Magnetic Resonance Imaging Agents Research Articles

Controlled Synthesis of Iron Oxide Nanoparticles via QBD for Biomedical Applications

Introduction: Iron oxide nanoparticles have gained significant attention in pharmaceutical applications because of their unique properties. The hydrothermal method is employed for the synthesis of iron nanoparticles [IONPs], which offers advantages such as uniform composition and size distribution. Method: However, the size and properties of IONPs can be influenced by various factors. In this study, we utilized quality by design [QBD] via response surface methodology to investigate the impact of temperature, time, and pH on the size of hydrothermally prepared IONPs. The optimized synthesis conditions were determined, and the resulting nanoparticles were characterized using techniques such as dynamic light scattering [DLS], scanning electron microscopy [SEM], transmission electron microscopy [TEM], vibrating sample magnetometry [VSM], X-ray diffraction [XRD], and Fourier-transform infrared spectroscopy [FTIR]. Results: The findings contribute to a better understanding of the controlled synthesis of IONPs and their potential applications in nanomedicine. The XRD characterization revealed that the product was Fe3O4. The FTIR results indicate that Fe3O4 nanoparticles were coated with PEG- 400. The SEM and HRTEM images of the Fe3O4 nanoparticles showed that they were spherical and had a well-distributed size with an optimized hydrodynamic size of 65 nm. Conclusion: The magnetic properties of the Fe3O4 nanoparticles indicated that they exhibited ferromagnetic properties. These prepared nanoparticles are suitable for biomedical purposes, like serving as contrast agents for magnetic resonance imaging in different cancers and delivering drugs.

One-Pot Fabrication of Kinetically Inert Ultrasmall Manganese(II) Chelate-Backboned Polymer Contrast Agents for High-Performance Magnetic Resonance Imaging.

Traditional macromolecules or nanoscale Mn2+ chelate-based magnetic resonance imaging (MRI) contrast agents (CAs) suffer from complicated and laborious synthesis processes, relatively low kinetic stability and T1 relaxivity, limiting their clinical applications. Herein, we fabricated a series of kinetically inert Mn2+ chelate-backboned polymers, P(MnL-PEG), through a facile and one-pot polymerization process. Particularly, P(MnL-PEG)-3 demonstrates a significantly higher T1 relaxivity of 23.9 Mn mM-1 s-1 at 1.5 T than that of previously reported small molecules and macromolecules or nanoscale Mn2+ chelate-based CAs. Due to its high T1 relaxivity, extended blood circulation, hepatocyte-specific uptake, and kidneys metabolism, P(MnL-PEG)-3 presents significantly enhanced contrast in blood vessel, liver, and kidneys imaging compared to clinical Gd3+-based CAs (Gd-EOB-DTPA and Gd-DOTA) at a dosage of 0.05 mmol Mn/Gd kg-1 BW, and can accurately diagnose orthotopic H22 liver tumors in vivo in animal models. We anticipate that this work will promote the development of clinically relevant MRI CAs.

A Multifunctional Nanodrug Increases the Therapeutic Sensitivity of Lenvatinib to Hepatocellular Carcinoma by Inhibiting the Stemness of Hepatic Cancer Stem Cells.

Drug resistance resulting from diverse mechanisms including the presence of cancer stem cells (CSCs) is the main obstacle for improving therapeutic efficacy of lenvatinib in hepatocellular carcinoma (HCC). Herein, a nanomedicine (siCD24-Len-MnO@PLAP) is developed by incorporating manganese oxide (MnO), lenvatinib (Len), and siRNA against CD24 (siCD24) into micelles composed of methoxypolyethylene glycol (mPEG), poly-L-lysine (PLLys), and polyasparagyl(N-(2-Aminoethyl)piperidine) (PAsp(PIP)) triblock copolymer. The nanomedicine can respond to the tumor microenvironment (TME) to release lenvatinib, and produce Mn2+ and O2, accompanied by changes in nanoparticle charge, which facilitates cellular endocytosis of siCD24-loaded nanoparticles. The released siCD24 and lenvatinib synergistically reduces CD24 expression, resulting in a more pronounced inhibition of stemness of CSCs. In the mouse models of HCC using Huh7-derived CSCs and Hepa1-6-derived CSCs, the nanomedicine shows remarkable anti-cancer effect by enhancing the therapeutic effects of lenvatinib against HCC via reducing the expression level of CD24 and decreasing the expression of hypoxia inducible factor-1α (HIF-1α). Moreover, in situ production of paramagnetic Mn2+ from the nanomedicine serves as an excellent contrast agent for magnetic resonance imaging (MRI) to monitor the therapeutic process. This study demonstrates that this multifunctional MRI-visible siCD24- and lenvatinib-loaded nanodrug holds great potential in enhancing therapeutic sensitivity for HCC lenvatinib therapy.

