Development of Antibody Conjugated Nanoparticles for Targeting Cerebrovascular Amyloid Deposits

Abstract

Cerebral Amyloid Angiopathy (CAA) is characterized by the deposition of amyloid beta (Aβ) proteins in the cerebral vasculature. CAA could independently cause massive lobar hemorrhages and stroke. Moreover, CAA affects majority of Alzheimer’s Disease (AD) patients and is associated with a rapid decline in memory and cognition in AD1. Currently, there is no pre-mortem diagnosis available for CAA, the treatment options are ineffective, and just provide symptomatic relief. Also, the current diagnostic agents do not provide the required spatial resolution and contrast enhancement for the early detection of cerebrovascular amyloid deposits. To overcome these issues, our lab aims to design novel theranostic nanovehicles capable of targeting the cerebrovascular amyloid deposits. These nanovehicles are expected to facilitate the early diagnosis of CAA by enabling the detection of cerebrovascular amyloid with high specificity and sensitivity. The goal of the current study was to optimize the amyloid targeting and contrast enhancement for cerebrovascular amyloid detection by positron emission tomography (PET) and magnetic resonance imaging (MRI). Chitosan-polycarbophil nanoparticles (NPs) were functionalized with the anti-amyloid antibody IgG4.1 using carbodiimide chemistry. We characterized the particles for various physicochemical properties. The NPs were fluorescently labeled with Alexa Fluor 647 to evaluate amyloid protein targeting in vitro using human cerebral microvascular endothelial cell (hCMEC/D3) monolayers and in mouse models in vivo. We optimized the labeling of the NPs with PET isotope 89Zr followed by their serum stability studies prior to in vivo injections. The nanoprobe could also be employed for the early detection of other cerebrovascular diseases, by incorporating appropriate targeting moieties.