Human Serum Research Articles

Integration of Samarium Vanadate/Halloysite Nanotubes: Electrochemical Determination of Furaltadone Using Flexible Electrode

In this study, a composite comprising a rare‐earth metal, samarium vanadate (SmVO4, SmV), anchored to halloysite nanotube (HNT) making SmV/HNT nanocomposite is synthesized for the sensitive electrochemical determination of furaltadone (FLD) through differential pulse voltammetry analysis based on the synergistic effect of SmV/HNT (the catalytic activity and chemical stability of SmV, which was further boosted by the improved surface area and conductance of HNT). Further, in the microscopic studies, it is revealed that SmV exhibits a tetragonal zircon‐type crystalline structure, with I41/amd (141) space group, whereas HNT comprises a multiphase kaolin composition as a gibbsite‐like octahedral sheet with multivalency, and the morphological irregularities of the individual constituents are rectified in the composite. The SmV/HNT composite is spray‐coated on polyethylene terephthalate sheet, which delivered a promising trace level limit of detection (0.009 μm) over a wide working range (0.05–194.4 μm) for FLD. Furthermore, real sample analysis is performed using human serum, and pharmaceutical tablet and the results reveal exceptional repeatability and sensitivity, indicating the real‐time application of SmV/HNT in the pharmaceutical domain.

Comparative Analysis of Laboratory-Scale Immunoglobulin G Purification Methods from Human Serum.

Immunoglobulin G (IgG) purification is a critical process for evaluating its role in autoimmune diseases, which are defined by the occurrence of autoantibodies. Affinity chromatography with protein G is widely considered to be the optimal technique for laboratory-scale purification. However, this technique has some limitations, including the exposure of IgG to low pH, which can compromise the quality of the purified IgG. Here, we show that alternative methods for IgG purification are possible while maintaining the quality of IgG. Different techniques for IgG purification from serum were evaluated and compared with protein G-based approaches: Melon Gel, caprylic acid-ammonium sulfate (CAAS) precipitation, anion-exchange chromatography with diethylamino ethyl (DEAE) following ammonium sulfate (AS) precipitation, and AS precipitation alone. The results demonstrated that the purification yield of these techniques surpassed that of protein G. However, differences in the purity of IgG were observed using GeLC-MS/MS. The avidity of purified IgG against selected targets (SARS-CoV-2 and topoisomerase-I) was similar between purified IgG obtained using all techniques and unpurified sera. Our work provides valuable insights for future studies of IgG function by recommending alternative purification methods that offer advantages in terms of yield, time efficiency, cost-effectiveness, and milder pH conditions than protein G.

The utilization of blood serum ATR-FTIR spectroscopy for the identification of gastric cancer

Gastric cancer represents a significant public health challenge, necessitating advancements in early diagnostic methodologies. This investigation employed attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to conduct a multivariate analysis of human serum. The study encompassed the examination of blood samples from 96 individuals diagnosed with gastric cancer and 96 healthy volunteers. Principal component analysis (PCA) was utilized to interpret the infrared spectral data of the serum samples. Specific spectral bands exhibiting intensity variations between the two groups were identified. The infrared spectral ranges of 3500 ~ 3000 cm⁻1, 1700 ~ 1600 cm⁻1, and 1090 ~ 1070 cm⁻1 demonstrated significant diagnostic value for gastric cancer, likely attributable to differences in protein conformation and nucleic acids. By employing machine learning algorithms to differentiate between gastric cancer patients (n = 96) and healthy controls (n = 96), we achieved a sensitivity of up to 89.7% and a specificity of 87.2%. Receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.901. These findings underscore the potential of our serum-based ATR-FTIR spectroscopy examination method as a straightforward, minimally invasive, and reliable diagnostic test for the detection of gastric cancer.

Luminescence "Turn-On" Sensing of Brain Natriuretic Peptide (BNP) - Dilated Cardiomyopathy Biomarker Based on the MoS2 Nanosheet Quenched Terbium Citrate Complex.

