Enhanced conjugation stability and blood circulation time of macromolecular gadolinium-DTPA contrast agent

GCN5-targeted dual-modal probe across the blood-brain barrier for borders display in invasive glioblastoma

Glioblastoma (GBM) is a highly invasive malignancy with a poor prognosis, primarily attributable to its diffuse infiltration into adjacent brain tissue, thereby complicating effective surgical resection. Current imaging modalities often struggle to accurately identify tumor boundaries. Here, we identify general control non-repressed protein 5 (GCN5) as a promising molecular target for GBM imaging, as it is expressed in GBM lesions within brain tissue, and its expression levels are significantly correlated with GBM grading. We develop a dual-modal probe with a particle size of 20 nm, capable of efficiently traversing the blood-brain barrier (BBB) to target GCN5 through adsorptive-mediated transcytosis (AMT). The probe employs dendrimers (Den) as carriers, which are loaded with a small molecule inhibitor specifically designed to target GCN5. This probe enhances the preoperative delineation of GBM boundaries using magnetic resonance imaging (MRI) and facilitates intraoperative fluorescence image-guided surgical procedures. Our work introduces a promising tool for boundary delineation, offering new opportunities for the precise resection of GBM.

Multifunctional Nanoprobe Au@Gd-SiO2-HA-Lyp-1/DOX with Dual-Targeting Functions Derived from HA and LyP-1: Diagnostic and Therapeutic Potential for Tumor Lymphatic Metastasis

To address lymphatic metastasis in lung cancer, we developed the Au@Gd-SiO2-HA-LyP-1 nanoprobe, assessing its diagnostic and therapeutic capabilities. This nanoprobe integrates a Au core with a Gd-SiO2 shell and dual-targeting HA-LyP-1 molecules. We evaluated its size, shape, and functional properties using various characterization techniques, alongside in vivo and in vitro toxicity tests. The spherical nanoprobes have a 50 nm diameter and contain 1.37% Gd. They specifically target lymphatic metastasis sites and tumor cells, showing enhanced MRI contrast and effective, targeted DOX delivery with reduced normal tissue toxicity. The Au@Gd-SiO2-HA-LyP-1 nanoprobe is a promising tool for diagnosing and treating lung cancer lymphatic metastasis, featuring dual-targeting and superior imaging capabilities.

Polarizable Additive with Intermediate Chelation Strength for Stable Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are promising due to inherent safety, low cost, low toxicity, and high volumetric capacity. However, issues of dendrites and side reactions between zinc metal anode and the electrolyte need to be solved for extended storage and cycle life. Here, we proposed that an electrolyte additive with an intermediate chelation strength of zinc ion-strong enough to exclude water molecules from the zinc metal-electrolyte interface and not too strong to cause a significant energy barrier for zinc ion dissociation-can benefit the electrochemical stability by suppressing hydrogen evolution reaction, overpotential growth, and dendrite formation. Penta-sodium diethylene-triaminepentaacetic acid salt was selected for such a purpose. It has a suitable chelating ability in aqueous solutions to adjust solvation sheath and can be readily polarized under electrical loading conditions to further improve the passivation. Zn||Zn symmetric cells can be stably operated over 3500 h at 1 mA cm-2. Zn||NH4V4O10 full cells with the additive show great cycling stability with 84.6% capacity retention after 500 cycles at 1 A g-1. Since the additive not only reduces H2 evolution and corrosion but also modifies Zn2+ diffusion and deposition, highlyreversible Zn electrodes can be achieved as verified by the experimental results. Our work offers a practical approach to the logical design of reliable electrolytes for high-performance aqueous batteries.

Relaxivity Enhancement of Hybrid Micelles via Modulation of Water Coordination Numbers for Magnetic Resonance Lymphography

Considerable efforts have been made to develop nanoparticle-based magnetic resonance contrast agents (CAs) with high relaxivity. The prolonged rotational correlation time (τR) induced relaxivity enhancement is commonly recognized, while the effect of the water coordination numbers (q) on the relaxivity of nanoparticle-based CAs gets less attention. Herein, we first investigated the relationship between T1 relaxivity (r1) and q in manganese-based hybrid micellar CAs and proposed a strategy to enhance the relaxivity by increasing q. Hybrid micelles with different ratios of amphiphilic manganese complex (MnL) and DSPE-PEG2000 were prepared, whose q values were evaluated by Oxygen-17-NMR spectroscopy. Micelles with lower manganese doping density exhibit increased q and enhanced relaxivity, corroborating the conception. In vivo sentinel lymph node (SLN) imaging demonstrates that DSPE-PEG/MnL micelles could differentiate metastatic SLN from inflammatory LN. Our strategy makes it feasible for relaxivity enhancement by modulating q, providing new approaches for the structural design of high-performance hybrid micellar CAs.

