Browsing by Author "Anamika Chaturvedi"

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In vitro and ex vivo relaxometric properties of ethylene glycol coated gadolinium oxide nanoparticles for potential use as contrast agents in magnetic resonance imaging
(American Institute of Physics Inc., 2020) Anamika Chaturvedi; Pranjali Pranjali; Mukesh Kumar Meher; Ritu Raj; Madhuri Basak; Ranjan Kumar Singh; Krishna Mohan Poluri; Dinesh Kumar; Anupam Guleria
Magnetic nanoparticles (MNPs) have widely demonstrated their applicability in many biomedical applications including magnetic resonance imaging (MRI), hyperthermia, and drug delivery. However, the effectiveness of MNPs can be limited for in vivo applications due to their hydrophobic surfaces leading to nanoparticle agglomeration and thus requires appropriate surface modification to enhance colloidal stability. Glycols are widely used coating material for surface modifications of MNPs to improve their physicochemical properties and biocompatibility. The present work reports the preparation of two different sized ethylene glycol coated gadolinium oxide nanoparticles (EG@Gd2O3 NPs) using two different synthesis approaches and their applicability as contrast agents in MRI. Thermo-gravimetric analysis and Fourier transform infrared spectroscopy confirmed the successful coating of ethylene glycol on the surface of NPs. We found that independent of the size of NPs, the globular shaped EG@Gd2O3 NPs exhibited similar crystal structures, magnetic properties, and cellular cytotoxicity behavior. However, a significant impact of size on MRI contrast enhancement properties was seen. It was revealed that the relaxivity of EG@Gd2O3 NPs increases with a decrease in particle size. Small sized EG@Gd2O3 NPs (∼12 nm) exhibited a high specific in vitro and ex vivo longitudinal relaxivity of 3.7 and 1.5 mM-1 s-1, respectively, thus clearly elucidating the potential of these NPs for use as local contrast enhancement agents. The present study gives insights into the intrinsic dependence of magnetic resonance contrast effects of NPs on particle size and surface coating layer mass ratio and thus demonstrates the development of efficient magnetic nanoparticles based contrast agents by fine tuning of particle size and surface properties. © 2020 Author(s).
Investigation of magnetic resonance contrast properties of PEG-coated gadolinium oxide nanoparticles in various biological environments
(Institute of Physics, 2024) Anamika Chaturvedi; Pranjali Pranjali; Ritu Raj; Ayush Shukla; Ranjana Singh; Deepak Kumar Tripathi; Krishna Mohan Poluri; Ranjan Kumar Singh; Dinesh Kumar; Anupam Guleria
Magnetic nanoparticles (MNPs) are promising tools for biomedical applications, particularly in molecular imaging using magnetic resonance imaging (MRI). The unique magnetic properties of MNPs, combined with their similarity in size to biological objects, make them ideal candidates for in situ imaging probes. The present study explores the use of magnetic nanoparticles (MNPs) as contrast agents in magnetic resonance imaging (MRI) for improved diagnostic accuracy. Specifically, the study investigates the MR contrast properties of polyethylene glycol-coated gadolinium oxide nanoparticles (PEG@GONPs) in five different biological fluids. The nanoparticles were synthesized using the polyol route and their size, shape, and morphology were characterized using TEM, SEM, and FT-IR spectroscopy. The magnetic resonance (MR) relaxivity of PEG@GONPs was studied in different biologically relevant media, and results revealed highest relaxivity in plasma as compared to other media. In addition, comparative analysis of proton relaxivity of the synthesized nanoparticles was carried out with a well-known gadolinium-based contrast agent, Omniscan, in various medium. The present findings revealed that PEG@GONPs can serve as an effective contrast agent for MRI imaging in biological fluids such as plasma, which is crucial for preclinical diagnosis of specific diseases and lesions. The high relaxivity observed in plasma could be attributed to the interaction of the nanoparticles with plasma proteins, amplifying their magnetic properties which further improve their ability to produce contrast in MR images. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Role of surface hydrophilicity on MR relaxivity of PEG coated- gadolinium oxide nanoparticles
(Institute of Physics, 2023) Pranjali Pranjali; Deepak Kumar Tripathi; Anamika Chaturvedi; Ranjan Kumar Singh; Krishna Mohan Poluri; Dinesh Kumar; Anupam Guleria
The magnetic resonance (MR) contrast enhancement capabilities of gadolinium oxide nanoparticles (GONPs) have high dependency on its surface chemistry- as the solution properties such as colloidal stability and hydrodynamic diameter of nanoparticles which are prime regulatory parameter for MR relaxivity, are all governed by grafting density of surface material. However, the purification of synthesized surface coated nanoparticles, without compromising the surface properties, remains a major challenge. Among the various cleaning methods, dialysis is often used to remove the unwanted by-products produced during synthesis. However, the effect of dialysis time may significantly impact the surface properties and hence, the MR contrast properties of such nano-formulations. The aim of the present study is to evaluate the effect of dialysis time on surface chemistry and MR contrast enhancement properties of GONPs by comparing the proton relaxivity data. Ultra-small polyethylene glycol (PEG)-coated GONPs with an average particle diameter of 17 nm were synthesized using polyol method. The impact of dialysis time has been investigated systematically on the size distribution, hydrophilicity, magnetic properties, polymer grafting density and relaxometric properties of the as synthesized GONPs. A significant impact of dialysis time was observed on surface chemistry and hence, on the MR relaxivity of synthesized NPs. We evidenced a dramatic decrease in the proton relaxivities of GONPs with increase in dialysis time, which correlated well with the observed decrease in the grafting density of surface polymer. The results clearly indicate that the proton relaxivity of GONPs of similar size and same coating material depends on the surface coating thickness and hydrophilicity of the coating polymer. Overall, it is essential to optimize the accurate time duration of dialysis treatment as the prolonged dialysis may have negative effect on the relaxation times and hence on MR contrast enhancement properties of GONPs. This study is a strategic pathway to fine-tune the dialysis treatment of as-synthesized surface-capped GONPs for pre-eminent MR contrast imaging. © 2022 IOP Publishing Ltd.