Human Blood Serum Research Articles

Smartphone-based device for rapid and single-step detection of piRNA–651 using anti-DNA:RNA hybrid antibody and enzymatic signal amplification

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs/piRs) are a class of small noncoding RNAs that play a crucial role in regulating various biological processes, including carcinogenesis. One specific piRNA, piR–651, has been reported to be overexpressed in both human blood serum and solid cancer tissues, that can be used a viable biomarker in cancer diagnosis. Early diagnosis of cancer can help reduce the burden of the disease and improve survival rates. In the present work, we report for the first time a smartphone-based colorimetric biosensor for highly sensitive and specific detection of piR–651 thanks to an enzymatic signal amplification, which yielded high colorimetric intensities. Indeed, a heteroduplex DNA:RNA was formed in the presence of piR–651 with the capture DNA probe immobilized on the magnetic beads for easy magnetic separation. Then, a HRP tethered to anti-DNA:RNA (S9.6) was used to reveal the DNA-RNA heteroduplex formed by catalyzing the oxidation of TMB substrate into colorimetric TMBox, which absorbs at 630 nm. The absorbance is positively proportional to the piR–651 concentrations. On the other hand, the colorimetric product of the assay can be photographed with a smartphone camera and analyzed using ImageJ software. Using a smartphone and under optimal conditions, the biosensor responded linearly to the logarithm of piRNA–651 from 8 fM to 100 pM with a detection limit of 2.3 fM and discriminates against other piRNAs. It was also successfully applied to the determination of piRNA–651 levels in spiked human serum.

Nanostructures of Prussian blue supported on activated biochar for the development of a glucose biosensor

This work emphasizes the utilization of biochar, a renewable material, as an interesting platform for anchoring redox mediators and bioreceptors in the development of economic, environmentally friendly biosensors. In this context, Fe(III) ions were preconcentrated on highly functionalized activated biochar, allowing the stable synthesis of Prussian blue nanostructures with an average size of 58.3 nm. The determination of glucose was carried out by indirectly monitoring the hydrogen peroxide generated through the enzymatic reaction, followed by its subsequent redox reaction with reduced Prussian blue (also known as Prussian white) in a typical electrochemical-chemical mechanism. The EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-Hydroxysuccinimide) pair was employed for the stable covalent immobilization of the enzyme on biochar. The biosensor demonstrated good enzyme-substrate affinity, as evidenced by the Michaelis-Menten apparent kinetic constant (4.16 mmol L−1), and analytical performance with a wide linear dynamic response range (0.05–5.0 mmol L−1), low limits of detection (0.94 μmol L−1) and quantification (3.13 μmol L−1). Additionally, reliable repeatability, reproducibility, stability, and selectivity were obtained for the detection of glucose in both real and spiked human saliva and blood serum samples.

A Comparative study of Fe (II) doped Chiral L/D-Methionine Carbon Dots (MCDs) as a “Turn-on” Fluorescent probe for the Sensitive Detection of L – Cysteine

Chiral carbon dots have prominently influenced in the field of chemical, biological, and medicinal research. Comparing to achiral carbon dots, chiral carbon dots exhibit unique characteristics in biosensing application. In this perspective, we have developed bright blue, fluorescent L and D-Methionine Chiral carbon dots (MCDs) using a simple microwave assisted process for effective sensing of L-Cysteine. L-Cysteine plays a vital role in balancing the physiological redox in the body. These MCDs can be complexed with Fe2+ ions to create an energy transfer quenching system due to distinctive N and S functional group distribution on their surface. However, L-Cysteine attaches to Fe2+ ions in a competitive manner, leads to recovery of MCDs fluorescence. As a result, a "turn-on" fluorescent sensing platform based on L and D-Methionine-CDs has been developed for the rapid identification and detection of L-Cysteine. The probe shows good selectivity and sensitivity with coexisting biomolecules and ions. From comparative PL studies, D- MCDs are more responsive than L-Meth CDs towards the detection of L-cysteine with LOD of 0.71 µM and 0.94 µM respectively. The chiroptical properties were evaluated and the probe extends its practical application in paper strip and in biological matrix such as human blood serum with satisfactory recoveries in the range 85-104%.