Facile Synthesis of Weakly Ferromagnetic Organogadolinium Macrochelates-Based T1 -Weighted Magnetic Resonance Imaging Contrast Agents

To surmount the major concerns of commercial small molecule Gd chelates and reported Gd-based contrast agents (GBCAs) for magnetic resonance imaging (MRI), a new concept of organogadolinium macrochelates (OGMCs) constructed from the coordination between Gd3+ and macromolecules is proposed. A library of macromolecules were screened for Gd3+ coordination, and two candidates [i.e., poly(acrylic acid) (PAA), and poly(aspartic acid) (PASP)] succeeded in OGMC formation. Under optimized synthesis conditions, both Gd-PAA12 and Gd-PASP11 OGMCs are outstanding T1 -weighted CAs owing to their super high r1 values (> 50 mm-1  s-1 , 3.0 T) and ultralow r2 /r1 ratios (< 1.6, 3.0 T). The ferromagnetism of OGMCs is completely different from the paramagnetism of commercial and reported GBCAs. The ferromagnetism is very weak (Ms  < 1.0 emu g-1 ) leading to a low r2 , which is preferred for T1 MRI. Gd3+ is not released from the OGMC Gd-PAA12 and Gd-PASP11, ensuring biosafety for in vivo applications. The safety and T1 -weighted MRI efficiencies of the OGMC Gd-PAA12 and Gd-PASP11 are tested in cells and mice. The synthesis method of the OGMCs is facile and easy to be scaled up. Consequently, the OGMC Gd-PAA12 and Gd-PASP11 are superior T1 -weighted CAs with promising translatability to replace the commercial Gd chelates.

Modified amino-dextrans as carriers of Gd-chelates for retrograde transport and visualization of peripheral nerves by magnetic resonance imaging (MRI)

Amino-dextrans (AD) conjugated with gadolinium (Gd3+) were developed as neuro-specific contrast agents (CA) for the visualization of the sciatic nerve in rats by magnetic resonance imaging (MRI). AD with 3, 10, and 70 kDa molecular weights were assessed as carrier molecules known to be transported with various speed by axonal microtubules. Detailed spectroscopic characterizations, analyses by Fast Protein Liquid Chromatography (FPLC), Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE), and inductively coupled plasma-mass spectrometry (ICP-MS), were carried out. For MRI, the paramagnetic Gd3+ ion was coupled as a T1 signal enhancer. The well-established linear chelator, diethylenetriaminepentaacetic acid (DTPA), was used and subsequently replaced by the more stable cyclic chelator 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). In addition, a fluorescently labeled AD-DTPA-Gd was prepared to demonstrate an active transport to the spinal cord by histochemistry. After successful synthesis and characterization, molecular migration of the AD-DTPA-Gd in the sciatic nerve of healthy Sprague Dawley rats was monitored by MRI for up to seven days. Enhancement of nerve structures was evaluated by MRI and correlated with ICP-MS analyses. To investigate the distribution of CA along the neuraxis, all animals were sacrificed after the final MRI monitoring. Nerves, spinal ganglions, and corresponding spinal cord sections were harvested, to determine the localization and concentration of the paramagnetic element. This is the first report that demonstrates the active uptake and transport of AD-Gd conjugates within the sciatic nerve. This new concept may serve as a potential diagnostic tool for the direct visualization and monitoring of the continuity of injured nerves.

Retinoic acid-conjugated chitosan/manganese porphyrin ionic-complex nanoparticles for improved T1 contrast MR imaging of hepatic fibrosis

Noninvasive and precise diagnosis of hepatic fibrosis is very important for the preventive therapeutic regimen of hepatic cirrhosis and cancer. In this study, we fabricated T₁ contrast Mn-porphyrin (MnTPPS₄ )/retinoic acid-chitosan ionic-complex nanoparticles (MRC NPs). The functional properties of MRC NPs were evaluated via transmission electron microscopy (TEM) imaging, release study, cytotoxicity assay, hepatocyte-specific uptake assay, and magnetic resonance (MR) imaging study. TEM images confirmed the typical structure of an ionic-complex NPs with around 100-200 nm of diameter. MnTPPS₄ is released from MRC NPs for up to 24 hr in controlled pattern which implies that more reliable and convenient hepatic MR imaging is possible using of MRC NPs in clinical practice. Hepatocytes uptake assay proved retinoic acid-specific targeting of MRC NPs. The same results were observed in animal pharmacokinetic studies. In vitro MR phantom study, MRC NPs showed an increased T₁ relaxivity (r₁  = 6.772 mM^-1  s^-1 ) in comparison with 3.242 mM^-1  s^-1 of MnTPPS₄ . The result was confirmed again in vivo MR imaging studies. Taken together, MRC NPs displayed a potential for noninvasive diagnostic T₁ MR imaging of hepatic fibrosis with improved target specificity and prolonged MR imaging time window.