Dilated cardiomyopathy (DCM), known as myocardial metabolic dysfunction, is recognized as a clinical condition characterized by left ventricular dilation or improper contraction of cardiac muscles in the absence of coronary atherosclerosis and hypertension. It is an independent risk factor for cardiac function caused by a hyperglycemic condition in diabetic patients leading to heart failure (HF), which renders the early diagnosis of DCM highly challenging. Hence, detection of early diagnostic biomarkers in blood serum to identify DCM conditions is quite requisite. Brain natriuretic peptide (BNP) is a well-recognized biomarker for heart failure and reported as an early diagnostic biomarker for DCM. In this work, we developed a terbium citrate based MoS2 nanosheet (NS) coupled immunoprobe for the sensitive detection of BNP. The antibody conjugated Tb-citrate complex exhibits green fluorescence, which is quenched by the introduction of MoS2 NS. On subsequent addition of antigen BNP, the fluorescence is enhanced because of specific antigen-antibody interaction. The probe is selective and sensitive toward BNP in a linear range from 30.76 to 849.85 pg/mL with a low LOD of 3.87 pg/mL. The probe is validated in spiked human serum samples with good recovery percentage.

Host-induced cell wall remodeling impairs opsonophagocytosis of Staphylococcus aureus by neutrophils.

Understanding how bacteria adapt to the host environment is critical in determining fundamental mechanisms of immune evasion, pathogenesis, and the identification of targets for new therapeutic approaches. Previous work demonstrated that Staphylococcus aureus remodels its cell envelope in response to host factors and we hypothesized that this may affect recognition by antibodies and thus killing by immune cells. As expected, incubation of S. aureus in human serum resulted in rapid binding of antibodies. However, as bacteria adapted to the serum, the increase in cell wall thickness resulted in a significant reduction in exposure of bound antibodies. This reduced antibody exposure, in turn, led to reduced killing by human neutrophils. Importantly, while antibodies bound to some cell surface structures became obscured, this was not the case for those bound to wall teichoic acid, which may have important implications for vaccine design.

Simultaneous noninvasive ultrasensitive detection of prostate specific antigen and lncRNA PCA3 using multiplexed dual optical microfibers with strong plasmonic nanointerfaces

Low accuracy of diagnosing prostate cancer (PCa) was easily caused by only assaying single prostate specific antigen (PSA) biomarker. Although conventional reported methods for simultaneous detection of two specific PCa biomarkers could improve the diagnostic efficiency and accuracy, low detection sensitivity restrained their use in extreme early-stage PCa clinical assay applications. In order to overcome above drawbacks, this paper herein proposed a multiplexed dual optical microfibers separately functionalized with gold nanorods (GNRs) and Au nanobipyramids (Au NBPs) nanointerfaces with strong localized surface plasmon resonance (LSPR) effects. The sensors could simultaneously detect PSA protein biomarker and long noncoding RNA prostate cancer antigen 3 (lncRNA PCA3) with ultrahigh sensitivity and remarkable specificity. Consequently, the proposed dual optical microfibers multiplexed biosensors could detect the PSA protein and lncRNA PCA3 with ultra-low limit-of-detections (LODs) of 3.97 × 10−15 mol/L and 1.56 × 10−14 mol/L in pure phosphorus buffer solution (PBS), respectively, in which the obtained LODs were three orders of magnitude lower than existed state-of-the-art PCa assay technologies. Additionally, the sensors could discriminate target components from complicated physiological environment, that showing noticeable biosensing specificity of the sensors. With good performances of the sensors, they could successfully assay PSA and lncRNA PCA3 in undiluted human serum and urine simultaneously, respectively. Consequently, our proposed multiplexed sensors could real-time high-sensitivity simultaneously detect complicated human samples, that providing a novel valuable approach for the high-accurate diagnosis of early-stage PCa individuals.

DETERMINATION OF ANTIVIRAL-DRUG FAVIPIRAVIR FROM BIOLOGICAL SAMPLES BY USING MOLECULAR IMPRINTED POLYMER-BASED ELECTROCHEMICAL SENSOR

