AUTHOR=Song Gongshuai , Shui Ruofan , Wang Danli , Fang Ruosi , Yuan Tinglan , Li Ling , Feng Junli , Gao Feng , Shen Qing , Gong Jinyan , Zheng Fuping , Zhang Manman 

TITLE=Aptamer-conjugated graphene oxide-based surface assisted laser desorption ionization mass spectrometry for selective extraction and detection of Aβ1–42 in an Alzheimer’s disease SH-SY5 cell model

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=14

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.993281

DOI=10.3389/fnagi.2022.993281

ISSN=1663-4365

ABSTRACT=<p>The generation and accumulation of amyloid-beta peptide (Aβ<sub>1–42</sub>) in amyloid plaques are key characteristics of Alzheimer’s disease (AD); thus, specific detection of Aβ<sub>1–42</sub> is essential for the diagnosis and treatment of AD. Herein, an aptamer-conjugated graphene oxide (Apt-GO) sensor was synthesized by π-π and hydrophobic interactions using thiol poly (ethylene glycol) amine (SH-PEG-NH<sub>2</sub>) as a spacer unit. Then, it was applied to selective capture of Aβ<sub>1–42</sub>, and the resulting complex was directly analyzed by surface-assisted laser desorption ionization mass spectrometry (SALDI-MS). The results revealed that the Apt-GO could enhance the detection specificity and reduce non-specific adsorption. This method was validated to be sensitive in detecting Aβ<sub>1–42</sub> at a low level in human serum (ca. 0.1 μM) within a linear range from 0.1 to 10 μM. The immobilizing amount of aptamer on the GO was calculated to be 36.1 nmol/mg (RSD = 11.5%). In conclusion, this Apt-GO-based SALDI-MS method was sensitive and efficient in selective extraction and detection of Aβ<sub>1–42</sub>, which proved to be a good option for early AD diagnosis.</p>