Detection In Biological Fluids Research Articles

Hybrid Impedimetric Biosensors for Express Protein Markers Detection.

Impedimetric biosensors represent a powerful and promising tool for studying and monitoring biological processes associated with proteins and can contribute to the development of new approaches in the diagnosis and treatment of diseases. The basic principles, analytical methods, and applications of hybrid impedimetric biosensors for express protein detection in biological fluids are described. The advantages of this type of biosensors, such as simplicity and speed of operation, sensitivity and selectivity of analysis, cost-effectiveness, and an ability to be integrated into hybrid microfluidic systems, are demonstrated. Current challenges and development prospects in this area are analyzed. They include (a) the selection of materials for electrodes and formation of nanostructures on their surface; (b) the development of efficient methods for biorecognition elements' deposition on the electrodes' surface, providing the specificity and sensitivity of biosensing; (c) the reducing of nonspecific binding and interference, which could affect specificity; (d) adapting biosensors to real samples and conditions of operation; (e) expanding the range of detected proteins; and, finally, (f) the development of biosensor integration into large microanalytical system technologies. This review could be useful for researchers working in the field of impedimetric biosensors for protein detection, as well as for those interested in the application of this type of biosensor in biomedical diagnostics.

Aptamer-Based Fentanyl Detection in Biological Fluids.

Fentanyl is a widely abused analgesic and anesthetic drug with a narrow therapeutic window that creates easy opportunities for overdose and death. Rapid, accurate, and sensitive fentanyl detection in biosamples is crucial for therapeutic drug monitoring and overdose diagnosis. Unfortunately, current methods are limited to either sophisticated laboratory-based tests or antibody-based immunoassays, which are prone to false results and are mainly used with urine samples. Here, we have utilized library-immobilized SELEX to isolate new aptamers─nucleic acid-based bioreceptors that are well-suited for biosensing─that can specifically bind fentanyl under physiological conditions. We isolated multiple aptamers with nanomolar affinity and excellent specificity against dozens of interferents and incorporated one of these into an electrochemical aptamer-based sensor that can rapidly detect fentanyl at clinically relevant concentrations in 50% diluted serum, urine, and saliva. Given the excellent performance of these sensors, we believe that they could serve as the basis for point-of-care devices for monitoring fentanyl during medical procedures and determining fentanyl overdose.

Atomic layer deposition-fabricated two-dimensional MoO3-WO3 nanohybrid thin-film electrode for ultrasensitive and interference-free detection of dopamine

Atomically thin two-dimensional (2D) semiconductors and their hybrid electrodes show great promise in the advancement of neural sensors for detecting neurotransmitters either through implantation on the brain's surface or by direct detection in biological fluids. This research demonstrated the fabrication of a sub-10 nm thick 2D MoO3-WO3 heterostructure electrode via atomic layer deposition (ALD) for the first time to detect dopamine (DA). The developed thin-film with uniform surface morphology possessed monoclinic and orthorhombic crystal structures of WO3 and MoO3, respectively, with the presence of oxygen vacancies and their sub-stoichiometric phases. The MoO3-WO3 sensor showed excellent catalytic activity for the interference-free detection of DA by suppressing the redox activity of common interferences, ascorbic acid (AA) and uric acid (UA). The ultra-sensitivity of DA oxidation can be ascribed to the effective electrostatic interaction and chemical coordination between the positively charged DA (at pH 7.0) and the MoO3-WO3. In contrast, the predominant electrostatic repulsive force between the negatively charged AA and UA (at pH 7.0) and the MoO3-WO3 suppressed their electrochemical responses. The sensor showed a nanomolar detection limit (20 nM) and a wide linear range for DA detection, which is highly appropriate for its determination in biological samples. Additionally, the sensor demonstrated excellent electrochemical stability, high reproducibility, and good recoveries of DA determination in diluted human serum samples.

Facile Synthesis of Needle-like Copper Sulfide Structures as an Effective Electrochemical Sensor Material for Neurotransmitter Detection in Biological Samples.

