Since the last decade, electrospinning is garnering more attention in the scientific research community, industries, applications like sensing (glucose, H₂O₂, dopamine, ascorbic acid, uric acid, neurotransmitter, etc.), biomedical applications (wound dressing, wound healing, skin, nerve, bone tissue engineering, and drug delivery systems), water treatment, energy harvesting, and storage applications. This review paper provides a brief overview of the electrospinning method, history of the electrospinning, factors affecting the electrospun nanofibers, and their morphology with different materials and composites (metals, metal oxides, 2D material, polymers and copolymers, carbon‐based materials, etc.) used in the electrospinning technique with optical spinning parameters. Moreover, this paper deliberates the application of electrospun nanofibers and fibrous mats for sensing (electrochemical, optical, fluorescence, colorimetric, mechanical, photoelectric, mass sensitive change, resistive, ultrasensitive, etc.) in most illustrative representations. In the end, the challenges, opportunities of the electrospun nanofibers, and new direction for future progress are also discussed.

Dopamine plays an essential role in the proper functioning of the brain and the body. A change in the level of dopamine can lead to disorders related to the nervous system. Thus, detection of dopamine levels may aid in the diagnosis and treatment of various diseases. Enzymatic electrochemical sensors have been extensively studied for the detection of dopamine because they exhibit excellent selectivity and reliability. However, enzymatic electrochemical sensors suffer from several unavoidable drawbacks such as complex enzyme purification process, weak enzyme immobilization on the electrode, enzyme denaturation and low stability. On the other hand, non-enzymatic sensors are promising alternatives that offer high sensitivity, high electrocatalytic activity, long term stability and eliminate the problems associated with enzymes. Herein, we present a non-enzymatic nanocomposite (NC) of metal oxides (CuO-MgO) for efficient electrochemical detection of dopamine. Scalable sol-gel method is adopted for the controlled growth of CuO-MgO NC. The structural, elemental and morphological analysis is performed by XRD, Raman spectroscopy, and TEM characterization, respectively. The electrochemical analysis was carried out to study the electrocatalytic behavior of CuO-MgO in the detection of dopamine, by cyclic voltammetry and chronoamperometric methods. The electrocatalytic behavior was investigated at different scan rates and for different dopamine concentrations in artificial sweat solution. The CuO-MgO NC catalyst exhibited a sensitivity of $69~\mu $ Acm ⁻² mM ⁻¹ and the detection limit is computed to be $6.4~\mu \text{M}$ in the linear range of 10- $100~\mu \text{M}$ . Moreover, the NC apprehended a high degree of selectivity towards other bio-compounds present in the sweat, and no possible interfering cross-reaction from these species was observed. The as-synthesized CuO-MgO NC offered high sensitivity, selectivity, fast response and stability, which benchmarked its potential for dopamine sensing.

Recent research is focused on few layered graphene (FLG) with various metal oxides (MOs) as (MOs; CeO₂, CuO, SnO₂, CdO, ZnO, and TiO₂) nanocomposite materials are alternatives to critically important in the fabrication of solar cell devices. In this work, FLG with different MOs nanocomposites were prepared by a novel eco-friendly viable ultrasonic assisted route (UAR). The prepared FLG/MO nanocomposites were performed with various characterization techniques. The crystal and phase compositional were carried out through using X-ray diffraction technique. Surface morphological studies by field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). Spectroscopic methods were done by Raman and UV-Vis Diffuse reflectance spectra (UV-DRS). The prepared FLG/MO nanocomposites materials were used as a photoanode, in the fabrication of dye sensitized solar cells (DSSCs). Compared to TiO₂ nanoparticles (NPs) and other FLG/MO nanocomposites, FLG/TiO₂ nanocomposites exhibited superior photovoltaic properties. The obtained results indicate that FLG/TiO₂ nanocomposites significantly improved the power conversion efficiency (PCE) of DSSCs. The photovoltaic analyses were performed in a solar simulator with an air mass (AM) of 1.5 G, power density of 100 m W/m², and current density-voltage (J-V) was investigated using N719 dye.

Zinc oxide (ZnO) one-dimensional nanostructures are extensively used in ultra-violet (UV) detection. To improve the optical sensing capability of ZnO, various nickel oxide (NiO) based p–n junctions have been employed. ZnO/NiO heterojunction based sensing has been limited to UV detection and not been extended to the visible region. In the present work, p-NiO/n-ZnO composite nanowire (NW) heterojunction based UV-visible photodetector is fabricated. A porous anodic aluminum oxide template based electrochemical deposition method is adopted for well separated and vertically aligned growth of composite NWs. The photoresponse is studied in an out of plane contact configuration. The fabricated photodetector shows fast response under UV-visible light with a rise and decay time of tens of ms. The wide spectral photoresponse is analyzed in terms of conduction from defect states of ZnO and interfacial defects during p–n junction formation. Light interaction with heterojunction along the length of the composite NW results in enhanced visible photoresponse of the detector and is further supported by simulation.

Human breath analysis of volatile organic compounds has gained significant attention recently because of its rapid and noninvasive potential to detect various metabolic diseases. The detection of ketones in the breath and blood is key to diagnosing and managing diabetic ketoacidosis (DKA) in patients with type 1 diabetes. It may also be of increasing importance to detect euglycemic ketoacidosis in patients with type 1 or type 2 diabetes or heart failure, treated with sodium-glucose transporter-2 inhibitors (SGLT2-i). The present research evaluates the efficiency of colorimetry for detecting acetone and ethanol in exhaled human breath with the response time, pH effect, temperature effect, concentration effect, and selectivity of dyes. Using the proposed multidye system, we obtained a detection limit of 0.0217 ppm for acetone and 0.029 ppm for ethanol in the detection range of 0.05–50 ppm. A smartphone-assisted unit consisting of a portable colorimetric device was used to detect relative red/green/blue values within 60 s of the interface for practical and real-time application. The developed method could be used for rapid, low-cost detection of ketones in patients with type 1 diabetes and DKA and patients with type 1 or type 2 diabetes or heart failure treated with SGLT2-I and euglycemic ketoacidosis.