The use of enzyme-based biosensors for the detection and quantification of analytes of interest such as contaminants of emerging concern, including over-the-counter medication, provides an attractive ...alternative compared to more established techniques. However, their direct application to real environmental matrices is still under investigation due to the various drawbacks in their implementation. Here, we report the development of bioelectrodes using laccase enzymes immobilized onto carbon paper electrodes modified with nanostructured molybdenum disulfide (MoS2). The laccase enzymes were two isoforms (LacI and LacII) produced and purified from the fungus Pycnoporus sanguineus CS43 that is native to Mexico. A commercial purified enzyme from the fungus Trametes versicolor (TvL) was also evaluated to compare their performance. The developed bioelectrodes were used in the biosensing of acetaminophen, a drug widely used to relieve fever and pain, and of which there is recent concern about its effect on the environment after its final disposal. The use of MoS2 as a transducer modifier was evaluated, and it was found that the best detection was achieved using a concentration of 1 mg/mL. Moreover, it was found that the laccase with the best biosensing efficiency was LacII, which achieved an LOD of 0.2 µM and a sensitivity of 0.108 µA/µM cm2 in the buffer matrix. Moreover, the performance of the bioelectrodes in a composite groundwater sample from Northeast Mexico was analyzed, achieving an LOD of 0.5 µM and a sensitivity of 0.015 µA/µM cm2. The LOD values found are among the lowest reported for biosensors based on the use of oxidoreductase enzymes, while the sensitivity is the highest currently reported.
The correct detection and quantification of pollutants in water is key to regulating their presence in the environment. Biosensors offer several advantages, such as minimal sample preparation, short ...measurement times, high specificity and sensibility and low detection limits. The purpose of this review is to explore the different types of optical biosensors, focusing on their biological elements and their principle of operation, as well as recent applications in the detection of pollutants in water. According to our literature review, 33% of the publications used fluorescence-based biosensors, followed by surface plasmon resonance (SPR) with 28%. So far, SPR biosensors have achieved the best results in terms of detection limits. Although less common (22%), interferometers and resonators (4%) are also highly promising due to the low detection limits that can be reached using these techniques. In terms of biological recognition elements, 43% of the published works focused on antibodies due to their high affinity and stability, although they could be replaced with molecularly imprinted polymers. This review offers a unique compilation of the most recent work in the specific area of optical biosensing for water monitoring, focusing on both the biological element and the transducer used, as well as the type of target contaminant. Recent technological advances are discussed.
•A novel methodology using an effective refractive index to characterize the surface plasmon resonance angle.•Optical technique for detection of bovine serum albumin and carbamazepine•Possibility to ...infer changes onto the surface of gold films using microfluidic systems.
Surface plasmon resonance was used for the detection of different kinds of organic molecules, which was achieved employing a Kretschmann configuration. A simple theoretical model based on effective medium theory was used for estimation of the SPR angle. The employed model considers an effective refractive index, which has some advantages in comparison to other effective medium theories. This model depends on the surface coverage, size of the sample and also considers the scattering by molecules deposited on the surface of the thin film. Using an effective refractive index as a tool to predict the behavior of the SPR signal offers a significant advantage for the development of new biosensors, providing a deeper physical insight on the behavior of such phenomena, since inferring the behavior of SPR signals is of great importance for chemical analysis and bio-sensing. Therefore, in this work, an effective medium model was compared with experimental SPR measurements as a function of angle incidence of different molecules deposited onto thin films, specifically Bovine Serum Albumin (BSA) and carbamazepine attached to BSA, in order to validate the theoretical model. Evaluation of the proposed model for SPR signal was in good agreement with the experimental results. Statistical tests were obtained, with a 99% of correlation between the experimental data and the theoretical predictions around the resonance.
