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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. [ABSTRACT FROM AUTHOR]

Super Paramagnetic Iron Oxide Nanoparticles have attracted much attention in drug delivery systems because of their considerable surface-to-volume ratio and content as well. In this regard, in this study, four different formulations of magnetic nanoparticles were synthesized via various polymeric coating layer (beta-cyclodextrin, Chitosan, Gum Arabic, and Alginate) in order to find an appropriate polymer in terms of higher drug loading efficiency and capacity. Molecular dynamics simulation and Quantum mechanics were manipulated to examine the interaction mechanism between the polysaccharide polymers and Doxorubicin. Based on the calculated results, As the best candidate, bCD was chosen for DOX loading. DOX, a hydrophilic drug, was loaded into each of the four formulations. The optimum formulation, Fe3O4-ßCD, possessed loading efficiency and capacity, with 97% and 13%, respectively. The selected nanocarrier was fully characterized by Fourier Transform Infrared, VSM, TGA, XRD, SEM, UV-Vis, DLS, and TEM. TEM result exhibited the prepared Fe3O4-ßCD-DOX nanoparticles had a spherical shape (core and shell) and the size of around 15 nm. In vitro release investigation was conducted using HPLC analysis in the phosphate-buffered saline in acidic (pH=5.4) and neutral (pH=7.4) medium. The obtained results demonstrated that a sustain release performance for more than 72 h with the amount of 50% DOX release in pH=5.4. Cytotoxicity assay showed the toxicity of bare Fe3O4 and Fe3O4-ßCDNPsagainst MDA-MB468 cancerous cell and MCF10A normal cell was negligible and DOX-loaded NPs (Fe3O4-ßCD-DOX) illustrated a higher toxicity in MDA-MB468 cancerous cells than MCF 10A normal cells. The results showed that Fe3O4-ßCD-DOXNPs could improve the therapeutic efficacy and also reduce the adversarial effects; accordingly, the prepared system could be served as a promising drug delivery system in cancer treatment. [ABSTRACT FROM AUTHOR]

The combination of imaging contrast media and treatment strategies in one nanosystem has received great attention for cancer detection and treatment. This study aimed to develop Au@MnO/PEG/5FU (AMP/5FU) nanoparticles (NPs) for dual-modal CT/MRI and 5-Fluorouracil (5FU) anticancer drug delivery. The NPs showed a high 5FU loading capacity (90%), pH-responsive release profile, considerable X-ray attenuation, and MRI r1 relaxivity of 4.36 mM−1s−1. They had a significant toxic impact against A549 cancer cells that was greater than that of free 5FU. AMP/5FU NPs can be considered as a high potential multifunctional nanosystem for dual-modal CT/MRI and pH-responsive 5FU delivery. [ABSTRACT FROM AUTHOR]

This study introduces a simple method for preparing a new generation of MnO2 nanomaterials (MNMs) using tannic acid as a template. Two shapes of MnO2 NMs, flower-like M1-MnO2 and near-spherical M2-MnO2, were prepared and compared as dual-active nanozymes and contrast agents in magnetic resonance imaging (MRI). Various parameters, including the crystallinity, morphology, magnetic saturation (Ms), surface functionality, surface area, and porosity of the MNMs were investigated. Flower-like M1-MnO2 NMs were biocompatible and exhibited pH-sensitive oxidase and peroxidase mimetic activity, more potent than near-spherical M2-MnO2. Furthermore, the signal intensity and r1 relaxivity strongly depended on the crystallinity, morphology, pore size, and specific surface area of the synthesized MNMs. Our findings suggest that flower-like M1-MnO2 NM with acceptable dual-enzyme mimetic (oxidase-like and peroxidase-like) and T1 MRI contrast activities could be employed as a promising theranostic system for future purposes. [ABSTRACT FROM AUTHOR]

Objective: A novel efficient pH-sensitive targeted magnetic resonance imaging (MRI) contrast agent and innovative radio-sensitizing system were synthesized based on MnO2 NPs coated with biocompatible poly-dimethyl-amino-ethyl methacrylate-Co-itaconic acid, (DMAEMA-Co-IA) and targeted with methotrexate (MTX). Materials and methods: The as-established NPs were fully characterized and evaluated for MRI signal enhancement, relaxivity, in vitro cell targeting, cell toxicity, blood compatibility, and radiotherapy (RT) efficacy. Results: The targeted NPs MnO2@Poly(DMAEMA-Co-IA) and MTX-loaded NPs inhibited MCF-7 cell viability more effectively than free MTX after 24 and 48 h, respectively, with no noticeable toxicity. Additionally, the insignificant hemolytic activity demonstrated their proper hemo-compatibility. T1-weighted magnetic resonance imaging was used to distinguish the differential uptake of the produced MnO2@Poly(DMAEMA-Co-IA)-MTX NPs in malignant cells compared to normal ones in the presence of high and low MTX receptor cells (MCF-7 and MCF-10A, respectively). In MRI, the produced theranostic NPs displayed pH-responsive contrast enhancement. As shown by in vitro assays, treatment of cells with MnO2@Poly(DMAEMA-Co-IA)-MTX NPs prior to radiotherapy in hypoxic conditions significantly enhanced therapeutic efficacy. Conclusion: We draw the conclusion that using MnO2@Poly(DMAEMA-Co-IA)-MTX NPs in MR imaging and combination radiotherapy may be a successful method for imaging and radiation therapy of hypoxia cells. [ABSTRACT FROM AUTHOR]