Recent nanotheranostics applications for cancer therapy and diagnosis: A review

Nanotheranostics has attracted much attention due to its widespread application in molecular imaging and cancer therapy. Molecular imaging using nanoparticles has attracted special attention in the diagnosis of cancer at early stages. With the progress made in nanotheranostics, studying drug release, accumulation in the target tissue, biodistribution, and treatment effectiveness are other important factors. However, according to the studies conducted in this regard, each nanoparticle has some advantages and limitations that should be examined and then used in clinical applications. The main goal of this review is to explore the recent advancements in nanotheranostics for cancer therapy and diagnosis. Then, it is attempted to present recent studies on nanotheranostics used as a contrast agent in various imaging modalities and a platform for cancer therapy.

A biocompatible theranostic nanoplatform based on magnetic gadolinium-chelated polycyclodextrin: in vitro and in vivo studies

A novel theranostic nanoplatform was prepared based on Fe₃O₄ nanoparticles (NPs) coated with gadolinium ions decorated-polycyclodextrin (PCD) layer (Fe₃O₄@PCD-Gd) and employed for Curcumin (CUR) loading. The dissolution profile of CUR indicated a pH sensitive release manner. Fe₃O₄@PCD-Gd NPs exhibited no significant toxicity against both normal and cancerous cell lines (MCF 10A and 4T1, respectively); while the CUR-free NPs showed more toxicity against 4T1 than MCF 10A cells. In vivo anticancer study revealed appropriate capability of the system in tumor shrinking with no tissue toxicity and adverse effect on body weight. In vivo MR imaging of BALB/c mouse showed both T₁ and T₂ contrast enhancement on the tumor cells. Fe₃O₄@PCD-Gd/CUR NPs showed significant features as a promising multifunctional system having appropriate T₁-T₂ dual contrast enhancement and therapeutic efficacy in cancer theranostics.

Pullulan based stimuli responsive and sub cellular targeted nanoplatforms for biomedical application: Synthesis, nanoformulations and toxicological perspective

With growing interest in polymers of natural origin, innumerable polysaccharides have gained attention for their biomedical application. Pullulan, one of the FDA approved nutraceuticals, possesses multiple unique properties which make them highly advantageous for biomedical applications. This present review encompasses the sources, production, properties and applications of pullulan. It highlights various pullulan based stimuli-responsive systems (temperature, pH, ultrasound, magnetic), subcellular targeted systems (mitochondria, Golgi apparatus/endoplasmic reticulum, lysosome, endosome), lipid-vesicular systems (solid-lipid nanoparticles, liposomes), polymeric nanofibres, micelles, inorganic (SPIONs, gold and silver nanoparticles), carbon-based nanoplatforms (carbon nanotubes, fullerenes, nanodiamonds) and quantum dots. This article also gives insight into different biomedical, therapeutic and diagnostic applications of pullulan viz., imaging, tumor targeting, stem cell therapy, gene therapy, vaccine delivery, cosmetic applications, protein delivery, tissue engineering, photodynamic therapy and chaperone-like activities. The review also includes the toxicological profile of pullulan which is helpful for the development of suitable delivery systems for clinical applications.

A cation exchange strategy to construct a targeting nanoprobe for enhanced T1-weighted MR imaging of tumors

Excellent imaging performance and good biocompatibility of contrast agents are considered as prerequisites for accurate tumor diagnosis. In this study, a novel imaging nanoprobe with actively targeting performance based on ultrasmall paramagnetic iron oxide (USPIO) nanoparticles was constructed by a facile cation exchange strategy followed by conjugation with transferrin (Tf). The stable gadolinium (Gd3+) chelation endows the nanoparticles (NPs) with a low value of r2/r1 (1.28) and a relatively high r1 value of 3.2 mM-1 s-1, enabling their use for T1-weighted positive magnetic resonance (MR) imaging. This constructed transferrin modified gadolinium-iron chelate nanoprobe, named as TUG, shows high biocompatibility within a given dose range. More importantly, compared with clinically used Gd-based small molecule contrast agents, the obtained TUG can be more engulfed by breast cancer cells, showing much enhanced T1-weighted positive MR imaging in both subcutaneous and orthotopic tumor models of breast cancer. This novel nanoprobe holds great promise to be utilized as a targeting contrast agent with high efficacy for T1-weighted positive MR imaging.

