scholarly journals Electrochemical Biosensors Based on Nanomaterials for Early Detection of Alzheimer’s Disease

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4748 ◽  
Author(s):  
Celia Toyos-Rodríguez ◽  
Francisco Javier García-Alonso ◽  
Alfredo de la Escosura-Muñiz
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Detection ◽  
High Sensitivity ◽  
Cost Effective ◽  
Diagnostic Techniques ◽  
Electrochemical Biosensing ◽  
Biological Recognition ◽  
Sensitivity And Selectivity ◽  
Cost Effective Alternative

Alzheimer’s disease (AD) is an untreatable neurodegenerative disease that initially manifests as difficulty to remember recent events and gradually progresses to cognitive impairment. The incidence of AD is growing yearly as life expectancy increases, thus early detection is essential to ensure a better quality of life for diagnosed patients. To reach that purpose, electrochemical biosensing has emerged as a cost-effective alternative to traditional diagnostic techniques, due to its high sensitivity and selectivity. Of special relevance is the incorporation of nanomaterials in biosensors, as they contribute to enhance electron transfer while promoting the immobilization of biological recognition elements. Moreover, nanomaterials have also been employed as labels, due to their unique electroactive and electrocatalytic properties. The aim of this review is to add value in the advances achieved in the detection of AD biomarkers, the strategies followed for the incorporation of nanomaterials and its effect in biosensors performance.

scholarly journals Novel Blood Biomarkers for an Earlier Diagnosis of Alzheimer’s Disease: A Literature Review

2020 ◽  
Author(s):  
Shiavax Rao ◽  
Andrew J. Boileau
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Literature Review ◽  
Clinical Diagnosis ◽  
Sensitivity And Specificity ◽  
Memory Loss ◽  
High Sensitivity ◽  
Diagnostic Techniques ◽  
Pubmed Database ◽  
Diagnostic Approaches

Alzheimer’s disease is a neurodegenerative condition associated with neurofibrillary tangles and cortical deposition of amyloid plaques. Clinical presentation of the disease involves manifestations such as memory loss, cognitive decline and dementia with some of the earliest reported deficits being episodic memory impairment and olfactory dysfunction. Current diagnostic approaches rely on autopsy characterization of gross brain pathology, or brain imaging of biomarkers late in the disease course. The aim of this literature review is to identify and compare newly emerging and novel CSF, serum and mucosal biomarkers, with the potential of making an earlier clinical diagnosis of Alzheimer’s disease. Utilizing such techniques may allow for earlier therapeutic intervention, reduction of disability and enhancement of quality of life. Literature review and analysis was performed by screening the PubMed database for relevant studies within the past 5 years. All studies showed statistically significant (P < 0.05) differences in testing between AD patients and controls. Two categories of serum biomarkers (redox-reactive antiphospholipid antibodies and microRNAs) and an olfactory mucosal marker (microRNA-206) could discriminate between early AD patients and controls with high sensitivity and specificity. In conclusion, certain studies have shown promising results with high sensitivity and specificity, high discriminative potential for Alzheimer’s disease early in its progression, and statistically significant results in larger study samples. Utilization of such diagnostic techniques should increase the efficacy of making an earlier clinical diagnosis of Alzheimer’s disease.

scholarly journals New approaches for Alzheimer early detection

2021 ◽  
Author(s):  
Jordy Silva de Carvalho ◽  
Marina Galdino da Rocha Pitta ◽  
César Augusto Souza de Andrade
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Detection ◽  
Biological Fluids ◽  
The Elderly ◽  
Diagnostic Techniques ◽  
Csf Biomarkers ◽  
Non Invasive ◽  
Pubmed Database ◽  
The Brain

