MnCO3@BSA-ICG nanoparticles as a magnetic resonance/photoacoustic dual-modal contrast agent for functional imaging of acute ischemic stroke

Timely and accurate diagnosis of acute ischemic stroke (AIS) and simultaneous functional imaging of cerebral oxygen saturation (sO2) are essential to improve the survival rate of stroke patients but remains challenging. Herein, we developed a pH-responsive manganese (Mn)-based nanoplatform as a magnetic resonance/photoacoustic (MR/PA) dual-modal contrast agent for AIS diagnosis. The Mn-based nanoplatform was prepared via a simple and green biomimetic method using bovine serum albumin (BSA) as a scaffold for fabrication of MnCO3 NPs as the T1 MR contrast agent and accommodation of indocyanine green (ICG) as the PA probe. The obtained MnCO3@BSA-ICG NPs were biocompatible and exhibited a pH-responsive longitudinal relaxation rate and a concentration-dependent PA signal. In vivo MR/PA dual-modal imaging demonstrated that MnCO3@BSA-ICG NPs quickly and efficiently led to the MR/PA contrast enhancements in the infarcted area while not in the normal region, allowing a timely and accurate diagnosis of AIS. Moreover, PA imaging could directly monitor the sO2 level, enabling a functional imaging of AIS. Therefore, MnCO3@BSA-ICG NPs could be applied as a potential MR/PA contrast agent for timely and functional imaging of AIS.