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The analysis of additional aspects of thermal influence on the sensory effect of the three-layer optical structure "prism - gold nanolayer - water" was continued. Here, the influence of the initial temperature of the "gold nanolayer - water" system on the surface plasmon resonance wavelength change is studies. It was established that the change in the value of the sensor effect along the wavelength of the surface plasmon resonance in the range of initial temperatures from 20 °C to 25 °C is insignificant. With an increase in the initial temperature to ∼100 °C, the change in the surface plasmon resonance wavelength can reach 0.75%, and is fixed experimentally. [ABSTRACT FROM AUTHOR]

We designed composite materials containing silver nanoparticles (AgNPs) and cotton fabric (CF). The cellulose in cotton fabric contains -OH groups. These -OH groups were deprotonated by a pretreatment process, and Ag+ ions were allowed to bind. In the consecutive step, the Ag+ ions were reduced to fiber-bound AgNPs, generating AgNP@CF. Three different AgNP@CF composites were created, varying the concentration of the precursor AgNO3 solution. The composite materials were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), and FTIR spectroscopy. The AgNP@CF composites were assessed for the detection of toxins using the surface-enhanced Raman scattering (SERS) technique. [ABSTRACT FROM AUTHOR]

The study aims to synthesize a selective matrix imprinted sorbent for the extraction of parathion and malathion. The structural unit of the polymeric framework was 2-methylpropanoic acid, the intermolecular crosslinker was ethylene glycol dimethacrylate, the polymerization initiator was azobisisobutyronitrile, the porogen was xylene, and the analyte was parathion. The synthesis was carried out under conditions of heating the reaction mixture to 65 °C, after which the matrix was washed with methanol to remove the analyte. For comparison purposes, non-imprinted control polymer was used as a negative control, which was prepared similarly, but without the addition of the analyte. The identification and quantification of organophosphates were performed by gas chromatography, and the morphological characteristics of the sorbents were evaluated by scanning electron microscopy. The optimal buffer for the purification of organophosphates was acetate buffer with a pH of 4; the optimal organic eluent was methanol. The limit of detection for para- and malathion was 0.1 μg/ml; the limit of quantification was 0.3 μg/ml. Linearity in the extraction conditions was observed in the range of 0.1–1 μg/ml for parathion and 0.1–2 μg/ml for malathion. The developed method will enable quick, selective, and cost-effective extraction of organophosphates from various substrates. [ABSTRACT FROM AUTHOR]

The distillation method for extracting anhydrous ethanol from the volatile benzene water requires continuous supervision in the petro-chemical industry. This paper describes the design process and numerical analyses of a PCF sensor with a hollow core for sensing the petro-chemical constituents, namely ethanol, water, and benzene, in the 2 THz range. Photonic crystal fiber sensors have many possible applications in the petro-chemical industry, environmental monitoring, biomedicine, and food preservation. An optical fiber-based sensor with simultaneous low loss and enhanced sensitivity is intended to detect this petro-chemical effectively and safely. The Finite Element Method (FEM) framework is used to quantify the exhibition of the suggested fiber sensor. The simulation outcomes on the suggested sensor model demonstrate very satisfactory results on the relative sensitivity as 99.55 %, 99.44 % and 99.59 % confinement loss as 2×10−17 dB/cm, 1×10−16 dB/cm and 1.17×10−16 dB/cm, Effective Material Loss (EML) as 0.00043 cm−1, 0.00054 cm−1 and 0.00038 cm−1 for Ethanol, Water and Benzene, respectively and the Effective areas (EAs) are 2.85×10−7 m2 for Ethanol, 2.91×10−7 m2 for Water and 2.82×10−7 m2 for Benzene at 2 THz frequency regime.

Purpose: This review provides an overview of recent advances in electrochemical sensors for analyte detection in saliva, highlighting their potential applications in diagnostics and health care. The purpose of this paper is to summarize the current state of the field, identify challenges and limitations and discuss future prospects for the development of saliva-based electrochemical sensors. Design/methodology/approach: The paper reviews relevant literature and research articles to examine the latest developments in electrochemical sensing technologies for saliva analysis. It explores the use of various electrode materials, including carbon nanomaterial, metal nanoparticles and conducting polymers, as well as the integration of microfluidics, lab-on-a-chip (LOC) devices and wearable/implantable technologies. The design and fabrication methodologies used in these sensors are discussed, along with sample preparation techniques and biorecognition elements for enhancing sensor performance. Findings: Electrochemical sensors for salivary analyte detection have demonstrated excellent potential for noninvasive, rapid and cost-effective diagnostics. Recent advancements have resulted in improved sensor selectivity, stability, sensitivity and compatibility with complex saliva samples. Integration with microfluidics and LOC technologies has shown promise in enhancing sensor efficiency and accuracy. In addition, wearable and implantable sensors enable continuous, real-time monitoring of salivary analytes, opening new avenues for personalized health care and disease management. Originality/value: This review presents an up-to-date overview of electrochemical sensors for analyte detection in saliva, offering insights into their design, fabrication and performance. It highlights the originality and value of integrating electrochemical sensing with microfluidics, wearable/implantable technologies and point-of-care testing platforms. The review also identifies challenges and limitations, such as interference from other saliva components and the need for improved stability and reproducibility. Future prospects include the development of novel microfluidic devices, advanced materials and user-friendly diagnostic devices to unlock the full potential of saliva-based electrochemical sensing in clinical practice. [ABSTRACT FROM AUTHOR]

