Photothermally Enhanced Magneto-Nano Drug Delivery for Treating Hearing Loss

Sensorineural hearing loss (SNHL) was a pervasive global health challenge, affecting millions worldwide. Despite advances, efficient drug delivery to the inner ear remained elusive, hindering therapeutic progress. This study aimed to characterize the transport dynamics of superparamagnetic iron oxide nanoparticles (SPIONs) and Brain-Derived Neurotrophic Factor (BDNF) across the round window membrane (RWM) of guinea pigs, a crucial barrier for drug delivery to the cochlea. SPION transport was investigated in relation to core size and magnetic field strength. Size-dependent transport rates were explored using custom-synthesized SPIONs under varying magnetic field strengths and exposure times. Methodology included seed-mediated growth synthesis, and rigorous physicochemical characterization. The effect of SPION surface charge on transport across the RWM was assessed. Positively and negatively charged SPIONs were tested for transport efficiency. Data analysis elucidated the impact of surface charge on SPION-RWM interactions. The photothermally-enhanced SPION transport was also investigated. Laser-induced photothermal activation was aimed at augmenting nanoparticle transport through the RWM. Photothermal experiments and transport studies were conducted under laser irradiation. The optimal SPION properties were identified for enhanced BDNF delivery across the RWM, elucidating the roles of surface charge and photothermal activation on nanoparticle transport, and assessing transport dynamics in guinea pig and human RWM models. These findings advanced our understanding of nanoparticle-mediated drug delivery mechanisms, offering insights for targeted SNHL therapies.