Construction of CXCR4 Receptor-Targeted CuFeSe2 Nano Theranostic Platform and Its Application in MR/CT Dual Model Imaging and Photothermal Therapy.

Targeting, imaging, and treating tumors represent major clinical challenges. Developing effective theranostic agents to address these issues is an urgent need. We introduce an "all-in-one" tumor-targeted theranostic platform using CuFeSe2-based composite nanoparticles (CuFeSe2@PA) for magnetic resonance (MR) and computed tomography (CT) dual model imaging-guided hyperthermia tumor ablation. Plerixafor (AMD3100) is bonded to the surface of CuFeSe2 as a targeting unit. Due to the robust interaction between AMD3100 and the overexpressed Chemokine CXC type receptor 4 (CXCR4) on the membrane of 4T1 cancer cells, CuFeSe2@PA specifically recognizes 4T1 cancer cells, enriching the tumor region. CuFeSe2@PA serves as a contrast agent for T2-weighted MR imaging (relaxivity value of 1.61 mM-1 s-1) and CT imaging. Moreover, it effectively suppresses tumor growth through photothermal therapy (PTT) owing to its high photothermal conversion capability and stability, with minimized side effects demonstrated both in vitro and in vivo. CuFeSe2@PA nanoparticles show potential as dual-mode imaging contrast agents for MR and CT and provide an effective means of tumor treatment through photothermal therapy. The surface modification with Plerixafor enhances the targeting ability of the nanoparticles, performing more significant efficacy and biocompatibility in the 4T1 cancer cell model. The study demonstrates that CuFeSe2@PA is a promising multifunctional theranostic platform with clinical application potential.

Bifunctional Bismuth-Based Layered Double Hydroxide Sonosensitizer for Magnetic Resonance Imaging-Guided Sonodynamic Cancer Therapy.

Novel inorganic sonosensitizers with excellent reactive oxygen species (ROS) generation activity and multifunctionality are appealing in sonodynamic therapy (SDT). Herein, amorphous bismuth (Bi)-doped CoFe-layered double hydroxide (a-CoBiFe-LDH) nanosheets are proposed via crystalline-to-amorphous phase transformation strategy as a new type of bifunctional sonosensitizer, which allows ultrasound (US) to trigger ROS generation for magnetic resonance imaging (MRI)-guided SDT. Importantly, a-CoBiFe-LDH nanosheets exhibit much higher ROS generation activity (≈6.9 times) than that of traditional TiO2 sonosensitizer under US irradiation, which can be attributed to the acid etching-induced narrow band gap, high electron (e-)/hole (h+) separation efficiency and inhibited e-/h+ recombination. In addition, the paramagnetic properties of Fe ion endow a-CoBiFe-LDH with excellent MRI contrast ability, making it a promising contrast agent for T2-weighted MRI. After modification with polyethylene glycol, a-CoBiFe-LDH nanosheets can function as a high-efficiency sonosensitizer to activate p53, MAPK, oxidative phosphorylation, and apoptosis-related signaling pathways, ultimately inducing cell apoptosis in vitro and tumor ablation in vivo under US irradiation, which shows great potential for clinical cancer treatment.

