Monitoring pharmaceuticals in the aquatic environment using enzyme-linked immunosorbent assay (ELISA)-a practical overview

A sensitive analytical strategy of oligonucleotide functionalized fluorescent probes for detection of nusinersen sodium in human serum

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disease. Nusinersen sodium (NS) is the world's first antisense oligonucleotide (ASO) drug for SMA precise targeted therapy. However, the limited half-life of oligonucleotides and their tendency to accumulate in hepatic and renal tissues presented significant challenges for clinical investigation and therapeutic drug monitoring. In this study, we proposed an analytical strategy based on the specific capture of oligonucleotide functionalized fluorescent probes by single stranded binding proteins (SSB) for ultra-sensitive and high-throughput detection of nusinersen sodium in human serum. The magnetic nanoparticles modified with single-strand binding protein (MNPs-SSB) selectively bonded to the red fluorescent quantum dots functionalized with oligonucleotides (RQDs-ssDNA) that were complementary to nusinersen sodium. Upon interaction with nusinersen sodium, RQDs-ssDNA formed a double-stranded complex (RQDs-ssDNA-NS), resulting in enhanced red fluorescence after magnetic separation as it was no longer captured by MNPs-SSB but remained in the supernatant. A quantitative analysis of nusinersen sodium in biological samples was successfully achieved by establishing a relationship between fluorescence intensity and its concentration. The detection signal F/F0 exhibited a linear correlation (R2 = 0.9871) over a wide range from 0.1 nM to 200 nM, with a limit of detection (LOD) of 0.03 nM, demonstrating the high specificity and rapid analysis time (only 30 min). This method provided a novel approach for sensitive, high-throughput, and specific analysis of nusinersen sodium and similar ASO drugs.

Development of a Rapid Detection Method to Prorocentrum lima by Loop-Mediated Isothermal Amplification with Hydroxy Naphthol Blue

Prorocentrum lima, a widely distributed dinoflagellate known for its production of harmful biotoxins, poses a significant threat to humans, aquaculture, and marine ecosystems. As a result, the detection of this toxic alga in coastal waters has become an urgent research focus. In this study, a rapid, sensitive, and cost-effective detection method based on loop-mediated isothermal amplification (LAMP) was developed to identify P. lima. In this method, cell extracts of P. lima were diluted and used directly as templates for amplification, eliminating the need for nucleic acid purification and simplifying the detection process. Hydroxy naphthol blue (HNB) was incorporated into the reaction mix to facilitate result interpretation, enabling visual determination of the amplification outcome with the naked eye. The entire detection process, from DNA extraction to template amplification and product detection, could be completed within 80 min using a simple constant temperature-control device. This LAMP-based detection method demonstrated excellent reliability, specificity, and a low detection limit of 5.87 cells/mL for DNA crude extract. The assay offered an efficient alternative to PCR for rapid detection of P. lima. By streamlining the detection process and offering a visual readout, this technique holds promise for efficient and routine monitoring of harmful algal species, benefitting both research efforts and environmental management strategies.

Utilizing olive leaves biomass as an efficient adsorbent for ciprofloxacin removal: characterization, isotherm, kinetic, and thermodynamic analysis

Olive leaves were utilized to produce activated biomass for the removal of ciprofloxacin (CIP) from water. The raw biomass (ROLB) was activated with sodium hydroxide, phosphoric acid, and Dead Sea water to create co-precipitated adsorbent (COLB) with improved adsorption performance. The characteristics of the ROLB and COLB were examined using SEM images, BET surface area analyzer, and ATR-FTIR spectroscopy. COLB has a BET surface area of 7.763 m2/g, markedly higher than ROLB's 2.8 m2/g, indicating a substantial increase in adsorption sites. Through investigations on operational parameters, the optimal adsorption efficiency was achieved by COLB is 77.9% within 60 min, obtained at pH 6, and CIP concentration of 2 mg/mL. Isotherm studies indicated that both Langmuir and Freundlich models fit the adsorption data well for CIP onto ROLB and COLB, with R2 values exceeding 0.95, suggesting effective monolayer and heterogeneous surface adsorption. The Langmuir model revealed maximum adsorption capacities of 636 mg/g for ROLB and 1243 mg/g for COLB, highlighting COLB's superior adsorption capability attributed to its enhanced surface characteristics post-modification. Kinetic data fitting the pseudo-second-order model with R2 of 0.99 for ROLB and 1 for COLB, along with a higher calculated qe for COLB, suggest its modified surface provides more effective binding sites for CIP, enhancing adsorption capacity. Thermodynamic analysis revealed that the adsorption process is spontaneous (∆Go < 0), and exothermic (∆Ho < 0), and exhibits a decrease in randomness (∆So < 0) as the process progresses. The ΔH° value of 10.6 kJ/mol for ROLB signifies physisorption, whereas 35.97 kJ/mol for COLB implies that CIP adsorption on COLB occurs through a mixed physicochemical process.