Exposure to certain metal ions can lead to many diseases including cardiovascular, reproductive, and kidney disorders. Certain inorganic anions and organic species can also adversely affect living organisms as well as pose a severe threat to the environment. Detection and determination of biological analytes or biomarkers can help in the early diagnosis and treatment of several human diseases. Accordingly, great efforts have been devoted to the development of fluorescent and colorimetric sensors. Compared to many other detection techniques, the optical sensor stands unique. Porphyrins are excellent fluorophores with strong absorption and emission in the visible region. This highly conjugated macrocycle can be tuned to desirable properties with proper substituents at the periphery and complex formation with a vast number of metal ions. This detailed review discusses optical sensors that encompass both colorimetric and fluorescence sensors based on porphyrin/metalloporphyrin and their various forms for sensing metal ions, inorganic anions, organic moieties, and biologically significant molecules. In the presence of the concerned analyte, rearrangement of energy level of optical probe occurs and further facilitates interaction with the analyte which is mainly operated through various mechanisms like FRET, PET, ground state complex formation, intramolecular charge transfer, exciplex formation, etc. [ABSTRACT FROM AUTHOR]

Abstract Background and objectives Oral fluid (OF) is an easy-to-collect, inexpensive, fast and non-invasive sample to characterize health and welfare status of the pig. However, further standardisation of the collection methods is needed in order to use it regularly in veterinary practice. Cotton ropes are routinely used to collect OF for pathogen detection but they may not be optimal for biomarker analysis due to sample contamination. This study compared two methods (cotton ropes and sponges) to collect porcine OF for biomarker analysis. A panel of 11 biomarkers of stress, inflammation, sepsis, immunity, redox status and general homeostasis was studied. Materials and methods Eighteen farrow-to-finish pig farms were included in the study. In each farm, three (for sponges) or four pens of pigs (for ropes) were sampled at four age categories: the week after weaning (5 weeks), before (11–12 weeks) and after (12–13 weeks) moving to finisher facility and the week before slaughter (22–25 weeks). In total, 288 OF samples were collected with cotton ropes and 216 with sponges and analysed for the biomarkers: cortisol, alpha-amylase, oxytocin (stress), haptoglobin (inflammation), procalcitonin (sepsis), adenosine deaminase, immunoglobulin G (immune system), ferric reducing antioxidant power (redox status), and creatine kinase, lactate dehydrogenase and total protein (general homeostasis). Samples were also scored visually for dirtiness using a score from 1 (clean) to 5 (very dirty). Results Rope-collected OF had higher levels of dirtiness (3.7 ± 0.04) compared to sponge-collected OF (2.7 ± 0.15) and had higher values than sponges for cortisol, procalcitonin, oxytocin, haptoglobin, total protein, lactate dehydrogenase and ferric reducing antioxidant power. All biomarkers decreased in value with age. Immunoglobulin G did not perform well for any of the two collection methods. Discussion and conclusion The results showed a clear effect of age on the biomarkers in OF collected with both, sponges or ropes. Sponges provided a cleaner sample than cotton ropes for biomarker analysis. Both methods are easy to apply under the commercial conditions in pig farms although sponges may take more time in early weaner stages. From a practical point of view, sampling with sponges achieved the best combination of reduced sampling time and low contamination.

We designed composite materials containing silver nanoparticles (AgNPs) and cotton fabric (CF). The cellulose in cotton fabric contains -OH groups. These -OH groups were deprotonated by a pretreatment process, and Ag+ ions were allowed to bind. In the consecutive step, the Ag+ ions were reduced to fiber-bound AgNPs, generating AgNP@CF. Three different AgNP@CF composites were created, varying the concentration of the precursor AgNO3 solution. The composite materials were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), and FTIR spectroscopy. The AgNP@CF composites were assessed for the detection of toxins using the surface-enhanced Raman scattering (SERS) technique.

