Development of cationic peptide-based hydrogels loaded with iopamidol for CEST-MRI detection

Peptide-based hydrogels have been recently investigated as materials for biomedical applications like tissue engineering and delivery of drugs and imaging agents. Among the synthetic peptide hydrogelators, the cationic hexapeptides Ac-K1 and Ac-K2 were proposed as scaffolds for bioprinting applications. Here, we report the formulation of Ac-K1 and Ac-K2 hydrogels loaded with iopamidol, an iodinated contrast agent clinically approved for X-ray computed tomography, and more recently identified as an efficient CEST-MRI probe. Iopamidol-loaded hydrogels were soft, injectable and non-toxic both in vitro (on three tumor cell lines: GL261, TS/A and 3T3-NIH) and in vivo (in Balb/c mice inoculated with TS/A breast cancer cells). The in vitro CEST-MRI study evidenced the typical features of the CEST pattern of iopamidol, with a CEST contrast higher than 50%. Due to their injectability and good ability to retain the contrast agent, the herein investigated systems can be considered as promising candidates for the development of smart MRI detectable hydrogels.

Automated summary

Peptide-based hydrogels have been investigated as potential materials for biomedical applications. In this study, hydrogels loaded with iopamidol, an approved contrast agent, were developed. The hydrogels showed desirable properties such as injectability, retention of the contrast agent, and non-toxicity in vitro and in vivo. The CEST-MRI study demonstrated a high CEST contrast of iopamidol in the hydrogels. These findings suggest that the developed hydrogels have great potential as smart MRI detectable materials.