Nanohybrid nanozyme based colourimetric immunosensor for porcine gelatin

Enzyme mimicking nanomaterials, nanozymes, have gained considerable interest in the scientific community because of their superior properties compared to natural enzymes, including their high stability at extreme conditions, cheaper availability, and ease of synthesis. Herein, we report novel colloidal gold nanoparticles - graphene nanoplatelets - chitosan (CS) with peroxidase mimicking properties used to carry out highly sensitive and selective immunoassay for porcine gelatin detection. The interaction between anti-gelatin antibody conjugated nanozyme with porcine gelatin proteins produced an ultrasensitive immunoassay response in the form of a colourimetric signal directly proportional to the porcine gelatin protein concentration. The nanozyme produced a colourimetric response in the presence of its substrate, 3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), demonstrating its peroxidase mimicking properties. The results revealed that the nanozyme exhibited remarkable selectivity and sensitivity in the assay, detecting proteins at concentrations as low as 86.42 pg/mL. Additionally, the immunosensor demonstrated a broad linear detection range spanning from 200 pg/mL to 2 ng/mL.

A detection method for Prorocentrum minimum by an aptamer-gold nanoparticles based colorimetric assay

Here, to give early waring for harmful algal blooms caused by Prorocentrum minimum, we reported a simple and rapid colorimetric assay that is named aptamer-gold nanoparticles (GNPs) based colorimetric assay (AGBCA). The GNPs maintain a dispersed state and have a strong characteristic absorption peak at 520 nm. With the addition of NaCl, the stability of the solution will be destroyed and the dispersed GNPs will aggregate. Therefore, the characteristic absorption peak of the GNPs solution will change from 520 nm to 670 nm. Aptamers can be adsorbed on the surface of GNPs, effectively preventing the aggregation of GNPs. In the presence of P. minimum, aptamers will specifically bind to P. minimum, causing the dissociation of the aptamers from GNPs. Consequently, the GNPs will aggregate in the NaCl solution, corresponding to a new absorption peak at 670 nm. A linear relationship between the absorbance ratio variation (ΔA₆₇₀/A₅₂₀) and the P. minimum concentration was observed in the concentration range of 1 × 10² - 1 × 10⁷ cells mL^-1, with a low detection limit of 8 cells mL^-1. The developed AGBCA is characterized by simplicity, strong specificity, and high sensitivity and is thus promising for the quantitative detection of P. minimum in natural samples.

Advancements in nanomaterial-based aptasensors for the detection of emerging organic pollutants in environmental and biological samples

The combination of nanomaterials (NMs) and aptamers into aptasensors enables highly specific and sensitive detection of diverse pollutants. The great potential of aptasensors is recognized for the detection of diverse emerging organic pollutants (EOPs) in different environmental and biological matrices. In addition to high sensitivity and selectivity, NM-based aptasensors have many other advantages such as portability, miniaturization, facile use, and affordability. This work showcases the recent advances achieved in the design and fabrication of NM-based aptasensors for monitoring EOPs (e.g., hormones, phenolic contaminants, pesticides, and pharmaceuticals). On the basis of their sensing mechanisms, the covered aptasensing systems are classified as electrochemical, colorimetric, PEC, fluorescence, SERS, and ECL. Special attention has been paid to the fabrication processes, analytical achievements, and sensing mechanisms of NM-based aptasensors. Further, the practical utility of aptasensing approaches has also been assessed based on their basic performance metrics (e.g., detection limits, sensing ranges, and response times).

Comparison of two commercial methods with a UHPLC-MS/MS method for the determination of multiple mycotoxins in cereals

Immunoassay-based techniques are important on-site screening tools for the detection of mycotoxins in cereals. This study aims to evaluate the trueness, precision, repeatability and cross-reactivity of commercially available test strips, ELISA kits and UHPLC-MS/MS on analyzing zearalenone, ochratoxin A, deoxynivalenol, T-2 toxin and fumonisin B₁. The results showed that false negative rate (25.7 %-37.4 %) of all tested mycotoxins by test strips was higher than the false positive rate (0 %-31.0 %). The repeatability of ELISA kits at the declared LOD dispersed from -85.7 % to +98.4 %. ELISA kits were more accurate at 50 % of the maximum residue limit (MRL) of mycotoxins than 150 % and 200 %. All the tested deoxynivalenol/zearalenone derivatives had cross-reactivity with different level, and sample matrix could reinforce this overestimation of target mycotoxin. This study emphasized that higher-quality antibody screening and more analytical performance investigations are need to address for on-site detection of mycotoxins in the future.