Objective: The molecularly imprinted polymer (MIP) technique was applied in this study for selective, fast, and sensitive electrochemical determination of antiviral drug favipiravir (FAVI). Material and Method: By electropolymerizing the functional monomer o-phenylenediamine (o-PD) on a glassy carbon electrode (GCE) in the presence of a template molecule FAVI, the new MIP-based sensor (MIP@o-PD/GCE) was constructed using cyclic voltammetry (CV). For the removal and rebinding procedures, as well as the optimization of conditions and performance measurement of MIP@o-PD/GCE, differential pulse voltammetry (DPV) was used. The ferrocyanide/ferricyanide redox marker was used to monitor each step of the experimental procedure using DPV. Result and Discussion: MIP@o-PD/GCE has a linear response to FAVI in the range from 10 pM to 90 pM under optimal experimental conditions for human serum samples. The detection limit of MIP@o-PD/GCE was obtained to be 1.80 pM, whereas the quantification limit was found to be 6.23 pM. The designed sensor was successfully applied to a synthetic human serum sample to verify its applicability and validity. Electrochemical sensor selectivity was evaluated by comparing the binding of paracetamol and tenofovir, which are similar to favipiravir, and also oseltamivir and famciclovir, which are other drugs used in the treatment of COVID-19.

THE FABRICATION OF MIP BASED ELECTROCHEMICAL SENSOR FOR THE DETERMINATION OF DOBUTAMINE

Objective: Dobutamine (DBT), one of the most common synthetic catecholamines, is important in the renal, cardiovascular, hormonal, and central nervous systems. In our study, it is proposed to produce the first MIP-based electrochemical sensor for DBT analysis. MIP(DBT)/GCE was developed by electropolymerization of 4-aminobenzoic acid (4-ABA) in the presence of DBT. Analytical performance and validation evaluation were performed on both standard solution and commercial serum samples. Material and Method: DBT was supplied by the Vem pharmaceutical company. For the preparation of 5 mM [Fe(CN)6]3-/4- solution, known amounts of potassium ferricyanide ([K3Fe(CN)6]) and potassium ferrocyanide (K4[Fe(CN)6].3H2O mixed in 0.1 M KCl solution. The 4-ABA was used to create the polymeric film in the presence of DBT. Electrochemical measurements were actualized in IVIUM compactStat.h potentiostat (Eindhoven, The Netherlands) using a three-electrode system consisting of Pt wire, Ag/AgCl reference electrode, and glassy carbon electrode (GCE). Result and Discussion: The MIP(DBT)/GCE sensor was applied to standard solution and commercial serum samples. When DBT concentrations were plotted against ΔI values, a linear response between 1×10-13 and 1×10-12 M was obtained in both environments. LOD results were found to be 0.087×10-13 M and 0.033×10-13 M in standard solution and commercial human serum, respectively. Recovery% and RSD% were found to be 99.68-100.32% and 1.38-1.66%, respectively.

Beyond Glucose Monitoring: Multianalyte Sensor Use in Diabetes.

The incidence, prevalence, mortality, and health expenditure associated with diabetes continue to grow, despite efforts. The use of multianalyte sensors, which detect glucose as well as key analytes such as ketones, lactate, insulin, uric acid, and electrolytes, may provide additional information to guide earlier identification and management of diabetes and its complications. We undertook a narrative review using a systematic approach in May 2023, with a bridge search undertaken in April 2024. Four biomedical databases were searched: MEDLINE (Ovid), Embase, Emcare, and Cochrane Library. Searches for gray literature were conducted on ClinicalTrials.gov, Google Scholar, and websites of relevant organizations. Included studies incorporated articles on multianalyte sensors in diabetes and single-analyte sensors proposing integration into multianalyte diabetes management, with no limits placed on publication date and study design. Data were screened and extracted using CovidenceTM software. Overall, 11 articles were included, of which 7 involved multianalyte sensors (involving glucose and other analytes) and 4 single-analyte sensors (measuring non-glucose substances for proposed future integration into multianalyte systems). Analytes examined were ketones (n = 3), lactate (n = 4), uric acid (n = 3), insulin (n = 1), and potassium (n = 1). Results demonstrated that in vitro and invivo measurements of multi- and single-analyte sensors accurately and reliably corresponded with human capillary and serum samples. While the literature on this topic is sparse, our review demonstrated that measurement of glucose and other analytes can be feasibly undertaken using multi- and single-analyte sensors. More studies in humans are needed to establish clinical utility in diabetes self-management and assist with technological improvements.

Novel Dissymmetric Formal Quinoidal Molecules End-capped by Dicyanomethylene and Triphenylphosphonium.

