Nanoparticle-Mediated Signaling for Aptamer-Based Multiplexed Detection of Cortisol and Neuropeptide Y in Serum

Multiplexed profiling of the expression of neurochemical biomarkers of stress, for periodic assessment to enable augmentation of human performance, requires wash-free detection platforms that exhibit reproducible signals from samples in biological matrices. However, alterations in aptamer conformation after binding to targets, such as cortisol, are minimal based on NMR spectra, and the methylene blue signaling is blocked by serum proteins. Hence, in this study, we explore aptamer derivatization with magnetic nanoparticles that are conjugated with multiple methylene blue moieties, to amplify signals and alter the net charge configuration for repulsing serum proteins, so that the aptamer conformation upon target recognition can lead to a signal ON assay in serum media. Based on this, a microchip platform with addressable electrodes that are immobilized with selective aptamer receptors is developed for multiplexed detection of cortisol (1-700 ng/mL) and neuropeptide Y (5-1000 pg/mL) in patient-derived serum samples, which is validated by immunoassays. We envision the application of this sensor for profiling a wider array of human performance biomarkers under stress-related events to develop stress augmentation methodologies.

Automated summary

This study explores the use of magnetic nanoparticles to amplify signals and alter the charge configuration of aptamers, enabling wash-free multiplexed detection of neurochemical biomarkers in serum media. A microchip platform with immobilized selective aptamer receptors is developed for the detection of cortisol and neuropeptide Y in patient-derived serum samples, validated by immunoassays. This sensor has the potential to profile a wider range of human performance biomarkers under stress-related events and develop stress augmentation methodologies.