Macromolecular Crowding Promotes Re-entrant Liquid-Liquid Phase Separation of Human Serum Transferrin and Prevents Surface-Induced Fibrillation.

Protein aggregation and inactivation upon surface immobilization are major limiting factors for analytical applications in biotechnology-related fields. Protein immobilization on solid surfaces often requires multi-step surface passivation, which is time-consuming and inefficient. Herein, we have discovered that biomolecular condensates of biologically active human serum transferrin (Tf) can effectively prevent surface-induced fibrillation and preserve the native-like conformation of phase-separated Tf over a period of 30 days. It has been observed that macromolecular crowding promotes homotypic liquid-liquid phase separation (LLPS) of Tf through enthalpically driven multivalent hydrophobic interactions possibly via the involvement of its low-complexity domain (residues 3-20) containing hydrophobic amino acids. The present LLPS of Tf is a rare example of salt-mediated re-entrant phase separation in a broad range of salt concentrations (0-3 M) solely via the involvement of hydrophobic interactions. Notably, no liquid-to-solid-like phase transition has been observed over a period of 30 days, suggesting the intact conformational integrity of phase-separated Tf, as revealed from single droplet Raman, circular dichroism, and Fourier transform infrared spectroscopy measurements. More importantly, we discovered that the phase-separated condensates of Tf completely inhibit the surface-induced fibrillation of Tf, illustrating the protective role of these liquid-like condensates against denaturation and aggregation of biomolecules. The cell mimicking compact aqueous compartments of biomolecular condensates with a substantial amount of interfacial water preserve the structure and functionality of Tf. Our present study highlights an important functional aspect of biologically active protein condensates and may have wide-ranging implications in cell physiology and biotechnological applications.

Interdigitated electrodes-based Au-MoS2hybrid gas sensor for sensing toxic CO and NH3gases at room temperature.

In the quest to create effective sensors that operate at room temperature, consume less power and maintain their stability over time for detecting toxic gases in the environment, molybdenum disulfide (MoS2) and MoS2-based hybrids have emerged as potent materials. In this context, the current work describes the fabrication of Au-MoS2hybrid gas sensor fabricated on gold interdigitated electrodes (GIEs) for sensing harmful CO and NH3gases at room temperature. The GIEs-based Au-MoS2hybrid sensors are fabricated by decorating MoS2nanoflowers (MNF) with varying size of Au nanoparticles using an inert gas evaporation technique. It is observed that by varying the size of Au nanoparticles, the crystallinity gets modified, as confirmed by x-ray diffraction and Micro-Raman spectroscopy (µRS). The gas sensing measurements revealed that the best sensing response is found from the Au-MoS2hybrid (with an average particle size of 10 nm). This particular hybrid shows a 79% response to CO exposure and a 69% response to NH3exposure. The measurements are about 3.5 and 5 times higher than the bare MoS2when exposed to CO and NH3at room temperature, respectively. This enhancement in sensing response is attributed to the modified interfacial interaction between the Au nanoparticles and MNF gets improved, which leads to the formation of a Schottky barrier, as confirmed using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy analysis. This enables the development of efficient gas sensors that respond quickly to changes in the gas around them.

Energy dispersive anti-anharmonic effect in a Fano intervened semiconductor: revealed through temperature and wavelength-dependent Raman scattering.

It is always interesting to understand how the interplay between two perturbations, affects any physical process and gets manifested in a semiconductor. Temperature- and wavelength-dependent Raman Spectromicroscopy was performed on heavily-doped Si to reveal an unusual anti-anharmonic effect. Additionally, the energy dispersive behaviour of Fano coupling strength was also studied and its possible interrelation with the observed anti-anharmonic effect was explored. A systematic study revealed that at the different excitation wavelengths, the strength of the Fano interaction was different, where the involved electron-phonon (Fano-Fano-interferon) bound states were counted together with different energies. By understanding how the interplay manifests in terms of the Raman line shape, a method to calculate the Fano-interferon dissociation energy was developed. The slope of the Raman linewidth at different excitation wavelengths with temperature showed a negative temperature coefficient and sign reversal on decreasing the doping concentration. A wavelength-dependent empirical relation is proposed to calculate the required thermal energy, required to dissociate the electron-phonon bound state.

Raman Spectroscopy as a Simple yet Effective Analytical Tool for Determining Fermi Energy and Temperature Dependent Fermi Shift in Silicon.

The Fermi energy is known to be dependent on doping and temperature, but finding its value and corresponding thermal Fermi shift experimentally is not only difficult but is virtually impossible if one attempts their simultaneous determination. We report that temperature dependent Raman spectromicroscopy solves the purpose easily and proves to be a powerful technique to determine the position and temperature associated Fermi shift in an extrinsic semiconductor as demonstrated for silicon in the present study. The typical asymmetrically broadened Raman spectral line-shape from sufficiently doped n- and p-type silicon contains the information about the Fermi level position through its known association with the Fano coupling strength. Thus, Raman line-shape parameters, the terms quantify the Fano-coupling, have been used as experimental observables to reveal the value of the Fermi energy and consequent thermal Fermi shift. A simple formula has been developed based on existing established theoretical frameworks that can be used to calculate the position of the Fermi level. The proposed Raman spectroscopy-based formulation applies well for n- and p-type silicon. The calculated Fermi level position and its temperature dependent variation are consistent with the existing reports.

