p-cresyl sulfate (pCS) is a prominent uremic toxin and biomarker for the progression of chronic kidney disease (CKD). This article reports a highly selective and sensitive electrochemical sensor, designed for the early diagnosis of pCS. The sensor is designed with a screen-printed carbon electrode (SPCE) modified by multi-walled carbon nanotube (MWCNT), which improve electrical conductivity as well as helps in fast electron transfer. The detection of pCS was performed using molecularly imprinted polymer (MIP) synthesized with pyrrole as monomer to obtain polypyrrole (Ppy) polymer matrix, and a SnO2-rGO (Stannic oxide-reduced graphene oxide) nanocomposite was incorporated into the Ppy matrix during the process of polymerization. The resulted PpySnO2-rGO-MIP was immobilized onto the MWCNT-modified SPCE surface to produce highly selective binding cavities for pCS recognition. Structural analysis of the nanocomposite and MIP matrix was performed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Electrochemical characterization through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed a superior sensor performance with sensitivity of 12.81 Omega (ng/mL)-1 cm-2, wide linear range of 50-3100 ng/mL, and low detection limit of 11.24 ng/mL. Density functional theory (DFT) calculations were performed with B3LYP/3-21 G method, which revealed a favorable interaction between pCS and pyrrole with a binding energy of -12.5 kcal/ mol and was supported by theoretical IR spectral shifts. Analysis on real sample by using pCS-spiked urine was also done, which indicated good recovery (102.2-103.2 %) and reproducibility (RSD: 1.5-3.8 %).

Indoxyl sulfate (IS) is a gut microbiota derived metabolite having various adverse implications in chronic kidney disease, cardiovascular disease, uremic syndrome. IS is also known as protein bound uremic toxin. Due to the serious issues caused by IS its timely quantification is important for the diagnosis and prevention of several diseases. Several traditional methods are available for detecting IS, including mass spectrometry and liquid chromatography. However, as these techniques are both time-consuming and costly our work represents the first demonstration of an electrochemical immunosensor for detecting IS using an anti-IS monoclonal antibody. The screen-printed carbon electrode (SPCE) was modified with a tertiary nanocomposite of chitosan-Au nanoparticles-CeO2 nanoparticles to provide abundant chemical groups through chitosan for the immobilization of antibodies and to deliver the synergistic effects of the Au-CeO2 nanocomposite such as improved surface area to volume ratio, electrical conductivity, and biocompatibility. The detection of IS using the fabricated label-free sensor was performed using the cyclic voltammetry technique. The fabricated sensor showed the sensitivity of 22.8 μA log10 (μM) cm-2 and LOD of 0.06 μM in the linear range of 1 nM to 1000 μM. The selectivity test was also performed on this immunosensor in the presence of various possible interference molecules found in human urine. The performance of the fabricated sensor was also assessed using a spiked urine sample, showing an acceptable recovery rate of 92.54-107.27%.

Conventional hydrogel systems for biomedical applications face critical limitations in mechanical robustness, therapeutic functionality, and responsiveness to physiological stimuli, hindering their translation to precision medicine. The rational integration of engineered nanomaterials into injectable hydrogel matrices has emerged as a transformative strategy to overcome these constraints, enabling hierarchical, stimuli-responsive functionalities unattainable in traditional polymer networks. This review provides a mechanistic and translational analysis of injectable nanocomposite (NC) hydrogels, systematically examining how nanoparticle-polymer interfacial interactions govern gelation kinetics, mechanical properties, and controlled therapeutic release. Unlike previous reviews focused on material cataloguing, we critically evaluate the distinctive advantages of NC hydrogels over conventional dynamic hydrogels; including hierarchical drug release profiles, enhanced tumour penetration, and multiscale environmental responsiveness; whilst providing evidence-based assessment of clinical translation pathways. The strategic incorporation of metal-based nanostructures, carbon nanomaterials, lipid carriers, and black phosphorus nanosheets is analysed across four key biomedical domains: advanced drug delivery systems, tissue engineering scaffolds, chronic wound healing platforms, and biosensing technologies. We provide systematic coverage of injectability parameters, smart responsive behaviours, and patient-specific customisation strategies essential for minimally invasive delivery. Critically, this review addresses the gap between preclinical promise and clinical reality by examining actual clinical trial data, regulatory challenges, and manufacturing scalability barriers. Emerging artificial intelligence and machine learning tools for accelerated NC hydrogel design, predictive modelling, and real-time therapeutic monitoring are evaluated as enabling technologies for next-generation precision biomedicine. This comprehensive roadmap equips researchers and clinicians with mechanistic frameworks and practical guidance for translating injectable NC hydrogels from laboratory innovation to clinical impact.

