This review synthesizes recent nanomedicine strategies that aim to bridge the gap between biomarker-oriented nanosensors and imaging probes for earlier detection with targeted nanocarriers designed to overcome delivery barriers, particularly the blood–brain barrier, while improving pharmacokinetics and limiting off-target exposure.
Abstract
Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and is characterized by amyloid-beta deposition, tau pathology, synaptic dysfunction, and progressive cognitive decline. Currently approved symptomatic therapies, including acetylcholinesterase inhibitors and the NMDA receptor antagonist memantine, provide modest and time-limited benefit and do not directly modify upstream disease drivers. This review synthesizes recent nanomedicine strategies that aim to bridge this gap by integrating biomarker-oriented nanosensors and imaging probes for earlier detection with targeted nanocarriers designed to overcome delivery barriers, particularly the blood–brain barrier, while improving pharmacokinetics and limiting off-target exposure. We highlight converging design principles, including stimulus-responsive release, receptor- and ligand-guided targeting, biomimetic coatings, and organelle-focused delivery to mitochondria and lysosome-autophagy pathways. Beyond repackaging existing agents, nano-enabled approaches are discussed in relation to amyloid and tau clearance or neutralization, redox and mitochondrial rescue, microglia-centered immunomodulation, and regenerative support for neuronal and neurovascular repair. To move beyond a descriptive overview, this review presents a stage-informed and pathology-guided framework for matching nanomedicine design to amyloid-predominant, tau-dominant, neuroinflammatory, mitochondrial, and advanced neurovascular phenotypes. We also evaluate translational constraints, including long-term safety, biodistribution, reproducibility, immunogenicity, scalable manufacturing, regulatory characterization requirements, and the trade-off between biological sophistication and clinical manufacturability. Finally, we distinguish platforms with nearer-term translational potential, such as selected lipid, polymeric, and extracellular vesicle-based systems, from exploratory multifunctional inorganic or highly complex biomimetic designs. This balanced framing clarifies where nanomedicine may realistically advance disease-modifying therapy while identifying evidence gaps that still limit translation.
Alzheimer’s disease (AD), a progressive neurodegenerative disorder, remains a major global health challenge owing to its complex pathogenesis and the presence of the blood-brain barrier (BBB), which substantially limits the delivery of effective therapeutics to the brain. Extracellular vesicles (EVs), which exhibit favorable biocompatibility, low immunogenicity, and an intrinsic capacity to cross the BBB, have emerged as promising therapeutic agents and delivery platforms for AD. This review focuses on the therapeutic potential of EV-based interventions in AD and summarizes recent advances in EV-mediated modulation of AD-related pathological processes, including amyloid-β (Aβ) clearance, tau protein regulation, neuroinflammation suppression, oxidative stress attenuation, and synaptic repair. Although EV-based therapies offer notable advantages, such as targeted BBB penetration and reduced immunogenic responses, their clinical translation remains constrained by safety concerns, including off-target effects, dose-dependent toxicity, and potential disturbances in neuroplasticity. In addition, this review discusses EV engineering strategies aimed at regulating the gut-brain axis (GBA), enhancing brain targeting, and advancing clinical translation. EV-based therapeutic interventions should therefore be developed within a safety-oriented framework supported by rigorous short- and long-term toxicological evaluation. Overall, this review highlights the therapeutic promise of EVs for AD while underscoring the need for rational engineering, standardized characterization, and safety-centered translational strategies to ensure clinical feasibility.
Ailin Wu, Yan Zeng, Yilin Huang et al.· Extracellular Vesicles and C...· 0 citations
BACKGROUND
Alzheimer's disease (AD) is a significant global health challenge characterized as a multifactorial neurodegenerative disorder, involving amyloid-β (Aβ) and Tau aggregation, neuroinflammation and progressive neuronal injury. While Amyloid-targeted therapies have achieved a breakthrough in prevention of Aβ aggregation, the strategies face notable limitations in achieving curative outcomes and management of amyloid-independent central nervous system (CNS) dysfunction. Consequently, targeting microglia, the central immune cells of the brain, has emerged as a promising strategy to enhance the specificity and efficacy of AD interventions.
MAIN BODY
Accumulating evidence indicates microglial dysfunction is not a passive immune bystander of AD, but serves as a critical mechanistic nexus linking Aβ accumulation and AD symptomatic phenotype. This review critically examines the "next generation" of microglial therapeutics, moving beyond broad immunosuppression to precision phenotype modulation. We highlight breakthrough strategies in recent years including immune reconstitution, metabolic reprogramming, nanomaterial-mediated drug delivery, and the revolutionary potential of iPSC-derived microglia replacement. By elucidating the rationale underlying the specific strategies based on microglial biofunction and potential molecular mechanism in AD pathology, we provide an overview of current development of clinical trials and cutting-edge modalities aimed at restoring microglial homeostasis, affording an opportunity to alter the AD trajectory.
