Multifunctional bioreactive-nanoconstructs for sensitive and accurate MRI of cerebrospinal fluid pathology and intervention of Alzheimer’s disease

•A novel multifunctional and bioreactive nanoconstruct (NC) system is designed and synthesized by self-assembly in one-pot.•The NCs efficiently cross the blood-brain barrier and target amyloid-β and oxidative stress-affected AD brain regions.•The NCs enhance MRI contrast enabling non-invasive early detection of CSF pathology with high sensitivity and accuracy.•The NCs facilitate oxygenation, reduce oxidative stress and pro-inflammatory cytokines, and increase neuron survival.