Abstract A dual-mode smart colorimetric and fluorometric aptasensor is reported for the sensitive and selective detection of gentamicin (GENTA) in milk and egg samples. Gold nanoparticles (AuNPs) and carbon quantum dots (CQDs) formed a fluorescence resonance energy transfer pair to develop a dual-mode aptasensor. The aptasensor utilized the distance-dependent color-changing properties of AuNPs, energy transfer between CQDs (donor) and AuNPs (acceptor), and the change in the aptasensor’s emission intensity. With the optimized concentration of CQDs, AuNPs start to agglomerate due to electrostatic interactions between positively charged CQDs and negatively charged AuNPs. When aptamers (Apta) are immobilized on the surface of AuNPs, they provide a protective layer that prevents their agglomeration in the presence of CQDs. With GENTA, the Apta bind to it, detach from the AuNPs’ surface, and change the color and emission intensity of the aptasensor. The dual-mode response was analyzed with GENTA concentrations ranging from 0.09 μM to 8.17 μM, with lower detection limits (LOD) of 0.425 μM and 0.519 μM in the colorimetric and fluorometric modes, respectively. The concentration of GENTA was quantified as 1.40 μM in the colorimetric mode and 1.71 μM in the fluorometric mode. The smartphone-enabled RGB color analysis enabled real-time monitoring of food samples and their results, and the LOD values are comparable to experimental results. The LOD was calculated as 0.434 μM (colorimetric) and 0.587 μM (fluorometric). The developed aptasensor exhibited good selectivity and practical applicability, as analysis in spiked milk and egg confirmed its potential for food safety applications.

This study presents a novel high-performance gas sensor for the detection of ammonia (NH₃) at ambient temperatures, utilizing the unique characteristics of a p–n heterojunction comprising Cu₂O–ITO (Copper(I) oxide-Indium Tin Oxide). The main innovation in this work is the in-situ conversion of a hierarchical CuO nanostructure to Cu₂O during electrophoretic deposition, as verified by X-ray photoelectron spectroscopy (XPS). The conversion results in an unusual sensing mechanism: the electrical resistance decreases when exposed to the reducing gas NH₃, unlike conventional p-type oxide semiconductor sensors, which show an increase in resistance. The improvement in the sensing performance results from the integration of two critical factors: the hierarchical nanosheet-nanorod structure and efficient charge transfer between Cu₂O and ITO. The sensor displays a response of 7.52

Carcinoembryonic antigen (CEA) is a critical biomarker expressed in several cancers, necessitating the development of an ultrasensitive and selective detection platform for early-stage cancer diagnosis and monitoring treatment responses. Therefore, a comparative study related to electrochemical immunosensor for CEA detection between utilization of biopolymer functionalized graphitic carbon nitride nanosheets (f-gC₃N₄ NS) and pristine graphitic carbon nitride nanosheets (gC₃N₄ NS) onto screen printed electrode (SPE) is presented. The synthesis of gC₃N₄ NS was achieved via exfoliation process, followed by the functionalization of prepared gC₃N₄ NS using chitosan and their depostion onto SPE surface. Further, prepared f-gC₃N₄ NS/SPE surface was immobilized with specific activated antibodies for CEA (anti-CEA) using N-ethyl-N′-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) coupling chemistry, ensuring sturdy and stable antibody attachment. In addition, bovine serum albumin (BSA) protein was used as a blocking agent to minimize non-specific interactions. The stepwise modified SPE platform was confirmed through morphological, structural and electrochemical techniques. The fabricated f-gC₃N₄ NS based immunoelectrode i.e. BSA/anti-CEA/f-gC₃N₄ NS/SPE was tested with various CEA concentrations ranging from 0.0001 to 20 ng/mL using differential pulse voltammetry (DPV) technique, showcasing a sensitivity of 4.71 µA/log(ng/mL)/cm². However, a comparison study was performed with pristine gC₃N₄ NS i.e.BSA/anti-CEA/gC₃N₄ NS/SPE, showed change in current response with the function of CEA concentrations ranging from 0.0001 to 5 ng/mL, exhibiting a sensitivity of 1.42 µA/log(ng/mL)/cm². The highly improved electrochemical performance of the BSA/anti-CEA/f-gC₃N₄ NS/SPE immunosensor was achieved due to the availibility of abundant functional groups present in f-gC₃N₄ NS providing strong biomolecular interactions with anti-CEA as well as improved surface area. Further, the obtained electrochemical immunosensing results with standard CEA biomarker were compared and validated with colorimetric immunoassay kit. The findings highlights the performance of the fabricated BSA/anti-CEA/f-gC₃N₄ NS/SPE in terms of selectivity, specificity, reproducibility and accuracy along with its capability to be used for onsite diagnosis of CEA biomarker in serum samples using smartphone assisted portable electrochemical device.