Fano-type discrete-continuum interaction in perovskites and its manifestation in Raman spectral line shapes.

Fano resonance is one of the most significant physical phenomena that correlates microscopic processes with macroscopic manifestations for experimental observations using different spectroscopic techniques. Owing to its importance, a focused study is required to clearly understand the origin of certain modifications in spectral behaviour, the nature of which is different for different materials. This means that a careful understanding of Fano interactions can enhance the understanding of several technologically important materials, including perovskites, which are also important in the area of energy storage and conversion. In semiconductors and nano materials (including 2-D materials), Fano interactions occur due to the intervalence or interconduction band transitions. However, in perovskites, Fano interactions are dominated by the interaction between polar phonons or excitons with electronic continuum. Raman spectroscopy, being a sensitive and non-destructive tool, detects subtle scale phenomena, such as Fano interactions, by analysing the Raman line shape. Herein, different dimensions associated with the identification and thereafter the origin of the Fano resonance in perovskites, which are used in energy related areas, have been highlighted using Raman scattering.

Developments in Raman Spectromicroscopy for Strengthening Materials and Natural Science Research: Shaping the Future of Physical Chemistry.

Spectroscopic techniques, especially Raman spectroscopy, cover a large subset in the teaching and research domain of physical chemistry. Raman spectroscopy, and other Raman based techniques, establishes itself as a powerful analytical tool with diverse applications across scientific, industrial, and natural science (including biology and pharmacy) fields and helps in the progress of physical chemistry. Recent advancements and future prospects in Raman spectroscopy, focusing on key areas of innovation and potential directions for research and development, have been highlighted here along with some of the challenges that need to be addressed to prepare Raman based techniques for the future. Significant progress has been made in enhancing the sensitivity, spatial resolution, and time resolution of Raman spectroscopy techniques. Raman spectroscopy has applications in all areas of research but especially in biomedical applications, where Raman spectroscopy holds a great promise for noninvasive or minimally invasive diagnosis, tissue imaging, and drug monitoring. Improvements in instrumentation and laser technologies have enabled researchers to achieve higher sensitivity levels, investigate smaller sample areas with improved spatial resolution, and capture dynamic processes with high temporal resolution. These advancements have paved the way for a deeper understanding of molecular structure, chemical composition, and dynamic behavior in various materials and biological systems. It is high time that we consider whether Raman based techniques are ready to be improved based on the strength of the current era of AI/ML and quantum technology.

Lipid Horizons: Recent Advances and Future Prospects in LBDDS for Oral Administration of Antihypertensive Agents.

The lipid-based drug delivery system (LBDDS) is a well-established technique that is anticipated to bring about comprehensive transformations in the pharmaceutical field, impacting the management and administration of drugs, as well as treatment and diagnosis. Various LBDDSs verified to be an efficacious mechanism for monitoring hypertension systems are SEDDS (self-nano emulsifying drug delivery), nanoemulsion, microemulsions, vesicular systems (transferosomes and liposomes), and solid lipid nanoparticles. LBDDSs overcome the shortcomings that are associated with antihypertensive agents because around fifty percent of the antihypertensive agents experience a few drawbacks including short half-life because of hepatic first-pass metabolism, poor aqueous solubility, low permeation rate, and undesirable side effects. This review emphasizes antihypertensive agents that were encapsulated into the lipid carrier to improve their poor oral bioavailability. Incorporating cutting-edge technologies such as nanotechnology and targeted drug delivery, LBDDS holds promise in addressing the multifactorial nature of hypertension. By fine-tuning drug release profiles and enhancing drug uptake at specific sites, LBDDS can potentially target renin-angiotensin-aldosterone system components, sympathetic nervous system pathways, and endothelial dysfunction, all of which play crucial roles in hypertension pathophysiology. The future of hypertension management using LBDDS is promising, with ongoing reviews focusing on precision medicine approaches, improved biocompatibility, and reduced toxicity. As we delve deeper into understanding the intricate mechanisms underlying hypertension, LBDDS offers a pathway to develop next-generation antihypertensive therapies that are safer, more effective, and tailored to individual patient needs.

Nanoemulsion: An Emerging Novel Technology for Improving the Bioavailability of Drugs.

