A novel morphine electrochemical biosensor based on intercalative and electrostatic interaction of morphine with double strand DNA immobilized onto a modified Au electrode

How new nanotechnologies are changing the opioid analysis scenery? A comparison with classical analytical methods

Opioids such as heroin, fentanyl, raw opium, and morphine have become a serious threat to the world population in the recent past, due to their increasing use and abuse. The detection of these drugs in biological samples is usually carried out by spectroscopic and/or chromatographic techniques, but the need for quick, sensitive, selective, and low-cost new analytical tools has pushed the development of new methods based on selective nanosensors, able to meet these requirements. Modern sensors, which utilize "next-generation" technologies like nanotechnology, have revolutionized drug detection methods, due to easiness of use, their low cost, and their high sensitivity and reliability, allowing the detection of opioids at trace levels in raw, pharmaceutical, and biological samples (e.g. blood, urine, saliva, and other biological fluids). The peculiar characteristics of these sensors not only have allowed on-site analyses (in the field, at the crime scene, etc.) but also they are nowadays replacing the gold standard analytical methods in the laboratory, even if a proper method validation is still required. This paper reviews advances in the field of nanotechnology and nanosensors for the detection of commonly abused opioids both prescribed (i.e. codeine and morphine) and illegal narcotics (i.e. heroin and fentanyl analogues).

Binding of dicoumarol analog with DNA and its antioxidant studies: A biophysical insight by in-vitro and in-silico approaches

DNA is the major target for a number of pharmaceutical drugs. The interaction of drug molecules with DNA plays a major role in pharmacokinetics and pharmacodynamics. Bis-coumarin derivatives have diverse biological properties. Here, we have explored the antioxidant activity of 3,3'-Carbonylbis (7-diethylamino coumarin) (CDC) using DPPH, H₂O_2, and superoxide scavenging studies followed by its binding mode in calf thymus-DNA (CT-DNA) using several biophysical methods including molecular docking. CDC exhibited comparable antioxidant activity to standard ascorbic acid. The UV-Visible and fluorescence spectral variations indicate the CDC-DNA complex formation. The binding constant in the range of 10⁴ M^-1 was obtained from spectroscopic studies at room temperature. The fluorescence quenching of CDC by CT-DNA suggested a quenching constant (K_SV) of 10³ to 10⁴ M^-1 order. Thermodynamic studies at 303, 308, and 318 K revealed the observed quenching as a dynamic process besides the spontaneity of the interaction with negative free energy change. Competitive binding studies with site markers like ethidium bromide, methylene blue, and Hoechst 33258 reflect CDC's groove mode of interaction. The result was complemented by DNA melting study, viscosity measurement, and KI quenching studies. The ionic strength effect was studied to interpret the electrostatic interaction and found its insignificant role in the binding. Molecular docking studies suggested the binding location of CDC within the minor groove of CT-DNA, complementing the experimental result.

Nanobiosensors for detection of opioids: A review of latest advancements

Opioids are generally used as analgesics in pain treatment. Like many drugs, they have side effects when overdosing and causeaddiction problems.Illegal drug use and misuse are becoming a major concern for authorities worldwide; thus, it is critical to have precise procedures for detecting them in confiscated samples, biological fluids, and wastewaters. Routine blood and urine tests are insufficient for highly selective determinations and can cause cross-reactivities. For this purpose, nanomaterial-based biosensors are great tools to determine opioid intakes, continuously monitoring the drugs with high sensitivity and selectivity even at very low sample volumes.Nanobiosensors generally comprise a signal transducer nanostructure in which a biological recognition molecule is immobilized onto its surface. Lately, nanobiosensors have been extensively utilized for the molecular detection of opioids. The usage of novel nanomaterials in biosensing has impressed biosensing studies. Nanomaterials with a large surface area have been used to develop nanobiosensors with shorter reaction times and higher sensitivity than conventional biosensors. Colorimetric and fluorescence sensing methods are two kinds of optical sensor systems based on nanomaterials. Noble metal nanoparticles (NPs), such as silver and gold, are the most frequently applied nanomaterials in colorimetric techniques, owing to their unique optical feature of surface plasmon resonance. Despite the progress of an extensive spectrum of nanobiosensors over the last two decades, the future purpose of low-cost, high-throughput, multiplexed clinical diagnostic lab-on-a-chip instruments has yet to be fulfilled. In this review, a concise overview of opioids (such as tramadol and buprenorphine, oxycodone and fentanyl, methadone and morphine) is provided as well as information on their classification, mechanism of action, routine tests, and new opioid sensing technologies based on various NPs. In order to highlight the trend of nanostructure development in biosensor applications for opioids, recent literature examples with the nanomaterial type, target molecules, and limits of detection are discussed.