Functional Micro-/Nanostructures in Agrofood Science: Precise Inspection, Hazard Elimination, and Potential Health Risks

Nanotechnology, biotechniques, and chemical engineering have arisen as new trends with significant impacts on agrofood science development. Advanced analytical techniques with high sensitivity, specificity, and automation based on micro-/nanomaterials for food hazard elimination have become leading research hotspots in agrofood science. Research progress in micro-/nanomaterials has provided a solid theoretical basis and technical support to solve problems in the industry. However, the rapid development of micro-/nanostructures has also raised concerns regarding potential risks to human health. This review presents the latest advances in the precise inspection and elimination of food hazards from micro-/nanomaterials and discusses the potential threats to human health posed by nanomaterials. The theoretical reference was provided for the application trend of micro-/nanomaterials in the field of agrofood science in the future.

Bio-inspired aptamers decorated gold nanoparticles enable visualized detection of malathion

Biosensors always respond to the targets of interest in a specific manner, employing biological or bio-mimic recognition elements such as antibodies and aptamers. Inspired by target recognition in nature, an aptamer-mediated, gold nanoparticle-based sensing approach is developed in this work for effective determination of malathion. The sensing system consists of negatively charged aptamer probes, and polycationic proteins, protamine, as well as exceptional colorimetric nanoprobes, barely gold nanoparticles (AuNPs). Protamine molecules bound to aptamer probes hinder the aggregation of AuNPs, while no such inhibition is maintained when aptamer-specific malathion is introduced into the solution, thus leading to the solution colour change from red to blue observable by the naked eye. The assay is accomplished via a mix-and-measure step within 40 min with a detection limit as low as 1.48 μg/L (3σ/s rule). The assay method also exhibits high selectivity and good applicability for the quantification of malathion in tap water with recovery rates of 98.9%-109.4%. Additionally, the good detection accuracy is also confirmed by the high-performance liquid chromatography method. Therefore, the non-enzymatic, label- and device-free characteristics make it a robust tool for malathion assay in agricultural, environmental, and medical fields.

Effect of triclosan exposure on ovarian hormones, trace elements and growth in female rats

Triclosan (TCS) is an antibacterial compound used mainly in personal care products. Its widespread use for decades has made it one of the most widely detected compounds in environmental matrices and in biological fluids. Although it has been shown to be an endocrine disruptor in rats and aquatic species, its safe use by humans is unclear. The aim of the present study was to evaluate the effects of exposure to TCS in female rats. To this end, 14 rats were divided into two groups and fed daily as follows: the control group with sesame oil and the TCS group at a dose of 50 mg/kg/day for 28 days. Any signs of toxicity in the rats were observed daily, and the weight and phase of the estrous cycle were recorded. At the end, the rats were decapitated, the serum and ovaries were collected. The levels of testosterone and progesterone in serum were determined by immunoassay and mass spectrometry. Estradiol (in serum) and kisspeptin-10 (in serum and ovary) were measured only by immunoassays. Trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The weight gain study of the rats showed a significant decrease by exposure to TCS, while the estrous cycle was not significantly affected compared to the control. The optimized methods based on mass spectrometry showed a significant decrease in the levels of progesterone and testosterone due to exposure to TCS. In addition, elements determined by ICP-MS in rat serum showed significant changes in calcium, lithium and aluminum due to TCS treatment. Finally, the kisspeptin-10 levels did not show a negative effect due to the treatment by TCS. The results suggest that medium-term exposure to TCS did not significantly alter estrous cyclicity but caused alterations in growth, sex hormone levels and some elements in the rat serum.