A number of quinoidal molecules with symmetric end-capping groups, particularly dicyanomethylene units, have been synthesized for organic optoelectronic materials. In comparison, dissymmetric quinoidal molecules, characterized by end-capping with different groups, are less explored. In this paper, we present the unexpected formation of new formal quinoidal molecules, which are end-capped with both dicyanomethylene and triphenylphosphonium moieties. The structures of these dissymmetric quinoidal molecules were firmly verified by single crystal structural analyses. On the basis of the control experiments and DFT calculations, we proposed the reaction mechanism for the formation of these dissymmetric quinoidal molecules. The respective zwitterionic forms should make contributions to the ground state structures of these quinoidal molecules based on the analysis of their bond lengths and aromaticity and Mayer Bond Orbital (MBO) calculation. This agrees well with the fact that negative solvatochromism was observed for these quinoidal molecules. Although these new quinoidal molecules are non-emissive both in solutions and crystalline states, they become emissive with quantum yields up to 51.4% after elevating the solvent viscosity or dispersing them in a PMMA matrix. Interestingly, their emissions can also be switched on upon binding with certain proteins, in particular with human serum albumin.

Electrochemical-Fluorescent Bimodal Biosensor Based on Dual CRISPR-Cas12a Multiple Cascade Amplification for ctDNA Detection.

Circulating tumor DNA (ctDNA) is a critical biomarker for early tumor detection. However, accurately quantifying low-abundance ctDNA in human serum remains a significant challenge. To address this challenge, we introduce a bimodal biosensor tailored for detecting the epidermal growth factor receptor (EGFR) mutation L858R in specific nonsmall cell lung cancer (NSCLC) patients. This biosensor utilizes dual CRISPR-Cas12a systems to quantify the target via fluorescence and electrochemical signals. In our system, the EGFR L858R exhibits resistance to digestion by the restriction enzyme MscI, which activates the first CRISPR-Cas12a protein and inhibits the binding of magnetic beads with fluorescein (FAM)-labeled hybridization chain reaction (HCR) products, thereby reducing the fluorescence signal. This activation also inhibits the cleavage activity of the second CRISPR-Cas12a protein, allowing the electrode to sustain a higher electrochemical signal from nanomaterials. The wild-type EGFR (wt EGFR) produces the opposite effect. Consequently, the concentration of EGFR L858R can be accurately quantified and verified using both fluorescence and electrochemical signals. The biosensor offers a dynamic detection ranging from 10 fM to 1 μM, with a detection limit of 372 aM. It demonstrates excellent specificity, reproducibility, stability, and recovery rates. Moreover, the sensor's enhanced analytical sensitivity highlights its critical role in biosensing applications and early disease diagnosis.

Quinoline yellow acts as a novel amyloid fibrillation probe by using surface-enhanced Raman spectroscopy

Protein amyloid fibrillation is linked to a wide range of neurodegenerative diseases. Protein oligomer is an intermediate substance in the process of fibrillation, which is neurotoxic and formed by the aggregation of protein molecules under physiological stress. Early detection of protein oligomers could make timely intervention of protein fibrillation related diseases. Therefore, it is crucial to develop efficient inhibitors and probes for monitoring amyloid fibril formation. In this study, we developed a novel amyloid inhibitor quinoline yellow (QY), which was proved to be effective in inhibiting insulin protein fibrillation as demonstrated by fluorescence, morphology characterization and circular dichroism. When QY binds to insulin, it exerts inhibitory effects on the nucleation process and effectively impedes the formation of fibrillar fibrils. In addition, we present the application of surface-enhanced Raman spectroscopy (SERS) as an extremely sensitive technique for identifying amyloid oligomers. The investigation employed the probe QY, which demonstrated a linear reaction for identifying oligomers in the concentration range of 1.0–58.0 μM. Impressively, it showcased an exceptionally sensitive detection threshold of 0.2 μM. And also illustrating the binding sites and interaction mechanisms between small molecules of QY and insulin by SERS. The aforementioned methodology was also employed for the identification of insulin oligomers in human serum samples. Thereby, the proposed approach presenting a promising avenue with extensive implications in the realms of pharmaceutical exploration and disease diagnosis.