Electrochemical sensors, due to their excellent and unique features, are of high interest nowadays for the detection and monitoring of several biological compounds. In such a case, serotonin (SRN), an important neurotransmitter, was herein studied for its detection in biological fluids since its presence is more crucial to be monitored and detected in clinical and medical applications. Several study strategies have been used to determine the chemical and physical properties. The crystalline size of the constructed copper sulfide (Cu2S) material was measured to be 25.92 nm. The Cu2S was fabricated over the working surface and further analyzed for several sensor parameters to be optimized. The charge transfer resistance of the copper sulfide-modified glassy carbon electrode (Cu2S/GCE) was determined to be about 277.0 Ω. With the linear range from about 0.029 μM to 607.6 μM for SRN, the limit of detection (LOD) was calculated as 3.2 nM, with a good sensitivity of 13.23 μA μM-1 cm2. The sensor experienced excellent repeatability, reproducibility, and long-term stability. The fabricated electrode was selective with the presence of different interfering compounds. The real sample analysis, as determined with the regular addition method with human serum and urine samples, revealed a good recovery percentage. Thus, the employed fabricated electrode material will be highly effective in sensing other analytes of choice.

General Review on Opioids

Opioids are widely utilized by the public as both legal and illegal substances. Opiates, particularly heroin, are among the most widely used illicit narcotics and still account for the majority of seizures globally, despite the development of Novel Psychoactive Substances (NPS), particularly new fentanyl derivatives. The article gives a general review of opiates' pharmacology, analgesic action, and classification. It discussed how they might be abused by the general public and in the event of tampering. Because of the hazards of accidents linked to opiate use and dependence, opiates are furthermore closely monitored in workplace drug testing programs around the world. Also it covered analytical techniques for opiate detection in biological fluids. In the modern era, substance abuse has emerged as a global epidemic. Opium and its derivatives are second only to cannabis in terms of global consumption among illegal narcotics.

Aptamer-coated track-etched membranes with a nanostructured silver layer for single virus detection in biological fluids.

Aptasensors based on surface-enhanced Raman spectroscopy (SERS) are of high interest due to the superior specificity and low limit of detection. It is possible to produce stable and cheap SERS-active substrates and portable equipment meeting the requirements of point-of-care devices. Here we combine the membrane filtration and SERS-active substrate in the one pot. This approach allows efficient adsorption of the viruses from the solution onto aptamer-covered silver nanoparticles. Specific determination of the viruses was provided by the aptamer to influenza A virus labeled with the Raman-active label. The SERS-signal from the label was decreased with a descending concentration of the target virus. Even several virus particles in the sample provided an increase in SERS-spectra intensity, requiring only a few minutes for the interaction between the aptamer and the virus. The limit of detection of the aptasensor was as low as 10 viral particles per mL (VP/mL) of influenza A virus or 2 VP/mL per probe. This value overcomes the limit of detection of PCR techniques (∼103 VP/mL). The proposed biosensor is very convenient for point-of-care applications.

Gold nanostar and graphitic carbon nitride nanocomposite for serotonin detection in biological fluids and human embryonic kidney cell microenvironment.

Ananosensor comprising of gold nanostars (Au-Nstars)-graphitic carbon nitride (g-C3N4) nanocomposite layered on a glassy carbon electrode (GCE) to detect serotonin (ST) in various body fluidshas been fabricated. The nanocomposite and the sensing platform have been thoroughly characterized with UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray photoelectron spectroscopy (EDX), and electrochemical techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The designed ST detection probe has achieved a linear dynamic range (LDR) in the range5 × 10-7 and 1 × 10-3M with a limit of detection (LOD) of 15.1nM (RSD < 3.3%). The ST detection capability of the fabricated sensor ranges between the normal and several abnormal pathophysiological situations. The sensor effectively detects ST in real matrices such as urine and blood serum, thus, showing its direct diagnostic applicability. Additionally, the sensor has been tested in the microenvironment of human embryonic kidney (HEK) cells to assess the possibility of ST secretion in cell lines. Interferences because of co-existing molecules have been evaluated, and the shelf-life of the fabricated sensor has been obtained as 8weeks.