An Immunocolorimetric Sensing System for Highly Sensitive and High-Throughput Detection of BNP with Carbon-Gold Nanocomposites Amplification

Conventional immunocolorimetric sensing of biomolecules continues to be challenged with low sensitivity although its wide application as a diagnostic tool in medicine and biotechnology. Herein, we present a multifunctional immunocolorimetric sensing system for sensitive and high-throughput detection of B-type natriuretic peptide (BNP) with carbon-gold nanocomposite (CGNs) amplification. Using a “green” strategy, monodisperse carbon nanospheres (CNs) were successfully synthesized by glucose carbonization. A simple and efficient hydrothermal method was developed to assemble abundant gold nanoparticles (AuNPs) onto the surfaces of CNs. The resulting CGNs were characterized and utilized for biomarker detection with superior properties of easy manufacturing, good biocompatibility, satisfactory chemical stability, and high loading capacity for biomolecules. As a proof of concept, the as-prepared CGNs were conjugated with horseradish peroxidase-labeled antibody against BNP (CGNs@AntiBNP-HRP) functioning as the carrier, signal amplifier, and detector for the sensitive detection of BNP. Under optimal conditions, the established CGNs@AntiBNP-HRP immunoprobe remarkably enhanced the detection performance of BNP, achieving signal amplification of more than 9 times compared to the conventional method. Based on our self-developed bionic electronic eye (e-Eye) and CGNs@AntiBNP-HRP immunoprobe, the multifunctional sensing system displayed a wide dynamic linear range of 3.9–500 ng/mL and a LOD of 0.640 ng/mL for BNP detection with high specificity, good accuracy and reproducibility. This portable sensing system with enhanced performance demonstrates great potential for BNP detection in point of care applications, and offers a universal and reliable platform for in vitro biomarker detection.

A review of the current and emerging detection methods of marine harmful microalgae

In recent years, the scale and frequency of outbreaks of harmful algal blooms (HABs) have increased year by year due to the intensification of seawater eutrophication and global climate change. HABs have become a global marine ecological and environmental problem, which poses a serious threat to human health, marine ecological security, and economic development. The establishment of detection technology for harmful microalgae is fundamental to the early warning and prevention of HABs. To date, several detection methods have been developed for harmful microalgae, they however lack a unified classification standard. It is difficult to use a reasonable mix of all the developed methods to improve the accuracy of detection results. Here, all of the established detection methods for harmful microalgae were reviewed, including morphological structure-based detection methods, cytochrome-based detection techniques, immunoassays, and nucleic acid-based detection methods. The principles, advantages, and weaknesses of these methods were highlighted. Their application in the detection of harmful microalgae was summarized. Overall, different detection methods are suitable for different purposes. Further development of more accurate, cost-effective, efficient, and rapid detection technology is required in the future. This review is expected to provide a reference for research related to the monitoring of marine environment, early warning of HABs, and the molecular identification of harmful microalgae.

Recent Developments in Innovative Magnetic Nanoparticles-Based Immunoassays: From Improvement of Conventional Immunoassays to Diagnosis of COVID-19

During the ongoing COVID-19 pandemic, the development of point-of-care (POC) detection with high sensitivity and rapid detection time is urgently needed to prevent transmission of infectious diseases. Magnetic nanoparticles (MNPs) have been considered attractive materials for enhancing sensitivity and reducing the detection time of conventional immunoassays due to their unique properties including magnetic behavior, high surface area, excellent stability, and easy biocompatibility. In addition, detecting target analytes through color development is necessary for user-friendly POC detection. In this review, recent advances in different types of MNPs-based immunoassays such as improvement of the conventional enzyme-linked immunosorbent assay (ELISA), immunoassays based on the peroxidase-like activity of MNPs and based on the dually labeled MNPs, filtration method, and lateral-flow immunoassay are described and we analyze the advantages and strategies of each method. Furthermore, immunoassays incorporating MNPs for COVID-19 diagnosis through color development are also introduced, demonstrating that MNPs can become common tools for on-site diagnosis.

Xenobiotics-Division and Methods of Detection: A Review

Xenobiotics are compounds of synthetic origin, usually used for domestic, agricultural, and industrial purposes; in the environment, they are present in micropollutant concentrations and high concentrations (using ng/L to µg/L units). Xenobiotics can be categorized according to different criteria, including their nature, uses, physical state, and pathophysiological effects. Their impacts on humans and the environment are non-negligible. Prolonged exposure to even low concentrations may have toxic, mutagenic, or teratogenic effects. Wastewater treatment plants that are ineffective at minimizing the release of xenobiotic compounds are one of the main sources of xenobiotics in the environment (e.g., xenobiotic compounds reach the environment, affecting both humans and animals). In order to minimize the negative impacts, various laws and regulations have been adopted in the EU and across the globe, with an emphasis on xenobiotics removal from the environment, in a way that is economically, environmentally, and socially acceptable, and will not result in their accumulation, or creation of compounds that are more harmful. Detection methods allow detecting even small concentrations of xenobiotics in samples, but the problem is the diversity and mix of compounds present in the environment, in which it is not known what their effects are). In this review, the division of xenobiotics and their detection methods will be presented.