Background: Alzheimer’s disease (AD) is neurodegenerative and complex, characterized by the progressive loss of neurons, causing cognitive deficits. It’s the leading cause of dementia in the elderly, affecting about 35.6 million people worldwide. The high costs of invasive diagnostic techniques have limited early detection and intervention. Objectives: This review approached some new non-invasive diagnostic techniques involved in AD. Methods: The descriptors used were “Alzheimer’s Disease”, “Biomarkers” and “Early diagnosis”. PubMed database was used during the period of 2016-2021. Articles not related to the proposed theme were excluded, leaving 4 articles. Results: In the last few years, great advances have been made in diagnosing AD, such as brain NMR, CSF biomarkers, Pittsburgh compound B and brain PET scan. Beta-amyloid proteins (βA) and TAU in CSF are the only available markers for AD diagnosis in the clinic. The main limitations are early detection, differential diagnosis and progress disease report. Salivary biomarkers are being studied as a simple non-invasive diagnostic tool, with βA1-42/1-40 and pTAU being the most investigated in AD. Acting as a window on the brain, the retina can reflect the pathogenesis of the brain, with a focus on neurodegeneration and microvascular changes measured using optical coherence tomography technologies. Conclusions: Several criteria have been proposed for the diagnosis of AD, including biomarkers, biological fluids and brain changes detectable by imaging. Early detection of AD is vitally important, as it’ll allow patients to receive adequate and individualized information, care and support.

Development and Evaluation of a Tactile Cognitive Function Test Device for Alzheimer’s Disease Early Detection

2015 ◽  
Vol 3 (2) ◽  
pp. 58-65 ◽  
Author(s):  
Jiajia Yang ◽  
Mohd Usairy Syafiq ◽  
Yinghua Yu ◽  
Satoshi Takahashi ◽  
Zhenxin Zhang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Function ◽  
Early Detection ◽  
Test Device ◽  
Function Test ◽  
Cognitive Function Test

scholarly journals Optical Imaging of Beta-Amyloid Plaques in Alzheimer’s Disease

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 255
Author(s):  
Ziyi Luo ◽  
Hao Xu ◽  
Liwei Liu ◽  
Tymish Y. Ohulchanskyy ◽  
Junle Qu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Imaging ◽  
Imaging Techniques ◽  
High Sensitivity ◽  
Pathological Feature ◽  
Promising Tool ◽  
Abnormal Accumulation ◽  
Accumulation Mechanism ◽  
The Brain

Alzheimer’s disease (AD) is a multifactorial, irreversible, and incurable neurodegenerative disease. The main pathological feature of AD is the deposition of misfolded β-amyloid protein (Aβ) plaques in the brain. The abnormal accumulation of Aβ plaques leads to the loss of some neuron functions, further causing the neuron entanglement and the corresponding functional damage, which has a great impact on memory and cognitive functions. Hence, studying the accumulation mechanism of Aβ in the brain and its effect on other tissues is of great significance for the early diagnosis of AD. The current clinical studies of Aβ accumulation mainly rely on medical imaging techniques, which have some deficiencies in sensitivity and specificity. Optical imaging has recently become a research hotspot in the medical field and clinical applications, manifesting noninvasiveness, high sensitivity, absence of ionizing radiation, high contrast, and spatial resolution. Moreover, it is now emerging as a promising tool for the diagnosis and study of Aβ buildup. This review focuses on the application of the optical imaging technique for the determination of Aβ plaques in AD research. In addition, recent advances and key operational applications are discussed.

scholarly journals A two-stage amplified PZT sensor for monitoring lung and heart sounds in discharged pneumonia patients

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hongbin Chen ◽  
Shuai Yu ◽  
Haiyang Liu ◽  
Jie Liu ◽  
Yongguang Xiao ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Cost Effective ◽  
High Ratio ◽  
Heart Sounds ◽  
Two Stage ◽  
Diagnosis And Prognosis ◽  
Sensor Device ◽  
Cost Effective Alternative ◽  
A Charge ◽  
Highly Sensitive Detection

AbstractAssessment of lung and heart states is of critical importance for patients with pneumonia. In this study, we present a small-sized and ultrasensitive accelerometer for continuous monitoring of lung and heart sounds to evaluate the lung and heart states of patients. Based on two-stage amplification, which consists of an asymmetric gapped cantilever and a charge amplifier, our accelerometer exhibited an extremely high ratio of sensitivity to noise compared with conventional structures. Our sensor achieves a high sensitivity of 9.2 V/g at frequencies less than 1000 Hz, making it suitable to use to monitor weak physiological signals, including heart and lung sounds. For the first time, lung injury, heart injury, and both lung and heart injuries in discharged pneumonia patients were revealed by our sensor device. Our sound sensor also successfully tracked the recovery course of the discharged pneumonia patients. Over time, the lung and heart states of the patients gradually improved after discharge. Our observations were in good agreement with clinical reports. Compared with conventional medical instruments, our sensor device provides rapid and highly sensitive detection of lung and heart sounds, which greatly helps in the evaluation of lung and heart states of pneumonia patients. This sensor provides a cost-effective alternative approach to the diagnosis and prognosis of pneumonia and has the potential for clinical and home-use health monitoring.

