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Biotin Conjugated Fe(III)-Triscatecholate Complex as Tumour Targeting T1 MRI Contrast Agent via Second Sphere Water
Maheshwaran Duraiyarasu1,2, S Senthil Kumaran3, Ramasamy Mayilmurugan1
1Department of Chemistry, & Department of Bioscience & Biomedical Engineering, Indian Institute of Technology Bhilai, Durg, 491002, Chattisgarh, India.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|December 10, 2024
Summary
A new biotin-conjugated iron complex, Fe(BioL)3, shows promise as a targeted magnetic resonance imaging contrast agent. It enhances tumor imaging by increasing payload and demonstrating good cell viability and iron uptake in cancer cells.
Area of Science:
- Biomedical Imaging
- Nanotechnology
- Materials Science
Background:
- Early-stage tumor detection requires advanced imaging techniques.
- Targeted contrast agents (CAs) can improve diagnostic accuracy in magnetic resonance imaging (MRI).
- Biotin conjugation offers a specific targeting mechanism for cancer cells.
Purpose of the Study:
- To develop and characterize a novel biotin-conjugated Fe(III) catecholate complex, Fe(BioL)3, as a targeted MRI contrast agent.
- To evaluate the potential of Fe(BioL)3 for enhanced early-stage tumor imaging.
- To assess the complex's relaxivity, stability, and cellular interactions.
Main Methods:
- Synthesis and characterization of the biotin-conjugated Fe(III) catecholate complex, Fe(BioL)3.
- Electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) for structural and electronic analysis.
- Relaxivity measurements (r1 and r2) at different temperatures and in the presence of serum albumin (BSA/HSA) and avidin.
- Cell viability assays using human gastric adenocarcinoma (AGS) cells.
Main Results:
- Fe(BioL)3 exhibits a high formation constant (log K = 45), exceeding that of [Fe(EDTA)].
- The complex shows temperature-dependent relaxivity (r1 = 3.09 mM⁻¹s⁻¹ at 25°C, 1.95 mM⁻¹s⁻¹ at 37°C) due to second-sphere water interactions.
- Binding to BSA and HSA significantly enhances relaxivity (up to 10.0 mM⁻¹s⁻¹).
- Uptake studies with avidin show substantial increases in r1 (46%) and r2 (37%) relaxivities.
- Fe(BioL)3 demonstrates good biocompatibility with 80% cell viability in AGS cells and high iron uptake (89%).
Conclusions:
- The biotin-conjugated Fe(III) complex Fe(BioL)3 is a stable and effective MRI contrast agent.
- Its targeted nature and enhanced relaxivity properties make it a promising candidate for early-stage tumor imaging.
- The complex's biocompatibility and cellular uptake further support its potential clinical applications.