Emerging Contaminants: An Overview of Recent Trends for Their Treatment and Management Using Light-Driven Processes

The management of contaminants of emerging concern (CECs) in water bodies is particularly challenging due to the difficulty in detection and their recalcitrant degradation by conventional means. In this review, CECs are characterized to give insights into the potential degradation performance of similar compounds. A two-pronged approach was then proposed for the overall management of CECs. Light-driven oxidation processes, namely photo/Fenton, photocatalysis, photolysis, UV/Ozone were discussed. Advances to overcome current limitations in these light-driven processes were proposed, focusing on recent trends and innovations. Light-based detection methodology was also discussed for the management of CECs. Lastly, a cost–benefit analysis on various light-based processes was conducted to access the suitability for CECs degradation. It was found that the UV/Ozone process might not be suitable due to the complication with pH adjustments and limited light wavelength. It was found that EEO values were in this sequence: UV only > UV/combination > photocatalyst > UV/O3 > UV/Fenton > solar/Fenton. The solar/Fenton process has the least computed EEO < 5 kWh m−3 and great potential for further development. Newer innovations such as solar/catalyst can also be explored with potentially lower EEO values.

Nanobody-based immunosensing methods for safeguarding public health

Immunosensing methods are biosensing techniques based on specific recognition of an antigen-antibody immunocomplex, which have become commonly used in safeguarding public health. Taking advantage of antibody-related biotechnological advances, the utilization of an antigen-binding fragment of a heavy-chain-only antibody termed as 'nanobody' holds significant biomedical potential. Compared with the conventional full-length antibody, a single-domain nanobody retaining cognate antigen specificity possesses remarkable physicochemical stability and structural adaptability, which enables a flexible and efficient molecular design of the immunosensing strategy. This minireview aims to summarize the recent progress in immunosensing methods using nanobody targeting tumor markers, environmental pollutants, and foodborne microbes.

Development of an enzyme-linked immunosorbent assay for the detection of mebendazole in chicken and mutton

Mebendazole (MBZ), a synthetic benzimidazole, is most widely used for the treatment of intestinal helminthiasis. In the present study, a hapten mimicking the MBZ structure was designed by introducing propanoic acid and coupling to carrier proteins by the active ester method to immunize New Zealand rabbits. A sensitive enzyme-linked immunosorbent assay (ELISA) was developed for the analysis of MBZ in food samples. The rabbit IgG based ELISA had a half-maximum inhibition concentration (IC₅₀) of 7.41 ng mL^-1, with a limit of detection of 0.27 ng mL^-1. The ELISA showed negligible cross reactivity (<1%) with structural analogs, including hydroxy-MBZ, albendazole, oxfendazole, fenbendazole, flubendazole and oxfendazole, except the value of 90.5% for amino-MBZ. The average recoveries of MBZ spiked in chicken and mutton muscle samples by the assay ranged from 84.31% to 106.28% and agreed well with those of high-performance liquid chromatography. The above results indicated that the generated anti-MBZ IgG-based ELISA showed promise in routine screening analysis of MBZ residues in food samples.

Ball-lens assisted sensitivity improvement of fluorescence immunoassay in microchannels

A contactless and ball-lens assisted sensitivity improvement method was present for the fluorescence or luminescence immunoassay in microchannel.

Application of Molecularly Imprinted Polymers (MIP) and Flowing Atmospheric-Pressure Afterglow Mass Spectrometry (FAPA-MS) to Analysis of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

In recent years, the rapid development of the pharmaceutical industry and the extensive and illicit use of painkillers have led to increased levels of nonsteroidal anti-inflammatory drugs (NSAIDs) in the environment. In view of the significant impact of NSAIDs on living organisms, including humans, their presence in the environment needs to be continuously monitored at trace levels. For this purpose, a combination of molecularly imprinted solid-phase extraction (MISPE) and HPLC-MS analysis is commonly used. MISPE has been utilized in direct, fast, and ecological analysis of drugs using a flowing atmospheric-pressure afterglow ion source for mass spectrometry (FAPA-MS). The new method was applied herein in the determination of naproxen, diclofenac, and ibuprofen. The linear dependence of the intensity of analytical signals on the amount of drugs is in the range of 0.2 μg to 1 g and the method detection limit (MDL) for all drugs is 0.2 μg in environmental samples. The new method also decreased the number of analytical stages, the time and cost of analysis, and the organic solvent consumption, besides being environmentally friendly.