Surface plasmon resonance biosensors for simultaneous monitoring of amyloid-beta oligomers and fibrils and screening of select modulators

Abstract

Oligomeric amyloid-beta (Aβ) peptides are considered as the most toxic species in Alzheimer's disease (AD). Monitoring of the Aβ aggregation profiles is critical for elucidating the oligomer toxicity and may serve as a therapeutic target for AD. By immobilizing the capture antibodies of A11 and OC that are specific to the oligomers and fibrils, respectively, in separate fluidic channels, a novel surface plasmon resonance (SPR) biosensor was designed for monitoring the oligomeric and fibrillar species of Aβ(1-42) simultaneously. The influence of curcumin, Cu(2+) and methylene blue on the amount of toxic oligomers and fibrils was evaluated. The half maximal inhibitory concentration (IC50) of curcumin and methylene blue was determined. The formation of Aβ fibrils was also validated by the thioflavin T (ThT) fluorescence assay. The results demonstrate the utility of SPR as an analytical tool for rapid and comprehensive monitoring of Aβ aggregation and screening of Aβ modulators.

Protective Effects of Indian Spice Curcumin Against Amyloid-β in Alzheimer’s Disease

“…The formation of amyloid-β fibrils was also validated by the thioflavin T fluorescence assay. The results demonstrate the utility of surface plasmon resonance as an analytical tool for rapid and comprehensive monitoring of amyloid-β aggregation and screening of Aβ modulators [79]. …”

“…Yi and colleagues (2016) [79] studied the inhibitory properties of curcumin in amyloid-β aggregation. By immobilizing the capture oligomeric and fibrils specific antibodies, in separate fluidic channels, a novel surface plasmon resonance biosensor was designed for monitoring the oligomeric and fibrillar species of Aβ42 simultaneously.…”

“…Yi and colleagues (2016) [79] studied effects of the co-receptor (Nogo receptor; NgR) of three axonal growth-inhibitory proteins was examined, and effects of curcumin on spatial learning and memory abilities and hippocampal axonal growth were investigated in Aβ40-induced AD rats. Results showed that the expression of NgR in the AD group significantly increased and the number of axonal protein-positive fibers significantly reduced.…”

“…Together, these results suggested that curcumin could improve the spatial learning and memory abilities of AD rats. The mechanism might be related with its lowering of hippocampal NgR expression and promoting axonal regeneration [79]. …”

A sensitive and selective electrochemical biosensor for the determination of beta-amyloid oligomer by inhibiting the peptide-triggered in situ assembly of silver nanoparticles

“…22,23 Therefore, the direct detection of Aβ oligomer level would be more reliable for AD diagnosis than assay of its monomer. 24,25 Recently, a few novel biosensors have been developed for the detection of Aβ oligomer, including electrochemistry, [26][27][28][29] surface plasma resonance (SPR), 30 localized surface plasmon resonance (LSPR), 24,31 fluorescence, 32,33 nuclear magnetic resonance, 34 and surface-enhanced Raman spectroscopy. 35 These methods are feasible, but they require the use of special instruments and/or relatively expensive and variable antibodies for the capture and recognition of Aβ oligomer.…”