Cellular uptake, imaging and pathotoxicological studies of a novel Gd[iii]–DO3A-butrol nano-formulation

Toxicity Mechanisms of Gadolinium and Gadolinium-Based Contrast Agents-A Review

Gadolinium-based contrast agents (GBCAs) have been used for more than 30 years to improve magnetic resonance imaging, a crucial tool for medical diagnosis and treatment monitoring across multiple clinical settings. Studies have shown that exposure to GBCAs is associated with gadolinium release and tissue deposition that may cause short- and long-term toxicity in several organs, including the kidney, the main excretion organ of most GBCAs. Considering the increasing prevalence of chronic kidney disease worldwide and that most of the complications following GBCA exposure are associated with renal dysfunction, the mechanisms underlying GBCA toxicity, especially renal toxicity, are particularly important. A better understanding of the gadolinium mechanisms of toxicity may contribute to clarify the safety and/or potential risks associated with the use of GBCAs. In this work, a review of the recent literature concerning gadolinium and GBCA mechanisms of toxicity was performed.

Radioiodination of Modified Porous Silica Nanoparticles as a Potential Candidate of Iodine-131 Drugs Vehicle

There are challenges related to cancer treatment, namely, targeting and biocompatibility associated with a drug vehicle. This research aims to prepare a theranostic cancer vehicle based on porous silica nanoparticles (PSN) with controllable nanoparticle size, supporting targeting properties, and biocompatible. The synthesis method combined the Stöber process and liquid crystal templating using a dispersant and pore expander. Triethanolamine (TEA) and Pluronic F-127 were combined as a steric stabilizer and dispersing agent, while n-hexane was used as a pore expander. The amine functionalization was carried out using the 3-aminopropyl-triethoxysilane solution. Furthermore, radiolabeling of PSN using Iodine-131 and iodogen as oxidizing agents was carried out. The results showed that the best achievable PSN size was 100-150 nm with a polydispersity index of 0.24 using TEA-Pluronic F-127. The functionalization results did not significantly affect the radioiodination result. Radiochemical purity (RCP) values up to 95% were obtained in the radioiodination, while the labeled compounds were relatively stable with 12 mCi radioactivity, indicating the absence of radiolysis. The synthesized PSN was not toxic to normal cell samples up to a concentration of 150 μg/mL for PSN and 170 μg/mL for PSN-NH2. The cellular uptake testing results of the PSN-131I in cancer cell samples showed promising uptake ability.

Using ELP Repeats as a Scaffold for De Novo Construction of Gadolinium-Binding Domains within Multifunctional Recombinant Proteins for Targeted Delivery of Gadolinium to Tumour Cells

Three artificial proteins that bind the gadolinium ion (Gd3+) with tumour-specific ligands were de novo engineered and tested as candidate drugs for binary radiotherapy (BRT) and contrast agents for magnetic resonance imaging (MRI). Gd3+-binding modules were derived from calmodulin. They were joined with elastin-like polypeptide (ELP) repeats from human elastin to form the four-centre Gd3+-binding domain (4MBS-domain) that further was combined with F3 peptide (a ligand of nucleolin, a tumour marker) to form the F3-W4 block. The F3-W4 block was taken alone (E2-13W4 protein), as two repeats (E1-W8) and as three repeats (E1-W12). Each protein was supplemented with three copies of the RGD motif (a ligand of integrin αvβ3) and green fluorescent protein (GFP). In contrast to Magnevist (a Gd-containing contrast agent), the proteins exhibited three to four times higher accumulation in U87MG glioma and A375 melanoma cell lines than in normal fibroblasts. The proteins remained for >24 h in tumours induced by Ca755 adenocarcinoma in C57BL/6 mice. They exhibited stability towards blood proteases and only accumulated in the liver and kidney. The technological advantages of using the engineered proteins as a basis for developing efficient and non-toxic agents for early diagnosis of tumours by MRI as well as part of BRT were demonstrated.