Naturally occurring mycotoxins present significant health risks to humans and animals due to their toxic and carcinogenic properties, often contaminating food supplies. Therefore, the development of a highly sensitive and selective detection method for mycotoxins is essential. In this study, we report an electrochemical biosensing platform for the detection of the most abundant mycotoxin, fumonisin B1 (FB1), using a nanocomposite of hematite (alpha-Fe2O3) and reduced graphene oxide (rGO) nanosheets. The successful synthesis of the alpha-Fe2O3/rGO nanocomposite was validated using various characterization techniques, including x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Raman spectroscopy, and high resolution transmission electron microscopy (HR-TEM). A smooth, uniform, and thin layer of alpha-Fe2O3/rGO was successfully deposited onto an indium tin oxide (ITO) glass substrate using the electrophoretic deposition (EPD) process. Subsequently, anti-FB1 antibodies (ab-FB1) were covalently immobilized onto the alpha-Fe2O3/rGO/ITO surface using EDC-NHS chemistry enabling the fabrication of a stable immunoelectrode for biosensing applications. To block nonspecific binding sites, the immunoelectrode was treated with bovine serum albumin (BSA). The biosensor exhibited a decreasing electrochemical response with increasing concentrations of FB1 in the range of 1 & times; 10-3-700 ng mL-1, with a limit of detection (LOD) of 0.0052 ng mL-1. The fabricated BSA/ab-FB1/alpha-Fe2O3/rGO/ITO biosensor demonstrated a sensitivity of 6.36 & micro;A mL ng- 1 cm- 2 and a high correlation coefficient (R 2 = 0.98831). When the fabricated immunoelectrode was tested with spiked sweet corn samples, satisfactory percentage recovery values were achieved in the range of 97.2% to 99.4%, indicating its excellent analytical performance andpotential applicability for real-sample biosensing analysis.

4-Ethyl phenyl sulfate (4-EPS), a gut microbiota-derived metabolite, is identified in ailments like chronic kidney disease (CKD) and numerous neurodegenerative conditions like autism spectrum disorders (ASD). This study is a novel attempt to comprehend the interaction of 4-ethyl phenyl sulfate (4-EPS) with human serum albumin (HSA). This interaction was examined using spectroscopic techniques like circular dichroism (CD), Fourier transform infrared (FTIR), UV-vis absorption, fluorescence spectroscopy, and molecular docking studies. The conformation investigation through FTIR and CD confirmed the alteration in the secondary structure of HSA due to the binding of 4-EPS. Fluorescence spectroscopy revealed the formation of a complex between HSA and 4-EPS upon interaction via static quenching. The spontaneity of the binding process was indicated by the negative ΔG value. Absorption spectroscopy demonstrated that in the presence of 4-EPS (2-48 μM), the absorbance of HSA progressively declined as a result of the formation of the 4-EPS-HSA complex. Contact angle measurements showed the involvement of hydrophobic interactions between HSA and 4-EPS. Molecular modeling was performed, followed by optimization using the DFT approach. Molecular docking study revealed moderate binding between the metabolite and HSA. It was further confirmed that hydrophobic interaction and hydrogen bonds were the main forces responsible for stabilizing the 4-EPS-HSA complex.