The use of enzyme-based biosensors for the detection and quantification of analytes of interest such as contaminants of emerging concern, including over-the-counter medication, provides an attractive ...alternative compared to more established techniques. However, their direct application to real environmental matrices is still under investigation due to the various drawbacks in their implementation. Here, we report the development of bioelectrodes using laccase enzymes immobilized onto carbon paper electrodes modified with nanostructured molybdenum disulfide (MoSsub.2). The laccase enzymes were two isoforms (LacI and LacII) produced and purified from the fungus Pycnoporus sanguineus CS43 that is native to Mexico. A commercial purified enzyme from the fungus Trametes versicolor (TvL) was also evaluated to compare their performance. The developed bioelectrodes were used in the biosensing of acetaminophen, a drug widely used to relieve fever and pain, and of which there is recent concern about its effect on the environment after its final disposal. The use of MoSsub.2 as a transducer modifier was evaluated, and it was found that the best detection was achieved using a concentration of 1 mg/mL. Moreover, it was found that the laccase with the best biosensing efficiency was LacII, which achieved an LOD of 0.2 µM and a sensitivity of 0.108 µA/µM cmsup.2 in the buffer matrix. Moreover, the performance of the bioelectrodes in a composite groundwater sample from Northeast Mexico was analyzed, achieving an LOD of 0.5 µM and a sensitivity of 0.015 µA/µM cmsup.2. The LOD values found are among the lowest reported for biosensors based on the use of oxidoreductase enzymes, while the sensitivity is the highest currently reported.
A Surface Plasmon Resonance (SPR) biosensor based on an inhibition immunoassay was developed for the detection of diclofenac (DCF) in aqueous solution. Due to the small size of DCF, an hapten-protein ...conjugate was produced by coupling DCF to bovine serum albumin (BSA). DCF-BSA conjugate formation was confirmed via MALDI-TOF mass spectrometry. The resulting conjugate was immobilized onto the surface of a sensor fabricated via e-beam deposition of a 2 nm chromium adhesion layer followed by a 50 nm gold layer onto precleaned BK7 glass slides. Immobilization onto the nano thin gold surface was accomplished by covalent amide linkage through a self-assembled monolayer. Samples were composed of a mixture of antibody at a fixed concentration and DCF at different known concentrations in deionized water, causing the inhibition of anti-DCF on the sensor. The DCF-BSA was obtained with a ratio of 3 DCF molecules per BSA. A calibration curve was performed using concentrations between 2 and 32 μg L−1. The curve was fitted using the Boltzmann equation, reaching a limit of detection (LOD) of 3.15 μg L−1 and limit of quantification (LOQ) of 10.52 μg L−1, the inter-day precision was calculated and an RSD value of 1.96% was obtained; and analysis time of 10 min. The developed biosensor is a preliminary approach to the detection of DCF in environmental water samples, and the first SPR biosensor developed for DCF detection using a hapten-protein conjugate.
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•An SPR immunosensor was developed to detect diclofenac in water samples.•The configuration of the immunosensor involves the conjugation of diclofenac and BSA as a carrier protein.•This is the first SPR immunosensor for diclofenac that uses the target analyte conjugated to a protein.•The obtained results are comparable with the only other work published for diclofenac detection using SPR.•The development of this kind of biosensors could help to star regulating the discharge of diclofenac in water.
Intrinsic radiosensitivity is a biological parameter known to influence the response to radiation therapy in cancer treatment. In this study, Raman spectroscopy and surface enhanced Raman ...spectroscopy (SERS) were successfully used in conjunction with principal component analysis (PCA) to discriminate between radioresistant (LY-R) and radiosensitive (LY-S) murine lymphoma sublines (L5178Y). PCA results for normal Raman analysis showed a differentiation between the radioresistant and radiosensitive cell lines based on their specific spectral fingerprint. In the case of SERS with gold nanoparticles (AuNPs), greater spectral enhancements were observed in the radioresistant subline in comparison to its radiosensitive counterpart, suggesting that each subline displays different interaction with AuNPs. Our results indicate that spectroscopic and chemometric techniques could be used as complementary tools for the prediction of intrinsic radiosensitivity of lymphoma samples.
The use of enzyme-based biosensors for the detection and quantification of analytes of interest such as contaminants of emerging concern, including over-the-counter medication, provides an attractive ...alternative compared to more established techniques. However, their direct application to real environmental matrices is still under investigation due to the various drawbacks in their implementation. Here, we report the development of bioelectrodes using laccase enzymes immobilized onto carbon paper electrodes modified with nanostructured molybdenum disulfide (MoS
). The laccase enzymes were two isoforms (LacI and LacII) produced and purified from the fungus
CS43 that is native to Mexico. A commercial purified enzyme from the fungus
(TvL) was also evaluated to compare their performance. The developed bioelectrodes were used in the biosensing of acetaminophen, a drug widely used to relieve fever and pain, and of which there is recent concern about its effect on the environment after its final disposal. The use of MoS
as a transducer modifier was evaluated, and it was found that the best detection was achieved using a concentration of 1 mg/mL. Moreover, it was found that the laccase with the best biosensing efficiency was LacII, which achieved an LOD of 0.2 µM and a sensitivity of 0.108 µA/µM cm
in the buffer matrix. Moreover, the performance of the bioelectrodes in a composite groundwater sample from Northeast Mexico was analyzed, achieving an LOD of 0.5 µM and a sensitivity of 0.015 µA/µM cm
. The LOD values found are among the lowest reported for biosensors based on the use of oxidoreductase enzymes, while the sensitivity is the highest currently reported.
