Browsing by Author "Cooper, Jonathan M."
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Item Open Access Low sample volume origami-paper-based graphene-modified aptasensors for label-free electrochemical detection of cancer biomarker-EGFR(Nature Publishing Group, 2020-05-18) Wang, Yang; Sun, Shuai; Luo, Jinping; Xiong, Ying; Ming, Tao; Liu, Juntao; Ma, Yuanyuan; Yan, Shi; Yang, Yue; Yang, Zhugen; Reboud, Julien; Yin, Huabing; Cooper, Jonathan M.; Cai, XinxiaIn this work, an electrochemical paper-based aptasensor was fabricated for label-free and ultrasensitive detection of epidermal growth factor receptor (EGFR) by employing anti-EGFR aptamers as the bio-recognition element. The device used the concept of paper-folding, or origami, to serve as a valve between sample introduction and detection, so reducing sampling volumes and improving operation convenience. Amino-functionalized graphene (NH2-GO)/thionine (THI)/gold particle (AuNP) nanocomposites were used to modify the working electrode not only to generate the electrochemical signals, but also to provide an environment conducive to aptamer immobilization. Electrochemical characterization revealed that the formation of an insulating aptamer–antigen immunocomplex would hinder electron transfer from the sample medium to the working electrode, thus resulting in a lower signal. The experimental results showed that the proposed aptasensor exhibited a linear range from 0.05 to 200 ngmL−1 (R2 = 0.989) and a detection limit of 5 pgmL−1 for EGFR. The analytical reliability of the proposed paper-based aptasensor was further investigated by analyzing serum samples, showing good agreement with the gold-standard enzyme-linked immunosorbent assayItem Open Access Paper-based nanosensors to evaluate community-wide illicit drug use for wastewater-based epidemiology(Elsevier, 2020-10-23) Mao, Kang; Yang, Zhugen; Zhang, Hua; Li, Xiqing; Cooper, Jonathan M.Wastewater-based epidemiology (WBE) is a powerful technique for monitoring illicit drugs of abuse in the community. Here, we report on a surface-enhanced Raman scattering/spectroscopy (SERS) sensor for the sensitive and selective detection of methamphetamine based on the assembly of noble metal core-shell nanoparticles on a bespoke glassy nanofibrous electrospun paper matrix. The hierarchical structure of the fibrous paper, modified with the synthesized Au@Ag core-shell nanoparticles (Au@Ag) possessing good SERS efficiency, enables us to evaluate the community-wide prevalence of methamphetamine in wastewater treatment plants around Beijing. We show that when normalized for the daily flow of the wastewater treatment plants, higher mass loads of drugs are found in sewage influent from urban areas, implying greater local methamphetamine usage than that in less populated areas. These user-friendly and disposable paper devices demonstrate the applicability of rapid on-site illicit drug detection, illustrating the application to wastewater-based epidemiology, which has the potential to inform government agencies regarding societal interventions.