A regenerable electrochemical sensor for electro-inactive cyclovirobuxine D detection in biological samples.

Based on the pKa determination of cyclovirobuxine D (CVB-D) using the method of potentiometry, we predicted the ionization state of CVB-D at physiological pH. Thus, by taking advantage of the ionization state and consequent non-covalent interactions between protonated CVB-D and deprotonated polymerized bromothymol blue (poly-BTB) under physiological conditions, we developed a simple and reusable electrochemical sensor that contains a poly-BTB/SWNT-modified electrode for electro-inactive CVB-D detection in biological fluids using poly-BTB as both the recognition unit and the electrochemical probe. Upon being immersed in the solution of CVB-D, the poly BTB-based electrode shows a current decrease due to the interaction-driven binding of CVB-D on the electrode surface. The current decrease in the electrochemical sensor toward CVB-D concentration shows a linear relationship in the dynamic ranges of 0.01-1 μM and 1-50 μM with a detection limit of 1.65 nM based on 3σ. The sensor can be easily regenerated through the removal of the binding of CVB-D from the electrode surface by highly negatively charged heparin, and it presents high repeatability with an RSD of less than 4.0% for seven measurements. In animal experiments, the electrochemical sensor was selective and sensitive for CVB-D determination in plasma and liver homogenates. The electrochemical sensor is readily accessible, robust, and cost-effective and holds good promise for more applications in biological and clinical fields associated with CVB-D using less technically demanding and simple operating procedures.

The Challenges of O2 Detection in Biological Fluids: Classical Methods and Translation to Clinical Applications.

Dissolved oxygen (DO) is deeply involved in preserving the life of cellular tissues and human beings due to its key role in cellular metabolism: its alterations may reflect important pathophysiological conditions. DO levels are measured to identify pathological conditions, explain pathophysiological mechanisms, and monitor the efficacy of therapeutic approaches. This is particularly relevant when the measurements are performed in vivo but also in contexts where a variety of biological and synthetic media are used, such as ex vivo organ perfusion. A reliable measurement of medium oxygenation ensures a high-quality process. It is crucial to provide a high-accuracy, real-time method for DO quantification, which could be robust towards different medium compositions and temperatures. In fact, biological fluids and synthetic clinical fluids represent a challenging environment where DO interacts with various compounds and can change continuously and dynamically, and further precaution is needed to obtain reliable results. This study aims to present and discuss the main oxygen detection and quantification methods, focusing on the technical needs for their translation to clinical practice. Firstly, we resumed all the main methodologies and advancements concerning dissolved oxygen determination. After identifying the main groups of all the available techniques for DO sensing based on their mechanisms and applicability, we focused on transferring the most promising approaches to a clinical in vivo/ex vivo setting.

MiRNA Signature in CSF From Patients With Primary Progressive Multiple Sclerosis.

Primary progressive multiple sclerosis (PPMS) displays a highly variable disease progression with a characteristic accumulation of disability, what makes difficult its diagnosis and efficient treatment. The identification of microRNAs (miRNAs)-based signature for the early detection in biological fluids could reveal promising biomarkers to provide new insights into defining MS clinical subtypes and potential therapeutic strategies. The objective of this cross-sectional study was to describe PPMS miRNA profiles in CSF and serum samples compared with other neurologic disease individuals (OND) and relapsing-remitting MS (RRMS). First, a screening stage analyzing multiple miRNAs in few samples using OpenArray plates was performed. Second, individual quantitative polymerase chain reactions (qPCRs) were used to validate specific miRNAs in a greater number of samples. A specific profile of dysregulated circulating miRNAs (let-7b-5p and miR-143-3p) was found downregulated in PPMS CSF samples compared with OND. In addition, in serum samples, miR-20a-5p and miR-320b were dysregulated in PPMS against RRMS and OND, miR-26a-5p and miR-485-3p were downregulated in PPMS vs RRMS, and miR-142-5p was upregulated in RRMS compared with OND. We described a 2-miRNA signature in CSF of PPMS individuals and several dysregulated miRNAs in serum from patients with MS, which could be considered valuable candidates to be further studied to unravel their actual role in MS. This study provides Class II evidence that specific miRNA profiles accurately distinguish PPMS from RRMS and other neurologic disorders.