Tracking the distribution of persistent and mobile wastewater-derived substances in the southern and central North Sea using anthropogenic gadolinium from MRI contrast agents as a far-field tracer

The use of the rare earth element gadolinium (Gd) in contrast agents for magnetic resonance imaging has led to a significant (micro-)contamination of riverine and coastal environments in many parts of the world. This study comprises a detailed investigation on the rare earth elements and yttrium inventory of the North Sea and also reports data for the major tributaries Thames, Rhine, Ems, Weser and Elbe. We show that large parts of the southern North Sea, including the Wadden Sea UNESCO Natural World Heritage site, are (micro)contaminated with Gd from Gd-based contrast agents (GBCA). Their dispersion reveals their estuarine input and allows to effectively track water masses and currents. The chemical persistence and conservative behavior of GBCA, coupled with the low detection limits of state-of-the-art analytical methods, makes the anthropogenic Gd a sensitive screening proxy for monitoring similarly stable, but potentially hazardous, persistent chemical/pharmaceutical substances in natural waters.

Antispasmodic Agents in Magnetic Resonance Imaging of the Urinary Bladder-A Narrative Review.

Accurate assessment of muscular layer infiltration of the urinary bladder wall is crucial for diagnostic precision and is significantly influenced, among other factors, by the elimination of motion artifacts. This review explores the potential benefits of using spasmolytic agents to achieve improved imaging results. Specifically, it examines two commonly available pharmaceutical preparations: butylscopolamine (buscolysin) and glucagon. The review highlights the similarities and differences between these agents and discusses the optimal methods of administration to enhance urinary bladder imaging. By addressing these factors, the article aims to provide insights into improving diagnostic accuracy in clinical practice.

W(h)Ither Fullerenes in Medicine? Challenges and Opportunities in Industrial Translation

The fullerenes—C60 and its derivatives in particular—have been lauded for three decades now as having revolutionary potential for next-generation medical applications. These span therapeutics (e.g. enzyme inhibition and photodynamic therapy for treating cancers) and diagnostics (e.g. improved contrast agents for magnetic resonance imaging). But translating this potential beyond academic research studies and into scaled-up production and clinical practice has proved far more elusive than the much-sought-after widespread industrial adoption of graphene.In this talk I will first outline why the fullerenes do indeed offer such promise in these clinical application areas, before providing an exploration of many of the intersecting factors that have contributed to making the clinical translation of fullerene-based therapeutics and diagnostics such a seemingly insurmountable barrier up to this point. These factors include: A uniquely multi-dimensional chemical design space when considering fullerene size and both exohedral and endohedral functionalisation possibilities;The relationship of the above with understanding functionality and safety in vivo;Regulatory requirements pertaining to the above;The presence of unregulated fullerene-based products in the beauty and wellness sector;The fuzzy borderlands between science and pseudoscience that much of the narrative around fullerenes occupies;Loss of funding momentum;Lack of industrial bridges between materials manufacturers and technology developers. After characterising the state of affairs in this way, I will offer some specific suggestions for hope and opportunity as we move into a world where synthesis and testing bottlenecks can be overcome with the help of artificial intelligence and automation, and increased awareness of the diverse properties of different types of nanomaterials changes the regulatory and industrial landscapes. Thus, I hope to provide a case study of how one family of carbon nanomaterials could finally realise its promise of advancing medicine in the Industry 4.0 era.

Artificial magnetosomes: Molecularly restructured SPIONs with enhanced potential for magnetic imaging

Magnetosomes represent an elegant example of ultrastable nanomaterials that nature produces by encapsulating magnetic nanoparticles in liposomal sub-compartments of magnetotactic bacteria. Materials chemists continue to strive for ways to mimic the performance of natural systems, but the artificial synthesis of magnetosomes remains unrealized. Here, we report molecular restructuring of the surface of oleic-acid-capped superparamagnetic iron oxide nanoparticles (SPIONs) to produce magnetosomes. Our strategy involves the use of triethylamine as an amphiphilic surfactant that through a combination of ligand exchange and rearrangement mechanisms, facilitates an organic-to-aqueous phase transfer of SPIONs while turning them into magnetosomes. These liposome-encapsulated SPIONs showed dynamic aqueous stability alongside noticeably improved magnetic properties. This improved their performance as contrast agents for magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), the latter revealing a 33.5 % improvement in signal sensitivity over the original SPIONs. The presented strategy is extendable to prepare liposomal dispersions of other biomedically important nanomaterials.