Establishment of the rapid electrochemical-SELEX monitoring system by using ACEF technique and its application to dengue virus aptasensor fabrication

Aptamers, which consist of single-stranded DNA or RNA, possess considerable potential as biomolecular recognition elements. The systematic evolution of ligands by exponential enrichment (SELEX) serves as a general method for synthesizing aptamers. However, the conventional SELEX process for monitoring aptamer-target binding is time-consuming and labor-intensive, highlighting the need for rapid monitoring and selection methods. To address this problem, this study introduces a novel approach called rapid electrochemical-SELEX (RE-SELEX) monitoring method, which significantly reduces the target-aptamer binding time from 3 h to 10 min. This process is achieved by employing an alternating current electrothermal flow (ACEF) technique. The Au micro gap-type electrode was used to RE-SELEX monitoring device. As a proof-concept of this method, the dengue virus (DENV) aptamers were synthesized. For confirming the feasibility of this DENV aptamer, we analyzed target binding of produced aptamers test including gel electrophoresis, dissociation constant analysis. Then, two aptamers were selected for constructing the rapid electrochemical DENV aptasensor. The RE biosensor was achieved by ACEF technique that reduce the target-aptamer binding within 10 min. The fabricated device can detect 37 fM of the target dengue envelope protein in diluted human serum well. Thus, the proposed method provides a reliable SELEX-monitoring method for the rapid synthesis of aptamers using a simple electrochemical platform.

DETERMINATION OF ANTI-CANCER DRUG PALBOCICLIB FROM HUMAN BIOLOGICAL FLUIDS BY USING DIFFERENTIAL PULSE VOLTAMMETRIC METHOD AT BORON DOPED DIAMOND ELECTRODE

Objective: A very efficient and sensitive electrochemical technique utilizing differential pulse voltammetry (DPV) at a boron-doped diamond electrode (BDDE) was devised to measure Palbociclib in this study. Material and Method: All experiments employed typical three-electrode cell of 10 ml capacity in conjunction with boron-doped diamond electrode, a platinum wire counter electrode, and an Ag/AgCl reference electrode. During electrochemical measurements, DPV and cyclic voltammetry (CV) methods was utilized at BDDE. Result and Discussion: Based on experimental findings from electrochemical characterization investigations, it was determined that oxidation behavior of Palbociclib in BDDE is irreversible and regulated by diffusion. Anodic peak current exhibited a linear relationship within concentration range of 0.01–1 µM, 0.02–0.8 µM, and 0.02–0.8 µM in pH 2.0 phosphate buffer solution (PBS) for reference substance solution, human serum, and urine samples, respectively. Limits of detection were found as 2.28 nM, 2.93 nM, and 1.31 nM for standard drug solution, human serum and urine samples, respectively. In order to validate the developed method, its repeatability, reproducibility, selectivity, precision and accuracy in all environments were investigated and calculated. This method was successfully applied for the analysis of Palbociclib in human serum and urine samples .

4-Vinylpyridine copolymers for improved LC–MS tryptophan and kynurenine determination in human serum

Tryptophan (an essential amino acid) and its clinically important metabolite—kynurenine contribute to several fundamental biological processes and methods that allow their determination in biological samples are in demand. The novelty of the work was a demonstration of the utility of two polymers: 4-vinylpyridine crosslinked with trimethylolpropane trimethacrylate (poly(4VP-co-TRIM)) or 1,4-dimethacryloyloxybenzene (poly(4VP-co-14DMB))—in terms of human serum clean-up for simultaneous LC–MS determination of tryptophan and kynurenine. The goal was to achieve a reduction of the matrix effect, which is responsible for signal suppression, with minimal capture of analytes. The adsorption properties of the polymeric beads were studied by evaluating the adsorption kinetics and isotherms in model matrices. Therefore, the adsorption capacities of both molecules were not efficient, the tested 4-vinylpyridine-based copolymers have shown great promise (especially poly(4VP-co-TRIM)) as sorbents for serum clean-up. In the model human serum matrix, poly(4VP-co-TRIM) provided good recoveries of tryptophan and kynurenine (76% and 87%, respectively) and allowed for the reduction of the matrix effect. Performances of both copolymers were compared to those of commercially available sorbents (octadecylsilane, activated charcoal, and primary secondary amine).

