Nanocarrier-based drug delivery for mild cognitive impairment: Extracellular vesicles and carbon nanotubes as emerging therapeutic tools.

Mild cognitive impairment (MCI) is the in-between stage between healthy cognitive aging and neurodegenerative diseases such as Alzheimer's disease (AD). As MCI becomes increasingly prevalent in aging populations, there is an urgent need for innovative, targeted strategies to slow its progression. Among emerging tools, extracellular vesicles (EVs) and carbon nanotubes (CNTs) have attracted growing interest as nanocarrier systems with unique abilities to cross the blood-brain barrier (BBB) and deliver therapeutic cargo. This review gathers a detailed overview of their biological mechanisms, engineering strategies, and current preclinical applications, providing new perspectives on how these approaches can potentially delay the progression of MCI. Emphasis is placed on integrating these nanotechnologies into the pathological framework of MCI, highlighting their dual diagnostic and therapeutic potential. By connecting nanomedicine with the pathophysiology of cognitive impairment, this review outlines new frontiers in MCI intervention.