Browsing by Author "Alberkant, Jonathan"
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Item Flexible electrochemical aptasensor for cortisol detection in human sweat(2021) Mugo, Samuel; Alberkant, Jonathan; Bernstein, Nina; Zenkina, Olena V.This communication demonstrates an electrochemical DNA aptasensor for the detection of cortisol in human sweat. The aptasensor was fabricated via layer-by-layer assembly on stretchable polydimethylsiloxane (PDMS) coated with conductive nanoporous carbon nanotube-cellulose nanocrystals (CNC/CNT) film using a linker to a cortisol specific DNA aptamer. The flexible cortisol aptasensor had a dynamic range of 2.5–35 ng mL−1. The aptasensor precision was determined to be 2.7% relative standard deviation (%RSD) across the concentration dynamic range. The aptasensor was determined to have a limit of detection (LOD) of ∼ 1.8 ng mL−1. The aptasensor was demonstrated to have high selectivity to cortisol and was unresponsive to interfering species including glucose, sodium lactate, and β-estradiol. The aptasensor was successfully evaluated for the detection of cortisol in human sweat indicative of its high specificity.Item Flexible molecularly imprinted electrochemical sensor for cortisol monitoring in sweat(2020) Mugo, Samuel; Alberkant, JonathanA selective cortisol sensor based on molecularly imprinted poly(glycidylmethacrylate-co ethylene glycol dimethacrylate) (poly(GMA-co-EGDMA)) has been demonstrated for detection of cortisol in human sweat. The non-enzymatic biomimetric flexible sweat sensor was fabricated inexpensively by layer by layer (LbL) assembly. The sensor layers comprised a stretchable polydimethylsiloxane (PDMS) base with carbon nanotubes-cellulose nanocrystals (CNC/CNT) conductive nanoporous nanofilms. The imprinted (MIP) poly(GMA-co-EGDMA) deposited on the CNC/CNT was the cortisol biomimetric receptor. Rapid in analyte response (3 min), the cortisol MIP sensor demonstrated excellent performance. The sensor has a limit of detection (LOD) of 2.0 ng/mL ± 0.4 ng/mL, dynamic range of 10–66 ng/mL, and a sensor reproducibility of 2.6% relative standard deviation (RSD). The MIP sensor also had high cortisol specificity and was inherently blind to selected interfering species including glucose, epinephrine, β-estradiol, and methoxyprogestrone. The MIP was four orders of magnitude more sensitive than its non-imprinted (NIP) counterpart. The MIP sensor remains stable over time, responding proportionately to doses of cortisol in human sweat.