Functional Nanomaterials for the Diagnosis of Alzheimer's Disease: Recent Progress and Future Perspectives

Abstract

Alzheimer's disease (AD) is one of the main causes of dementia worldwide, whereby neuronal death or malfunction leads to cognitive impairment in the elderly population. AD is highly prevalent, with increased projections over the next few decades. Yet current diagnostic methods for AD occur only after the presentation of clinical symptoms. Evidence in the literature points to potential mechanisms of AD induction beginning before clinical symptoms start to present, such as the formation of amyloid beta (Aβ) extracellular plaques and neurofibrillary tangles (NFTs). Biomarkers of AD, including Aβ40, Aβ42, and tau protein, amongst others, show promise for early AD diagnosis. Additional progress is made in the application of biosensing modalities to measure and detect significant changes in these AD biomarkers within patient samples, such as cerebral spinal fluid (CSF) and blood, serum, or plasma. Herein, a comprehensive review of the emerging nano‐biomaterial approaches to develop biosensors for AD biomarkers’ detection is provided. Advances, challenges, and potential of electrochemical, optical, and colorimetric biosensors, focusing on nanoparticle‐based (metallic, magnetic, quantum dots) and nanostructure‐based biomaterials are discussed. Finally, the criteria for incorporating these emerging nano‐biomaterials in clinical settings are presented and assessed, as they hold great potential for enhancing early‐onset AD diagnostics.

Engineering Exosomes for Therapeutic Applications: Decoding Biogenesis, Content Modification, and Cargo Loading Strategies

“…Aside from the results of NMR and mass spectrometric biometabolite research, exosomes may be a feasible option for identifying and treating neurodegenerative disorders. 63 Some exosome biomarkers of neurodegenerative diseases include the formation of amyloid-beta, amyloid precursor proteins, 64 and lactoferrin 65 in Alzheimer’s diseases, aggregation of misfolded alpha-synuclein, 66 muted protein deglycase (DJ-1) 67 in Parkinson’s disease, lower activity of acetylcholinesterase 68 and phosphorylated tau 69 in Parkinson diseases, superoxide dismutase 1 (SOD1) 70 and tar-DNA binding protein-43 (TDP-43) in Amyotrophic lateral sclerosis 71 and mutant huntingtin protein (mHtt) in Huntington disease, 72 as well as miRNA changing in all diseases. 73 In Alzheimer’s disease, released amyloid-beta binds glycoprotein and glycolipid on the exosome.…”

Electrochemical Immunosensors Developed for Amyloid-Beta and Tau Proteins, Leading Biomarkers of Alzheimer’s Disease

“…There are several other challenges and limitations associated with electrochemical immunosensors. They may face limitations in terms of sensitivity, especially when detecting low concentrations of analytes or using complex biological samples [117,118]. Biological samples often contain various interfering substances that can affect the accuracy and reliability of electrochemical immunosensors.…”

Au-Coated ZnO Surface-Enhanced Raman Scattering (SERS) Substrates: Synthesis, Characterization, and Applications in Exosome Detection

“…Accurate detection of biological constituents and molecules is essential to understanding molecular changes in pathophysiological conditions, which can serve as an important target for therapeutic interventions and biomarker discovery. Exosomes, which are a subclass of extracellular vesicles, are now recognized as novel mediators for cell-to-cell communication and repositories for biomarkers in various diseases, including cancer [1,2], Alzheimer's disease [3][4][5], and cardiovascular disease [6,7]. To detect exosomes for diagnostic applications, surface-enhanced Raman scattering (SERS)-based methods have several unique capabilities, such as fingerprint-like identification, non-destructive analysis, easy sample preparation, low sample interference with water, high sensitivity, and multiplexing capabilities [8].…”