| 1. |
- Saladino, Giovanni Marco, et al.
(författare)
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A versatile strategy to synthesize sugar ligand coated superparamagnetic iron oxide nanoparticles and investigation of their antibacterial activity
- 2021
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Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 613
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Tidskriftsartikel (refereegranskat)abstract
- For the time being, a great attention has been given to the search of green and reusable materials with antibacterial properties. The present research focused on the design and synthesis of hybrid structures constituting superparamagnetic iron oxide nanoparticles (SPIONs) coated with sugar ligands (SL), synthesized using a green and efficient microwave (MW)-assisted hydrothermal synthesis. The sugar ligands were selectively engineered to obtain antibacterial characteristics towards multi-drug resistant bacterial strains, which are among the most problematic bacterial species in antibiotic development efforts. The superparamagnetic behavior was obtained by synthesizing core iron oxide nanoparticles with a diameter below twenty nm. The MW-assisted hydrothermal method yielded a uniform coating of SPIONs with several sugar ligands, granting strongly negative-charged surfaces, which have eventually contributed to their bactericidal activity. The research work allowed to get insights into the magnetic properties of the sugar ligand coated SPIONs, as well as on morphological and functional characteristics of the hybrid nanoparticles, by employing both spectroscopy and imaging techniques, such as FT-IR, Scanning/Transmission Electron Microscopy (S/TEM). Detailed characterizations of the nanoparticles' charge, using zeta potential analysis helped to identify the highly charged hybrids for antibacterial applications. Furthermore, studies on the bactericidal properties of selected SL-SPION hybrids highlighted a high selectivity towards both gram-negative and gram-positive bacteria along with improving bactericidal activity of streptomycin/penicillin mixture. Detailed studies done on Pseudomonas aeruginosa revealed that the SPIONs selectively downregulated the virulence factor pyoverdine and altered bacterial morphology depending on the SL chemistry. The synthesized materials with antibacterial activity pave the way for an effective path towards the design and development of nanostructures and coatings against antibiotic-resistant bacterial species.
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| 2. |
- Saladino, Giovanni Marco, et al.
(författare)
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Functional Coatings for X-ray Fluorescent Nanoparticles
- 2022
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Ingår i: Proceedings of the 6th International Conference on Theoretical and Applied Nanoscience and Nanotechnology, TANN 2022. - : Avestia Publishing.
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Konferensbidrag (refereegranskat)abstract
- In recent years, the design and synthesis of bio-compatible coatings leading to hybrid nanoparticles (NPs) as the contrast agents have gained substantial relevance. Furthermore, the addition of several functionalities for bio-imaging applications represents a key step for non-invasive bio-diagnostics. In this context, we design and utilize hybrid nanostructures for X-ray fluorescence computed tomography (XFCT). The combination of a ceramic or metallic core–based on MoO2, Rh or Ru–with a protective shell allows the generation of bio-compatible nanohybrids for dual mode bio-imaging, where the core NPs constitute the X-ray fluorescence (XRF) contrast agents [1]–[3]. Core NPs are synthesized via polyol, hydrothermal or microwave-assisted hydrothermal methods, yielding uniform shape and high dispersibility in aqueous media. Different approaches have been pursued for the fabrication of a bio-compatible shell coating. A modified sol-gel based silica coating process, doped with a commercial fluorophore (Cy5.5), was developed and shown to be applicable to both ceramic and metallic NPs [4], forming core-shell NPs with both optical and X-ray fluorescence properties. Alternatively, carbon quantum dots (CQDs) were synthesized via citrate pyrolysis using microwave-assisted hydrothermal method, exhibiting uniform size distribution (1.6±0.4 nm) and excitation-independent emission (440 nm). Conjugation of these CQDs, via cross-linking, with Rh NPs led to excitation-independent hybrid NPs, with a red-shifted emission wavelength (520 nm), attributed to the reduction of pyrrolic nitrogen on CQDs [5]. These hybrid NPs exhibit improved in vitro biocompatibility in comparison with bare XRF contrast agents. Furthermore, the optical fluorescence–provided by Cy5.5 or CQDs–allows the localization of the NPs in the intracellular environment while the XRF signal from the core NPs is utilized for XFCT, in small animals, leading to both a microscopic and macroscopic bio-imaging contrast agent.
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| 3. |
- Saladino, Giovanni Marco, et al.
(författare)
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Iterative nanoparticle bioengineering enabled by x-ray fluorescence imaging
- 2024
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles (NPs) are currently developed for drug delivery and molecular imaging. However, they often get intercepted before reaching their target, leading to low targeting efficacy and signal-to-noise ratio. They tend to accumulate in organs like lungs, liver, kidneys, and spleen. The remedy is to iteratively engineer NP surface properties and administration strategies, presently a time-consuming process that includes organ dissection at different time points. To improve this, we propose a rapid iterative approach using whole-animal x-ray fluorescence (XRF) imaging to systematically evaluate NP distribution in vivo. We applied this method to molybdenum-based NPs and clodronate liposomes for tumor targeting with transient macrophage depletion, leading to reduced accumulations in lungs and liver and eventual tumor detection. XRF computed tomography (XFCT) provided 3D insight into NP distribution within the tumor. We validated the results using a multiscale imaging approach with dye-doped NPs and gene expression analysis for nanotoxicological profiling. XRF imaging holds potential for advancing therapeutics and diagnostics in preclinical pharmacokinetic studies.
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| 4. |
- Saladino, Giovanni Marco
(författare)
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Preclinical X-Ray Fluorescence Imaging with Multifunctional Nanoparticles
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- X-ray fluorescence imaging (XFI) is an emerging technique for preclinical studies, characterized by high resolution, specificity, and sensitivity. It relies on nanoparticles (NPs) as contrast agents, which must be constituted of specific elements that match the X-ray source energy for detection. Laboratory liquid metal-jet X-ray sources enable compact in vivo XFI, thereby extending the accessibility of this imaging technique beyond synchrotron facilities.When designing NPs as contrast agents, biocompatibility is essential for both preclinical and clinical imaging, often requiring a passivating biocompatible coating on the NP surface. The NP cores can provide contrast by their elemental composition, while coating, conjugation, and decoration strategies can add other functionalities and improve biocompatibility.In this thesis, multifunctional NPs are designed to extend the functionality of XFI contrast agents by incorporating optically fluorescent or magnetically active components: conjugated carbon quantum dots, dye-doped silica shell, and decorated superparamagnetic iron oxide NPs. The designed multifunctional NPs allow correlative and multiscale imaging with complementary techniques such as confocal optical microscopy or magnetic resonance imaging (MRI). Furthermore, these NPs also facilitate more comprehensive studies on NP pharmacokinetics, paving the way for more robust investigations in the field of nanomedicine.The benefits of multifunctional NPs are demonstrated with two approaches. First, in vivo correlative imaging with MRI and XFI is shown to reduce false positives caused by MRI artifacts in the lungs and abdomen. Second, XFI is employed to enable rapid NP bioengineering, by iteratively improving NP properties and administration strategies for passive tumor targeting. Optical and X-ray fluorescent multifunctional NPs enable the co-localization of NPs at both macroscopic and microscopic levels with XFI and confocal microscopy, correlating NP accumulation in organs with NP-cell interactions. These results highlight the role of XFI in the field of nanomedicine, with potential applications in pharmacokinetics, tumor targeting, treatment monitoring, and the development of medical devices.
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