Electrospun polymer membranes are regarded as prospective biosensor components due to their large specific surface area and diverse opportunities for chemical modifications. However, their intricate porous structure can impede diffusion and render some analyte-binding sites inaccessible. To overcome these diffusion limitations and improve analyte adsorption onto the polymer, a pressure-driven sample flow through the membrane can be employed. To date, the efficiency of pressure-driven analyte delivery into these membranes has not been quantified. Here, we compare forced flow and passive sample diffusion through poly(dioxanone) electrospun membranes. We examine two model analytes, BSA and interleukin-1 beta (IL1b), to address both non-specific and specific binding. Following exposure of the membranes to the test solutions, we measured the residual concentrations of the analytes using fluorometry and enzyme-linked immunosorbent assay (ELISA) techniques. The pressure-driven sample loading was superior to passive diffusion, with a 2.8–11.5-fold change for physical adsorption and a 2.4–3.4-fold difference for specific binding. Our data can be useful for the development of immunoassays and microfluidic devices.

Background and objectives: Oral fluid (OF) is an easy-to-collect, inexpensive, fast and non-invasive sample to characterize health and welfare status of the pig. However, further standardisation of the collection methods is needed in order to use it regularly in veterinary practice. Cotton ropes are routinely used to collect OF for pathogen detection but they may not be optimal for biomarker analysis due to sample contamination. This study compared two methods (cotton ropes and sponges) to collect porcine OF for biomarker analysis. A panel of 11 biomarkers of stress, inflammation, sepsis, immunity, redox status and general homeostasis was studied. Materials and methods: Eighteen farrow-to-finish pig farms were included in the study. In each farm, three (for sponges) or four pens of pigs (for ropes) were sampled at four age categories: the week after weaning (5 weeks), before (11–12 weeks) and after (12–13 weeks) moving to finisher facility and the week before slaughter (22–25 weeks). In total, 288 OF samples were collected with cotton ropes and 216 with sponges and analysed for the biomarkers: cortisol, alpha-amylase, oxytocin (stress), haptoglobin (inflammation), procalcitonin (sepsis), adenosine deaminase, immunoglobulin G (immune system), ferric reducing antioxidant power (redox status), and creatine kinase, lactate dehydrogenase and total protein (general homeostasis). Samples were also scored visually for dirtiness using a score from 1 (clean) to 5 (very dirty). Results: Rope-collected OF had higher levels of dirtiness (3.7 ± 0.04) compared to sponge-collected OF (2.7 ± 0.15) and had higher values than sponges for cortisol, procalcitonin, oxytocin, haptoglobin, total protein, lactate dehydrogenase and ferric reducing antioxidant power. All biomarkers decreased in value with age. Immunoglobulin G did not perform well for any of the two collection methods. Discussion and conclusion: The results showed a clear effect of age on the biomarkers in OF collected with both, sponges or ropes. Sponges provided a cleaner sample than cotton ropes for biomarker analysis. Both methods are easy to apply under the commercial conditions in pig farms although sponges may take more time in early weaner stages. From a practical point of view, sampling with sponges achieved the best combination of reduced sampling time and low contamination. [ABSTRACT FROM AUTHOR]

Gas sensors are currently employed in various applications in fields such as medicine, ecology, and food processing, and serve as monitoring tools for the protection of human health, safety, and quality of life. Herein, we discuss a promising direction in the research and development of gas sensors based on peptides—biomolecules with high selectivity and sensitivity to various gases. Thanks to the technique developed in this work, which uses a framework based on the density-functional tight-binding theory (DFTB), the most probable adsorption centers were identified and used to describe the interaction of some analyte molecules with peptides. The DFTB method revealed that the physical adsorption of acetone, ammonium, benzene, ethanol, hexane, methanol, toluene, and trinitrotoluene had a binding energy in the range from −0.28 eV to −1.46 eV. It was found that peptides may adapt to the approaching analyte by changing their volume up to a maximum value of approx. 13%, in order to confine electron clouds around the adsorbed molecule. Based on the results obtained, the prospects for using the proposed peptide configurations in gas sensor devices are good. [ABSTRACT FROM AUTHOR]

Electrospun polymer membranes are regarded as prospective biosensor components due to their large specific surface area and diverse opportunities for chemical modifications. However, their intricate porous structure can impede diffusion and render some analyte-binding sites inaccessible. To overcome these diffusion limitations and improve analyte adsorption onto the polymer, a pressure-driven sample flow through the membrane can be employed. To date, the efficiency of pressure-driven analyte delivery into these membranes has not been quantified. Here, we compare forced flow and passive sample diffusion through poly(dioxanone) electrospun membranes. We examine two model analytes, BSA and interleukin-1 beta (IL1b), to address both non-specific and specific binding. Following exposure of the membranes to the test solutions, we measured the residual concentrations of the analytes using fluorometry and enzyme-linked immunosorbent assay (ELISA) techniques. The pressure-driven sample loading was superior to passive diffusion, with a 2.8–11.5-fold change for physical adsorption and a 2.4–3.4-fold difference for specific binding. Our data can be useful for the development of immunoassays and microfluidic devices. [ABSTRACT FROM AUTHOR]