A novel targeted tumor contrast agent in magnetic resonance imaging (MRI) was synthesized based on Fe3O4@Au nanoparticle coated with polyethylene glycol (PEG) and decorated with trastuzumab (TZ). The prepared system was fully characterized, and relaxivity, cytotoxicity, colloidal stability, blood compatibility, in vitro cell targeting ability, cytotoxicity, and in vivo MR contrast enhancement were evaluated. The developed system with a size of about 30 nm exhibited excellent stability, blood compatibility, proper relaxivity, negligible in vitro cytotoxicity, and suitable in vivo negative contrast enhancement. Appropriate negative signal enhancement in MRI confirmed the efficiency of the system to be suggested as an encouraging candidate for accurate cancer diagnosis. [ABSTRACT FROM AUTHOR]

Background: Nowadays, there has been a growing demand for low-dose computed tomography (LDCT) protocols. CT has a critical role in the management of the diagnosis chain of pulmonary disease, especially in lung cancer screening. There have been introduced several dose reduction methods, however, most of them are time-consuming, intricate, and vendor-based strategies that are hardly used in clinics routinely. This study aims to evaluate the image quality and pulmonary nodule detectability of LDCT protocols that are feasible and easy implemented. Image quality was analyzed in a general quality control phantom (Gammex) and then in a manmade lung phantom with nodules-equivalent objects. Methods: This study was designed in a two steps, in the first step, a feasible low-dose lung CT protocol was selected with quality assessment of accreditation phantom image. In the second step, the selected low-dose protocol with an appropriate image quality was performed on a manmade lung phantom in which there were objects equivalent to the pulmonary nodule. Finally, image quality parameters of the phantom at the appropriate scan protocol were compared with the standard protocol. Results: A reduction of about 17% of kVp and 46% in tube current leads to dose reduction by about 70%. The contrast-to-noise ratio in the low-dose protocol remained almost unchanged. The signal-to-noise ratio in the low-dose protocol decreased by approximately 32%, and the noise level has increased by about 1.5 times. However, this reduction method hardly affected the detectability of nodules in man-made pulmonary phantom. Conclusions: Here, we demonstrated that the LDCT scan has an insignificant effect on the perception of lung nodules. In this study, patient dose in lung CT was reduced by modifying of kVp and mAs about approximately 70%. Hence, to step in toward low-dose strategies in medical imaging clinics, using easy-implemented and feasible low-dose strategies may be helpful. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed. Materials and methods: A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method. Results: Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%). Findings: CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment. [ABSTRACT FROM AUTHOR]

Contrast agents (CAs) play a critical role in high-resolution magnetic resonance imaging (MRI) applications to enhance the low intrinsic sensitivity of MRI. Manganese oxide nanoparticles (MnO) have gotten developing consideration as substitute spin-lattice (T1) MRI CAs as a result of the Gd-based CAs which are related with renal fibrosis as well as the inherent dark imaging characteristics of superparamagnetic iron oxide NPs. In this review, previous developments in the usage of MnO nanoparticles as MRI CAs for cancer theranostic applications such as developments in toxicological properties, distribution and tumor microenvironment (TME)-responsive biomaterials were reviewed. A literature search was accomplished to discover distributed research that elaborates the use of MnO in multimodal imaging and therapy. In the current study, the electronic search including PubMed/Medline, Embase, ProQuest, Scopus, Cochrane and Google Scholar was performed dependent on Mesh key words. CAs can significantly improve the imaging contrast among the lesions and normal tissues. In this study we generally concentrate on typical advancements of MnO nanoparticles about properties, bimodal or multimodal imaging, and therapy. Numerous researches have demonstrated MnO-based nanostructure produce considerable biocompatibility with the lack of cytotoxicity. Therefore, remarkable features improved photothermal therapy, chemotherapy and Chemodynamic therapy. [ABSTRACT FROM AUTHOR]

β-Cyclodextrine-based polyester was coated on the surface of gadolinium oxide nanoparticles (NPs) and then functionalised with folic acid to produce an efficient pH-sensitive targeted theranostic system (Gd2O3@PCD-FA) for doxorubicin delivery and magnetic resonance imaging (MRI). Gd2O3@PCD-FA was fully characterised by FTIR, vibrating sample magnetometer, TGA, XRD, SEM and TEM analyses. The dissolution profile of DOX showed a pH sensitive release. No significant toxicity was observed for the targeted NPs (Gd2O3@PCD-FA) and DOX-loaded NPs inhibiting M109 cells viability more efficiently than free DOX. Moreover, the negligible hemolytic activity of the targeted NPs showed their appropriate hemocompatibility. The preferential uptake was observed for the developed Gd2O3@PCD-FA-DOX NPs in comparison with Dotarem using T1- and T2-weighted MRI in the presence of folate receptor-positive and folate receptor-negative cancer cells (M109 and 4T1, respectively). Furthermore, in vivo studies revealed that Gd2O3@PCD-FA-DOX not only exhibited considerably relaxivity performance as a contrast agent for MRI, but also improved in vivo anti-tumour efficacy of the system. The results suggest that Gd2O3@PCD-FA-DOX improves its therapeutic efficacy in the treatment of solid tumours and also reduces the adverse effects, so it could be proposed as a promising drug delivery system for chemotherapy and molecular imaging diagnosis in MRI. [ABSTRACT FROM AUTHOR]