PMON255 Inflammation and Oxidative Stress in Seminal Plasma: Role of Free Light Chains of Immunoglobulins and Antioxidants as Biomarkers in Male Infertility

Abstract Oxidative and inflammatory damage are underlying mechanisms in various conditions related to male infertility, including varicocele. Free light chains of immunoglobulins (FLCs) are considered markers of low-grade inflammation in various conditions. Nowadays it is known that they may play enzymatic and proteolytic activities; they may activate complement cascade and mast cells, with crucial role in the development of contact sensibility; they may also inhibit the autonomous signaling ability of the B-cell receptor. Their detection in biological fluids may be useful as biomarker of inflammation or altered immune response. Coenzyme Q10 (CoQ10), a lipidic antioxidant and component of the mitochondrial respiratory chain, is involved in spermatozoa energy metabolism and motility. Therefore, we aimed to evaluate FLCs seminal levels in patients with varicocele in comparison to control subjects and to correlate them with CoQ10 and Total Antioxidant Capacity (TAC) in human semen. A total of 65 patients were enrolled, aged 18-50 years. Semen analysis was performed; patients were divided into three groups: controls (CTRL), 12 normozoospermic patients aged 34 (33-41) years; varicocele (VAR), 29 patients aged 33 (26-37) years; idiopathic (IDIO), 24 oligo-, astheno- and oligoasthenozoospermic patients aged 37 (33.5-40.5) years. FLCs were assayed by turbidimetric method; CoQ10 by HPLC; TAC by spectrophotometric method. Λ FLCs showed a trend towards higher levels in VAR vs CTRL and IDIO. VAR showed a trend towards lower κ FLCs levels vs the other two groups. Comparing κ/λ ratio VAR showed significantly lower levels vs CTRL and IDIO (Mean±SEM 3.18±0.75; 8.28±1.71; 8.90±2.94, respectively; p&amp;lt;0.05). CoQ10 seminal levels showed higher levels in VAR and IDIO compared to CTRL (57.7±4.13; 65.50±6.95 and 38.30±3.35 mcg/ml, respectively; p&amp;lt;0.05) No different TAC values were found between groups. Our data confirm lower levels of κ/λ ratio in VAR as previously reported and suggest a possible application as clinical biomarkers for male infertility. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Current Challenges and Developments in Perovskite-Based Electrochemical Biosensors for Effective Theragnostics of Neurological Disorders.

Early-stage diagnosis of neurological disease and effective therapeutics play a significant role in improving the chances of saving lives through suitable and personalized courses of treatment. Biomolecules are potential indicators of any kind of disorder in a biological system, and they are recognized as a critical quantitative parameter in disease diagnosis and therapeutics, collectively known as theragnostics. The effective diagnosis of neurological disorders solely depends on the detection of the imbalance in the concentration of neurological biomarkers such as nucleic acids, proteins, and small metabolites in bodily fluids such as blood serum, plasma, urine, etc. This process of neurological biomarker detection can lead to an effective prognosis with a prediction of the treatment efficiency and recurrence. While review papers on electrochemical, spectral, and electronic biosensors for the detection of a wide variety of biomarkers related to neurological disorders are available in the literature, the prevailing challenges and developments in perovskite-based biosensors for effective theragnostics of neurological disorders have received scant attention. In this Mini-Review, we discuss the topical advancements in design strategies of perovskite-based electrochemical biosensors with detailed insight into the detection of neurological disease or disorder-specific biomarkers and their trace-level detection in biological fluids with high specificity and sensitivity. The tables in this Review give the performance analysis of recently developed perovskite-based electrochemical biosensors for effective theragnostics of neurological disorders. To conclude, the current challenges in biosensing technology for early diagnosis and therapeutics of neurological disorders are discussed along with a forecast of their anticipated developments.