A new metamaterial refractive index sensor based on the impedance matching idea is suggested to provide an ultra-narrowband absorption response at terahertz frequencies. In order to accomplish this, the graphene layer has been modeled as circuit components using the recently developed transmission line method and the recently proposed circuit model of Periodic Arrays of Graphene Disks. The given research gives a flowchart and equations for designing a sensor, greatly simplifying the sensor design approach. This study only explores Periodic Arrays of Graphene Disks but we think the offered technique is extensible to any available graphene forms that past designers supplied with a circuit model. We compare and contrast the full-wave simulation results with the suggested circuit model. The metallic ground prohibited the transmission of the episode wave, and all occurrence electromagnetic waves are restricted in the basic design between the graphene disk. As a consequence, a perfect narrowband absorption peak is obtained. Disk absorption spectra have been discovered for a variety of refractive lists. The findings of the circuit model and full-wave simulations appear to be balanced. This RI sensor is suitable for biomedical sensing because of the combination of its features. The proposed sensor's performance as a cancer early detection sensor was evaluated among biomedical sensors, and the findings indicated that the proposed sensor is an excellent candidate for this application. [ABSTRACT FROM AUTHOR]

Background: Interpretation laboratory analyses are crucial when assessing the patient’s condition. Reference intervals from apparently healthy and disease-free individuals may cause problems when outcomes from elderly patients with chronic diseases and on medications are being interpreted. Elderly individuals are a heterogeneous group ranging from individuals managing their daily life independently to individuals with diseases and impairment, in need of nursing care around the clock, that is, frail; a term widely used although there is no consensus on the definition. Aims and Objectives: The aim of the study was to study the effect of classification of elderly into healthy, moderately healthy, and frail, based on activities of daily living (ADL) and Mini-Mental State Examination (MMSE) or frailty index (FI), on the interpretation of outcomes regarding: Albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and gamma-glutamyltransferase (γ-GT) levels. Materials and Methods: Individuals ≥80 years (n=568) were classified either on ADL and MMSE or number of deficits, (FI). Results: Individuals classified as frail based on FI had lower mean levels for ALT, creatinine and γ-GT than individuals classified based on ADL and MMSE (P

Background: A non-invasive method capable of promptly detecting clinically important blood potassium changes could benefit care and safety for significant patient populations, including those with end-stage kidney disease. Methods: A total of 96 patients receiving maintenance hemodialysis participated in service evaluations of a wearable biosensor across four renal centers (two in UK, one in US and one in Saudi Arabia). All the patients had standard blood tests taken before and after their routine hemodialysis sessions and the results were used as reference potassium measurements for simultaneous, photoplethysmography-based, non-invasive digital samples obtained by the wearable biosensor. These digital samples were subsequently analyzed utilizing a machine learning model designed to identify excursions in serum potassium concentration by quantifying changes across a ternary classification strategy— hyperkalemia (K+ > 5.2 mEq/L), normokalaemia (K+ 3.5–5.2 mEq/L) or hypokalemia (K+ 5.2 mEq/L) or normokalemia (3.5 ≥ K+ ≤ 5.2). The total weighted recall of the biosensor and model was 86%. The overall weighted precision of the model was 86% with an F1-score of 0.86 indicating that the model achieved both high sensitivity and a low rate of false positives Conclusions: This evaluation demonstrates wearable technology capable of identifying important blood potassium changes outside of the normal reference range, in a group of patients receiving hemodialysis.

Background: Interpretation laboratory analyses are crucial when assessing the patient's condition. Reference intervals from apparently healthy and disease-free individuals may cause problems when outcomes from elderly patients with chronic diseases and on medications are being interpreted. Elderly individuals are a heterogeneous group ranging from individuals managing their daily life independently to individuals with diseases and impairment, in need of nursing care around the clock, that is, frail; a term widely used although there is no consensus on the definition. Aims and Objectives: The aim of the study was to study the effect of classification of elderly into healthy, moderately healthy, and frail, based on activities of daily living (ADL) and Mini-Mental State Examination (MMSE) or frailty index (FI), on the interpretation of outcomes regarding: Albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and gamma-glutamyltransferase (γ-GT) levels. Materials and Methods: Individuals ≥80 years (n=568) were classified either on ADL and MMSE or number of deficits, (FI). Results: Individuals classified as frail based on FI had lower mean levels for ALT, creatinine and γ-GT than individuals classified based on ADL and MMSE (P<0.05). Conclusion: The model to define health status to some extent affected laboratory analyte levels in ≥80 years old, classified as healthy, moderately healthy, and frail based on ADL and MMSE versus FI. [ABSTRACT FROM AUTHOR]

