Green nitrogen and sulfur co-doped carbon dots derived from eggshell as a high performance aptasensing interface for non-invasive detection of metronidazole.

Background: The concentration monitoring of the banned metronidazole (MTZ) drug as the alarmed carcinogenic agent in human biofluids is medically essential. The electrochemical aptasensors are good candidates to overcome some presence challenges in the detection process.

Results: Herein, an electrochemical aptasensor based on nitrogen and sulfur co-doped carbon dots (NcS-CDs) has been developed for the high-sensitive detection of MTZ for the first time.

Applicability of a green nanocomposite consists of reduced graphene oxide and β-cyclodextrin for electrochemical tracing of methadone in human biofluids validated by international greenness indexes.

Background: Detecting methadone (MET) is crucial due to its severe side effects.

Method: Herein, a green nanocomposite based on reduced graphene (rGO) and β-cyclodextrin (β-CD) has been introduced to modify a glassy carbon electrode (GCE) for real-time measurement of MET. This eco-friendly sensing interface has synergistically benefited from both advantages of rGO and β-CD including excellent electron transfer tunneling and surface area enhancement to selectively trap MET based on its shape and size.

Central composite design-assisted visual and non-invasive detection of sertraline by sweet lemon waste-derived core-shell AuNPs@CDs.

This study reports a fast and visual detection method of antidepressant sertraline (SRT) drug by the core-shell AuNPs@CDs as the nanoprobes. The CDs has been eco-friendly synthesized from sweet lemon wastes to directly reduce Au to AuNPs without any external photoirradiation process or additional reductants. Optimizing key variables that impact the sensing process has been done using the central composite design (CCD) approach to simulate the assay condition before the analysis.

A nitrogen-doped hollow carbon nanospheres-based aptasensor for non-invasive salivary detection of progesterone.

Developing an easy-to-use and non-invasive sensor for monitoring progesterone (P4) as a multi-functional hormone is highly demanded for point-of-care testing. In this study, an ultrasensitive electrochemical aptasensor is fabricated for monitoring P4 in human biofluids. The sensing interface was designed based on the porous nitrogen-doped hollow carbon spheres (N-HCSs).

A smartphone-based colorimetric assay using Cu-tannic acid nanosheets (Cu-TA NShs) as a laccase-mimicking nanozyme for visual detection of quercetin in vegetables.

The interaction of Cu-tannic acid nanosheets (Cu-TA NShs) as nanozyme in a surfactant solution of CTAB under relatively acidic conditions is shown to exhibit a catalytic effect on quercetin (Qur). This catalytic property of Cu-TA NShs, which mimics laccase enzyme with many advantages, has been applied to developing a selective colorimetric sensor for the determination of trace amounts of Qur in vegetable samples. This strategy presents a desirable linear relationship between the absorbance signal intensity and the concentrations of Qur from 0.

Copper-Guanosine Nanorods (Cu-Guo NRs) as a Laccase Mimicking Nanozyme for Colorimetric Detection of Rutin.

Inspired by laccase activity, herein, Cu-guanosine nanorods (Cu-Guo NRs) have been synthesized for the first time through a simple procedure. The activity of the Cu-Guo NR as the laccase mimicking nanozyme has been examined in the colorimetric sensing of rutin (Rtn) by a novel and simple spectrophotometric method. The distinct changes in the absorbance signal intensity of Rtn and a distinguished red shift under the optimum condition based on pH and ionic strength values confirmed the formation of the oxidized form of Rtn (o-quinone) via laccase-like nanozyme activity of Cu-Guo NRs.

Applicability of a Green Nanocomposite Consisted of Spongin Decorated CuWO(OH) and AgNPs as a High-Performance Aptasensing Platform in Detection.

This study reports the synthesis of a nanocomposite consisting of spongin and its applicability in the development of an aptasensing platform with high performance. The spongin was carefully extracted from a marine sponge and decorated with copper tungsten oxide hydroxide. The resulting spongin-copper tungsten oxide hydroxide was functionalized by silver nanoparticles and utilized in electrochemical aptasensor fabrication.

Voltammetric determination of pethidine in biofluids at a carbon cloth electrode modified by carbon selenide nanofilm.

Developing a sensitive portable sensor for the screening of illicit drugs is always challenging. Due to the importance of pethidine (PTD) tracking in addiction diagnosis, many demands have recently increased for a selective and real-time sensor. Herein, a simple electrochemical sensor has been developed based on conductive carbon cloth (CC) modified with carbon selenide nanofilms (CSeNF) to provide a CSeNF/CC electrode as a novel PTD sensing tool.