Point-of-care vertical flow immunoassay system for ultra-sensitive multiplex biothreat-agent detection in biological fluids

This paper presents simple, fast, and sensitive detection of multiple biothreat agents by paper-based vertical flow colorimetric sandwich immunoassay for detection of Yersinia pestis (LcrV and F1) and Francisella tularensis (lipopolysaccharide; LPS) antigens using a vertical flow immunoassay (VFI) prototype with portable syringe pump and a new membrane holder. The capture antibody (cAb) printing onto nitrocellulose membrane and gold-labelled detection antibody (dAb) were optimized to enhance the assay sensitivity and specificity. Even though the paper pore size was relaxed from previous 0.1 μm to the current 0.45 μm for serum samples, detection limits as low as 0.050 ng/mL for LcrV and F1, and 0.100 ng/mL for FtLPS have been achieved in buffer and similarly in diluted serum (with LcrV and F1 LODs remained the same and LPS LOD reduced to 0.250 ng/mL). These were 40, 80, and 50X (20X for LPS in serum) better than those from lateral flow configuration. Furthermore, the comparison of multiplex format demonstrated low cross-reactivity and equal sensitivity to that of the singleplex assay. The optimized VFI platform thus provides a portable and rapid on-site monitoring system for multiplex biothreat detection with the potential for high sensitivity, specificity, reproducibility, and multiplexing capability, supporting its utility in remote and resource-limited settings.

Construction of sphere like samarium vanadate nanoparticles anchored graphene nanosheets for enhanced electrochemical detection of nitrofurantoin in biological fluids

In recent times rare earth metal vanadate (REVO) has received a lot of attention in the research of electrocatalysts . Accordingly, we construct a novel fabrication strategy nanoarchitecture for an electrochemical sensor . In addition, the highly effective nitrofurantoin (NFT) antibiotic drug is mainly used for the treatment of urinary tract infections. However, when the level of NFT use in the human body increases, the pulmonary develops toxic and many side effects. Hence, the detection of NFT in biological fluids is much important. This electrochemical detection approach is a better way to detect the NFT precisely. Herein, the pristine samarium vanadate nanoparticles (SV NPs) synthesized were Co-precipitation method. The collected sample was sintered at 450, 550, and 650 °C (denoted as SV-1, SV-2, SV-3). The above-mentioned samples were incorporated with graphene nanosheets (GNSs) through an ultra-sonication method to obtained SmVO 4 -GNSs (SVG) nanocomposites namely (SVG-1, SVG-2, SVG-3), which were utilized for various analytical, spectroscopic and microscopic techniques. Interestingly, the as-prepared SVG-2/GCE was demonstrated an enhanced the electrochemical activity due to the synergetic effect between SV-2 and GNSs, which significantly enhanced the reduction signal of NFT. Thereby, SVG-2/GCE has exhibited a good linear range (0.035–672.3 μM), good sensitivity (0.875 μA μA −1 cm −2 ) with a limit of detection (0.0087 μM). The anti-interference ability, good sensitivity, and operational stability were performed in the proposed electrode. The SVG-2 modified RRD electrode was capable of detecting NFT in blood serum and human urine samples in real-time monitoring analysis. These electrochemical tests were revealed an entirely new perspective on the electrocatalytic activity as well as outstanding amplification results at ultra-trace levels. Schematic illustration of the facile synthesis of SmVO 4 NPs anchored GNSs nanocomposites and their electrochemical application. • Samarium vanadate anchored graphene nanosheets nanocomposites was successfully prepared through ultrasonication. • The synergistic effect of SmVO 4 and GNSs enhanced electrochemical detection of nitrofurantoin. • The SVG sensor exhibited a higher linear range of 0.035–672.3 μM, low detection limit of 0.0087 μM towards nitrofurantoin detection. • The SVG-2 modified electrode were applied for NFT detection with acceptable operational stability, reproducibility, and real-time detection in biological fluids.