A biosensor is a self-reliant integrated device that is proficient in providing specific quantitative or semi-quantitative analytical information. It has been using a biological recognition component that is in direct spatial contact with a transduction component. It is an appliance that consists of two main parts: a bioreceptor and a transducer. Bioreceptor is a biological component that recognizes the objective of an analyte and a transducer. A physicochemical detector component has also been employed that converts the recognition incident into a measurable signal. All the biological materials including enzymes, antibodies, nucleic acids, hormones, receptors, organelles, or whole cells can be used as sensors or detectors in a device. Biosensors can provide low-priced and highly capable devices for being used in other day-to-day applications. It has multifarious potential applications of various types such as monitoring of treatment, disease progression, drug discovery, food control, and environmental monitoring as well as it continues to play a crucial role across numerous fields including biomedical diagnosis. In this review, we give a general introduction to biosensors and their applications, including a brief historical overview. [ABSTRACT FROM AUTHOR]

Optical immunosensors represent a research field of continuously increasing interest due to their unique features, which can mainly be attributed to the high-affinity and specific antibodies they use as biorecognition elements, combined with the advantageous characteristics of the optical transducing systems these sensors employ. The present work describes new developments in the field, focusing on recent bioanalytical applications (2021–2022) of labeled and label-free optical immunosensors. Special attention is paid to a specific immunosensing platform based on White Light Reflectance Spectroscopy, in which our labs have gained specific expertise; this platform is presented in detail so as to include developments, improvements, and bioanalytical applications since the mid-2000s. Perspectives on the field are been briefly discussed as well, highlighting the potential of optical immunosensors to eventually reach the state of a reliable, highly versatile, and widely applicable analytical tool suitable for use at the Point-of-Care. [ABSTRACT FROM AUTHOR]

Renal disease is often identified as a cause of morbidity and mortality in avian patients. However, currently, early antemortem detection of renal disease in avian patients is difficult. Anatomical and physiological differences between mammals and birds mean the use of commonly employed diagnostic testing (ie, measurement of blood urea nitrogen [BUN] and serum creatinine, urinalysis, and ultrasonography) are either nondiagnostic or difficult to achieve. Symmetric dimethylarginine (SDMA) is considered a more sensitive marker for renal disease in humans, dogs, and cats. However, SDMA has not yet been assessed for diagnostic use in any psittacine species. In this study, we establish reference ranges for SDMA in both Hispaniolan Amazon parrots ( Amazona ventralis , HAP) and Quaker parrots ( Myiopsitta monachus , QP). Blood was collected from 23 Amazon parrots and 32 Quaker parrots maintained in research facilities. Measurement of SDMA through a commercially available immunoassay (IA-SDMA) as well as creatinine, BUN, uric acid, phosphorus, calcium, sodium, potassium, and chloride were determined through IDEXX Laboratories. Plasma SDMA concentrations ranged from 6 to 15 µg/dL and 3 to 15 µg/dL for the HAP and QP, respectively. Sex was a confounding factor for the QP population, but sex did not have a significant effect on SDMA for the HAP population. No significant correlations were identified between SDMA concentrations and other parameters in either psittacine species. Our results show proof of concept for the IA-SDMA and provide reference intervals for SDMA in HAP and QP. Further investigation is required to determine the validity of this assay and the predictive power of SDMA in the detection of renal impairment for parrots and other common companion birds.

Objectives: Pediatric hospitals are always challenged by specimen volumes and thus any innovation in this realm is very welcome. With the introduction of Microslide assay pairs, we aimed to evaluate the analytical performance of the Vitros XT MicroSlide assay pairs on the Vitros XT 7600 compared to single MicroSlides. Design: Performance characteristics included within-run precision, analytical measurable range, method comparison, and interference verification. We compared six XT MicroSlide pairs on the Vitros XT 7600 with twelve corresponding single slide assays on the Vitros 5600 system. Results: The XT MicroSlides on Vitros XT 7600 demonstrated excellent precision, equivalent analytical measurable range, and strong method correlation with single slide assays on Vitros 5600 for most of the assays tested. Within-run CVs of the analytes ranged between 0.32% and 2.93% with between-run CV of less than 8.8% and linearity for all analytes was within the manufacturer's specified range. Interference studies showed comparable effects of hemolysis, lipemia, and bilirubin on both instruments. Conclusions: The XT MicroSlides are comparable to the single MicroSlide assays with improved efficiency, turnaround times and lower sample volumes.

