Gd (III) complex conjugate of low-molecular-weight chitosan as a contrast agent for magnetic resonance/fluorescence dual-modal imaging
Yan Huang, Peter Osei Boamah, Jianbo Gong, Qi Zhang, Mingqing Hua, Yuzhen Ye
The fusion of molecular and anatomical modalities facilitates more reliable and accurate detection in clinic. In this work, we prepared gadolinium (III) complex Gd-DTPA-FITC-CS11 with magnetic resonance (MR) and fluorescence dual-modal imaging modalities. Gd-DTPA-FITC-CS11 consisted of fluorescein isothiocyanate and low-molecular-weight chitosan (CS11) units conjugated with gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Gd-DTPA-FITC-CS11 exhibited a higher longitudinal relaxivity (14.09 mM−1 s−1) than the clinical Gd-DTPA (3.85 mM−1 s−1). T1-weighted MR contrast enhancement was also demonstrated the comparability to Gd-DTPA at lower dosage. The binding with bovine serum albumin (BSA) was investigated. The fluorescence of BSA in the presence of Gd-DTPA-FITC-CS11 was weakened due to static quenching mechanism. The conformation of BSA was slightly changed but α-helix was dominant. The binding was entropy-driven and spontaneous and the main contribution was hydrophobic interaction. Our results suggested the potential of Gd-DTPA-FITC-CS11 as an MR/fluorescence dual-modal imaging contrast agent in improving the diagnostic sensitivity and accuracy.
Circular dichroism, Secondary structure, Ligand binding, Biochemistry, Polymers