Enhanced cysteine sensor based on modified gold nanoparticles with synergistic role of pH-responsive poly (N,N-dimethylaminoethyl methacrylate)

The development of a highly sensitive and easy-to-prepare sensor for the detection of cysteine (Cys) is of great importance. Gold nanoparticles (AuNPs) have been frequently utilized as a Cys sensor owing to high affinity of the thiol group to gold. However, the presence of additional materials, such as stabilizers, can impact the sensitivity of this sensor. Herein, pH-sensitive gold nanoparticles (Au-PDA) were synthesized using poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) for the purpose of Cys detection based on the aggregation size-dependent optical property of gold nanoparticles. Detection of cysteine was also followed by UV–Vis analysis, showing a decrease in intensity of localized surface plasmon resonance (LSPR) peak, a red shift from 525 to 550 nm as well as the appearance of a new peek at 650 nm. To enhance sensor performance, systematic investigations were conducted to optimize sensing conditions, focusing on pH, gold concentration, and ionic strength of the medium. Remarkably, the proposed sensor exhibited excellent selectivity towards Cys compared to other amino acids. The sensitivity of the sensor was evaluated using two methods: changes in the absorption intensity and the LSPR shift. The pH-sensitivity of PDMAEME led to a significant improvement in sensing parameters through a synergistic effect on the Au-Cys interaction, leading to a remarkably low LOD of 0.0004 nM, which is the lowest ever reported LOD for detection of Cys. Finally, practical application of the proposed sensor was validated in human blood serum.

Water Suppression 101 for Benchtop NMR– An Accessible Guide and Primer including Fully Interactive Training Videos

Benchtop NMR is enjoying a renaissance with numerous manufacturers bringing products to the market over the last decade. The improved accessibility, lower cost of ownership and ease of use (vs high field NMR), is attracting new users into NMR spectroscopy, which is highly beneficial for the field in general. As benchtop NMR systems seldom require deuterated solvents, this allows samples to be analyzed “as is”, without extraction or alteration. However, many interesting samples, be it an organic reaction mixture, beer, or a biofluid, contain one or more solvent/water signals, which often require suppression. Due to the lower spectral dispersion of benchtop NMR's (vs high field) the frequency of solvent/water is much closer to the analytes of interest, making solvent suppression more challenging. As such, there is a conundrum, where novel users wish to analyze unaltered samples but are quickly faced with the challenge of water suppression, and the wealth of options in the high field literature can be overwhelming. It is important to note that all manufacturers offer some sort of automated water suppression that can be performed with a “single click” that are sufficient for “walk-up” applications or occasional users. This primer is aimed as an accessible guide to those wishing to take the next step and is suitable for users who; 1) would like to pick the optimal water suppression approach for their sample type and 2) wish to understand how water suppression works. The guide focuses on water suppression approaches that are easy to apply, namely presaturation based sequences, binomial sequences for aggressive suppression, and WET for multiple signal suppression, across a range of samples including sucrose standards, espresso, human blood serum and wine. The primer finishes with a flow chart that can be used to guide users in choosing the optimal water suppression approach for their specific sample type, with considerations, including exchangeable signals and the preservation of macromolecular signals, amongst others. In addition, the primer includes 3 fully interactive videos based on H5P technology, focusing on how to acquire data using the approaches described here. The videos include quizzes, with a first-person-perspective of the spectrometer software with interactive elements, as if the users were acquiring the data themselves. In summary, the primer is aimed at advanced undergraduates, graduate students, new users, or users wishing to expand their water/solvent suppression skills/knowledge using benchtop NMR.

A Screening Approach to the Safe-and-Sustainable-by-Design Development of Advanced Insulation Materials.

