitudinal relaxivity (r1) than that of commonly used clinical MRI contrast agents (eg, gadopentetic acid dimeglumine salt injection). The in vivo T1-weighted MRI results revealed their effectiveness at mapping SLNs. And their biological safety was also verified.

CONCLUSIONS

Dextran-MBA-polyacrylic acid-Gd NPs were synthesized and validated by in vitro and in vivo experiments for their ability to visualize SLNs by MRI with accurate positioning and excellent biosafety, and they have great potential for clinical SLN mapping.

Carbon-Based Nanomaterials for Cancer Therapy via Targeting Tumor Microenvironment

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

Fullerene Polyglycerol Amphiphiles as Unimolecular Transporters

Due to their unique structure and properties, water-soluble fullerene derivatives are of great interest for various biomedical purposes. In this work, solution behavior, encapsulation and release properties, biocompatibility, and cellular uptake pathways of fullerene-polyglycerol amphiphiles (FPAs) with defined structures are investigated. The number of polyglycerol branches attached to the surface of fullerene affects the physicochemical properties of FPAs dramatically but not their cellular uptake. Release of encapsulated hydrophobic dyes from FPAs strongly depends on the number of their branches. Conjugation of a pH-sensitive dye to the FPAs as a probe showed that their self-assemblies are taken up through endocytotic pathways. It was observed that FPAs are able to transfer small molecules into cells both above and below their critical aggregation concentration. Taking advantage of the water solubility, biocompatibility, and transfer-ability of FPAs, they might find use as unimolecular carriers for future biomedical applications.

The evolution of gadolinium based contrast agents: from single-modality to multi-modality

Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications.

Synthesis of a UCNPs@SiO2@gadofullerene nanocomposite and its application in UCL/MR bimodal imaging

A novel bimodal imaging agent (GdF–UCNPs) has been designed through conjugating the water-soluble polyhydroxy Gd@C₈₂-PCBM with silica coated UCNPs.

The effect of hemiketals on the relaxivity of endohedral gadofullerenols

Gd@C₈₂(OH)_xO_y with more hemiketals show much higher relaxivities than those with fewer hemiketals.

β-conjugation of gadolinium(III) DOTA complexes to zinc(II) porpholactol as potential multimodal imaging contrast agents

Synthesis of two bimodal imaging agents consist of a hydrophobic zinc(II) tetrapentafluorophenylporpholactol core and a β-substituted hydrophilic Gd ( III ) DO3A (ZnLGd539) or DOTA (ZnLGd595) like moiety has been described (DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). Through β-conjugation approach, the absorption at deep red region increases compared to traditional conjugation methods at meso-position. More importantly, these new complexes possess largely improved ionic relaxitivites relative to the sole Gd ( III ) magnetic resonance imaging (MRI) agents such as Gd ( III ) DO3A and Gd ( III ) DOTA like complexes. Combining the optical and magnetic resonance measurements in aqueous media, the largely enhanced r1 relaxivities was attributed to the aggregation of ZnLGd539 and ZnLGd595 in aqueous media. Furthermore, fluorescence and magnetic resonance imaging experiment showed that both ZnLGd539 and ZnLGd595 can be applied as potential bimodal imaging contrast agents. Finally, both compounds showed no dark cytotoxicity and good photocytotoxicity (IC50 = 1.73 ± 0.13 and 1.52 ± 0.10 μM for ZnLGd539 and ZnLGd595 respectively) on Hela cells.