3D printing of compact electrochemical cell for sequential analysis of steroid hormones

3D printing technology revolutionized the development of electrochemical sensors allowing the fabrication of custom devices that can be adapted to meet specific applications. This study describes the development of a miniaturized electrochemical cell containing integrated electrodes manufactured entirely by 3D printing for the sequential detection of steroid hormones. The electrochemical sensor was manufactured in a single step by combining two types of thermoplastic filaments. Polylactic acid-Carbon Black (PLA-CB) was used in the electrode region and acrylonitrile butadiene styrene (ABS) was used in the insulating region. Chemical/electrochemical treatments were used to remove the inert polymer matrix and expose the electroactive sites of the CB electrodes. These pre-treatment procedures significantly enhanced the electrochemical response of the printed sensor. The analytical performance of the activated 3D printed electrochemical cell was demonstrated in the sequential detection of estradiol (E2) and progesterone (P4) in artificial urine. The electrochemical cell offered good repeatability (RSD = 3.1%) and reproducibility (RSD = 10.7%) between analyses reaching detection limits of 0.11 and 17.8 µmol L-1 for E2 and P4, respectively. In this sense, these results demonstrate that the use of 3D printing paves the way for the fast and economical fabrication of miniaturized electrochemical cells for hormone detection in biological fluids.

A new strategy to count and sort neutrophil-derived extracellular vesicles: Validation in infectious disorders.

Newly recognized polymorphonuclear neutrophil (PMNs) functions include the ability to release subcellular mediators such as neutrophil‐derived extracellular vesicles (NDEVs) involved in immune and thrombo‐inflammatory responses. Elevation of their plasmatic level has been reported in a variety of infectious and cardiovascular disorders, but the clinical use of this potential biomarker is hampered by methodological issues. Although flow cytometry (FCM) is currently used to detect NDEVs in the plasma of patients, an extensive characterization of NDEVs has never been done. Moreover, their detection remains challenging because of their small size and low antigen density. Therefore, the objective of the present study was first to establish a surface antigenic signature of NDEVs detectable by FCM and therefore to improve their detection in biological fluids by developing a strategy allowing to overcome their low fluorescent signal and reduce the background noise. By testing a large panel of 54 antibody specificities already reported to be positive on PMNs, we identified a profile of 15 membrane protein markers, including 4 (CD157, CD24, CD65 and CD66c) never described on NDEVs. Among them, CD15, CD66b and CD66c were identified as the most sensitive and specific markers to detect NDEVs by FCM. Using this antigenic signature, we developed a new strategy combining the three best antibodies in a cocktail and reducing the background noise by size exclusion chromatography (SEC). This strategy allowed a significant improvement in NDEVs enumeration in plasma from sepsis patients and made it feasible to efficiently sort NDEVs from COVID‐19 patients. Altogether, this work opens the door to a more valuable measurement of NDEVs as a potential biomarker in clinical practice. A similar strategy could also be applied to improve detection by FCM of other rare subpopulations of EVs generated by tissues with limited access, such as vascular endothelium, cancer cells or placenta.

Chitosan polymer matrix-derived nanocomposite (CuS/NSC) for non-enzymatic electrochemical glucose sensor

In this study, N and S co-doped chitosan polymer matrix-derived composite (CuS/NSC) was synthesized via a one-step hydrothermal technique using a low-cost copper complex of chitosan polymer. Cyclic voltammetry and chronoamperometry revealed excellent electrocatalytic performance. The glucose sensor exhibited a linear range of 160 μM to 11.76 mM, a low detection limit 2.72 μM and a sensitivity of 13.62 mA mM−1 cm−2 with an excellent linear response. Furthermore, the sensor also displayed selectivity for glucose over potential interfering agents and exhibited a satisfactory recovery percentage using real sample in human serum. The results demonstrate that, CuS/NSC is an efficient nanocomposite material for non-enzymatic glucose sensors and is applicable for glucose detection in biological fluids.