Herein, a Safe-and-Sustainable-by-Design (SSbD) screening strategy on four different inorganic aerogel mats and two conventional mineral wools for ranking purposes is demonstrated. Given that they do not consist of particles, the release is first simulated, addressing three occupational exposure scenarios, realistic for their intended use as building insulators. No exposure to consumers nor to the environment is foreseen in the use phase, however, aerosols may be released during mat installation, posing an inhalation risk for workers. All four aerogel mats release more respirable dust than the benchmark materials and 60% thereof deposits in the alveolar region according to modelling tools. The collected aerogel dust allows for subsequent screening of hazard implications via two abiotic assays: 1) surface reactivity in human blood serum; 2) biodissolution kinetics in lung simulant fluids. Both aerogels and conventional insulators show similar surface reactivity. Differences in biodissolution are influenced by the specifically designed organic and inorganic structural modifications. Aerogel mats are better-performing insulators (2-fold lower thermal conductivity than the benchmark) However, this work demonstrates how investment decisions can be balanced with safety and sustainability aspects. Concepts of analogy and similarity thus support easily accessible methods to companies for safe and economically viable innovation with advanced materials.

Serum Induces the Subunit-Specific Activation of NF-κB in Proliferating Human Cardiac Stem Cells.

Cardiovascular diseases (CVDs) are often linked to ageing and are the major cause of death worldwide. The declined proliferation of adult stem cells in the heart often impedes its regenerative potential. Thus, an investigation of the proliferative potential of adult human cardiac stem cells (hCSCs) might be of great interest for improving cell-based treatments of cardiovascular diseases. The application of human blood serum was already shown to enhance hCSC proliferation and reduce senescence. Here, the underlying signalling pathways of serum-mediated hCSC proliferation were studied. We are the first to demonstrate the involvement of the transcription factor NF-κB in the serum-mediated proliferative response of hCSCs by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). RNA-Sequencing (RNA-Seq) revealed ATF6B, COX5B, and TNFRSF14 as potential targets of NF-κB that are involved in serum-induced hCSC proliferation.

CuCoP@Cu(OH)2 core-shell nanostructure as a robust electrochemical sensor for glucose detection in biological and beverage samples

The direct growth of transition metal phosphides with a highly accessible surfaces and copper electroactive centers can be considered as an efficient method to modify the electrode surface and use them as an electrochemical sensor. Herein, a direct, efficient, low-cost and rapid method is used for growing core–shell nanostructures of CuCoP nanosheets on Cu(OH)2 nanotubes (pre-deposited on glassy carbon electrode). The Cu(OH)2 nanotubes act as a conductive intermediate and directing agent to obtain CuCoP@Cu(OH)2 core–shell structure. The growth of CuCoP on Cu(OH)2 nanotubes provides structural stability and large surface area as well as increases the availability of the catalytic sites for diffusion of analyte species and electrolyte ions into the electrode surface, leading to excellent electrocatalytic performance towards glucose electro-oxidation. The amperometric studies of glucose for electrode modified with CuCoP@Cu(OH)2 showed two linear ranges of 0.001 mM to 0.105 mM and 0.105 mM to 2.530 mM with very high sensitivities of 8351 and 3932 μA/mM.cm2, respectively. Also, the fabricated sensing platform exhibited excellent selectivity and resistance to chloride ion poisoning, good reproducibility and repeatability, as well as low detection limit of 2.3 μM. In addition, the modified electrode showed a very quick reaction time of 2 s. Finally, to assess the usability of the designed non-enzymatic sensor in practical applications, the as-prepared nanocomposite was examined for measuring the glucose content in biological samples such as human blood serum, saliva, and beverage samples. The outcomes showed that the designed platform can be used as a reliable and efficient sensor for accurate detection and measurement of glucose in real samples.

