Flow injection amperometric sandwich-type electrochemical aptasensor for the determination of adenocarcinoma gastric cancer cell using aptamer-Au@Ag nanoparticles as labeled aptamer

摘要: Abstract Herein, a flow injection amperometric aptasensor was developed for the determination of adenocarcinoma gastric cell (AGS) cancer cells in presence hydrogen peroxide (H 2 O ). For this purpose, aptamer/gold-core and silver-shell (Au@Ag) nanoparticles were synthesized as secondary labeled aptamers using thiolated cytosine-rich aptamer. First, aptamer self-assembled to gold (AuNPs) surface through S-AuNPs bonds. Then, aptamer/AuNPs added Ag + solution form (C-Ag -C) n complexes. The adsorbed ions on then reduced shell AuNPs core by thyme leaves extract green reducing agent. screen printed electrode (SPE) also modified with multiwall carbon nanotube decorated (MWCNT-Au nano ) nano-platform increase area immobilize primary non-cytosine-rich improve electron transfer property electrode. MWCNT-Au , AGS -Au@Ag characterized transmission microscopy (TEM) energy dispersive X-ray (EDX). Cyclic voltammetry electrochemical impedance spectroscopy (EIS) used confirm stepwise changes properties processes performed microchannel device under optimized conditions. selective interactions between aptamer/AGS/secondary aptamer-Au@Ag led response 0.1 mM H because electrocatalytic activity Au@Ag toward reduction . proposed sandwich-type exhibited good logarithmic value range 1 × 10 1 5 × 10 5 mL −1 low limit detection 6 process. target-aptamer dissociation constant (k d calculated based change current be 104 fabricated applied human serum sample. linear responsibility, selectivity, stability.