A Dual-Amplification Electrochemical Aptasensor for Profenofos Detection

Abstract

The present study reported a dual-amplification electrochemical aptasensor for sensitive detection of profenofos (PFF) in vegetables. A screen-printed carbon electrode (SPCE) modified with graphitized multi-walled carbon nanotubes (MWCNTGr) and Au nanoshell was used as a test platform, which ensured a rapid detection process and showed a favorable electrochemical performance. MWCNTGr and Au nanoshell enhanced the electrical conductivity and the surface area, thus the detection signal was amplified. The affinity between PFF and its aptamer (Apt) was verified firstly by dot blot hybridization (DBH), and the result was exciting. Furthermore, the effects of the aptamers modified respectively with -NH2 and -SH on the current signal were compared with each other by cyclic voltammetry (CV), and results showed that the aptamers modified with -NH2 made the current signal change more obvious. Based on all above, a high-efficiency electrochemical aptasensor was fabricated with a wide linear range from 0.1–1 × 105 ng · ml−1 and a detection limit of 0.052 ng · ml−1 under the optimized conditions. This aptasensor had great specificity, stability and reproducibility. Hence, the developed aptasensor was successfully used to detect PFF in vegetables. The proposed method also has a potential for the detection of other organophosphorus pesticide (OPs).

Functional Janus Membranes: Promising Platform for Advanced Lithium Batteries and Beyond

“…Sodium-ion batteries have attracted lots of attention due to the similar reaction mechanism compared to LIB in the past 10 years. [115][116][117][118] SIBs not only fulfill the requirements of low cost, long life, and high safety performance in the new energy field, but also have some unique merits, such as the abundant and wide-distributed rich sodium resource reserves, high power density, safety, and wide working temperature range. [119,120] Moreover, the adaptability and compatibility with existing production equipment of LIBs render the SIBs as an excellent alternative for LIBs.…”

Bioengineered multi-walled carbon nanotube (MWCNT) based biosensors and applications thereof

“…Aptamer immobilization is usually based on three mechanisms: physical adsorption, covalent bonding, and affinity binding. 57,124 Recently, electrochemical aptasensors developed with MWCNT composites have been utilized in the detection of microbial pathogens and toxins, 56,94,125–127 bisphenol A, 128–130 pesticides, 95,131 antibiotics, 93,132–134 and biomolecules. 135–139 MWCNT-based aptamers provide certain advantages such as good sensitivity, portable nature, rapid detection, simple instrumentation, and low fabrication costs, as compared to traditional immunoassays.…”

Advances in Electrochemical Aptasensors Based on Carbon Nanomaterials

“…Moreover, in some cases concerning the determination of organophosphate pesticide, the concentrations determined are so small that it is hard to find the analytical problems corresponding to their value. Indeed, the detection of profenofos on the level of 0.025 ng/mL [174] or malathion on the level of 0.1 fM [168] does not have sense in terms of food safety or contamination assessment. To some extent, this also refers to the determination of some metabolites, such as trypthophan and urea.…”

“…Carboxylated MWCNTs with adsorbed thionine and Au nanoparticles bearing aptamer are attached to the surface via hybridization of the aptamer with capturing DNA strand DPV current of thionine oxidation 1 × 10 −13 -1 × 10 −5 g/mL, LOD 3.1 × 10 −14 g/mL [172] Potassium ion Field effect transistor with SWCNT as a gate and aptamer immobilized via 1-pyrene butanoic acid Changes in conductivity of SWCNT 1 pM-11 nM, LOD 10 pM [173] Profenofos Screen-printed electrode modified with graphitized MWCNTs and Au nanoparticles. Thiolated or aminated aptamers are immobilized by covalent bonds formed in carbodiimide binding or Au-SH interactions DPV current of the [Fe(CN) 6 ] 3-/4redox indicator 0.1-1 × 10 5 ng/mL, LOD 0.052 ng/mL[174]…”