Human Blood Serum Counteracts EGFR/HER2-Targeted Drug Lapatinib Impact on Squamous Carcinoma SK-BR-3 Cell Growth and Gene Expression

Human Blood Serum Counteracts EGFR/HER2-Targeted Drug Lapatinib Impact on Squamous Carcinoma SK-BR-3 Cell Growth and Gene Expression

Bio-functionalized carbon dots for signaling immuno-reaction of carcinoembryonic antigen in an electrochemical biosensor for cancer biomarker detection

Early diagnosis of cancer demands sensitive and accurate detection of cancer biomarkers in blood. Carbon dots (CDs) bio-functionalization with antibodies, peptides or aptamers have played significant role in cancer diagnosis and targeted cancer therapy. Herein, a biosensor for detection of cancer biomarker carcinoembryonic antigen (CEA) in blood serum has been designed using CDs bio-functionalized with HRP-conjugated CEA antibody (CUCDs@CEAAb2) as detection probe. CDs were synthesized by upscaling of cow urine, a nitrogen rich biomass waste, by hydrothermal method. Detection probe based on CDs resulted in 3.5 times higher sensitivity as compared to conventional electrochemical sandwich immunoassay. To further improve the sensor performance, hyper-branched polyethylenimine grafted poly amino aniline (PEI-g-PAANI) was used as the sensing interface, which enabled immobilization of higher amount of capture antibody. Detection of CEA in human blood serum coupled with wide linear range (0.5–50 ng/ml), good specificity, stability, reproducibility and low detection limit (10 pg/ml) signified the excellence of CUCDs based CEA immunosensor. CUCDs exhibited excitation wavelength dependent fluorescence property and showed strong blue emission under UV irradiation. MTT assay indicated that the material is not toxic towards human dental pulp stem cells (hDPSCs) and MG63 osteosarcoma cells (cell viability > 90%). The present study demonstrates a methodology for valorization of animal waste to a cost-effective carbon based functional nanomaterial for clinical detection of cancer biomarkers.

Functional Group-Assisted Fluorescence Sensing Platform for Nanomolar-Level Detection of an Antineoplastic Drug and a Neurotransmitter from Environmental Water and Human Biofluids.

A fast, sensitive, selective, and biocompatible dual sensor of an antineoplastic medication (methotrexate) and a neurotransmitter (adrenaline) is still being searched by present-day scientists. To overcome this issue, we have designed a functionalized, robust, bio-friendly luminescent MOF for the sensitive, selective, and rapid monitoring of methotrexate and adrenaline. This probe is the first ever reported MOF-based fluorescence sensor of methotrexate and second only for adrenaline. This fluorescence probe has a very low limit of detection (LOD) of 0.34 and 11.2 nM for adrenaline and methotrexate, respectively. The sensor can detect both the targeted analytes rapidly within 5 s. It can also detect adrenaline and methotrexate from human blood serum and urine accurately and precisely. This reusable sensor is equally efficient in detecting methotrexate from environmental water specimens. Biocompatible, user-friendly, and inexpensive chitosan@MOF@cotton composites were fabricated for the detection of adrenaline and methotrexate from the nanomolar to the micromolar range by the naked eye under a fluorescence lamp. This probe displayed high reproducibility, precision, and accuracy in sensing methotrexate and adrenaline. Fluorescence resonance energy transfer (FRET) and the inner filter effect (IFE) are the possible mechanisms for adrenaline and methotrexate sensing, respectively. The possible mechanism was supported by using required instrumental techniques and theoretical simulations.

Development of [64Cu]Cu-NODAGA-RGD-BBN as a Novel Radiotracer for Dual Integrin and GRPR-targeted Tumor PET Imaging.

In this study, [64Cu]Cu-NODAGA-RGD-BBN was prepared and its preclinical assessments were evaluated for PET imaging of GRPR overexpressing tumors. NODAGA-RGD-BBN heterodimer peptide was successfully labeled with cyclotronproduced copper-64 at optimized conditions. The radiochemical purity of the radiotracer was checked by HPLC and RTLC methods. The stability of the radiolabeled compound was assessed in PBS (4°C) and in human blood serum (37°C). Binding affinity and internalization of [64Cu]Cu-NODAGA-RGD-BBN were studied on PC3, LNCaP, and CHO cell lines. The biodistribution of the radiotracer was evaluated in normal and tumor-bearing mice. [64Cu]Cu-NODAGA-RGD-BBN was prepared with radiochemical purity >99 ± 0.7% (HPLC/ITLC) and specific activity of 18.5 ± 2.2 TBq/mmol. The radiotracer showed high stability in PBS (95 ± 1.05%) and in human blood serum (96 ± 1.24%) and, high affinity to the GRP expressing tumor cells. [64Cu]Cu-NODAGA-RGD-BBN showed hydrophilic (log p = -1.14) and agonistic nature. The biodistribution and imaging studies demonstrated high uptake at the tumor site at all intervals post-injection and 3-4 h post-injection can be considered an appropriate time of imaging. The results indicated that [64Cu]Cu-NODAGA-RGD-BBN radiolabeled heterodimer peptide can be considered as a high-potential agent for PET imaging of GRPRoverexpressing tumors.

