Implantable Intraocular Fluorescence Sensor for Visualized Monitoring of Alzheimer's Disease

Abstract

With an increase in the older individuals, the global incidence of Alzheimer's disease (AD) is increasing. Early diagnosis of AD necessitates long-term monitoring; however, conventional diagnostic methods such as positron emission tomography (PET) and magnetic resonance imaging (MRI) are unsuitable for frequent use because of infrastructure limitations. The eye, connected to the brain via the optic nerve, offers a potential window for monitoring neurodegenerative diseases. This study presents a novel system for continuous intraocular monitoring using a fluorescent aptamer-conjugated intraocular lens (FAIOL). FAIOL emits fluorescent signals in the presence of beta-secretase-1 (BACE1), an enzyme associated with amyloid beta 1–42 production. These signals can be analyzed using mobile phone applications. In vitro, experiments demonstrates that FAIOL responded to BACE1 by detecting low concentrations of the target molecule over extended periods. Ex vivo tests using porcine eyeballs shows an increase in the fluorescence signal intensity by more than 8% within 5 h in the presence of BACE1. The integrated image analysis program reduces sensor noise and provides numerical signal values, facilitating a straightforward interpretation. FAIOL holds significant potential as an innovative platform for the early diagnosis and long-term monitoring of AD and promises improved patient outcomes through timely intervention and ongoing surveillance.