In this work, we have developed an optical fluorometric sensor for detection of lead (II) ion (Pb 2+ ) and copper (II) ion (Cu 2+ ) in wastewater using fluorescent amine‐modified graphene quantum dots (a‐GQDs). A simple preparation process, i.e., hydrothermal method is used for the preparation of a‐GQDs. The prepared a‐GQDs emits green luminescence and have an average particle size around 1.26 ± 0.16 nm with uniform distribution. The a‐GQDs utilized for detection of various biologically essential metal ions like Pb 2+ and Cu 2+ ions in aqueous solution using fluorescence‐based spectroscopic technique. Here, UV–visible absorption spectra of a‐GQDs with and without Pb 2+ and Cu 2+ ions, shows no variation in the absorbance of a‐GQDs. Further, lifetime analysis of a‐GQDs shows that lifetime of a‐GQDs changed from 2.02 ns to 1.37 ns in presence of Pb 2+ and 2.02 ns to 1.62 ns in presence of Cu 2+ ions, confirms the dynamic quenching mechanism. The a‐GQDs have detected Pb 2+ and Cu 2+ ions in the linearity range of 2–200 µM and 2–300 µM with limit of detection (LOD) of 1.60 µM and 1.66 µM, respectively. Therefore, this work demonstrates the sustainability of a‐GQDs as a favorable fluorescence (FL) probe that may be used to detect heavy metal ions in wastewater and aqueous solution.

The present work focuses on the development of a disposable electrochemical biosensor for simultaneous dual cancer biomarker detection onto a single-sensing platform. For this, an indigenously designed four-electrode system having two working areas of electrodes on a single screen-printed electrode (SPE) substrate was coated by graphite-based conductive ink. The first working electrode surface decorated by the prepared complex is composed of chitosan-functionalized 1T phase of tungsten disulfide-gold nanoparticles (f-WS2@AuNPs) composite and activated antibodies of tagged Cancer Antigen 125 (ab-tg-CA-125), while the second working electrode contained f-WS2@AuNPs and antibody of Human Epididymis protein 4 (ab-HE4). Further, both working electrodes were passivated by BSA to block nonspecific signals. Dual antibody-immobilized platforms of ab-tg-CA-125/f-WS2@AuNPs/SPE and ab-HE4/f-WS2@AuNPs/SPE were further used for simultaneous detection of two ovarian cancer biomarkers of CA-125 and HE4 using an electrochemical differential pulse voltammetry (DPV) technique. Fabricated electrochemical immunosensing platforms of ab-tg-CA-125/f-WS2@AuNPs/SPE and ab-HE4/f-WS2@AuNPs/SPE worked in the range of 0.001-25 μg mL-1 for CA-125 detection and 0.001-10 ng mL-1 for HE4 detection. The developed immunosensor showed a limit of detection of 0.001 μg mL-1 for CA-125 and 0.001 ng mL-1 for HE4. Also, the sensitivity of the developed electrochemical biosensor was calculated for CA-125 and HE4 and found to be 1.43 μA(log μg mL-1)-1 cm-2 and 1.092 μA(log ng mL-1)-1 cm-2, respectively. Both ab-CA-125 and ab-HE4 antibodies exhibit a larger value of association constant (Ka) and reveals strong binding affinity of antibodies toward respective cancer biomarkers. Moreover, the developed biosensors were tested with clinical ovarian patient serum samples, and the results were compared with the immunoassay kit. Therefore, these findings show the effective biosensor performance in terms of sensitivity, selectivity, accuracy, and faster response for simultaneous ovarian biomarker detection in clinical samples.

