A scalable solution for precisely measuring low abundant neurobiomarkers from micro‐sampling

• DOI: 10.1002/alz.093328
• Publication Date: 2025-01-09T11:48:11Z
• Authors: Tsz Wing Fan; WonHee Kim; Corinne Thomas; Wenjing Jiang; Jeremy Tan; Feng Xuan

Abstract Background Cutting‐edge ultrasensitive immunoassay platforms have unveiled the potential of blood‐based biomarkers, offering detection at low fg/mL levels for early neurodegenerative disorder prognosis, screening, and therapeutic monitoring. Current immunoassays, such as single molecule array (SIMOA) mesoscale multi‐array (MSD), face limited adoption due to their reliance on specialized equipment. Additionally, they require immobilization probe reagents a washing process, demanding tens thousands proteins achieve Limit Detection (LOD), leading requirement high sample volume affinity antibodies sensitivity. Addressing escalating need non‐invasive, small‐volume collection, along with an accessible platform frequent longitudinal monitoring population‐scale solution these features is imperative. Method Introducing Successive Proximity Extension Amplification Reactions (SPEAR), which employs unique two‐factor authentication mechanism that eliminates background in conventional homogeneous assay, detects down single‐digit copies proteins. SPEAR utilizes simple three‐step wash‐free workflow adaptable any liquid handler readable ubiquitous PCR machines. To showcase its utility detecting neurobiomarkers concentrations blood, we demonstrate NFL assay using just 1‐mircorliter diluted plasma reach sensitivity excellent precision. Comprehensive testing included spike‐in recovery, dilution linearity specificity against neurofilaments (Nf‐M, Nf‐H, peripherin, α‐internexin), precision accuracy. Result exhibited remarkable LOD Lower Quantification (LLOQ) from two commercial readily available antibody pairs. The was measured 51 90 1 µL 1:4 plasma. Robust indicated by intraplate lot‐to‐lot %CV (6% 7%, respectively), concordance Simoa® NF‐light™ V2 Advantage Kit MSD Splex kit 36 K2EDTA samples. Conclusion has demonstrated validated existing platforms. Its standout features, including minimal compatibility standard machines, coupled advances portable machines remote collection devices, position robust tool neurodisease diagnostic research.