Recent Developments in the Sensitive Electrochemical Assay of Common Opioid Drugs

Opioids are a class of drugs used to treat moderate to severe pain and have short-term adverse effects. Nevertheless, they are considered necessary for pain management. However, well-known hazards are connected with an opioid prescription, such as overuse, addiction, and overdose deaths. For example, the death rate from opioid analgesic poisoning in the USA approximately doubled, owing to the overuse and addiction of opioid analgesics. Also, opioids are a very important group of analytes in forensic chemistry, so it is necessary to use reliable, fast, and sensitive analytical tools to determine opioid analgesics. This review focuses on the opioid overdose crisis, the properties of commonly used opioid drugs, their mechanism, effects, and some chromatographic and spectroscopic detection methods are explained briefly. Then most essentially recent developments covering the last ten years in the sensitive electrochemical methods of common opioid analgesics, their innovations and features, and future research directions are presented.

Advances of Drugs Electroanalysis Based on Direct Electrochemical Redox on Electrodes: A Review

The strong development of mankind is inseparable from the proper use of drugs, and the electroanalytical research of drugs occupies an important position in the field of analytical chemistry. This review mainly elaborates the research progress of drugs electroanalysis based on direct electrochemical redox on various electrodes for the recent decade from 2011 to 2021. At first, we summarize some frequently used electrochemical data processing and electrochemical mechanism research derivation methods in the literature. Then, according to the drug therapeutic and application/usage purposes, the research progress of drugs electrochemical analysis is classified and discussed, where we focus on drugs electrochemical reaction mechanism. At the same time, the comparisons of electrochemical sensing performance of the drugs on various electrodes from recent studies are listed, so that readers can more intuitively compare and understand the electroanalytical sensing performance of each modified electrode for each of the drug. Finally, this review discusses the shortcomings and prospects of the drugs electroanalysis based on direct electrochemical redox research.

Nanoarchitectonics for Abused-Drug Biosensors

Rapid, accessible, and highly accurate biosensors for the detection of addictive and abused drugs are needed to reduce the adverse personal and societal impacts of addiction. Modern sensors that utilize next-generation technologies, e.g., nanobiotechnology and nanoarchitectonics, have triggered revolutionary progress in the field as they allow accurate detection and tracking of trace levels of major classes of drugs. This paper reviews advances in the field of biosensors for the detection of commonly abused drugs, both prescribed such as codeine and morphine, and illegal narcotics like cocaine.

Emerging trends in point-of-care sensors for illicit drugs analysis

Consumption of illicit narcotic drugs and fatal or criminal activities under their influence has become an utmost concern worldwide. These drugs influence an individual's feelings, perceptions, and emotions by altering the state of consciousness and thus can result in serious safety breaches at critical workplaces. Point-of-care drug-testing devices have become the need-of-the-hour for many sections such as the law enforcement agencies, the workplaces, etc. for safety and security. This review focuses on the recent progress on various electrochemical and optical nanosensors developed for the analysis of the most common illicit drugs (or their metabolites) such as tetrahydrocannabinol (THC), cocaine (COC), opioids (OPs), amphetamines & methamphetamine, and benzodiazepine (BZDs). The paper also highlights the sensitivity and selectivity of various sensing modalities along with evolving parameters such as real-time monitoring and measurement via a smart user interface. An overall outlook of recent technological advances in point of care (POC) devices and guided insights and directions for future research is presented.