The world is facing the problem of the water crisis, and people do not have access to a good quantity of water that is free from any toxic chemicals and pathogens for their daily use worldwide. The pharmaceutical waste polluted the water with access to antibiotics, pathogenic bacteria, and other poisonous substances. The massive amount of antibiotics accelerated the resistance of bacteria to antibiotics. They developed antibiotic resistance (ABR), which created a dangerous and perilous situation for human health and enhanced society's economic burden. Photodegradation is an efficient and economically feasible way to remove and break down antibiotics in H2O and CO2 molecules as a final product. So, in this work, photocatalytic degradation of two antibiotics, ampicillin and tetracycline, is reported by taking advantage of the catalytic activity of carbon quantum dots (CQDs). The catalytic properties of CQDs were investigated during the photodegradation of antibiotics under UV light. With an optimized amount of CQDs, the degradation of two antibiotics was carried out under the irradiation of UV light, and the degradation percentage was calculated as 92% and 94% for ampicillin and tetracycline, respectively, in just 120 min. This reaction's pseudo-first-order rate constant was determined to be 0.009 min(-1) for tetracycline and 0.006 min(-1) for ampicillin, respectively. The value of percentage degradation confirms that the antibiotics are massively removed from the water body, and the proposed method can be utilized further in applying a polluted water cleanup system.

Vitamin D (VD) is of interest to an internist, pediatricians, physicians, orthopediacian, pathologists, endocrinologists, nutritionists, ecologists, geneticists, and others for almost a century due to its wide range of etiologies, clinical, biochemical, and pathological manifestations. VD insufficiency is a widespread problem that is often overlooked and not properly addressed as a dietary deficit worldwide. Nevertheless, traditional diagnostic techniques have limitations such as expensive costs, time-consuming procedures, and a substantial need for human resources. This emphasizes the necessity for intelligent, rapid, and on-site methods for diagnosis. Nano-enabled smart biosensors supported by artificial intelligence (AI) offer a promising solution for rapid point-of-care (POC) detection of VD. These advanced biosensors provide real-time, sensitive, and portable diagnostic capabilities. In this account of the literature, we want to present an update on VD recommendations and the current scientific knowledge about the role of VD in human health. We present a critical and detailed review on the growing risk of VD deficiency and its health importance, recommended intake, analytical methods of detection and future aspects. This review also thoroughly examines different kinds of optical and electrochemical nanobiosensor for VD diagnosis. By using the unique characteristics of nano-enabled intelligent biosensors, such as fast outcomes, heightened sensitivity, mobility, and compatibility with Internet-of-Things (IoT) technologies, it is feasible to bring about a significant transformation in the diagnosis of VD. In addition, nanomaterial-based biosensors allow for on-site monitoring and personalizedmonitoring, greatly cutting down on turnaround time and removing the requirement for human resources for sample transportation and preservation. Adopting these cutting-edge diagnostic technologies is expected to increase the ability of the global healthcare system to fight VD insufficiency and protect one’s health.

A correlation between the emerging high case fatality rate of head and neck cancer and its propensity to migrate metastatically to other parts of the body makes it a significant global danger. It raises the demand for low-level detection, which is useful for early-stage diagnostics. Graphitic carbon nitride (g-C3N4) has recently garnered considerable attention as a promising nanomaterials for biosensor due to its exceptional redox behavior, electrochemical activity, and abundance of electroactive sites. The current study presents research outcomes regarding the development of an ultra-sensitive platform for detecting interleukin-8 (IL8), a cytokine associated with oral cancer. This investigation involves fabricating the platform using 3-aminopropyl trimethoxysilane (APTES)-functionalized g-C3N4 and assessing its efficacy in both laboratory-made and real samples. The process of g-C3N4 synthesis involved the thermal pyrolysis of urea without any add-on material. Moreover, the APTES@g-C3N4 nanomaterial was subjected to electrophoretic deposition onto an ITO-coated glass electrode. The fabricated APTES@g-C3N4/ITO electrode was covalently immobilized by the EDC and NHS chemical reaction in conjunction with anti-interleukin-8 (anti-IL8) antibodies. Before using these sensors for interleukin-8 (IL8) sensing, the anti-IL8/APTES@g-C3N4/ITO electrode was treated with bovine serum albumin (BSA) molecules utilized to obstruct non-targeted areas. Such a fabricated BSA/anti-IL8/APTES@g-C3N4/ITO electrochemical immunosensing bioelectrode was characterized by various analytical, morphological, and electrochemical techniques to confirm the stepwise fabrication of the sensor. BSA/anti-IL8/APTES@g-C3N4/ITO demonstrates a noticeable DPV based electrochemical response as a function of IL8 in the concentration ranging from 500 fg mL-1 to 160 ng mL-1. This BSA/anti-IL8/APTES@g-C3N4/ITO also exhibits a lower limit of detection (LOD) of 0.04 ng mL-1, a sensitivity of 0.015 mA log10 [ng mL-1] cm-2, and stability for up to 10 weeks. The biosensor demonstrates excellent performance in analyzing real samples, indicating its practical utility. This efficacy can be attributed to the abundance of electroactive sites, confined electronic structures, and strong interactions among the active g-C3N4 matrix, anti-IL8 molecules, and IL8 molecules. Our findings are essential for advancing early and point-of-care diagnostics, where quick turnaround times and great sensitivity are critical.

