The chemistry underlying the storage phenomena in batteries and supercapacitors has been known to mankind for quite some time now. Nonetheless, a holistic apprehension of their rudimentary characteristics throughout their lifetime and beyond is imperative to accentuate their maximum potential. Although numerous reviews have addressed many of the facts individually, a consolidated report on the associated history, challenges, and environmental aspects considering the cutting‐edge advancements in this field is missing. This review gives a comprehensive insight into the two technologies by drawing a detailed comparison between their governing attributes and potential challenges. First, a brief history of batteries and supercapacitors along with their classifications based on materials and corresponding working mechanisms are delineated. Thereafter, some of the inexorable losses restricting the performance of these systems from reaching their theoretical limits are outlined. A picture of the significance of theoretical modeling of batteries and supercapacitors highlighting the associated challenges in the same is drawn. Furthermore, their fates after retirement as well as their scopes in the future based on their current trends are reported in the ensuing sections. Alongside detailed tutorial background of energy storage literature, this review compares different energy storage devices and the latest developments in this field.

No abstract

A potential cancer antigen (Ag), protein-phosphatase-1-gamma-2 (PP1γ2), with a restricted expression in testis and sperms has been identified as a biomarker specific to cervical cancer (CaCx). Detection of this cancer biomarker antigen (NCB-Ag) in human urine opens up the possibility of noninvasive detection of CaCx to supplement the dreaded and invasive Pap-smear test. A colorimetric response of an assembly of gold nanoparticles (Au NPs) has been employed for the quantitative, noninvasive, and point-of-care-testing of CaCx in the urine. In order to fabricate the immunosensor, Au NPs of sizes ∼5−20 nm have been chemically modified with a linker, 3,3′-di-thio-di-propionic-acid-di(n-hydroxy-succinimide-ester) (DTSP) to attach the antibody (Ab) specific to the NCB-Ag. Interestingly, the addition of Ag to the composite of Ab-DTSP-Au NPs leads to a significant hypsochromic shift due to a localized surface plasmon resonance phenomenon, which originates from the specific epitope−paratope interaction between the NCB-Ag and Ab-DTSP-Au NPs. The variations in the absorbance and wavelength shift during such attachments of different concentrations of NCB-Ag on the Ab-DTSP-Au NPs composite have been employed as a calibration to identify NCB-Ag in human urine. An in-house prototype has been assembled by integrating a light-emitting diode of a narrow range wavelength in one side of a cuvette in which the reaction has been performed while a sensitive photodetector to the other side to transduce the transmitted signal associated with the loading of NCB-Ag in the Ab-DTSP-Au NPs composite. The proposed immunosensing platform has been tested against other standard proteins to ensure noninterference alongside proving the proof-for-specificity of the NCB detection.

The present study focuses on the component transfer from one liquid phase to another liquid phase, commonly known as the extraction process, performed in a microchannel in the presence of spontaneous interfacial convection, driven by either an interfacial tension gradient or an applied external electric field. Marangoni instability occurs as a result of a lateral gradient of interfacial tension existing along the interface of the two fluids. Nonequilibrium phenomena associated with factors such as temperature imbalance, a nonuniform distribution of surface-active components at the interface, evaporation, etc. can lead to the interfacial Marangoni instability. In the present study, first, we have explored temperature gradient driven Marangoni instability, which deforms the interface with significant acceleration and induces local convective mass transfer along with the conventional diffusion mode. Next, we have explored the same phenomenon in the presence of an external electric field, which can also deform the liquid-liquid interface almost instantaneously to a considerable extent. The relative strength of the mass transfer rate for different cases, such as temperature driven instability, in the presence of uniform and nonuniform electric fields has been reported in detail. It has also been observed that, due to the larger mass transfer area, the annular flow offers an enhanced rate of mass transfer compared to the stratified flow. Additionally, this article reports that the nonuniform electric field could influence the process of interfacial instability more strongly compared to the uniform electric field. The effect of the nonuniform electric field with different spatial periodicity on the extraction process has been studied in detail.

We report the synthesis of gold nanotwins (Au NTs) on a solid and transparent glass substrate which in turn has been employed for the selective optoplasmonic detection of Escherichia coli (EC) bacteria in human urine for the point-of-care diagnosis of urinary tract infections (UTIs). As compared to the single nanoparticle systems (Au NPs), the Au NTs show an enriched localized surface plasmon resonance (LSPR) due to the enhancement of the electric field under electromagnetic irradiation, e.g., photon, which helps in improving the limits of detection. For this purpose, initially a simple glass surface has been coated with Au NPs, with the help of the linker 3-aminopropyl-triethoxysilane – APTES. The surface has been linked further with another Au NP with the help of the 1,10-alkane-dithiol linker with two thiol ends, which eventually leads to the development of the optoplasmonic surface with Au NTs and an enhanced LSPR response. Subsequently, the EC specific aptamer has been chemically immobilized on the surface of Au NTs with the blocking of free sites via bovine serum albumin (BSA). Remarkably, Raman spectroscopy unfolds a 7-fold increase in the peak intensities with the Au NTs on the glass surface as compared to the surface coated with isolated Au NPs. The enhancement in the LSPR response of glass substrates coated with Au NTs and the EC specific aptamer has been further utilized for the selective and sensitive detection of UTIs. The results have been verified with the help of UV–visible spectroscopy to establish the utility of the proposed sensing methodology. An extensive interference study with other bacterial species unveils the selectivity and specificity of the proposed optoplasmonic sensors toward EC with a detection range of 5 × 103 to 107 CFU/mL. Intuitively, the method is more versatile in a sense that the sensor can be made specific to any other pathogens by simply changing the design of the aptamer. Finally, a low-cost, portable, and point-of-care optoplasmonic transduction setup is designed with a laser light illumination source, a sample holder, and a sensitive photodetector for the detection of UTIs in human urine.

Flexible proton exchange membrane and bio-Fenton fuel cells for the application of energy harvesting, dye degradation and gas leakage sensor.

No abstract

No abstract