A new electrochemical impedance biosensor based on aromatic thiol for alpha-1 antitrypsin determination

Alpha-1 antitrypsin (A1AT) is one of the acute phase proteins which are synthesized in the liver. A1AT inhibits the activity of many proteases, but its main task is to protect the lungs from the attack of neutrophil elastase. In an autosomal hereditary disease known as alpha-1 antitrypsin deficiency, the A1AT level in blood serum decreases, increasing the risk of developing emphysema, liver apoptosis, and liver cancer. Thus, the detection of A1AT concentration in blood serum is very important. In this study, an impedimetric biosensor was developed, forming an SAM (self-assembled monolayer) with 4-mercaptophenylacetic acid (4MPA) on the surface of the gold electrode. An A1AT biosensor was constructed using immobilization of an A1AT-specific antibody (anti-A1AT) after activating the carboxyl groups of 4MPA with EDC/NHS. Each immobilization stage was characterized by using electrochemical impedance spectroscopy, cyclic voltammetry, and scanning electron microscopy with energy dispersive X-ray spectroscopy. With the designed biosensor, precise and highly reproducible results were obtained for A1AT concentrations in the range of 100-600 µg/mL. A1AT detection was also successfully carried out in artificial serum solutions spiked with A1AT.

Determination of morphine and its metabolites in the biological samples: an updated review

Morphine (MO) as an opioid analgesic is used for the treatment of moderate-to-severe pains, particularly cancer-related pains. Pharmacologic studies on MO are complicated due to drugs binding to the protein or metabolization to active metabolites, and even inter-individual variability. This necessitates the selection of a reliable analytical method for monitoring MO and the concentrations of its metabolites in the biological samples for the pharmacokinetic or pharmacodynamic investigations. Therefore, this study was conducted to review all the analytical research carried out on MO and its metabolites in the biological samples during 2007-2019 as an update to the study by Bosch et al. (2007).

Oxygen sensitive 1-amino-2-naphthol immobilized functionalized-carbon nanotube electrode

Immobilization of 1-amino-2napthol (AN) is enhanced complexing with Cu²⁺ on multiwalled carbon nanotubes (f-MWCNT) surface. Oxygen is reduced at the ligand (AN) site into water, therefore AN–Cu²⁺ immobilized on MWCNT exhibits oxygen sensing.

What Electrochemical Biosensors Can Do for Forensic Science? Unique Features and Applications

This article critically discusses the latest advances in the use of voltammetric, amperometric, potentiometric, and impedimetric biosensors for forensic analysis. Highlighted examples that show the advantages of these tools to develop methods capable of detecting very small concentrations of analytes and provide selective determinations through analytical responses, without significant interferences from other components of the samples, are presented and discussed, thus stressing the great versatility and utility of electrochemical biosensors in this growing research field. To illustrate this, the determination of substances with forensic relevance by using electrochemical biosensors reported in the last five years (2015–2019) are reviewed. The different configurations of enzyme or affinity biosensors used to solve analytical problems related to forensic practice, with special attention to applications in complex samples, are considered. Main prospects, challenges to focus, such as the fabrication of devices for rapid analysis of target analytes directly on-site at the crime scene, or their widespread use and successful applications to complex samples of interest in forensic analysis, and future efforts, are also briefly discussed.

Fabrication of a sensitive electrochemical sensor based on electrospun magnetic nanofibers for morphine analysis in biological samples

A sensitive electrochemical sensor for detection of morphine (MPH) at the surface of electrode modified with electrospun magnetic nanofibers (MNFs) was prepared. The features of constructed sensor were evaluated by scanning electron microscopy (SEM), X ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). The modified sensor was used for MPH analysis using of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) method. The calibration curve has been composed of a linear portion in the concentration range of 0.0033-55 μM and 55-245 μM and the detection limit was 1.9 nM. The reproducibility of the peak current with a reliable relative standard deviation (RSD) value was acquired. Based on the results, the fabricated sensor has good stability and reproducibility, as well as the sensitive and selective analysis of MPH in human serum samples as real samples had effectively been feasible. The results of the actual sample were measured by HPLC procedure, and the results were compared with the results of the electrochemical method and corroborated them.

