PET/MRI-Guided, FUS-Mediated, and Amyloid-Targeted PEG-PLGA Local Super-IDE Enzyme Delivery for Overcoming the Blood-Brain Barrier and Achieving Aβ42 Plaque Clearance

Current antibody treatments (like Lecanemab or Donanemab) for Alzheimer's disease (AD) present two major clinical hurdles: they cannot pass the blood-brain barrier (BBB) effectively, and they cause a dangerous side effect called ARIA (brain swelling and bleeding). Because only 0.1\% of the drug reaches the brain, administering elevated therapeutic doses becomes mandatory, which forces the immune system to attack blood vessels. In this paper, I propose a new theoretical solution to open the BBB safely and destroy the amyloid-beta (Aβ42) plaques without triggering ARIA. My hypothesis suggests using low-intensity Focused Ultrasound (FUS) under PET/MRI guidance to open the BBB only where the plaques are located. At the same time, we can inject smart PEG-PLGA nanoparticles that carry an engineered, acid-stable Insulin-Degrading Enzyme ("Super-IDE"). These nanoparticles will use specific ligands to ignore normal single proteins and bind only to large plaque structures. Once they reach the plaque, the acidic environment (pH around 6.0) will open the nanoparticle and release the enzyme to dissolve the plaque locally. This method avoids using the body's immune system, which means ARIA risks could be reduced to near zero, and it keeps the enzyme locked until it reaches the brain to prevent blood sugar drops. If tested and confirmed in a laboratory, this idea could offer a much safer way to clear toxic proteins in neurodegenerative diseases.