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Synthesis Gd Ion-Based Contrast Agent for MRI Imaging of Musculoskeletal Trauma

Zolala, Hanieh | 2025

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 58826 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madaah Hosseini, Hamid Reza; Khachatourian, Adrineh
  7. Abstract:
  8. Given the importance of detecting damaged tissue following musculoskeletal trauma and preventing osteoarthritis, various imaging modalities are employed. Among these, magnetic resonance imaging (MRI) is particularly valuable due to its high efficacy and lack of ionizing radiation, additionally enabling molecular imaging. To enhance image resolution, contrast agents can be utilized, and through their surface modification, targeted imaging of damaged tissue can be achieved. Following joint trauma, the levels of the inflammatory cytokine IL-1β rise; therefore, designing a targeted contrast agent for this molecule is of great importance. In this study, a gadolinium-based contrast agent was designed to interact with IL-1β, employing baicalin—a phytochemical derived from the root of Scutellaria baicalensis with anti-inflammatory and antioxidant properties, as well as the ability to bind to the active site of this cytokine. For this reason, nanoparticle surfaces were modified with baicalin to enable more effective interaction with the active site of the inflammatory cytokine IL-1β. in this research, ultra-small gadolinium oxide (Gd₂O₃) nanoparticles were synthesized as a positive contrast agent using the polyol method. According to Solomon–Morgan theory, restricting the motion of a positive contrast agent within its environment increases the rotational correlation time (τ_R), enhances the longitudinal relaxivity (r₁), and results in brighter T₁-weighted images. Hence, mesoporous hydroxyapatite nanoparticles (MPHAN) were employed to restrict the mobility of Gd₂O₃ nanoparticles. The nanoparticle surface was coated with the hydrophilic polymer polyethyleneimine (PEI) to facilitate more effective interaction with baicalin and to achieve relative colloidal stability. The synthesized Gd₂O₃ nanoparticles via the polyol method exhibited approximate dimensions of 4.16 nm, and VSM results confirmed their paramagnetic nature. TEM, BET, and FTIR analyses verified the removal of the F-127 soft template and the presence of porosity within the MPHAN nanoparticles. Furthermore, FESEM analysis confirmed the uniform and homogeneous distribution of Gd₂O₃ nanoparticles within the Gd₂O₃-MPHAN, Gd₂O₃-MPHAN-PEI, and Gd₂O₃-MPHAN-PEI-Ba nanostructures. Turbidimetry results demonstrated the colloidal stability of nanoparticles after PEI coating and relative stability following surface modification with baicalin. FTIR results also confirmed the presence of PEI on the surface of Gd₂O₃-MPHAN nanoparticles and the formation of amide bonds between PEI and baicalin. Docking studies revealed effective interaction and minimum binding energy between the baicalin-polyethyleneimine conjugate (PEI-Bai) and the active site of the inflammatory cytokine IL-1β. MRI at 3 Tesla magnetic field strength confirmed increased signal intensity following the addition of MPHAN nanoparticles to Gd₂O₃ nanoparticles, and a concentration-dependent signal enhancement relative to gadolinium ion concentration was verified for all nanostructures, including Gd₂O₃, Gd₂O₃-MPHAN, Gd₂O₃-MPHAN-PEI, and Gd₂O₃-MPHAN-PEI-Bai
  9. Keywords:
  10. Magnetic Resonance Imagin (MRI) ; Positive Imaging Contrast ; Gadolinium Contrast Agent ; Magnetic Resonance Imagin (MRI)Contrast Agent ; Baicalin ; Joint Trauma

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