Gas sensors are currently employed in various applications in fields such as medicine, ecology, and food processing, and serve as monitoring tools for the protection of human health, safety, and quality of life. Herein, we discuss a promising direction in the research and development of gas sensors based on peptides—biomolecules with high selectivity and sensitivity to various gases. Thanks to the technique developed in this work, which uses a framework based on the density-functional tight-binding theory (DFTB), the most probable adsorption centers were identified and used to describe the interaction of some analyte molecules with peptides. The DFTB method revealed that the physical adsorption of acetone, ammonium, benzene, ethanol, hexane, methanol, toluene, and trinitrotoluene had a binding energy in the range from −0.28 eV to −1.46 eV. It was found that peptides may adapt to the approaching analyte by changing their volume up to a maximum value of approx. 13%, in order to confine electron clouds around the adsorbed molecule. Based on the results obtained, the prospects for using the proposed peptide configurations in gas sensor devices are good.

A biosensor based on the modified Kretschmann configuration is proposed here. The sensitivity of the conventional prism-based sensor using angular interrogation is low. To enhance the sensor's performance, layers of zinc sulfide (ZnS) and graphene have been deposited over the metal layer. The angular interrogation technique is used to analyze the performance of the sensor. The thickness of the Ag metal has been optimized. The thickness of the Ag metal is taken as 50 nm because minimum reflectance has been achieved. With the combinations of the four layers of ZnS and one graphene layer, the maximum sensitivity attained is 292. 8 ∘ / R I U . Performance parameters such as detection accuracy, FWHM, and quality factor of the sensor have been evaluated as obtained as 0.16 deg - 1 , 6.37 deg , 46 R I U - 1 , respectively. The proposed sensor has potential application in the field of biochemical and biological analyte detection. [ABSTRACT FROM AUTHOR]

A sensor is a tool used to directly measure the test compound (analyte) in a sample. Ideally, such a device is capable of continuous and reversible response and should not damage the sample. Nanosensor refers to a system in which at least one of the nanostructures is used to detect gases, chemicals, biological agents, electric fields, light, heat, etc. in its construction. The use of nanomaterials significantly increases the sensitivity of the system. In biosensors, the part of the system used to attach to the analyte and specifically detect it is a biological element (such as a DNA strand, antibody, enzyme, whole cell). The “Nano Biosensors” series reviews various types of biosensors and biochips (including an array of biosensors), emphasizing the role of nanostructures, developed for medical and biological applications. Nano Biosensors Electrochemical sensors are sensors that use the biological element as a diagnostic component and the electrode as a transducer. The use of nanostructures in these systems is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Given the nature of the biomaterial detection process, electrochemical biosensors are divided into catalytic and propulsion. Common electrochemical techniques common in sensors include potentiometric, chronometry, voltammetry, impedance measurement, and field effect transistor (FET). Simultaneous use of the advantages of nanostructures and electrochemical techniques has led to the emergence of sensors with high sensitivity and decomposition power. The use of nanostructures in these sensors is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Various types of nanostructures including nanoparticles, nanotubes and nanowires, nanopores, self-adhesive monolayers and nanocomposites can be used to improve the performance and efficiency of sensors in their structure. Simultaneous use of the advantages of nanostructures and electrochemical techniques has led to the emergence of sensors with high sensitivity and decomposition power.

Background: During hemorrhage and resuscitation, clinical and laboratory monitoring is useful to guide further management. However, acute changes in the biochemistry due to blood loss and subsequent crystalloid fluid resuscitation have not been fully studied. Materials and methods: Twelve anesthetized, juvenile pigs were used. Atraumatic exsanguination, corresponding to a total blood loss of 40%, was performed through a catheter and completed 2 h after initiation of the experiment. Arterial samples were analyzed by point-of-care testing and venous samples were analyzed. Oxygen delivery was calculated. Results: Shortly after 40% hemorrhage and concomitant fluid supplementation, there were significant reductions in arterial hemoglobin and hematocrit (approximately 25%, respectively). Oxygen delivery was less than half of the baseline value. Lactate in arterial blood was more than doubled after 40% exsanguination. On average, no other clinically significant changes in any of the analytes were observed, but interindividual dispersion was pronounced. Conclusions: Acute exsanguination was associated with decreased hemoglobin and hematocrit levels and increased lactate levels but limited effects on the other biomarkers that were studied. Increased levels of biomarkers in severely bleeding patients could indicate tissue damage and the source should be further investigated.