Dynamic contrast-enhanced MRI with Gd-EOB-DTPA for the quantitative assessment of early-stage liver fibrosis induced by carbon tetrachloride in rabbits

PURPOSE

To explore quantitative parameters obtained by dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) with Gd-EOB-DTPA in discriminating early-stage liver fibrosis (LF) in a rabbit model.

MATERIALS AND METHODS

LF was established in 60 rabbits by the injection of 50% CCl₄ oil solution, whereas 30 rabbits served as the control group. All rabbits underwent pathological examination to determine the LF stage using the METAVIR classification system. DCE MRI was performed, and quantitative parameters, including K^trans, K_ep, V_e, V_p and Re were measured and evaluated among the different LF stages using spearman correlation coefficients and receiver operating characteristic curve.

RESULTS

In all, 24, 25, and 22 rabbits had stage F0, stage F1, and stage F2 LF, respectively. K^trans (r = 0.803) increased, and K_ep (r = -0.495) and Re (r = -0.701) decreased with LF stage progression (P < 0.001), while no significant correlation was found for V_e or V_p. K^trans and Re were significantly different between all LF stage pairs compared (F0 vs. F1, F0 vs. F2, F1 vs. F2, F0 vs. F1-F2, P < 0.05). With the exception of F0 vs. F1, K_ep differed significantly between stages (P < 0.05). The AUC of K^trans was higher than that of other quantitative parameters, with an AUC of 0.92, 0.99, 0.94 and 0.92 for staging F0 vs. F1, F0 vs. F2, F1 vs. F2, and F0 vs. F1-F2, respectively.

CONCLUSION

Among quantitative parameters of Gd-EOB-DTPA DCE MRI, K^trans was the best predictor for quantitatively differentiating early-stage LF.

Core–shell particles for drug-delivery, bioimaging, sensing, and tissue engineering

Core–shell particles offer significant advantages in their use for bioimaging and biosensors.

Functionalized graphene oxide/Fe3O4 hybrids for cellular magnetic resonance imaging and fluorescence labeling

In this work, we developed a T₂-weighted contrast agent based on graphene oxide (GO)/Fe₃O₄ hybrids for efficient cellular magnetic resonance imaging (MRI). The GO/Fe₃O₄ hybrids were obtained by combining with co-precipitation method and pyrolysis method. The structural, surface and magnetic characteristics of the hybrids were systematically characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), AFM, Raman, FT-IR and XRD. The GO/Fe₃O₄ hybrids were functionalized by modifying with anionic and cationic polyelectrolyte through layer-by-layer assembling. The fluorescence probe fluorescein isothiocyanate (FITC) was further loaded on the surface of functionalized GO/Fe₃O₄ hybrids to trace the location of GO/Fe₃O₄ hybrids in cells. Functionalized GO/Fe₃O₄ hybrids possess good hydrophilicity, less cytotoxicity, high MRI enhancement with the relaxivity (r₂) of 493mM^-1s^-1 as well as cellular MRI contrast effect. These obtained results indicated that the functionalized GO/Fe₃O₄ hybrids could have great potential to be utilized as cellular MRI contrast agents for tumor early diagnosis and monitoring.

Current and Future Theranostic Applications of the Lipid-Calcium-Phosphate Nanoparticle Platform

Over the last four years, the Lipid-Calcium-Phosphate (LCP) nanoparticle platform has shown success in a wide range of treatment strategies, recently including theranostics. The high specific drug loading of radiometals into LCP, coupled with its ability to efficiently encapsulate many types of cytotoxic agents, allows a broad range of theranostic applications, many of which are yet unexplored. In addition to providing an overview of current medical imaging modalities, this review highlights the current theranostic applications for LCP using SPECT and PET, and discusses potential future uses of the platform by comparing it with both systemically and locally delivered clinical radiotherapy options as well as introducing its applications as an MRI contrast agent. Strengths and weaknesses of LCP and of nanoparticles in general are discussed, as well as caveats regarding the use of fluorescence to determine the accumulation or biodistribution of a probe.