A biocompatible, highly sensitive hydrogel-based T1 thermometer for in vivo MRI applications

Le résumé fourni par la source

Accurate and non-invasive temperature mapping in vivo remains a pivotal challenge for biomedical imaging. Herein, we report the development of a biocompatible hydrogel-based thermometer for high-sensitivity temperature monitoring via T 1 -weighted magnetic resonance imaging (MRI). The system consists of the inclusion of the tri-phenyl Gd-DTPA derivative (Gd-1) into the self-assembling peptide hydrogel (Fmoc-K2) to yield a nanostructured network capable of amplifying temperature-dependent relaxivity changes. Unlike conventional aqueous Gd-complexes, the Fmoc-K2/Gd-1 hydrogel exhibits a strong positive correlation between relaxivity (r 1 ) and temperature, with a remarkable sensitivity of Δr 1 /°C = 0.54 s −1 /°C at 1T (40 MHz). This enhancement is attributed to temperature-driven modulation of water dynamics within the hydrogel matrix, as confirmed by 17 O-NMR and NMRD profiling. The device maintains structural and functional stability under physiological conditions and demonstrates reliable temperature reporting either in vitro and in vivo , with subcutaneously injected hydrogel yielding MRI-based thermal readouts in excellent agreement with invasive thermometry. This work establishes a new class of injectable, responsive soft materials for precise MRI thermometry, offering broad translational potential in thermal therapies and physiological monitoring.

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