The global rise in urbanization and industrial activity has led to the production and incorporation of foreign contaminant molecules into ecosystems, distorting them and impacting human and animal ...health. Physical, chemical, and biological strategies have been adopted to eliminate these contaminants from water bodies under anthropogenic stress. Biotechnological processes involving microorganisms and enzymes have been used for this purpose; specifically, laccases, which are broad spectrum biocatalysts, have been used to degrade several compounds, such as those that can be found in the effluents from industries and hospitals. Laccases have shown high potential in the biotransformation of diverse pollutants using crude enzyme extracts or free enzymes. However, their application in bioremediation and water treatment at a large scale is limited by the complex composition and high salt concentration and pH values of contaminated media that affect protein stability, recovery and recycling. These issues are also associated with operational problems and the necessity of large-scale production of laccase. Hence, more knowledge on the molecular characteristics of water bodies is required to identify and develop new laccases that can be used under complex conditions and to develop novel strategies and processes to achieve their efficient application in treating contaminated water. Recently, stability, efficiency, separation and reuse issues have been overcome by the immobilization of enzymes and development of novel biocatalytic materials. This review provides recent information on laccases from different sources, their structures and biochemical properties, mechanisms of action, and application in the bioremediation and biotransformation of contaminant molecules in water. Moreover, we discuss a series of improvements that have been attempted for better organic solvent tolerance, thermo-tolerance, and operational stability of laccases, as per process requirements.
This case series of 5 patients with severely necrotic mpox highlights the predominantly necrotic nature of lesions seen in cases of severe mpox as shown by skin and lung biopsy, as well as the ...extensive dissemination of the infection, as shown by polymerase chain reaction (PCR) assessment in different body sites.
Patients were male, the median age was 37, all lived with HIV (2 previously undiagnosed), the median CD4
cell count was 106 cells/mm
, and 2/5 were not receiving antiretroviral treatment. The most common complication was soft tissue infection. Skin and lung biopsies showed extensive areas of necrosis. Mpox PCR was positive in various sites, including skin, urine, serum, and cerebrospinal fluid. The initiation of antiretroviral treatment, worsened the disease, like that seen in immune reconstitution syndrome. Three patients died due to multiple organ failure, presumably associated with mpox since coinfections and opportunistic pathogens were ruled out.
Severely necrotic manifestations of mpox in people living with advanced and untreated HIV are related to adverse outcomes.
Neck circumference (NC) is being used to identify the risk of chronic diseases. There is a high prevalence of overweight and obesity in Latin America, and neck circumference is a simple and practical ...measurement to assess this, especially in primary health centers. We analyzed the correlation between the NC anthropometric indicator and other anthropometric measurements such as BMI and waist circumference (WC) in eight Latin American cities. We applied Pearson’s correlation to identify the correlate NC with the other anthropometric variables stratified by sex; the sensitivity (Se) and specificity (Sp) by sex were evaluated according to the cut-off established with the Youden Index. The strongest correlations between NC and WC were found when stratified by sex (women: r = 0.71; men: r = 0.69, respectively) followed by the correlation between NC and BMI (r = 0.65, both sex). NC cut-off points of 39.0 cm in men and 32.9 cm in women identified those individuals with an increased WC and 39.8 and 33.7 cm, respectively, for a substantial increase in WC. For BMI ≥ 25.0 kg/m2 for men, the cut-off point was 37.5 cm, and for women, it was 33.1 cm, and for BMI ≥ 30 kg/m2, the cut-off points were 39.2 and 34.2 cm, for men and women, respectively. Conclusion: NC proved to be a useful, practical, and inexpensive tool that can be used to identify, evaluate, and monitor overweight and obese individuals.
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