Tracing Gadolinium levels throughout wastewater treatment: Insights from a yearly assessment in northern Spain

Gadolinium (Gd) is a rare earth element (REE) used in the formulation of contrast agents for Magnetic Resonance Imaging (MRI) due to its paramagnetic properties. The growth in population and the improved quality of the healthcare systems over the last years, has promoted the use of MRI as an effective diagnostic tool thus increasing the consumption of gadolinium and its release into the wastewater treatment network. Therefore, the tracking and quantification of this metal in sewage treatment plants and water bodies, is of paramount importance since there are currently no specific rare earth treatment technologies installed in WWTPs, and consequently gadolinium is finally discharged into the environment. In this work, the presence of gadolinium and all other rare earth elements was monitored during a year in three WWTPs in northern Spain (Vuelta Ostrera and San Román in Cantabria and Galindo in País Vasco). These WWTPs are located close to urban centres with hospitals where MRI tests are performed. By tracing Gd throughout the wastewater treatment facilities, its presence was confirmed in water streams, in the order of ng per litter, and in sludge and ashes, in the order of mg per kilogram. A significant human influence was observed, with Gd anomaly values between 3.14 and 79.2 and anthropogenic Gd percentages above 90 %. The presence of Gd in water streams is affected by the sampling period due to the variations of the activity periods of the hospitals nearby the treatment plants. On the contrary, its content in sludge and ashes remains almost constant along the year. The concentration of this metal found in the ashes opens the door to its possible recovery together with other critical raw materials in the context of the circular economy.

A New Herbal Source of Synthesizing Contrast Agents for Magnetic Resonance Imaging

ABSTRACTThis study explores the potential of halophytes, plants adapted to saline environments, as a novel source for developing herbal MRI contrast agents. Halophytes naturally accumulate various metals within their tissues. These metal ions, potentially complexed with organic molecules, are released into aqueous solutions prepared from the plants. We investigated the ability of these compounds to generate contrast enhancement in MRI using a sequential approach. First, aqueous extracts were prepared from seven selected halophytes, and their capacity to induce contrast in MR images was evaluated. Based on these initial findings, sample halophytes were chosen for further investigations. Second, chemical analysis revealed aluminum as the primary potent metal which enhances the contrast. Third, the halophyte extract was fractionated based on polarity, and the most polar fraction exhibited the strongest contrast‐generating effect. Finally, the relaxivity of this fraction, a key parameter for MRI contrast agents, was measured. We propose that aluminum, likely complexed with a polar molecule within the plant extract, is responsible for the observed contrast enhancement in MRI.

Effect of precursor concentration, surfactant and temperature on the size, morphology and nanostructure of zero-valent iron nanocrystals synthesised by a polyol route

Iron metal nanoparticles, due to their magnetic properties, reducing power and low toxicity, have numerous applications not only in groundwater and contaminated soil remediation but also in biomedicine as contrast agents in magnetic resonance imaging. However, obtaining this nanomaterial involves the use of strongly reducing, polluting and expensive reagents and high temperatures. Herein, the use of ethylene glycol and diethylene glycol in a strong alkaline medium that allows the direct reduction of iron(II) salts to iron(0) in the absence of any added reducer has been analysed for preparation of well-defined nanoparticles. The key roles of the polyhydroxylated surfactants (D-mannitol, D-mannose, polyvinyl alcohol and polyvinyl pyrrolidone) were identified, and their efficiencies were evaluated. In addition, conclusions have been drawn regarding the existence of a minimum temperature required for the reduction of the precursor, as well as the observation that the size of the nanoparticles increases with reaction temperature. The main result is that by combining surfactants and controlling the reaction temperature, pure cubic iron(0) nanoparticles smaller than 100 nm were obtained, thereby reducing the formation of hydroxylated by-products. The high reactivity, high magnetic response, long-term stability and small size of the iron nanoparticles produced in this work will allow their use in various applications.