A Smartphone-Based Fluorescent Electronic Tongue for Tracing Dopaminergic Agents in Human Urine.

The importance of tracing dopaminergic agents in the progression assessment of Parkinson's disease has boosted the demand for fast, sensitive, and real-time multi-analyte detection. Herein, visual and fingerprint fluorimetric patterns have been created by an optical sensor array to simultaneously detect and discriminate among levodopa, carbidopa, benserazide, and entacapone, as important dopaminergic agents. A dual emissive nanoprobe consisting of red quantum dots and blue carbon dots with an overall pink emission has been fabricated to provide unique emission patterns in the presence of the target analytes.

Recent advances in developing optical and electrochemical sensors for analysis of methamphetamine: A review.

Recognition of misused stimulant drugs has always been a hot topic from a medical and judicial perspective. Methamphetamine (MAMP) is an addictive and illegal drug that profoundly affects the central nervous system. Like other illicit drugs, the detection of MAMP in biological and street samples is vital for several organizations such as forensic medicine, anti-drug headquarters and diagnostic clinics.

Spectrofluorimetric study of the complexation of ochratoxin A and Cu: Towards the hybrid fluorimetric sensor and visual detection of ochratoxin A in wheat flour samples from farm to fork.

In this study, the ochratoxin A (OTA) interaction with some metal cations exhibits a quenching effect of the Cu, Co, and Ni in the OTA intrinsic fluorescence intensity. The property of the OTA fluorescence change in complexation with the Cu has been applied in developing a label-free and selective fluorimetric sensor for fast detection of the OTA trace amounts in wheat flour samples. The achieved color difference map (CDM) based on the spectral profile provides the technical support for the rapid visual sensing of OTA in the wheat flour samples.

Voltammetric measurement of entacapone in the presence of other medicines against Parkinson's disease by a screen-printed electrode modified with sulfur-tin oxide nanoparticles.

A screen-printed electrode (SPE) is described modified with sulfur-tin oxide nanoparticles (S@SnONP) for the determination of entacapone (ENT) in the presence of other medicines against Parkinson's disease (PD). The S@SnONP was synthesized through the hydrothermal method and used in the modification of the SPE. The smart utilization of the S@SnONP and the SPE provided excellent properties such as high surface area and current density amplification by embedding an efficient sensing interface for highly selective electrochemical measurement.

Fabrication of an electrochemical biodevice for ractopamine detection under a strategy of a double recognition of the aptamer/molecular imprinting polymer.

The importance of RAC tracking in human biofluids has boosted many demands for designing an ultrasensitive tool to determine the trace value of the RAC from clinical, judicial, and forensic centers. In this study, an electrochemical biodevice has developed for the highly selective detection of this illegal feed additive under a double recognition strategy of the aptamer (Apt) and molecular imprinting polymer (MIP) on a glassy carbon electrode (GCE). The sensing relies on this fact that both the MIP and Apt act synergistically to trap the RAC molecules.

Optical nanoprobes for chiral discrimination.

Chiral discrimination has always been a hot topic in chemical, food and pharmaceutical industries, especially when dealing with chiral drugs. Enantiomeric recognition not only leads to better understanding of the mechanism of molecular recognition in biological systems, but may further assist in developing useful molecular devices in biochemical and pharmaceutical studies. By emerging nanotechnology and exploiting nanomaterials in sensing applications, a great deal of attention has been given to the design of optical nanoprobes that are able to discriminate enantiomers of chiral analytes.

A glassy carbon electrode modified with carbon nanoonions for electrochemical determination of fentanyl.

Fentanyl is a pain reliever stronger and deadlier than heroin. This lethal drug has killed many people in different countries recently. Due to the importance of the diagnosis of this drug, a fentanyl electrochemical sensor is developed based on a glassy carbon electrode (GCE) modified with the carbon nanoonions (CNOs) in this study.

Architecting of a biodevice based on a screen-printed carbon electrode modified with the NiONP nanolayer and aptamer in BCM-7 detection.

In this study, an ultrasensitive and robust biodevice implemented on a screen-printed carbon electrode (SPCE) surface is introduced. The β-casomorphin-7 (BCM-7) peptide as an early warning sign of autism disorder is distinguished in this system. The SPCE surface was directly electrodeposited with a nanolayer of the nickel oxide nanoparticles (NiONP).

AgNPs/QDs@GQDs nanocomposites developed as an ultrasensitive impedimetric aptasensor for ractopamine detection.

Developing easy-to-use and miniaturized sensors for in-field monitoring of targets which is related to human health is necessary. Ractopamine (RAC) is a feed additive with serious side effects that is forbidden in many countries. This study reports the fabrication of an impedimetric aptasensor for ultrasensitive and selective detection of the RAC in human biological fluids.

