Alzheimer’s Disease Determination by a Dual Probe on Gold Nanourchins and Nanohorn Hybrids

Abstract

Background: Alzheimer's disease (AD) is a neurodegenerative chronic disorder that causes dementia and problems in thinking, cognitive impairment and behavioral changes. Amyloidbeta (Aβ) is a peptide involved in AD progression, and a high level of Aβ is highly correlated with severe AD. Identifying and quantifying Aβ levels helps in the early treatment of AD and reduces the factors associated with AD. Materials and Methods: This research introduced a dual probe detection system involving aptamers and antibodies to identify Aβ. Aptamers and antibodies were attached to the gold (Au) urchin and hybrid on the carbon nanohorn-modified surface. The nanohorn was immobilized on the sensor surface by using an amine linker, and then a Au urchin dual probe was immobilized. Results: This dual probe-modified surface enhanced the current flow during Aβ detection compared with the surface with antibody as the probe. This dual probe interacted with higher numbers of Aβ peptides and reached the detection limit at 10 fM with R 2 =0.992. Furthermore, control experiments with nonimmune antibodies, complementary aptamer sequences and control proteins did not display the current responses, indicating the specific detection of Aβ. Conclusion: Aβ-spiked artificial cerebrospinal fluid showed a similar response to current changes, confirming the selective identification of Aβ.

Aptasensors versus immunosensors—Which will prevail?

“…Copyright 2021, the authors. Published under Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0) by Qiu et al [176]. They presented a carbon nanohornmodified electrode, functionalized with a dual probe of an aptamer-antibody-modified Au urchin for detection of amyloid-beta, an Alzheimer's disease biomarker; see Fig- ure 4C-i.…”

“…(C‐ii) Comparison of biosensing signal for detection of amyloid‐beta with the different platforms, presenting improved performance for the dual probe scheme. Adapted with permission from [ 176 ]. Copyright 2021, the authors.…”

“…Recently, a hybrid aptamer‐antibody biosensor that employs both probes in a dual manner has been reported by Qiu et al. [ 176 ]. They presented a carbon nanohorn‐modified electrode, functionalized with a dual probe of an aptamer‐antibody‐modified Au urchin for detection of amyloid‐beta, an Alzheimer's disease biomarker; see Figure 4C‐i .…”