Bimetallic porphyrin PET radiotracers for Low-Dose MRI contrast enhancement

In medical imaging, concerns over the risks associated with imaging agents have been consistently raised by doctors and patients, and ongoing efforts are being made to cautiously explore safer and more efficient compounds. There is continued interest in combining the well-known imaging modalities of positron emission tomography (PET) and magnetic resonance imaging (MRI). However, there has not been reported a single-molecule probe offering dual-modal imaging without performance degradation. We herein present a potential solution wherein the compound, PGaLGd, incorporates radioactive Ga(III) for PET imaging whilst simultaneously being able to exhibit MRI contrast through a coordinated Gd(III) ion but at low concentrations/doses. Besides elucidating MRI enhancing mechanisms through computational chemistry techniques, our compound has proven to be a successful dual-imaging agent for both PET and MRI in mice. Additionally, we conducted comprehensive in vitro and in vivo studies, assessing biosafety and photodynamic therapeutic potential across various cell lines and organoids. We have placed importance on interlinking structures, coordinated metals, adjacent ligands, and frontier molecular orbitals in our probe design to enhance water relaxation ability and move towards the design of next-generation low-dose imaging agents.

PH/glutathione-responsive theranostic nanoprobes for chemoimmunotherapy and magnetic resonance imaging of ovarian cancer cells

The integration of immunotherapy and standard chemotherapy holds great promise for enhanced anticancer effects. In this study, we prepared a pH- and glutathione (GSH)-sensitive manganese-doped mesoporous silicon (MMSNs) based drug delivery system by integrating paclitaxel (PTX) and anti-programmed cell death-ligand 1 antibody (aPD-L1), and encapsulating with polydopamine (PDA) for chemoimmunosynergic treatment of ovarian cancer cells. The nanosystem was degraded in response to the tumor weakly acidic and reductive microenvironment. The Mn2+ produced by degradation can be used as a contrast agent for magnetic resonance (MR) imaging to provide visual exposure to tumor tissue. The released PTX can not only kill tumor cells directly, but also induce immunogenic death (ICD) of tumor cells, which can play a synergistic therapeutic effect with aPD-L1. Therefore, our study is expected to provide a promising strategy for improving the efficacy of cancer immunotherapy and the detection rate of cancer.

Towards medical imaging of drug photoactivation: Development of light responsive magnetic resonance imaging and chemical exchange saturation transfer contrast agents

AbstractIn recent years, the use of light to selectively and precisely activate drugs has been developed along the fundamental concepts of photopharmacology. One of the key methods in this field relies on transiently silencing the drug activity with photocleavable protecting groups (PPGs). To effectively utilize light‐activated drugs in future medical applications, physicians will require a reliable method to assess whether light penetrates deep enough into the tissues to activate the photoresponsive theragnostic agents. Here, we describe the development and evaluation of magnetic resonance (MR) imaging agents that allow for the detection of light penetration and drug activation in the tissues using non‐invasive whole‐body magnetic resonance imaging (MRI) and chemical exchange saturation transfer (CEST)‐MRI modalities. The approach relies on the use of PPG‐protected MR contrast agents, which upon irradiation with light change their imaging signal. A Gadolinium(III)‐based MRI contrast agent is presented that undergoes a significant change in relaxivity (25%) upon uncaging, providing a reliable indicator of light‐induced cargo release. Additionally, we introduce the first light‐responsive CEST‐MRI imaging agent, enabling positive signal enhancement (off‐to‐on) upon light activation, offering a novel approach to visualize the activation of photoactive agents in living tissues. This research provides a proof‐of‐principle for the non‐invasive, whole‐body imaging of light penetration and drug activation with high temporal resolution characteristic of MR methods.