Non-enzymatic electrochemical sensing platform based on metal oxide-loaded biopolymer for voltammetric measurement of hepatoprotective metadoxine drug in pharmaceutical formulation and human blood serum

This study focuses on the first-ever high-sensitivity, low-cost, and quick response electrochemical estimation of metadoxine (MTD) in pharmaceuticals and human blood serum using a non-enzymatic nanocomposite modified glassy carbon electrode (CuO/CH/GCE) loaded with chitosan. The electroactive surface of GCE was produced by drop-casting a suspension of CuO/CH nanocomposite in N,N-dimethylformamide (DMF) onto the non-enzymatic electrode surface. Synthesized nanocomposite was characterised by using XRD, XPS, EDX, TEM, Raman and FESEM techniques. EIS technique was utilized to study the enhanced charge-transfer phenomenon occurring at the surface of modified sensor. The electrooxidation of MTD at CuO/CH/GCE surface is depending at pH of supporting electrolyte, scan rate and concentration of analyte. CV and SWV technique were used to carry out electrochemical study, optimised voltammetric response is observed in the BR buffer at pH 2.5, with irreversible diffusion-controlled process. Within the linear concentration range of MTD from 1.99 μg/L to 29.56 μg/L, this sensor exhibited lowest LOD (0.64 μg/L) and LOQ (2.14 μg/L). The MTD in pharmaceutical formulation and human blood serum can be determined with this highly selective peak potential (Ep ∼ 1.2 V), repeatable (%RSD 0.91), and reproducible (%RSD 2.31) method. The average percentage recovery in human blood serum and pharmaceutical formulation is 99.89% and 99.90%. This paper reports a lowest LOD value for MTD detection in the comparison with other reported methods (Table S1). None of the selected excipients were found to interfere more than 5% with redox potential of MTD without affecting the performance of sensor.

Synergistic integration of Ni-metal organic framework/SnS2 nanocomposite and nickel foam electrode for ultrasensitive and selective electrochemical detection of albumin in simulated human blood serum

Albumin is a vital blood protein responsible for transporting metabolites and drugs throughout the body and serves as a potential biomarker for various medical conditions, including inflammatory, cardiovascular, and renal issues. This report details the fabrication of Ni-metal organic framework/SnS2 nanocomposite modified nickel foam electrochemical sensor for highly sensitive and selective non enzymatic detection of albumin in simulated human blood serum samples. Ni-metal organic framework/SnS2 nanocomposite was synthesized using solvothermal technique by combining Ni-metal–organic framework (MOF) with conductive SnS2 leading to the formation of a highly porous material with reduced toxicity and excellent electrical conductivity. Detailed surface morphology and chemical bonding of the Ni-MOF/SnS2 nanocomposite was studied using scanning electron microscopy, transmission electron microscopy, Fourier transform infra-red, and Raman analysis. The Ni-MOF/SnS2 nanocomposite coated on Ni foam electrode demonstrated outstanding electrochemical performance, with a low limit of detection (0.44 μM) and high sensitivity (1.3 μA/pM/cm2) throughout a broad linear range (100 pM–10 mM). The remarkable sensor performance is achieved through the synthesis of a Ni-MOF/SnS2 nanocomposite, enhancing electrocatalytic activity for efficient albumin redox reactions. The enhanced performance can be attributed due to the structural porosity of nickel foam and Ni-metal organic framework, which favours increased surface area for albumin interaction. The presence of SnS2 shows stability in acidic and neutral solutions due to high surface to volume ratio which in turn improves sensitivity of the sensing material. The sensor exhibited commendable selectivity, maintaining its performance even when exposed to potential interfering substances like glucose, ascorbic acid, K+, Na+, uric acid, and urea. The sensor effectively demonstrates its accuracy in detecting albumin in real samples, showcasing substantial recovery percentages of 105.1%, 110.28%, and 91.16%.

