A Multi-Chamber Paper-Based Platform for the Detection of Amyloid β Oligomers 42 via Copper-Enhanced Gold Immunoblotting

Abstract

The early diagnosis of Alzheimer’s disease (AD) remains a challenge for medical scientists worldwide, leading to a number of research efforts that focus on biosensor development for AD biomarkers. However, the application of these complicated biosensors is limited in medical diagnosis, due to the difficulties in robust sensing platform development, high costs, and the necessity for technical professionals. We successfully developed a robust straightforward manufacturing process for the fabrication of multi-chamber paper devices using the wax printing method and exploited it to detect amyloid beta 42 oligomers (AβO42, a significant biomarker of AD) using copper-enhanced gold nanoprobe colorimetric immunoblotting. Small hydrophilic reaction chambers could concentrate the target sample to the desired size to improve the sensing performance. The copper-enhanced gold nanoprobe immunoblot using the designed multi-chamber platform exhibited a highly sensitive performance with a limit of detection of 320 pg/mL by the naked eye and 23.7 pg/mL by a smartphone camera. This process from sensing manufacture to sensing conduction is simple to perform whenever medical technicians require time- and cost-savings, without complicated instruments or the need for technical professionals, making it feasible to serve as a diagnostic tool worldwide for the early monitoring of AD and scalable devices for the sensing application of various biomarkers in clinical settings.

From Cerebrospinal Fluid Neurochemistry to Clinical Diagnosis of Alzheimer’s Disease in the Era of Anti-Amyloid Treatments. Report of Four Patients

“…They include markers of neuroinflammation such as the triggering receptor expressed on myeloid cells 2 (TREM2), progranulin, and chitinase-3-like protein-1 (YKL-40), markers of synaptic dysfunction such as neurogranin, and markers of neuronal injury such as neurofilament light (NfL) and visinin-like protein 1 (VILIP-1), while miR-NAs could also be helpful [72][73][74][75][76][77]. Oligomeric forms of Aβ 42 [78], α-synuclein [79], and TAR DNA-Binding Protein 43 (TDP43) [80] are emerging biomarkers, but work must still be carried out to achieve adequate diagnostic performance. Especially for α-synuclein, which has been traditionally considered as a marker of synuclein pathology, results are conflicting [79], partially due to the effect of preanalytical and analytical factors, including differences in a-synuclein species detected by different methods [81].…”

Fluorescent Aptasensor and Colorimetric Aptablot for p-tau231 Detection: Toward Early Diagnosis of Alzheimer’s Disease

“…The aptamer of p-tau231 was functionalized onto the surface of AuNPs by addition into AuNPs solution and incubation for 4 h after heating at 90 °C and cooling; then, the solution was washed 2 times by centrifugation. Multiple reaction chambers were created in nitrocellulose membrane using wax printing and heating at 95 °C, following the literature [ 19 ]. For different concentrations of p-tau231 of (0–1000 ng/mL), 2 µL was dropped onto the different reaction chambers, dried for 10 min, and followed by a blocking step with bovine serum albumin for 45 min.…”

Recent developments in the chemical biology of amyloid-β oligomer targeting

“…[84][85][86][87] Based on these macromolecules, various electrochemical and optical probes of AβOs have been designed. 88,89 For instance, a series of antibody candidates (DesAbs) that bind to different epitopes across the whole sequence of AβOs were screened via evaluation of their binding affinity by enzyme-linked immunosorbent assay (ELISA). 90 As a result, DesAbs-O was filtered out as a specific AβO antibody without the requirement of structural information of the transient oligomers (Fig.…”