Experimental and computational perspectives on the interaction of nerve agent VX metabolite ethyl methylphosphonic acid with human serum albumin

This study employed electrochemical methods to investigate the interaction between ethyl methylphosphonic acid (EMPA), the primary hydrolysis product of the nerve agent VX, and human serum albumin (HSA). Utilizing cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on the surface of a glassy carbon electrode (GCE). The interaction was analyzed based on changes in the electrochemical behavior of the K3Fe(CN)6/K4Fe(CN)6 redox species under physiological pH conditions. Electrochemical parameters of the redox probe in the presence of HSA, EMPA, and the EMPA-HSA complex were measured. The alteration of the redox couple responses indicates the formation of an electro-inactive complex between the protein and EMPA. The binding parameters of the EMPA-HSA interaction, including the binding constant and complex stoichiometry, were determined, revealing the formation of EMPA-HSA complex with a binding constant of 1.03 × 104M−1 and a binding number of 0.624, suggesting a 1:1 stoichiometry. Molecular modeling was also conducted to further investigate the binding mode of EMPA with HSA, where the binding energy of EMPA to HSA was calculated as −4.78 kcal/mol with hydrogen bonding and hydrophobic contacts being the main interactions behind the complex formation. This research offers valuable insights into the albumin-EMPA interaction, with implications for toxicology, pharmacokinetics, and environmental impact.

Human Serum Albumin Protein Corona in Prussian Blue Nanoparticles.

Prussian Blue nanoparticles (PBnps) are now popular in nanomedicine thanks to the FDA approval of PB. Despite the numerous papers suggesting or describing the in vivo use of PBnps, no studies have been carried out on the formation of a protein corona on the PBnp surface and its stabilizing role. In this paper, we studied qualitatively and quantitatively the corona formed by the most abundant protein of blood, human serum albumin (HSA). Cubic PBnps (41 nm side), prepared in citric acid solution at PB concentration 5 × 10-4 M, readily form a protein corona by redissolving ultracentrifuged PBnp pellets in HSA solutions, with CHSA ranging from 0.025 to 7.0 mg/mL. The basic decomposition of PBnp@HSA was studied in phosphate buffer at the physiological pH value of 7.4. Increased stability with respect to uncoated PBnps was observed at all concentrations, but a minimum CHSA value of 3.0 mg/mL was determined to obtain stability identical to that observed at serum-like HSA concentrations (35-50 mg/mL). Using a modified Lowry protocol, the quantity of firmly bound HSA in the protein corona (hard corona) was determined for all the CHSA used in the PBnp@HSA synthesis, finding increasing quantities with increasing CHSA. In particular, an HSA/PBnp number in the 1500-2300 range was found for CHSA 3.0-7.0 mg/mL, largely exceeding the 180 HSA/PBnp value calculated for an HSA monolayer on a PBnp. Finally, the stabilization brought by the HSA corona allowed us to carry out pH-spectrophotometric titrations on PBnp@HSA in the 3.5-9-0 pH range, revealing a pKa value of 6.68 for the water molecules bound to the Fe3+ centers on the PBnp surface, whose deprotonation is responsible for the blue-shift of the PBnp band from 706 nm (acidic solution) to 685 nm (basic solution).

Next-Generation Electrochemical Biosensing Based on Ternary Nanocomposites of nMoS2@Rgo@MWCNT for Label-Free Cancer Biomarker Detection in Undiluted Human Serum

