Journal of NanoScience in Advanced Materials

A Review on Nanostructured Electrochemical Immunosensors for the Determination of HER2, a Breast Cancer Biomarker

2025-10-19T08:42:36+03:00

The amplification or overexpression of HER2, which is observed in approximately 15–20 % of breast cancer patients, is known to be associated with unfavorable prognosis in patients with breast cancer. Current techniques which have been approved for the detection of HER2 status such as in-situ hybridization (ISH) and immunohistochemistry (IHC) are costly, time-consuming, have limited sensitivity and selectivity, and also very invasive, limiting their applicability at the clinic in certain settings. However, electrochemical biosensors are most appropriate based on their relative simplicity with respect to instrumentation and analysis, low cost per assay, high selectivity and superior sensitivity, reliability, fast response time and their potential for miniaturization and scalability. Electrochemical immunosensors have shown promise as fast, easy to fabricate, low-cost, and sensitive sensors for the determination of HER2 mRNA/protein levels. These biosensors take advantage of chemical stability, high surface area, and biocompatibility of antibodies, their high affinity and specificity, and unique conductive properties of nanomaterials to selectively and sensitively determine HER2 levels in biological fluids. In this review, we covered electrochemical immunosensors developed for the determination of HER2 levels in biological fluids such as human serum. We highlighted specific sensing capabilities and analytical performance parameters of these immunosensors, also detailing the design of these electrochemical HER2 immunosensors.

Superconductivity Properties of Bi-2223 Ceramics Substituted with Strontium Sites at Large Scale Nano-Sized Europium Nanoparticles

2025-10-07T12:10:00+03:00

Ceramic superconductor materials with an initial composition of Bi1.7Pb0.3Sr2Ca2Cu2.75Na0.25Oy and doping ratios of x = 0, 0.2, 0.25 and 0.3 were produced using the solid-state reaction method The effect of substituting high-nano-sized europium (80 nm) for Strontium on phase formation, morphological structure and superconducting properties were analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity (R-T) and magnetisation (M-H) measurements. XRD measurements revealed the formation of the Bi-2223 high-temperature phase, the Bi-2212 low-temperature superconducting phase, and secondary phases in all samples. Despite the formation of secondary phases, the primary phase structure was superconducting in all samples. However, the phase structure gradually deteriorated with increasing amounts of nanoparticle substitution. Scanning electron microscopy (SEM) microstructure analysis of the samples showed the existence of plate-like grains, which suggested the production of both B-2212 and Bi-2223 grain structures. In the electrical measurement results, superconductivity was exhibited in the samples up to the substitution value x = 30. In the sample containing nano-sized Eu at x = 0.20, the value of the superconductivity transition temperature increased due to the decrease in impurity phase density. M-H measurements were performed to characterize the magnetic properties of the samples. In M-H measurements, closed-loop hysteresis, a characteristic feature of Bi-2223 superconductors, occurred in a uniformly shaped sample containing no nano-sized europium. However, the hysteresis area decreased with increasing substitution, indicating a deterioration in magnetic properties.

Investigation of Structural and Electrical Properties of 90%La0.67Pb0.33MnO3 + 10%A and 90%La0.67Pb0.33CoO3 + 10%A (A= MnO2, NiO, SnO2 and Cu2O) Composite Materials

2025-11-26T20:46:05+03:00

In this study, the crystal structures, surface morphologies and electrical conductivity of composite materials, La_0.67Pb_0.33MnO₃, La_0.67Pb_0.33CoO₃ compounds and 90%La_0.67Pb_0.33MnO₃ + 10%A and 90%La_0.67Pb_0.33CoO₃ + 10%A (A= MnO₂, NiO, SnO₂ and Cu₂O), were investigated. As a result of the (X Ray Diffraction) XRD analysis, it was found that all materials have trigonal crystal symmetry (R ̅3c) . The refinements have demonstrated that MnO₂, NiO, SnO₂, and Cu₂O compounds, which are employed in the production of composite materials, are present within both the perovskite crystal structure of these compounds and as a secondary phase in the composite materials. The results from AFM and SEM analyses align with those from XRD refinement. Electrical resistance measurements were conducted to ascertain the metal-insulator phase transition temperatures (T_IM) of various compounds and composite materials. While La_0.67Pb_0.33MnO₃ compound and these compound-based composite materials exhibited a clear T_IM phase transition, no T_IM phase transition was observed in the La_0.67Pb_0.33CoO₃ compound and these compound-based composite materials.

Towards a Pressure-Sensitive FET-Based Sensor for Urodynamic Pressure Mapping

2025-11-08T22:17:39+03:00

Bladder dysfunctions, including urinary incontinence and neurogenic bladder, affect millions of individuals worldwide and are most commonly diagnosed using invasive, catheter-based urodynamic studies. While clinically reliable, these methods are uncomfortable, infection-prone, and unsuitable for long-term monitoring. This study presents the design and simulation of a MEMS-based pressure sensor utilizing a molybdenum disulfide (MoS2) field-effect transistor (FET) architecture for continuous bladder monitoring. The device operates through a suspended diaphragm that deflects under applied pressure, modulating the effective gate capacitance and thereby altering the transistor’s electrical response. COMSOL Multiphysics simulations were performed to evaluate diaphragm deflection across physiologically relevant pressures (0–400 cmH2O), and the results were coupled to a Python-based FET model to analyze current–voltage behavior. The simulations demonstrate a linear diaphragm response and corresponding threshold-voltage shifts, confirming the feasibility of pressure-to-current transduction. These findings establish the proposed MoS2 FET-based sensor as a promising candidate for minimally invasive and long-term bladder pressure monitoring, addressing key limitations of conventional catheter-based systems.

Effect of Polyvinylpyrrolidone (PVP) on the Structural and Morphological Properties of ZnO Nanoparticles

2025-11-18T12:26:04+03:00

In this study, zinc oxide (ZnO) nanoparticles were synthesized using polyvinylpyrrolidone (PVP) as a capping and stabilizing agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were used to investigate the structural and morphological properties. The XRD results confirmed the formation of the typical hexagonal wurtzite structure in all samples, with average crystallite sizes of 23, 24, and 27 nm for the as-prepared ZnO, PVP-ZnO-cal, and ZnO-cal, respectively. These results indicate that the PVP-assisted sample effectively limits crystal growth. SEM images revealed that the as-prepared ZnO NPs are irregular and agglomerated, while the calcinated samples display more defined morphologies with average particle sizes of 37, 50, and 65 nm for the as-prepared ZnO, PVP-ZnO-cal, and ZnO-cal, respectively. Both XRD and SEM show the same trend where PVP-ZnO-cal has smaller sizes than ZnO-cal, confirming PVP’s role in limiting growth and agglomeration. EDS confirmed the purity of Zn and O elements in all samples. These findings demonstrate the important role of PVP in controlling and modifying the growth of ZnO nanoparticles.