Characterizing Aptamer Interaction with the Oncolytic Virus VV-GMCSF-Lact.

Aptamers are currently being investigated for their potential to improve virotherapy. They offer several advantages, including the ability to prevent the aggregation of viral particles, enhance target specificity, and protect against the neutralizing effects of antibodies. The purpose of this study was to comprehensively investigate an aptamer capable of enhancing virotherapy. This involved characterizing the previously selected aptamer for vaccinia virus (VACV), evaluating the aggregation and molecular interaction of the optimized aptamers with the recombinant oncolytic virus VV-GMCSF-Lact, and estimating their immunoshielding properties in the presence of human blood serum. We chose one optimized aptamer, NV14t_56, with the highest affinity to the virus from the pool of several truncated aptamers and built its 3D model. The NV14t_56 remained stable in human blood serum for 1 h and bound to VV-GMCSF-Lact in the micromolar range (Kd ≈ 0.35 μM). Based on dynamic light scattering data, it has been demonstrated that aptamers surround viral particles and inhibit aggregate formation. In the presence of serum, the hydrodynamic diameter (by intensity) of the aptamer-virus complex did not change. Microscale thermophoresis (MST) experiments showed that NV14t_56 binds with virus (EC50 = 1.487 × 109 PFU/mL). The analysis of the amplitudes of MST curves reveals that the components of the serum bind to the aptamer-virus complex without disrupting it. In vitro experiments demonstrated the efficacy of VV-GMCSF-Lact in conjunction with the aptamer when exposed to human blood serum in the absence of neutralizing antibodies (Nabs). Thus, NV14t_56 has the ability to inhibit virus aggregation, allowing VV-GMCSF-Lact to maintain its effectiveness throughout the storage period and subsequent use. When employing aptamers as protective agents for oncolytic viruses, the presence of neutralizing antibodies should be taken into account.

Simple Solution Processed Solid‐State Organic Transistor Chip for Multi‐Ion Sensing

AbstractIon concentrations in the human body are closely tied to crucial biological functions and thus serve as important diagnostic health markers. Biological samples are chemically complex, containing a wide range of ions and molecules, necessitating the use of sensors that are highly selective to the target analyte. In this work, a multi‐ion sensing chip, capable of selectively detecting potassium (K+), sodium (Na+), and calcium (Ca2+) ions at physiologically relevant concentrations, is demonstrated. Each sensor consists of a simple, solution‐processed, all solid‐state, and low‐voltage organic thin film transistor, functionalized with polyvinyl chloride (PVC) ion selective membranes sandwiched between the insulator and gate electrode. The sensors are responsive to 4–5 decades of each primary ion. When a response from interfering ions is seen at higher concentrations, the sensors can uniquely discriminate between primary and interfering ions by a difference in the polarity of the current modulation. The sensors function well in mixed‐ion solutions, and can detect K+, Na+, and Ca2+ in simulated human blood serum, demonstrating the feasibility of using these devices for the analysis of complex analytes. This work represents an important step toward the development of simple, inexpensive organic multi‐ion sensors.

Dispersive Solid Phase Extraction/Back-Extraction Using Carbon Nanotubes as Sorbent for HPLC/UV Determination of Ibuprofen in Human Blood Serum Samples

Dispersive Solid Phase Extraction/Back-Extraction Using Carbon Nanotubes as Sorbent for HPLC/UV Determination of Ibuprofen in Human Blood Serum Samples

Point-of-care detection of hydroxyurea drug in serum using a supramolecular enzyme mimetic