Disposable electrochemical immunosensor array for the multiplexed detection of the drug metabolites morphine, tetrahydrocannabinol and benzoylecgonine

Heroin, marijuana and cocaine are widely abused drugs. Their use can be readily detected by analyzing urine for the metabolites morphine (MOR), tetrahydrocannabinol (THC) or benzoylecgonine (BZC). A multiplex immunosensor is described here for detection of MOR, THC and BZC using screen printed carbon array electrodes modified with gold nanoparticles. Antibodies against MOR, THC and BZC were immobilized on eight electrodes in a sensor array simultaneously, and a competitive assay was used for the detection. The free analytes in the sample compete with bovine serum albumin-conjugated analytes for the immobilized antibodies on the sensor surface. The array is capable of detecting the three drugs simultaneously within 20-40 min. The method has a high sensitivity, with detection limits as low as 1.2, 7.0, and 8.0 pg.mL^-1 for MOR, THC and BZC, respectively. Cross reactivity testing was preformed to monitor any nonspecific binding. The results revealed good selectivity. Urine samples were spiked with the 3 drugs and tested with the multiplexed immunosensor. Recovery percentages ranged between 88 to 115%. Graphical abstract Schematic presentation of the multiplexed immunosensor for drugs of abuse,viz. tetrahydrocannabinol (THC), morphine (MOR), and benzoylecgonine (BZC)) by using an array of modified electrodes.

Biosensors in Drug Discovery and Drug Analysis

Background:

The determination of drugs in pharmaceutical formulations and human biologic fluids is important for pharmaceutical and medical sciences. Successful analysis requires low sensitivity, high selectivity and minimum interference effects. Current analytical methods can detect drugs at very low levels but these methods require long sample preparation steps, extraction prior to analysis, highly trained technical staff and high-cost instruments. Biosensors offer several advantages such as short analysis time, high sensitivity, real-time analysis, low-cost instruments, and short pretreatment steps over traditional techniques. Biosensors allow quantification not only of the active component in pharmaceutical formulations, but also the degradation products and metabolites in biological fluids. The present review gives comprehensive information on the application of biosensors for drug discovery and analysis. Moreover, this review focuses on the fabrication of these biosensors.

Methods:

Biosensors can be classified as the utilized bioreceptor and the signal transduction mechanism. The classification based on signal transductions includes electrochemical optical, thermal or acoustic. Electrochemical and optic transducers are mostly utilized transducers used for drug analysis. There are many biological recognition elements, such as enzymes, antibodies, cells that have been used in fabricating of biosensors. Aptamers and antibodies are the most widely used recognition elements for the screening of the drugs. Electrochemical sensors and biosensors have several advantages such as low detection limits, a wide linear response range, good stability and reproducibility. Optical biosensors have several advantages such as direct, real-time and label-free detection of many biological and chemical substances, high specificity, sensitivity, small size and low cost. Modified electrodes enhance sensitivity of the electrodes to develop a new biosensor with desired features. Chemically modified electrodes have gained attention in drug analysis owing to low background current, wide potential window range, simple surface renewal, low detection limit and low cost. Modified electrodes produced by modifying of a solid surface electrode via different materials (carbonaceous materials, metal nanoparticles, polymer, biomolecules) immobilization. Recent advances in nanotechnology offer opportunities to design and construct biosensors. Unique features of nanomaterials provide many advantages in the fabrication of biosensors. Nanomaterials have controllable chemical structures, large surface to volume ratios, functional groups on their surface. To develop proteininorganic hybrid nanomaterials, four preparation methods have been used. These methods are immobilization, conjugation, crosslinking and self-assembly. In the present manuscript, applications of different biosensors, fabricated by using several materials, for drug analysis are reviewed. The biosensing strategies are investigated and discussed in detail.