Microglial activation-sensitive gadolinium complex as a potential MRI contrast agent for Alzheimer’s disease diagnosis

Numerous studies have developed gadolinium (Gd)-based contrast agents (GBCAs) for in-vivo magnetic resonance imaging (MRI) with the aim of diagnosing Alzheimer’s disease (AD). Nevertheless, GBCAs that are capable of identifying microglial activation, a critical early indicator of AD pathology, for in-vivo diagnosis remain scarce. In response to this, we synthesized a novel GBCA, Gd-DO3A-Va, designed specifically to detect microglial activation using MRI. This innovative GBCA, which was conjugated with vanillic acid, demonstrated a high selectivity for microglial activation by targeting Toll-like receptor 4 (TLR4). The use of Gd-DO3A-Va in in-vivo imaging successfully highlighted microglial activation in a transgenic AD mouse model. In particular, the use of Gd-DO3A-Va for contrast-enhanced T1-weighted MRI enabled the detection of microglial activation within the hippocampus and cortex, regions notably affected by AD. The observed enhancements in the MR contrast correlated well with immunohistological evidence of microglial activation. Consequently, Gd-DO3A-Va represents a highly promising GBCA for the identification of microglial activation, providing a novel pathway for the molecular diagnosis of AD.

Noninvasive platelet membrane-coated Fe3O4 nanoparticles identify vulnerable atherosclerotic plaques.

Vulnerable atherosclerotic plaques serve as the primary pathological basis for fatal cardiovascular and cerebrovascular diseases. The precise identification and treatment of these vulnerable plaques hold paramount clinical importance in mitigating the incidence of myocardial infarction and stroke. Nevertheless, the identification of vulnerable plaques within the diffuse atherosclerotic plaques dispersed throughout the systemic circulation continues to pose a substantial challenge in clinical practice. Double emulsion solvent evaporation method, specifically the water-in-oil-in-water (W/O/W) technique, was employed to fabricate Fe3O4-based poly (lactic-co-glycolic acid) (PLGA) nanoparticles (Fe3O4@PLGA). Platelet membranes (PM) were extracted through hypotonic lysis, followed by ultrasound-assisted encapsulation onto the surface of Fe3O4@PLGA, resulting in the formation of PM-coated Fe3O4 nanoparticles (PM/Fe3O4@PLGA). Characterization of PM/Fe3O4@PLGA involved the use of dynamic light scattering, transmission electron microscopy, western blotting, and magnetic resonance imaging (MRI). A model of atherosclerotic vulnerable plaques was constructed by carotid artery coarctation and a high-fat diet fed to ApoE-/- (Apolipoprotein E knockout) mice. Immunofluorescence and MRI techniques were employed to verify the functionality of PM/Fe3O4@PLGA. In this study, we initially synthesized Fe3O4@PLGA as the core material. Subsequently, a platelet membrane was employed as a coating for the Fe3O4@PLGA, aiming to enable the detection of vulnerable atherosclerotic plaques through MRI. In vitro, PM/Fe3O4@PLGA not only exhibited excellent biosafety but also showed targeted collagen characteristics and MR imaging performance. In vivo, the adhesion of PM/Fe3O4@PLGA to atherosclerotic lesions was confirmed in a mouse model of vulnerable atherosclerotic plaques. Simultaneously, PM/Fe3O4@PLGA as a novel contrast agent for MRI has shown effective identification of vulnerable atherosclerotic plaques. In terms of safety profile in vivo, PM/Fe3O4@PLGA has not demonstrated significant organ toxicity or inflammatory response in the bloodstream. In this study, we successfully developed a platelet-membrane-coated nanoparticle system for the targeted delivery of Fe3O4@PLGA to vulnerable atherosclerotic plaques. This innovative system allows for the visualization of vulnerable plaques using MRI, thereby demonstrating its potential for enhancing the clinical diagnosis of vulnerable atherosclerotic plaques.

Tumor Cell-Targeting and Tumor Microenvironment-Responsive Nanoplatforms for the Multimodal Imaging-Guided Photodynamic/Photothermal/Chemodynamic Treatment of Cervical Cancer.