The sole approved therapeutic drug for sickle cell disease management is provided by hydroxyurea, requiring its precise detection and monitoring in biological matrices such as human blood serum for personalized treatment. Herein, we introduce a direct colorimetric detection method for hydroxyurea in serum using a metallo-supramolecular assembly called Vesi-ImCu that mimics the peroxidase enzyme. The Vesi-ImCu enzyme mimetic comprises a catalytically active copper center coordinated to synthetic imidazole containing surfactant and iminodiacetic acid capping moieties. By leveraging the peroxidase-like activity of Vesi-ImCu, we have demonstrated that it catalyzes the efficient production of nitric oxide from hydroxyurea that reacts with the Griess reagent, producing an intense pink color. This approach enables the naked-eye detection of hydroxyurea, with notable efficacy even in complex biological matrices such as human blood serum. The Vesi-ImCu suprazyme-based approach offers several advantages, including high sensitivity (limit of detection of 75 µM), clinically relevant dynamic range of hydroxyurea detection, minimum batch-to-batch variation, and the ability to perform mobile phone-based quantification. To our knowledge, this is the first report on direct colorimetric quantification of HU in serum. With its visual detection ability, high-end equipment-free quantification, user-friendliness and portability, the present enzyme mimetic holds great promise for point-of-care detection applications.

Fabrication of a noveltantalum boride/vanadium carbidemodified screen-printed carbon electrode for voltammetric determination of pimonidazole in bio-fluids.

For the first time, a tumour hypoxia marker detection has been developedusing two-dimensional layered composite modified electrodes in biological and environmental samples. The concept of TaB2 and V4C3-based MXene composite materials is not reported hitherto using ball-milling and thermal methods and it remains the potentiality of the present work. Thesuccessful formation is confirmed through various characterisation techniques like X-ray crystallography, scanning electron microscopy photoelectron, and impedance spectroscopy. A reliable and repeatable electrochemical sensor based on TaB2@V4C3/SPCE was developed for quick and extremely sensitive detection of pimonidazole by various electroanalytical methods. It has been shown that the modified electrode intensifies the reduction peak current and causesa decrease in the potential for reduction, in comparison with the bare electrode. The proposed sensor for pimonidazole reduction has strong electrocatalytic activity and high sensitivity, as demonstrated by the cyclic voltammetry approach. Under the optimal experimental circumstances, differential pulse voltammetry techniques were utilised for generating the wide linear range (0.02 to 928.51µM) with a detection limit of 0.0072µM. The resultant data demonstrates that TaB2@V4C3/SPCE nano-sensor exhibits excellent stability, reliability, and repeatability in the determinationof pimonidazole. Additionally, the suggested sensor was successfully used to determine the presence of pimonidazole in several real samples, such as human blood serum, urine, water, and drugs.

Cadmium selenium quantum dot based nanosensor with femto molar level sensitivity for the detection of the pesticide endosulfan

Endosulfan (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine-3-oxide) is an off-patent insecticide used in agricultural farms. Its usage as a pesticide has become highly controversial during the last decades. This is due to its reported hazardous nature to the health and side effects like growth retardation, hydrocephalus, and undesired changes in the male and female hormones leading to complications in sexual maturity. Endosulfan is the main culprit among all pesticide poisoning incidents around the world. Though the usage of this dreaded pesticide is banned by most countries, the high stability of this molecule to withstand degradation for a long period poses a threat to mankind even today. So, it has become highly essential to detect the presence of this poisonous pesticide in the drinking water and milk around these places. It is also advisable to check the presence of this toxic material in the blood of the population living in and around these places so that an early and appropriate management strategy can be adopted. With this aim, we have developed a sensor for endosulfan that displayed high selectivity and sensitivity among all other common analytes in water and biological samples, with a wide linear concentration range (2 fM to 2 mM), a low detection limit (2 fM), and rapid response. A citrate functionalized cadmium selenium quantum dot was used for this purpose, which showed a concentration-dependent fluorescence enhancement, enabling easy and sensitive sensing. This sensor was utilized to detect endosulfan in different sources of water, human blood serum and milk samples with good recoveries. It is also noted that the quantum dot forms a stable complex with endosulfan and is easy to separate it from the contaminated source, paving a solution for purifying the contaminated water. More detailed tests and validation of the sensor is needed to confirm these observations.