The pharmaceutical sector has made considerable strides recently, emphasizing improving drug delivery methods to increase the bioavailability of various drugs. When used as a medication delivery method, nanoemulsions have multiple benefits. Their small droplet size, which is generally between 20 and 200 nanometers, creates a significant interfacial area for drug dissolution, improving the solubility and bioavailability of drugs that are weakly water-soluble. Additionally, nanoemulsions are a flexible platform for drug administration across various therapeutic areas since they can encapsulate hydrophilic and hydrophobic medicines. Nanoemulsion can be formulated in multiple dosage forms, for example, gels, creams, foams, aerosols, and sprays by using low-cost standard operative processes and also be taken orally, topically, topically, intravenously, intrapulmonary, intranasally, and intraocularly. The article explores nanoemulsion formulation and production methods, emphasizing the role of surfactants and cosurfactants in creating stable formulations. In order to customize nanoemulsions to particular medication delivery requirements, the choice of components and production techniques is crucial in assuring the stability and efficacy of the finished product. Nanoemulsions are a cutting-edge technology with a lot of potential for improving medication bioavailability in a variety of therapeutic contexts. They are a useful tool in the creation of innovative pharmaceutical formulations due to their capacity to enhance drug solubility, stability, and delivery. Nanoemulsions are positioned to play a crucial role in boosting medication delivery and enhancing patient outcomes as this field of study continues to advance.

Nonlinear Temperature-Dependent Phonon Decay in Heavily Doped Silicon: Predominant Interferon-Mediated Cold Phonon Annihilation.

A nonlinear Fano interaction has been reported here which is manifest in terms of a parabolic temperature-dependent phonon decay process observable in terms of a Raman spectral parameter. Temperature-dependent Raman spectroscopic studies have been carried out on heavily and moderately doped crystalline silicon to investigate the behavior of anharmonic phonon decay in semiconductor systems where Fano interactions are present inherently. Systematic study reveals that in heavily doped systems an interferon-mediated decay route exists for cold phonons present at lower temperatures (<475 K) where Fano coupling is stronger and dominates over the typical multiple-phonon decay process. On the other hand, the anharmonic phonon decay remains the predominant process at higher temperatures irrespective of the doping level. Temperature-dependent phonon self-energy has been calculated using experimentally observed Raman line-shape parameters to validate the fact that the nonlinear decay of phonons through interferon mediation is a thermodynamically favorable process at low temperatures.

Bifunctional Application of Viologen-MoS2-CNT/Polythiophene Device as Electrochromic Diode and Half-Wave Rectifier.

A dual purpose solid state electrochromic diode has been fabricated using polythiophene (P3HT) and ethyl Viologen (EV), predoped with multiwalled carbon nanotubes (MWCNTs) and MoS2. The device has been designed by considering two important aspects, first, the complementary redox activity of P3HT and EV and second, the electron holding properties of MoS2 and MWCNTs. The latter is found to enhance the electrochromic performance of the solid state device. On the other hand, the complementary redox nature gives the asymmetric diodic I-V characteristic to the device which has been exploited to use the electrochromic device for rectification application. The MoS2 nanoflower and MWCNTs are synthesized by one-step hydrothermal and pyrolysis techniques and well characterized by scanning electron microscopy (SEM), X-ray analysis (XRD), and Raman spectroscopy. Electrochromic properties of the device have been studied in detail to reveal an improvement in device performance in terms of faster speed and high coloration efficiency and color contrast. In situ bias-dependent Raman spectroscopy has been performed to understand the operation mechanism of the electrochromic diode which reveals (bi-)polaron formation as a result of dynamic doping eventually leading to color change. A half-wave rectifier has been realized from the electrochromic diode which rectifies an AC voltage of frequency 1 Hz or less making it suitable for low frequency operation. The study opens a new possibility to design and fabricate multipurpose frequency selective electrochromic rectifiers.

Fano-Type Wavelength-Dependent Asymmetric Raman Line Shapes from MoS2 Nanoflakes.

Excitation wavelength-dependent Raman spectroscopy has been carried out to study electron-phonon interaction (Fano resonance) in multi-layered bulk 2H-MoS2 nano-flakes. The electron-phonon coupling is proposed to be caused due to interaction between energy of an excitonic quasi-electronic continuum and the discrete one phonon, first-order Raman modes of MoS2. It is proposed that an asymmetrically broadened Raman line shape obtained by 633 nm laser excitation is due to electron-phonon interaction whose electronic continuum is provided by the well-known A and B excitons. Typical wavelength-dependent Raman line shape has been observed, which validates and quantifies the Fano interaction present in the samples. The experimentally obtained Raman scattering data show very good agreement with the theoretical Fano-Raman line-shape functions and help in estimating the coupling strength. Values of the electron-phonon interaction parameter obtained, through line-shape fitting, for the two excitation wavelengths have been compared and shown to have generic Fano-type dependence on the excitation wavelength.

Atypical Green Luminescence from Raw Cassia Siamea Extract: A Comparison with Red Emitting Tinospora Cordifolia.

Optical and electrochemical properties from Cassia and Giloy leaves' raw extract have been studied, and they show similar properties as UV absorber but different emission properties, under UV excitation, even though they appear the same in natural light. Giloy and Cassia extracts show red and green luminescence, respectively, under UV excitation. Like the appearance, their redox properties are also similar, which shows that both can act as antioxidants. Raman spectroscopy and excitation wavelength dependent photoluminescence data have been compared. The difference in relative emission intensities have been explained based on the presence of corresponding color centers in different ratios in the two leaves.