The antibiotic residue in food accelerates bacteria's resistance process that is responsible for serious health issues. A smartphone-integrated ratiometric colorimetric aptasensor has been developed for ampicillin (AMP) detection in milk and egg samples. The sensing phenomenon utilizes the optical and color-changing properties of gold nanoparticles (AuNPs) and specific aptamer with higher affinity towards AMP for its selective detection. The aptasensor shows linear response with AMP concentration 0.06-9.9 μM with a lower detection limit (LOD) of 45.0 nM. The smartphone-integrated color analyzer application was used to identify the solution's red, green, and blue (RGB) color intensity and calculate the G/R ratio of color intensities in the presence of AMP. Aptasensor show linear response with AMP concentration (0-6.6 μM), with a LOD of 53.0 nM. The sensor's results were further validated with liquid chromatography and mass spectroscopy techniques (LC-MS), showing that the developed sensor is suitable for food monitoring and safety applications.

Staphylococcus aureus (S. aureus) is a deadly, gram-positive bacterium causing life-threatening diseases such as fatal pneumonia, sepsis, and severe skin infections highlighting the need for urgent medical intervention. Metal–organic frameworks (MOFs), a novel class of porous materials have recently shown promising antibacterial action against various pathogens possibly due to the slow release of metal ions when dissolved in aqueous media. The current work focuses on exploring the antibacterial potential of Fe-MOF against S. aureus. The assay results substantiate the antibacterial action of Fe BDC MOF in an aqueous environment against S. aureus. Furthermore, a combination of Fe BDC MOF and antibiotic gentamicin exhibits a remarkable enhancement in antimicrobial efficacy with a 34 mm zone of inhibition in antibacterial action, demonstrating a synergistic effect between the two compounds against the pathogen. This work paves the way for the development of novel combination drug therapies against S. aureus and other deadly pathogens. To further advance the antibacterial research this study adopts a combination drug therapy approach, screening Fe BDC MOF with gentamicin to combat the growth of S. aureus.

An illustrative diagram outlining the ex situ PtNPs@rGO nanohybrid synthesis using Ficus religiosa leaf extract and PtNPs@rGO/SPCE development employing a drop-casting approach for F − determination is shown.

Vitamin D is a fat-soluble, a secosteroid hormone that is formed when the skin is exposed to sunlight and is essential for the growth and maintenance of healthy bones. It also plays a major role in muscle functioning, cell growth, etc. Vitamin D exits in two forms mainly Vitamin D3 and Vitamin D2 both of which can be obtained from diet or through sun exposure. In this work, an electrochemical sensor based on molecular imprinted polymer (MIP) technique has been devised utilizing polydopamine@MoSe2 nanosheet for the efficient detection of Vitamin D3. The characterizations of the fabricated MIP-based sensor are achieved by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and cyclic voltammetry. The electrochemical sensing was performed using electrochemical impedance spectroscopy. The linear range for the detection of Vitamin D3 was 25–200 ng/mL with a LOD of 0.69 ng mL−1 and sensitivity of 133 Ω (ng/mL)−1 cm−2. Also, the interference studies along with the control studies were performed to establish the validity of the fabricated sensor.