Results:

Several analytical techniques such as chromatography, spectroscopy, radiometry, immunoassays and electrochemistry have been used for drug analysis and quantification. Methods based on chromatography require timeconsuming procedure, long sample-preparation steps, expensive instruments and trained staff. Compared to chromatographic methods, immunoassays have simple protocols and lower cost. Electrochemical measurements have many advantages over traditional chemical analyses and give information about drug quantity, metabolic fate of drugs, and pharmacological activity. Moreover, the electroanalytical methods are useful to determine drugs sensitively and selectivity. Additionally, these methods decrease analysis cost and require low-cost instruments and simple sample pretreatment steps.

Conclusion:

In recent years, drug analyses are performed using traditional techniques. These techniques have a good detection limit, but they have some limitations such as long analysis time, expensive device and experienced personnel requirement. Increased demand for practical and low-cost analytical techniques biosensor has gained interest for drug determinations in medical sciences. Biosensors are unique and successful devices when compared to traditional techniques. For drug determination, different electrode modification materials and different biorecognition elements are used for biosensor construction. Several biosensor construction strategies have been developed to enhance the biosensor performance. With the considerable progress in electrode surface modification, promotes the selectivity of the biosensor, decreases the production cost and provides miniaturization. In the next years, advances in technology will provide low cost, sensitive, selective biosensors for drug analysis in drug formulations and biological samples.

Using gold nanostars modified pencil graphite electrode as a novel substrate for design a sensitive and selective Dopamine aptasensor

For the first time, gold nanostars (GNS) were applied for electrostatic and covalent immobilizing a thiol modified Dopamine aptamer on the pencil graphite electrode and signal amplification. Dopamine aptamer was immobilized on the gold nanostars through electrostatic interaction between negatively charged phosphate groups of aptamer and positively charged gold nanostars and AuS well known covalent interaction. In the presence of Dopamine in the test solution, the charge transfer resistance (R_CT) on the electrode surface increased with the increase of the Dopamine concentration due to specific interaction between Dopamine aptamer and Dopamine molecules, which made a barrier for electrons and inhibited the electron-transfer. So, the proposed approach showed a high sensitivity and a wide linearity to Dopamine in the range from 1.0 (±0.1) to 100.0 (±0.3) ngL^-1 (ppt) with detection and quantification limits of 0.29 (±0.10) and 0.90 (±0.08) ngL^-1 (ppt), respectively. Finally, the sensor was successfully used for determination of Dopamine in biological (human blood plasma and urine) samples. The results open up the path for manufacturing cost effective aptasensors for other biomedical applications.

Ultrasonic-assisted magnetic solid phase extraction of morphine in urine samples by new imprinted polymer-supported on MWCNT-Fe3O4-NPs: Central composite design optimization

Multiwalled carbon nanotubes (MWCNTs) were magnetized with Fe3O4 nanoparticles (MWCNTs-Fe3O4-NPs) and subsequently coated by vinyl end groups (Vinyltrimethoxysilane). MWCNT-Fe3O4-NPs were used as support for a new morphine (MO) molecularly imprinted polymer (MWCNT-Fe3O4-NPs@MO-MIP) by surface imprinting polymerization method. The MWCNT-Fe3O4-NPs@MO-MIP was characterized by FTIR, VSM and SEM techniques and successfully used for determination of MO. Ultrasonic-assisted magnetic solid phase extraction followed by UV-vis spectrophotometer (UAMSPE-UV-vis) was investigated for MWCNT-Fe3O4-NPs@MO-MIP and compared with non-imprinted polymer (NIP) using batch method. Central composite design under response surface methodology was used for the evaluation of the effect of variables, individually, as well as their possible interaction effects on the adsorption process. The variables such as sonication time, MWCNT-Fe3O4-NPs@MO-MIP mass, initial concentration of MO and pH were investigated in this study. At optimum experimental conditions, UAMSPE-UV-vis method was exhibited a linear range of 0.8-8.7mgL(-1) of the MO concentration with a detection limit of 0.18mgL(-1). The relative standard deviation for the analyte was found to be lower than 2.32%. The MWCNT-Fe3O4-NPs@MO-MIP adsorption capacity was found to be 37.01mgg(-1). The enrichment and preconcentration factors were found to be 107.01 and 98.21, respectively. The developed method was finally applied successfully to the determination of MO in urine and wastewater samples with the recoveries ranged from 96.40 to 105.6%.