Синтетичні каннабіноїди спайс: актуальні питання клінічної діагностики та екстреної медичної допомоги

Поширення за останні роки практики вживання трав’яних сумішей для паління (так званих спайс) призвело до виникнення в Україні численних отруєнь із смертельними наслідками. Новий різновид психоактивних речовин створив для лікарів суттєві труднощі в проведенні клінічної і лабораторної діагностики та лікуванні постраждалих. Клінічна картина гострого отруєння при вживанні продуктів спайс значно відрізняється від типових симптомів отруєнь героїном і марихуаною, а хімічний склад продуктів постійно змінюється, що практично унеможливлює їх своєчасне визначення в біологічних рідинах. Основними патологічними синдромами, що спостерігаються при отруєнні сумішами спайс, є синдроми збудження, пригнічення, галюцинаторний і змішаний. У випадках отруєння тяжкого ступеня пацієнти госпіталізуються до відділення інтенсивної терапії у тяжкому стані. Типовими проявами смертельно небезпечного отруєння є токсична кома, набряк мозку, судоми, дихальна та серцево-судинна недостатність. Клінічні прояви залежать від композиції токсичних речовин у кожній окремій партії продукту спайс. Це пояснює той факт, що пацієнти протягом декількох діб потрапляють до токсикологічного відділення зі схожою симптоматикою. Сьогодні у вітчизняній і зарубіжній літературі недостатньо систематизованих даних про клінічні прояви отруєнь, диференційну діагностику та лікування невідкладних станів, що обумовлені новими наркотичними засобами. Стаття являє собою спробу короткого огляду практичних питань з клінічної і диференційної діагностики та невідкладного лікування хворих в умовах стаціонару.

ACE2-based capacitance sensor for rapid native SARS-CoV-2 detection in biological fluids and its correlation with real-time PCR

The spread of the SARS-CoV-2 and its increasing threat to human health worldwide have necessitated the development of new technological tools to combat the virus. Particular emphasis is given to the development of diagnostic methods that monitor the spread of the virus rapidly and effectively. In this study, we report the development and testing of an antibody-free biosensor, based on the immobilization of ACE2 protein on the surface of gold interdigitated electrode. When the sensor was used in laboratory conditions for targeting the virus’ structural spike protein, it showed a limit of detection [LOD] of 750 pg/μL/mm2. Thereafter, the response of the sensor to swab and saliva samples from hospitalized patients was examined. The virus presence in the samples was confirmed by electrical effective capacitance measurements executed on the biosensor, and correlated with real-time PCR results. We verified that the biosensor can distinguish samples that are positive for the virus from those that are negative in a total of 7 positive and 16 negative samples. In addition, the biosensor can be used for semi-quantitative measurement, since its measurements are divided into 3 areas, the negative samples, the weakly positive and the positive samples. Reproducibility of the experiments was demonstrated with at least 3 replicates and stability was tested by keeping the sensor standby for 7 days at 4 °C before repeating the experiment. This work presents a biosensor that can be used as a fast-screening test at point of care detection of SARS-CoV-2 since it needs less than 2 min to provide results and is of simple operation.

A persistent luminescence resonance energy transfer-based molecular beacon probe for the highly sensitive detection of microRNA in biological samples

Herein, a time-resolved luminescence resonance energy transfer (TR-LRET) molecular beacon (MB) probe employing persistent luminescence nanoparticles (PLNPs) as the energy donors was first constructed, and further designed for microRNA21 (miR21) sensing. This probe (named as PLNPs-MB) was facilely fabricated by covalent bioconjugation between poly-(acrylic acid) (PAA) modified near-infrared (NIR) emissive PLNPs i.e. ZnGa2O4:Cr3+ and functionalized MB oligonucleotide (5′-NH2 and 3′-BHQ3). Accordingly, PLNPs and BHQ3 were in close proximity to each other, leading to the occurrence of LRET and obvious persistent luminescence (PL) quenching. In the presence of miR21, loop of the PLNP-MB was hybridized, accompanying BHQ3 away from PLNPs and the restraint of LRET process. As a result, PL of the PLNPs was recovered, which built the foundation of miR21 quantification. The probe provided a linear response range from 0.1 to 10 nM for miR21 detection. Quantification limit of this probe was competitive and about 1–2 orders of magnitude lower than that of other reported MB probes for nucleic acid. Moreover, the proposed probe was successfully adopted for miR21 detection in biological fluids (human serum, cell extraction). This work also provided a sensitive detection nanoplatform for other targets through modifying diverse MBs onto the surface of PLNPs.