scholarly journals Early Detection of Alzheimer’s Disease Using Polar Harmonic Transforms and Optimized Wavelet Neural Network

2021 ◽  
Vol 11 (4) ◽  
pp. 1574
Author(s):  
Shabana Urooj ◽  
Satya P. Singh ◽  
Areej Malibari ◽  
Fadwa Alrowais ◽  
Shaeen Kalathil
Keyword(s):  
Neural Network ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Detection ◽  
Differential Evolution ◽  
Early Stage ◽  
Selection Process ◽  
Parameter Tuning ◽  
Wavelet Neural Network ◽  
Tuning Parameter

Effective and accurate diagnosis of Alzheimer’s disease (AD), as well as early-stage detection, has gained more and more attention in recent years. For AD classification, we propose a new hybrid method for early detection of Alzheimer’s disease (AD) using Polar Harmonic Transforms (PHT) and Self-adaptive Differential Evolution Wavelet Neural Network (SaDE-WNN). The orthogonal moments are used for feature extraction from the grey matter tissues of structural Magnetic Resonance Imaging (MRI) data. Irrelevant features are removed by the feature selection process through evaluating the in-class and among-class variance. In recent years, WNNs have gained attention in classification tasks; however, they suffer from the problem of initial parameter tuning, parameter setting. We proposed a WNN with the self-adaptation technique for controlling the Differential Evolution (DE) parameters, i.e., the mutation scale factor (F) and the cross-over rate (CR). Experimental results on the Alzheimer’s disease Neuroimaging Initiative (ADNI) database indicate that the proposed method yields the best overall classification results between AD and mild cognitive impairment (MCI) (93.7% accuracy, 86.0% sensitivity, 98.0% specificity, and 0.97 area under the curve (AUC)), MCI and healthy control (HC) (92.9% accuracy, 95.2% sensitivity, 88.9% specificity, and 0.98 AUC), and AD and HC (94.4% accuracy, 88.7% sensitivity, 98.9% specificity and 0.99 AUC).

Extracellular vesicles as an emerging tool for the early detection of Alzheimer’s disease

2019 ◽  
Vol 184 ◽  
pp. 111175 ◽  
Author(s):  
Tao-Ran Li ◽  
Xiao-Ni Wang ◽  
Can Sheng ◽  
Yu-Xia Li ◽  
Frederic Zhen-Tao Li ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Detection ◽  
Extracellular Vesicles

scholarly journals Proteins and microRNAs are differentially expressed in tear fluid from patients with Alzheimer’s disease

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aidan Kenny ◽  
Eva M. Jiménez-Mateos ◽  
María Ascensión Zea-Sevilla ◽  
Alberto Rábano ◽  
Pablo Gili-Manzanaro ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Unmet Need ◽  
Cost Effective ◽  
Specific Protein ◽  
Tear Fluid ◽  
Initiation Factor ◽  
Non Invasive ◽  
A Genome ◽  
Potential Biomarker

Abstract Alzheimer’s disease (AD) is characterized by a progressive loss of neurons and cognitive functions. Therefore, early diagnosis of AD is critical. The development of practical and non-invasive diagnostic tests for AD remains, however, an unmet need. In the present proof-of-concept study we investigated tear fluid as a novel source of disease-specific protein and microRNA-based biomarkers for AD development using samples from patients with mild cognitive impairment (MCI) and AD. Tear protein content was evaluated via liquid chromatography-mass spectrometry and microRNA content was profiled using a genome-wide high-throughput PCR-based platform. These complementary approaches identified enrichment of specific proteins and microRNAs in tear fluid of AD patients. In particular, we identified elongation initiation factor 4E (eIF4E) as a unique protein present only in AD samples. Total microRNA abundance was found to be higher in tears from AD patients. Among individual microRNAs, microRNA-200b-5p was identified as a potential biomarker for AD with elevated levels present in AD tear fluid samples compared to controls. Our study suggests that tears may be a useful novel source of biomarkers for AD and that the identification and verification of biomarkers within tears may allow for the development of a non-invasive and cost-effective diagnostic test for AD.

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