Magnetic levitation assisted biofabrication, culture, and manipulation of 3D cellular structures using a ring magnet based setup

Diamagnetic levitation is an emerging technology for remote manipulation of cells in cell and tissue level applications. Low-cost magnetic levitation configurations using permanent magnets are commonly composed of a culture chamber physically sandwiched between two block magnets that limit working volume and applicability. This work describes a single ring magnet-based magnetic levitation system to eliminate physical limitations for biofabrication. Developed configuration utilizes sample culture volume for construct size manipulation and long-term maintenance. Furthermore, our configuration enables convenient transfer of liquid or solid phases during the levitation. Before biofabrication, we first calibrated/ the platform for levitation with polymeric beads, considering the single cell density range of viable cells. By taking advantage of magnetic focusing and cellular self-assembly, millimeter-sized 3D structures were formed and maintained in the system allowing easy and on-site intervention in cell culture with an open operational space. We demonstrated that the levitation protocol could be adapted for levitation of various cell types (i.e., stem cell, adipocyte and cancer cell) representing cells of different densities by modifying the paramagnetic ion concentration that could be also reduced by manipulating the density of the medium. This technique allowed the manipulation and merging of separately formed 3D biological units, as well as the hybrid biofabrication with biopolymers. In conclusion, we believe that this platform will serve as an important tool in broad fields such as bottom-up tissue engineering, drug discovery and developmental biology.

NIR triggered glycosylated gold nanoshell as a photothermal agent on melanoma cancer cells

Nowadays, gold nanoshells are used in targeted nano photothermal cancer therapy. This study surveyed the application of gold nanoshell (GNs) to thermal ablative therapy for melanoma cancer cells and it takes advantage of the near infrared absorption of gold nanoshells. The synthesis and characterization of glycosylated gold nanoshells (GGNs) were done. The cytotoxicity and photothermal effects of GNs on melanoma cells were evaluated using MTT assay and flow cytometry. The characterization data showed that GGNs are spherical, with a hydrodynamic size of 46.7 nm. Results suggest that the cellular uptake of GGNs was about 78%. Viability assays showed no significant toxicity at low concentrations of GNs. The higher heating rate and toxicity of cancer cells were obtained for the cells exposed to 808 nm NIR laser after incubation with GGNs rather than the GNs. The viability of these cells has dramatically decreased by 29%. Furthermore, 61% more cell lethality was achieved for A375 cells using combined photothermal therapy and treatment with GGNs in comparison to NIR radiation alone. In conclusion, our findings suggest that the synthesized gold/silica core-shell nanoparticles conjugated with glucosamine have high potentials to be considered as an efficient metal-nanoshell in the process of targeted cancer photothermal therapy.

Gd3+-Asparagine-Anionic Linear Globular Dendrimer Second-Generation G2 Complexes: Novel Nanobiohybrid Theranostics

Designing a unique theranostic biocompatible, biodegradable, and cost-effective agent which is easy to be synthesized as a biohybrid material was the aim of this study. In this matter, asparagine attached to anionic linear globular dendrimer G2 (as a biocompatible, biodegradable, and cost-effective agent which is negatively charged nanosized and water soluble polymer that outweighs other traditionally used dendrimers) and finally contrast agent (Gd3+) was loaded (which made complexes) in synthesized asparagine-dendrimer. Observations revealed that, in addition to successful colon cancer and brain targeting, Gd3+-dendrimer-asparagine, the proposed theranostic agent, could increase T1 MR relaxation times, decrease T2 MR relaxation times significantly, and improve contrast of image as well as illustrating good cellular uptake based on florescent microscopy/flow cytometry and ICP-mass data. In addition to that, it increased tumor growth inhibition percentage (TGI%) significantly compared to FDA approved contrast agent, Magnevist. Totally, Gd3+-anionic linear globular dendrimer G2-asparagine could be introduced to the cancer imaging/therapy (theranostics) protocols after in vivo MR and fluorescent analysis and passing clinical trials. Hence, this nanotheranostic agent would be a promising candidate for brain drug delivery and imaging in the future.