Common solvents are mainly volatile organic compounds derived from petroleum, which are harmful to human health and the environment. Reducing the consumption of these toxic solvents or replacing them with safe solvents is vital. Recently, it has suggested the use of green alternative solvents as a proper solution. The present study reviews various aspects of amino acid-based natural deep eutectic solvents (AABNADESs) from synthesis to application. This investigation can provide a theoretical basis for the extensive application of AABNADESs in extraction of various analytes and also can be a guidance to choose the proper solvent for each analyte. Amino acid-based deep eutectic solvents are natural plant metabolites with at least one amino acid component that can be synthesized in various physical ways through the formation of hydrogen bonds. These emerging and green solvents are competitive to organic solvents to recover a wide range of analytes and can be a suitable alternative to toxic solvents in the field of extraction due to reasons such as biodegradability, tunable features, and being safe. Adjusting the inherent characteristics of DESs and optimizing other factors are necessary in order to achieve the highest extraction efficiency. Application of amino acid-based natural deep eutectic solvents in the extraction of various analytes. [Display omitted] • Variable features of AABNADES as a green solvent reviewed. • Different strategies of synthesizing AABNADES are exhaustively examined. • Role of AABNADESs in extraction of pesticides and bioactive compounds explained. • AABNADESs for extracting metals, mycotoxins, drug residues, and non-starch polysaccharides introduced. • Optimizing other factors effecting extraction efficiency evaluated. [ABSTRACT FROM AUTHOR]

The paper studies the sensor properties of poly[(9,9-dioctylfluorenyl-2,7-diyl) polymer with terminal dimethylphenyl (ADS129) groups to detect the nitro compound vapor in a laser oscillation mode after the formation of the nitro compound molecular complex. Different solvents are used to obtain ADS129 films. [ABSTRACT FROM AUTHOR]

This research contains a comparison among technologies of SiNW-FET/InPNW-FET depending on the size of channel and dopants in channel for biosensing application for two types of silicon and InP materials in the nanowire channel. A device numerical modelling tool, Silvaco ATLAS is used in step one to design three p-type SiNW-FET/InPNW-FET biosensors with a channel width of 40, 60 and 70 nm for these two types of materials and in step two, to design three p-type SiNW-FET/InPNW-FET biosensors with different dopants of 0.1 × 1014, 1 × 1014 and 10 × 1014 cm−3 for these two types of materials. Their sensing process is depended on the alteration in charge density which causes changing in the electric field at the surface of the SiNW-FET/InPNW-FET. The resistivity of the device is changed when a negatively charged biomolecules species has a chemical reaction with the external surface of a P-type SiNW-FET/InPNW-FET. To investigate the effect of different channel width and dopants on the performance of the SiNW-FET/InPNW-FET biosensor, several negatively interface charge densities, QF (−0.1 × 1012, −0.5 × 1012 and −1 × 1012 cm−2) are introduced on the surface of the SiNW-FET/InPNW-FET channel to represent as the actual target analytics (DNA) captured by the bioreceptor of the biosensor. Based on the results, these negatively QF attract the hole carriers below the surface of p-type nanowire causes to collect carriers in the channel and make an increase in the device output ID. Increment of the applied negative charge density has allowed for more ID to flow across the channel between drain and source region. The changes of ID with the applied QF are utilized to determine the sensitivities for all designed biosensor with different channel width and channel dopants. The minimum nanowire width of 40 nm with the minimum nanowire dopants of 0.1 × 1014 cm−3 for the high sensitivity silicon state of 3.6 μA/cm−2 compared to the indium phosphide state of 2.8 μA/cm−2. Therefore, the best performance for detecting the desired analyte in the silicon state with the lowest width and dopant has been achieved. [ABSTRACT FROM AUTHOR]

Detection and quantification of biotargets are important analytical tasks, which are solved using a wide range of various methods. In recent years, methods based on the isothermal amplification of nucleic acids (NAs) have been extensively developed. Among them, a special place is occupied by rolling circle amplification (RCA), which is used not only for the detection of a specific NA but also for the analysis of other biomolecules, and is also a versatile platform for the development of highly sensitive methods and convenient diagnostic devices. The present review reveals a number of methodical aspects of RCA-mediated analysis; in particular, the data on its key molecular participants are presented, the methods for increasing the efficiency and productivity of RCA are described, and different variants of reporter systems are briefly characterized. Differences in the techniques of RCA-mediated analysis of biotargets of various types are shown. Some examples of using different RCA variants for the solution of specific diagnostic problems are given. [ABSTRACT FROM AUTHOR]

Bioanalyte collection by blood draw is a painful process, prone to needle phobia and injuries. Microneedles can be engineered to penetrate the epidermal skin barrier and collect analytes from the interstitial fluid, arising as a safe, painless, and effective alternative to hypodermic needles. Although there are plenty of reviews on the various types of microneedles and their use as drug delivery systems, there is a lack of systematization on the application of polymeric microneedles for diagnosis. In this review, we focus on the current state of the art of this field, while providing information on safety, preclinical and clinical trials, and market distribution, to outline what we believe will be the future of health monitoring.