A chitosan-modified nanocomposite of reduced graphene oxide and nanoceria (CH-(rGO@CeO2) NC) was synthesised using co-precipitation method to develop an electrochemical biosensor for the detection of the antibiotic gentamicin (GEN). Various techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS) and contact angle (CA) were employed for morphological and chemical characterization. Differential pulse voltammetry (DPV) demonstrated excellent electrochemical activity of CH-(rGO@CeO2) NC, making it an ideal transducer material for developing a highly sensitive electrochemical immunosensor. This immunosensor utilized monoclonal antibodies against gentamicin (anti-GEN) that was covalently bound to the CH-(rGO@CeO2) NC modified screen-printed electrode (SPE). Protein kinase A (PKA) was used to regulate immunologic interactions, while BSA was applied to block nonspecific binding sites on the anti-GEN/CH-(rGO@CeO2)/SPE surface. The DPV data for the BSA-anti-GEN/CH-(rGO@CeO2)/SPE immunoelectrode in GEN detection showed a satisfactory linear detection range (1 pM-100 µM), with a limit of detection (LOD) of 0.570 pM and a sensitivity of 2.88 µA pM−1 cm−2. The analysis exhibited a strong linear relationship with an R2 value of 0.973. This CH-(rGO@CeO2) electrochemical immunosensor demonstrated excellent potential for detecting GEN in spiked milk and tap water samples.

Hippuric acid (HA) is a well-known gut microbiota-derived metabolite involved in the development of various diseases such as chronic kidney disease, Chron's disease, and inflammatory bowel disease. HA being one of the most commonly found metabolites in gut microbiota is an important analyte considered for establishing an efficient, quick, sensitive, and reliable method for its detection in human samples. In this work, a molecularly imprinted polymer (MIP) technique has been focused on the electrochemical detection of HA using soft materials, as well as a bioinspired technique. Different characterization techniques have been used to validate the synthesis of MoSe2 NS, polypyrrole (PPY)@molybdenum diselenide (MoSe2)-MIP, such as X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, Brunauer-Emmett-Teller method, and transmission electron microscopy. Also, density functional theory computational study has been used to establish the theoretical interaction between the pyrrole (monomer) and HA (target analyte), as well as explore the highest occupied molecular orbital and lowest unoccupied molecular orbital interactions followed by molecular electrostatic potential and Mulliken charges. The chitosan-polypyrrole@MoSe2-MIP showed 14.92 μA log10(ng/mL)-1 cm-2 sensitivity and a low limit of detection of 0.76 ng/mL in the presence of the analyte using the differential pulse voltammetry technique. The fabricated sensor was also deployed to assess the level of HA in the spiked urine sample, further showing the recovery of 93-108%. Also, the green profile score for the PPY-MIP-based sensor is assessed using the Analytical GREEness MIP (AGREEMIP) metric tool.

In this work, two-dimensional tungsten disulfide (WS2) nanosheets and polyaniline (PANI) as WS2@PANI nanocomposites were used for constructing an electrochemical immunosensor for dual ovarian cancer biomarker detection, i.e., cancer antigen-125 (CA-125) and human epididymis protein 4 (HE4). A disposable screen-printed electrode (SPE) substrate, composed of graphite conductive ink, served as a platform onto which WS2@PANI was deposited. The WS2@PANI-modified SPE surface was further functionalized by immobilizing EDC:NHS-activated antibodies (ab-CA-125 and ab-HE4), followed by treatment with 1% bovine serum albumin (BSA) protein to block nonspecific binding sites. Further, the electrochemical performance of the fabricated immunoelectrodes, ab-CA-125/WS2@PANI/SPE and ab-HE4/WS2@PANI/SPE, was evaluated by a cyclic voltammetry (CV) technique. These modified immunoelectrodes demonstrated excellent detection capabilities for dual cancer biomarkers, with CA-125 detected in the concentration range from 0.0001 to 40 mu g/mL and the HE4 detection range being 0.0001-500 ng/mL, respectively. The dual electrochemical biosensing system for CA-125 biomarkers demonstrated a high sensitivity of 85.28 mu A/(mu g/mL)/cm2 with a low limit of detection (LOD) of 10 pg/mL. Similarly, the HE4 biomarker exhibited a sensitivity of 76.71 mu A/(ng/mL)/cm2 with an LOD of 15 fg/mL. The fabricated biosensing platform was further validated by serum samples of ovarian cancer patients, yielding results within the acceptable ranges, including %RSD and %recovery. Therefore, these findings underscore the potential of the WS2@PANI-based biosensing platform for highly sensitive, selective, and reliable dual cancer biomarker detection, positioning it as a promising tool for clinical cancer diagnostics.