Sperm protein-17 (Sp17) is a cancer-testicular antigen that is expressed in various types of cancers and has been proposed as a potential biomarker for cancer. However, the detection of Sp17 in human serum is challenging due to its low concentration and the lack of specific and sensitive methods. Hence, there is an urgent need to develop fast, accurate, reliable, and cost-effective disposable biosensors for Sp17 detection. Herein, we report sensing of Sp17 with a disposable carbon cloth-based electrode (CC) modified with a ternary nanocomposite comprising molybdenum disulphide (MoS2), reduced graphene oxide (rGO), and multi-walled carbon nanotube (MWCNT). The nanocomposite was synthesized by a facile hydrothermal method and was well-characterized in terms of structural, morphological, and chemical attributes using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy spectral techniques, and electrochemical studies to prove the robust formation of the electroactive ternary nanocomposite and its suitability for Sp17 detection. The nanocomposite exhibited excellent electrocatalytic activity, biocompatibility, and stability. We immobilized a Sp17-specific antibody on the surface of the nanocomposite-modified electrode and used it as a biosensor for Sp17 detection. The biosensor showed a linear response range from 0.01 to 11 ng mL-1 and a limit of detection (LOD) and limit of quantification (LOQ) of 0.23 ng mL-1 and 0.79 ng mL-1, respectively having sensitivity of 9.97 mA ng mL-1 cm-2. The biosensor was successfully applied to detect Sp17 in human serum samples and showed good accuracy, reproducibility, and selectivity, making it helpful for use in translational medicine research and clinical applications. The biosensor also demonstrated a high correlation with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Our results suggest that the proposed biosensor is a promising tool for Sp17 detection in human serum and could be useful for the diagnosis and prognosis of ovarian cancer and other Sp17-related cancers. Keywords: Carbon cloth; Biosensor; Electrochemistry; Sperm protein 17; Cancer biomarker; Nanocomposite

Glassy carbon electrodes modified with graphitic carbon nitride nanosheets and CoNiO2 bimetallic oxide nanoparticles as electrochemical sensor for Sunitinib detection in human fluid matrices and pharmaceutical samples.

Asophisticated electrochemical sensoris presented employing a glassy carbon electrode (GCE) modified with a novel composite of synthesized graphitic carbon nitride (g-C3N4) and CoNiO2 bimetallic oxide nanoparticles (g-C3N4/CoNiO2). The sensor's electrocatalytic capabilities for Sunitinib (SUNI) oxidation were demonstratedexceptional performance with a calculated detection limit (LOD) of 52.0nM. The successful synthesis and integrity of the composite were confirmed through meticulous characterization using various techniques. FT-IR analysis affirmed the successful synthesis of g-C3N4/CoNiO2 by providing insights into its molecular structure. XRD, FE-SEM, SEM-EDX, and BET analyses collectively validated the material's structural integrity, surface morphology, and electrocatalytic performance. Optimization of key analytical parameters, such as loading volume, concentration, electrolyte solution type, and pH, enhanced the electrocatalytic sensing capabilities of g-C3N4/CoNiO2. The synergistic interaction between g-C3N4 and CoNiO2 bimetallic oxide nanoparticles executed the sensor highly effective in the electrical oxidation of SUNI. Across a concentration range of 0.1-83.8µMSUNI, the anodic peak current exhibited a linear increasewith good precision. Application of the newly developed g-C3N4/CoNiO2 system to detect SUNI in a variety of samples, including urine, human serum, and capsule dosage forms, obtained satisfactory recoveries ranging from 97.1 to 103.0%. This methodology offers a novel approach to underscore the potential of the developed sensor for applications in biological and pharmaceutical monitoring.

Electrochemical-based amine functionalized gold nanoparticles decorated on nanosheets for normetanephrine detection in plasma and serum

Metals and metal oxide composites are prominent materials for detecting biomolecules in body fluids through electrochemical methods. In this study, iron-cobalt nanosheets (FeCoNS) decorated with glucosamine-functionalized gold nanoparticles (Gln-AuNPs) were synthesized to detect normetanephrine (NMN) in human plasma and serum samples. The morphology and chemical composition of the Gln-AuNPs@FeCoNS were analyzed via high-resolution transmission electron microscopy, field-emission scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. A glassy carbon electrode (GCE) was modified with Gln-AuNPs@FeCoNS, exhibiting high electrochemical activity for determining NMN in phosphate buffer saline (PBS) and in real samples. Importantly, the increase in the oxidation current during the reaction between the GCE modified with Gln-AuNPs@FeCoNS and NMN enabled the detection and quantification of NMN. Cyclic voltammetry, differential pulse voltammetry, and amperometry (i-t) were used to assess the sensing performance of the GCE modified with Gln-AuNPs@FeCoNS. The fabricated sensor was highly sensitive toward NMN, with a limit of detection of 0.066, 0.085, and 0.7 µM in PBS, plasma, and serum samples, respectively. The proposed electrochemical sensor provides a new platform for utilizing active metal-based catalysts to detect various biomolecules.