Methanol and Benzene are two volatile impurities that can be adulterate into Ethanol to make hand sanitizes, putting the disinfection practices at risk. In this paper, an optical fiber-based Photonic Crystal Fiber (PCF) sensor is developed to offer low loss and increased sensitivity concurrently in order to detect volatile contaminants combined with Ethanol in an efficient and safe manner. In the PCF, both the core and cladding area, rectangular air holes are utilized, and an absorbing layer, PML, is imposed to investigate a variety of optical characteristics. To quantify the exhibition of the recommended fiber sensor, Finite Element Method (FEM) framework is utilized. The simulation results on the proposed sensor model exhibit very gratifying results on the Relative Sensitivity (RS) as 99.15%, 99.36% and 99.41% confinement loss as 5 × 10−17 dB/cm, 2 × 10−16 dB/cm and 1.17 × 10−17 dB/cm, EML as 0.00065 cm−1, 0.00085 cm−1 and 0.00068 cm−1 for Ethanol, Methanol and Benzene, respectively at 2.2 THz frequency regime. Physical insights into the proposed fiber were also highlighted. The current manufacturing techniques are capable of producing the sensor we proposed. This PCF sensor is applicable to a larger variety of chemical, gas, and bio-sensing applications.

Optical immunosensors represent a research field of continuously increasing interest due to their unique features, which can mainly be attributed to the high-affinity and specific antibodies they use as biorecognition elements, combined with the advantageous characteristics of the optical transducing systems these sensors employ. The present work describes new developments in the field, focusing on recent bioanalytical applications (2021–2022) of labeled and label-free optical immunosensors. Special attention is paid to a specific immunosensing platform based on White Light Reflectance Spectroscopy, in which our labs have gained specific expertise; this platform is presented in detail so as to include developments, improvements, and bioanalytical applications since the mid-2000s. Perspectives on the field are been briefly discussed as well, highlighting the potential of optical immunosensors to eventually reach the state of a reliable, highly versatile, and widely applicable analytical tool suitable for use at the Point-of-Care.

We report a method for rapid detection and analysis of biological and environmental analytes by microwave-accelerated bioassays (MABs) and a novel MATLAB-based image processing of colorimetric signals. In this regard, colorimetric bioassays for histidine-rich protein 2 (HRP-2) and microcystin-leucine arginine (MC-LR) toxin were carried out using MABs and without microwave heating (i.e, gold standard bioassays). Our MATLAB-based detection method is based on the direct correlation of color intensity of a solution calculated from images captured with a smartphone with the concentration of the biomolecule of interest using a MATLAB code developed in-house. We demonstrated that our MATLAB-based detection method can yield bioassay sensitivity comparable to the colorimetric gold standard tool, i.e., UV-Visible spectroscopy. In addition, colorimetric bioassay time for the HRP-2 assay (used in malaria diagnosis) and colorimetric MC-LR bioassay (used in MC-LR toxin diagnosis) was reduced from up to 2 hours at room temperature without microwave heating to 15 minutes using the MABs technique.

Background: During hemorrhage and resuscitation, clinical and laboratory monitoring is useful to guide further management. However, acute changes in the biochemistry due to blood loss and subsequent crystalloid fluid resuscitation have not been fully studied. Materials and methods: Twelve anesthetized, juvenile pigs were used. Atraumatic exsanguination, corresponding to a total blood loss of 40%, was performed through a catheter and completed 2 h after initiation of the experiment. Arterial samples were analyzed by point-of-care testing and venous samples were analyzed. Oxygen delivery was calculated. Results: Shortly after 40% hemorrhage and concomitant fluid supplementation, there were significant reductions in arterial hemoglobin and hematocrit (approximately 25%, respectively). Oxygen delivery was less than half of the baseline value. Lactate in arterial blood was more than doubled after 40% exsanguination. On average, no other clinically significant changes in any of the analytes were observed, but interindividual dispersion was pronounced. Conclusions: Acute exsanguination was associated with decreased hemoglobin and hematocrit levels and increased lactate levels but limited effects on the other biomarkers that were studied. Increased levels of biomarkers in severely bleeding patients could indicate tissue damage and the source should be further investigated. [ABSTRACT FROM AUTHOR]