CONCLUSION
This review aims to delineate the path from bench to bedside and propose promising pathways to overcome current bottlenecks in AD drug development.
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with limited disease-modifying treatment options, partly because many therapeutic agents show insufficient brain exposure and dose-limiting systemic adverse effects after conventional administration. Nose-to-brain (N2B) delivery has emerged as a non-invasive strategy to transport therapeutics to the central nervous system through the olfactory and trigeminal pathways, thereby partially bypassing the blood-brain barrier. Recent advances in nanomedicine and biomaterial engineering have further improved this approach by enhancing drug stability, nasal residence, mucosal transport, and brain-targeting efficiency. This review examines nanocarrier-enabled N2B delivery strategies for AD from a mechanism-guided perspective, highlighting how AD-related pathological processes shape the selection of therapeutic cargos and formulation designs. We discuss recent progress in the intranasal delivery of repurposed small molecules, natural products, insulin-related agents, peptides and proteins, extracellular vesicles, antibodies, and nucleic acid-based therapeutics. We further summarize major nanocarrier and formulation platforms, including lipid-based systems, polymeric nanoparticles, micelles, extracellular vesicles, in situ gels, and device-assisted delivery technologies. Particular attention is given to the design parameters that influence N2B performance, including particle size distribution/PDI, surface charge, mucus interaction, cargo protection, targeting modification, biodistribution, and deposition reproducibility. Finally, we critically evaluate the translational challenges that continue to limit clinical application, including species differences in nasal anatomy, dose-volume restrictions, device-dependent variability, limited human pharmacokinetic evidence, manufacturing complexity, long-term safety, and regulatory requirements. By integrating disease mechanisms, nanocarrier design, and translational considerations, this review provides a structured perspective for developing more rational and clinically feasible N2B nanodelivery systems for AD.
Alzheimer’s disease (AD) remains a major neurodegenerative challenge with limited therapeutic options. Microglia, the resident immune cells of the central nervous system, shape key pathological processes in AD, including amyloid-beta (Aβ) clearance, neuroinflammation, tau pathology, and synaptic homeostasis. Accordingly, microglial receptors that regulate microglial sensing, phagocytosis, and inflammatory signaling have emerged as candidates for disease-modifying interventions. However, translation from preclinical discovery to clinical benefit is impeded by multiple barriers, including stage-dependent receptor functions, peripheral off-target effects, compensatory signaling within interconnected receptor networks, biomarker deficiencies, and species differences, all of which are key bottlenecks detailed in this review. We summarize preclinical and clinical progress in therapeutics targeting microglial receptors; analyze these critical translational bottlenecks; and discuss potential strategies including precision delivery, humanized experimental systems, and biomarker-forward trial designs, with the goal of supporting rigorously designed and biomarker-informed clinical translation.
Alzheimer's Disease (AD) is a prevalent neurodegenerative disorder characterized by progressive cognitive and behavioral impairment and represents a major cause of dementia worldwide. It primarily affects the elderly population. The disease is marked by progressive neuronal damage, leading to impairments in cognition, behavior, emotions, and communication. Although currently available therapies provide symptomatic relief, they fail to alter disease progression, necessitating the development of more effective therapeutic strategies. Phytoconstituents have gained considerable attention due to their neuroprotective properties and multitargeted mechanisms of action against pathways implicated in AD. However, their clinical application is limited by poor Blood-Brain Barrier (BBB) permeability, low bioavailability, and inadequate solubility. Nanotechnology offers a promising approach for brain-targeted drug delivery by enhancing the therapeutic efficacy of phytoconstituents through advanced nanocarrier systems. This review explores the synergistic potential of phytoconstituents and nanocarriers for the management of AD, aiming to improve therapeutic outcomes and overcome existing limitations. It further highlights the integration of medicinal plant-based compounds with nanotechnology as a novel strategy for AD treatment. The combination of nanocarriers and phytoconstituents may facilitate enhanced BBB penetration and improved neuroprotection. Notably, nanomedicine- based approaches, including phytoconstituent-loaded nanoparticles and liposomes, demonstrate significant potential to overcome delivery barriers and enable efficient drug transport to the brain.
Anushka Sharma, Awaneet Kaur, Javed Khan et al.· Central Nervous System Agent...· 0 citations