Amyloid Targeting "Artificial Chaperone" Impairs Oligomer Mediated Neuronal Damage and Mitochondrial Dysfunction Associated with Alzheimer's Disease.

Alzheimer's disease (AD) is an irreversible memory disorder associated with multiple neuropathological events including amyloid aggregation that triggers oxidative stress and mitochondrial dysfunction in humans. Herein, a new artificial chaperone, benzimidazole functionalized polyfluorene (PFBZ) is reported to efficiently sequester toxic amyloid beta (Aβ) by binding at their 'amyloidogenic domain' (Aβ16-21) with unprecedented selectivity and prevent amyloid-mediated neuronal damage in a wild-type (WT) mouse model. An accurate dose of PFBZ chaperone successfully attenuated an amyloid triggered internal hemorrhage and pyknosis in the cerebral cortex of WT mice. The structural advantage of the polymer results in an efficient Cu(II) chelation arresting a redox cycle to prevent reactive oxygen species (ROS) generation and protect mitochondria from ROS mediated damage. This was further evidenced by caspase activation and mitochondrial membrane potential (MMP) biomarkers and was complemented by brain histology and electron microscopy data which revealed that the PFBZ chaperone provided a protective coating over the amyloid surface and resists from interacting with cell membrane and prevents inducing toxicity. This conjugated polymer artificial chaperone-based nanodrug showed exceptional properties such as its multipotent and highly biocompatible nature, the first of its kind with specific amyloid (Aβ16-21) targeting behavior, bioimaging, and BBB permeability with a potential to suppress amyloid triggered neurotoxicity implicated in numerous human disorders through a rare synergistic mechanism.