Designing of an ultrasensitive BCM-7 aptasensor based on an SPCE modified with AuNR for promising distinguishing of autism disorder.

Abstractly, in this study, an aptasensor is introduced based on a platform consisting of the gold nanorod (AuNR) on a screen printed carbon electrode (SPCE) surface. The aptasensor is applied for detection of the β-casomorphin (BCM-7) as a promising biomarker of autism disorder. The NH-Apt sequence is directly immobilized onto the AuNR/SPCE surface by formation of a chemisorption bond between the amine-Au groups.

Electrochemical determination of the antipsychotic medication clozapine by a carbon paste electrode modified with a nanostructure prepared from titania nanoparticles and copper oxide.

A nanostructure was prepared from titania nanoparticles and copper oxide (TiONP@CuO) and used to modify a carbon paste electrode (CPE). The modified CPE is shown to enable sensitive voltammetric determination of the drug clozapine (CLZ). The sensor was characterized by various techniques and some key parameters were optimized.

A nanocomposite prepared from reduced graphene oxide, gold nanoparticles and poly(2-amino-5-mercapto-1,3,4-thiadiazole) for use in an electrochemical sensor for doxorubicin.

A nanocomposite was prepared with reduced graphene oxide, gold nanoparticles and an electropolymerized film made from 2-amino-5-mercapto-1,3,4-thiadiazole. An electrochemical sensor for doxorubicin (DOX) was constructed by modifying a glassy carbon electrode (GCE) with the nanocomposite. The modified GCE was studied by electrochemical techniques which showed it to enable highly sensitive sensing of DOX.

A carbon paste electrode modified with AlO-supported palladium nanoparticles for simultaneous voltammetric determination of melatonin, dopamine, and acetaminophen.

The authors have modified a carbon paste electrode with AlO-supported palladium nanoparticles (PdNP@AlO) to obtain a sensor for simultaneous voltammetric determination of melatonin (MT), dopamine (DA) and acetaminophen (AC). The PdNP@AlO was characterized by scanning electron microscopy and energy-dispersive X-ray spectra. The sensor can detect DA, AC, MT and their mixtures by giving distinct signals at working voltages of typically 236, 480 and 650 mV (vs.

A nanocomposite consisting of reduced graphene oxide and electropolymerized β-cyclodextrin for voltammetric sensing of levofloxacin.

A glassy carbon electrode (GCE) was modified with a nanocomposite prepared from polymerized β-cyclodextrin (β-CD) and reduced graphene oxide (rGO). The modified GCE is shown to enable the voltammetric determination of traces of levofloxacin (LEV) by various electrochemical techniques. Experimental factors affecting the results including the amount of the substrates in preparation of the nanocomposite, accumulation time, the scan rate and pH value of the electrolyte were optimized.

Applicability of AuNPs@N-GQDs nanocomposite in the modeling of the amplified electrochemical Ibuprofen aptasensing assay by monitoring of riboflavin.

Here, an ultrasensitive and low-cost electrochemical aptasensing assay is developed based on the applicability of a fabricated nanocomposite from nitrogen-doped graphene quantum dots (N-GQDs) and gold nanoparticles (AuNPs). A modified glassy carbon electrode (GCE) with the AuNPs@N-GQDs nanocomposite (AuNPs@N-GQDs/GCE) as an efficient platform has some unique properties such as high surface area and electrical conductivity. Furthermore, the prepared platform is capable of more loading of aptamer (Apt) molecules as a biological recognition element of Ibuprofen (IBP) on the modified electrode surface.

A glassy carbon electrode with electrodeposited silver nanoparticles for aptamer based voltammetric determination of trinitrotoluene using riboflavin as a redox probe.

An electrochemical nanoaptasensor is described that is based on the use of a glassy carbon electrode (GCE) modified with electrodeposited silver nanoparticles (AgNPs). An aptamer (Apt) against trinitrotoluene (TNT) was then immobilized on the AgNPs. The addition of TNT to the modified GCE leads to decrease in peak current (typically measured at a potential of -0.

Simultaneous voltammetric sensing of acetaminophen, epinephrine and melatonin using a carbon paste electrode modified with zinc ferrite nanoparticles.

A highly selective electrochemical sensor was fabricated based on a modified carbon paste electrode with zinc ferrite nanoparticles (ZnFeO NPs). The nanocomposite has attractive properties such as high surface-to-volume ratio and good electrocatalytic activity towards the drugs acetaminophen (AC), epinephrine (EP), and melatonin (MT), best at working voltages of 0.35, 0.