Decaheme Cytochrome MtrF Adsorption and Electron Transfer on Gold Surface

Emergent electrical properties of multiheme cytochromes have promising applications. We performed hybrid simulations (molecular dynamics, free energy computation, and kinetic Monte Carlo) to study decaheme cytochrome, MtrF adsorption on an Au (111) surface in water and the electron transfer (ET) efficiency. Our results reveal that the gold surface's dehydration serves as a crucial driving force for protein adsorption due to large surface tension. The most possible adsorption orientation is with the ET terminal (heme5) approaching the gold surface, which yields a pathway for ET between the substrate and the aqueous environment. Upon adsorption, protein's secondary structures and central domains (II and IV) bonded with heme-residues remain relatively stable. MtrF surface mobility is dictated by thiol-gold interaction and strong binding between Au(111) and peptide aromatic groups. ET transfer rate across protein heme-network along the solvent-to-surface direction is slightly larger than that of the reverse direction, but lower than that of the solvation structure.

Recent advances in immunosensor for narcotic drug detection

INTRODUCTION

Immunosensor for illicit drugs have gained immense interest and have found several applications for drug abuse monitoring. This technology has offered a low cost detection of narcotics; thereby, providing a confirmatory platform to compliment the existing analytical methods.

METHODS

In this minireview, we define the basic concept of transducer for immunosensor development that utilizes antibodies and low molecular mass hapten (opiate) molecules.

RESULTS

This article emphasizes on recent advances in immunoanalytical techniques for monitoring of opiate drugs. Our results demonstrate that high quality antibodies can be used for immunosensor development against target analyte with greater sensitivity, specificity and precision than other available analytical methods.

CONCLUSION

In this review we highlight the fundamentals of different transducer technologies and its applications for immunosensor development currently being developed in our laboratory using rapid screening via immunochromatographic kit, label free optical detection via enzyme, fluorescence, gold nanoparticles and carbon nanotubes based immunosensing for sensitive and specific monitoring of opiates.

Synergistic effect of magnetite and gold nanoparticles onto the response of a label-free impedimetric hepatitis B virus DNA biosensor

A magnetite and gold nanoparticle modified carbon paste electrode (CPE) was prepared for the immobilization of a thiol modified Hepatitis B virus (HBV) probe DNA and determination trace amount of target HBV DNA. Indeed, the sensing platform integrated two nanoparticles that had previously been employed individually in the DNA biosensors. The proposed DNA biosensor could measure target HBV DNA virus concentration with a low detection limit of 3.1 (±0.1)×10-(13)M, which was greatly lower than the detection limit reported with gold or magnetite nanoparticles alone. The change of interfacial charge transfer resistance (RCT) was confirmed the hybrid formation between probe and target HBV DNA. The RCT difference (before and after hybridization with the target HBV DNA) was in a linear relationship with the logarithm of complementary oligonucleotide concentrations in the range of 8.3 (±0.1)×10(-13) to 6.4 (±0.2)×10(-7)M. In addition, the novel methodology for specific DNA sequence detection was highly selective, repeatable, and reproducible. Finally, this work was successfully utilized for the sensitive and label free impedimetric determination of HBV target DNA in the urine and blood plasma samples.

Gold nanoparticles deposited on fluorine-doped tin oxide surface as an effective platform for fabricating a highly sensitive and specific digoxin aptasensor

Fabrication steps of digoxin aptasensor. The DPVs are for accumulated MB at FTO/GNPs/Ap, before (a) and after (b) incubation with digoxin.