Phototherapy, known for its high selectivity, few side effects, strong controllability, and synergistic enhancement of combined treatments, is widely used in treating diseases like cervical cancer. In this study, hollow mesoporous manganese dioxide was used as a carrier to construct positively charged, poly(allylamine hydrochloride)-modified nanoparticles (NPs). The NP was efficiently loaded with the photosensitizer indocyanine green (ICG) via the addition of hydrogen phosphate ions to produce a counterion aggregation effect. HeLa cell membrane encapsulation was performed to achieve the final M-HMnO2@ICG NP. In this structure, the HMnO2 carrier responsively degrades to release ICG in the tumor microenvironment, self-generates O2 for sensitization to ICG-mediated photodynamic therapy (PDT), and consumes GSH to expand the oxidative stress therapeutic effect [chemodynamic therapy (CDT) + PDT]. The ICG accumulated in tumor tissues exerts a synergistic PDT/photothermal therapy (PTT) effect through single laser irradiation, improving efficiency and reducing side effects. The cell membrane encapsulation increases nanomedicine accumulation in tumor tissues and confers an immune evasion ability. In addition, high local temperatures induced by PTT can enhance CDT. These properties of the NP enable full achievement of PTT/PDT/CDT and targeted effects. Mn2+ can serve as a magnetic resonance imaging agent to guide therapy, and ICG can be used for photothermal and fluorescence imaging. After its intravenous injection, M-HMnO2@ICG accumulated effectively at mouse tumor sites; the optimal timing of in-vivo laser treatment could be verified by near-infrared fluorescence, magnetic resonance, and photothermal imaging. The M-HMnO2@ICG NPs had the best antitumor effects among treatment groups under near-infrared light conditions, and showed good biocompatibility. In this study, we designed a nano-biomimetic delivery system that improves hypoxia, responds to the tumor microenvironment, and efficiently loads ICG. It provides a new economical and convenient strategy for synergistic phototherapy and CDT for cervical cancer.

Ligand-Induced Atomically Segregation-Tunable Alloy Nanoprobes for Enhanced Magnetic Resonance Imaging.

Bimetallic iron-noble metal alloy nanoparticles have emerged as promising contrast agents for magnetic resonance imaging (MRI) due to their biocompatibility and facile control over the element distribution. However, the inherent surface energy discrepancy between iron and noble metal often leads to Fe atom segregation within the nanoparticle, resulting in limited iron-water molecule interactions and, consequently, diminished relaxometric performance. In this study, we present the development of a class of ligand-induced atomically segregation-tunable alloy nanoprobes (STAN) composed of bimetallic iron-gold nanoparticles. By manipulating the oxidation state of Fe on the particle surface through varying molar ratios of oleic acid and oleylamine ligands, we successfully achieve surface Fe enrichment. Under the application of a 9 T MRI system, the optimized STAN formulation, characterized by a surface Fe content of 60.1 at %, exhibits an impressive r1 value of 2.28 mM-1·s-1, along with a low r2/r1 ratio of 6.2. This exceptional performance allows for the clear visualization of hepatic tumors as small as 0.7 mm in diameter in vivo, highlighting the immense potential of STAN as a next-generation contrast agent for highly sensitive MR imaging.

Synthesis, MTT assay, 99m-Technetium radiolabeling, biodistribution evaluation of radiotracer and in vitro magnetic resonance imaging study of P,N-doped graphene quantum dots as a new multipurpose imaging nano-agent

Abstract In this study, a new nano-structure, N,P-doped graphene quantum dots (N,P-GQDs), were synthesized as multipurpose imaging agent for performing scintigraphy and magnetic resonance imaging (MRI). Some standard characterization methods were used to identify the nano-structure. In vitro cytotoxicity evaluation using MTT assay revealed that N,P-GQDs nanoparticles had no significant cytotoxicity after 24 and 48 h against normal (MCF-10A) and cancerous (MCF 7) human breast cell line in concentration up to 200 μg/mL. The N,P-GQDs were radiolabeled with Technetium-99m as 99mTc-(N,P-GQDs) and the radiochemical purity was assayed by ITLC concluding RCP ≥ 95 %. The passing of 99mTc-(N,P-GQDs) through 0.1 µm filter demonstrated that 70.8 % of particles were <0.1 µm. In order to perform scintigraphy, the 99mTc-(N,P-GQDs) were injected to female healthy Wistar rats. The results showed that the radio-complex was captured and eliminated just by kidneys. Moreover, in vitro T1-weighted phantom MRI imaging showed that the N,P-GQDs have proper relaxivity in comparison to Dotarem® as a clinically available contrast agent. The results showed that the N,P-GQDs have potential to be considered as a novel and encouraging agent for both molecular MRI and nuclear medicine imagings.