Current Nanoscience - Volume 19, Issue 4, 2023

In this paper, the advanced preparation methods of nanocellulose are reviewed and their advantages and disadvantages are compared, especially the application of using a eutectic solvent to prepare nanocellulose instead of strong acid and strong base solvent is listed. In this paper, the wide application of nanocellulose in medicine, sewage treatment, electrochemistry, gas absorption and other fields is summarized, such as drug transport as a drug carrier and the construction of biological tissue scaffolds for the medical field. Further research is needed, and the expectation of more green and efficient preparation of nanocellulose and its application prospect in more fields is expressed.

Background: Propane dehydrogenation (PDH) is the most potential propylene production technology, which can make up the large gap in downstream products of propylene. The catalyst supports lay the foundation for the catalytic activity and stability of the prepared catalysts in PDH reactions. Therefore, we focus on the discussion of single oxides, composite oxides, zeolites, and carbon materials as supports to demonstrate the improvement of the catalytic performance of the PDH catalysts. Methods: Recent studies on catalyst supports are reviewed, including the preparation, characterization, and PDH performance. Results: The supports with different morphologies and crystal structures have been reported for PDH. The enhanced strong interaction between the support and metal components is responsible for the superior PDH performance. Conclusion: The PDH catalysts mainly depend on the development of the support with specific physicochemical properties for the corresponding PDH processes. Therefore, it is crucial to develop the optimal supports to improve the PDH performance in the area of nanoscience materials

Background: The development of cost-effective and high-activity hydrogen evolution reaction (HER) electrocatalysts is limiting the implementation of hydrogen production from electrochemical and photoelectrochemical water splitting, which is seen as a potential technology for clean energy production and long-term energy storage. Transition metal oxide catalysts, a large class of functional materials with variable elemental compositions and crystal shapes, have piqued the interest of scientists. Now, a scientific-based appraisal of the progress in this scientific field is required, as well as identification of the most promising materials and technologies, as well as present constraints and future commercialization chances. Method: This article presents a scientometric analysis of transition metal oxides as hydrogen evolution electrocatalysts in the scientific field. 1421 publications from the Web of Science (WoS) database were extracted using a mix of relevant keywords and examined using multiple scientometric indexes utilizing Python and Anaconda Prompt, ScientoPy, and Citespace. It stated that the first point on this subject was in 1992 and that scientific progress has substantially increased since 2015. Results: Articles and reviews account for 83.8 percent and 13.4 percent of all items published in this category, respectively. Conclusion: The top two contributor countries were identified as China and the United States. The most active journal in this field is Journal of Materials Chemistry A.

Background: Skin diseases represent a major health concern worldwide and negatively impact patients’ quality of life. Despite the availability of various efficacious drugs, their therapeutic outcome is often limited due to shortcomings related to the formidable skin barrier and unfavorable physicochemical properties of drugs. Flexible nano-vesicles have shown tremendous potential to overcome these hurdles and improve the local therapeutic effect of these drugs. Objective: This review article is aimed to shed light on flexible nano-vesicular carriers as a means to combat skin diseases. Methods: The literature was reviewed using PubMed database using various keywords such as liposomes, flexible (deformable liposomes) (transferosomes), ethosomes, transethosomes, niosomes, and spanlastics. Results: Liposomes and niosomes were found effective for the loading and release of both hydrophilic and lipophilic drugs. However, their limited skin penetration led to drug delivery to the outermost layers of skin only. This necessitates the search for innovative vesicular carriers, including liposomes, flexible (deformable liposomes), ethosomes, transethosomes, and spanlastics. These flexible nano-vesicular carriers showed enhanced drug delivery and deposition across various skin layers, which was better than their corresponding conventional vesicles. This resulted in superior drug efficacy against various skin diseases such as skin cancer, inflammatory skin diseases, superficial fungal infections, etc. Conclusion: Flexible nano-vesicular carriers have proven themselves as efficient drug delivery systems that are able to deliver their cargo into the deep skin layers and thus, improve the therapeutic outcome of various skin diseases. However, there remain some challenges that need to be addressed before these nanocarriers can be translated from the lab to clinics.

Biodegradable nanogels in the biomedical field are emerging vehicles comprising dispersions of hydrogel nanoparticles having 3D crosslinked polymeric networks. Nanogels show distinguished characteristics including their homogeneity, adjustable size, low toxicity, stability in serum, stimuli-responsiveness (pH, temperature, enzymes, light, etc.), and relatively good drug encapsulation capability. Due to these characteristics, nanogels are referred to as nextgeneration drug delivery systems and are suggested as promising carriers for dermal applications. The site-specific delivery of drugs with effective therapeutic effects is crucial in transdermal drug delivery. The nanogels made from biodegradable polymers can show external stimuliresponsiveness which results in a change in gel volume, water content, colloidal stability, mechanical strength, and other physical and chemical properties, thus improving the site-specific topical drug delivery. This review provides insight into the advances in development, limitations, and therapeutic significance of nanogels formulations. It also highlights the process of release of drugs in response to external stimuli, various biodegradable polymers in the formulation of the nanogels, and dermal applications of nanogels and their role in imaging, anti128;inflammatory therapy, antifungal and antimicrobial therapy, anti128;psoriatic therapy, and ocular and protein/peptide drug delivery.

Ultraviolet (UV) radiation serves as a principal carter to dermatoheliosis, also professed as extrinsic aging or photoaging that encompasses premature skin vicissitudes secondary to damage instigated by chronic sun exposure. The present literature study embarks on the fundamental understanding of molecular/pathophysiological mechanisms and signals transduction pathways convoluted in the process of photoaging. Special impetus has also been laid on the morphological, biological and histological aspects highlighting the impact of age, gender, type of skin, intensity of radiation exposure and cellular biomarkers. Further, this review examines the state-of-the-art practices or experimental models (such as in vitro cell lines/in vivo animal models/ex vivo skin models) employed for the physicochemical and toxicological characterization of nanobiomaterials in photoaging research. Efforts have been made to recapitulate the potential application of phytoprotectants-based monotherapies or approaches in the efficacious management of photoaging. Furthermore, the study aims to disseminate the recent advances (in terms of patented compositions, novel nanotechnologies and commercial nanoformulations (having diverse anti-aging and photo-protective product portfolio) available in the clinical settings or in the cosmaceutical sector for improvising the aesthetic performance) underlining the tremendous growth in the nutracosmaceutical sector. The authors firmly believe that the current review shall not only capture the interest of readers towards the process of dermatoheliosis but could also rekindle the attention of the scientific community for inclusive assimilation of nanotechnology with nutraceuticals that may aid as a barrier against exogenous or endogenous toxic substances currently in practice to treat a variety of skin disorders.

Background: Yellow curcumin, the “Indian Gold” has been known since ancient times to modulate the activities of a wide variety of targets. The voluminous literature and several patents are proof of the therapeutic value of curcumin. Tetrahydrocurcumin (THC), however, has remained an unexplored molecule, although its cosmeceutical properties have been documented. Their compromised bioavailability, poor aqueous solubility (curcumin 11 ng/mL, THC 56ng/mL), and high log P (Cur: 3.28; THC: 2.98) are hurdles to being developed as potential drugs. Objective: This article discusses the usefulness of lipidic nanoparticles of curcumin and THC for skin inflammation. Method: Nanocouturing to produce lipidic nanoparticles (LNs) of curcumin and THC was done via an optimized microemulsification technique. LNs were characterized by FTIR, TEM, pharmacokinetics, and pharmacodynamic study. Results: FTIR reflected the suitable incorporation of drugs into LNs. TEM examination revealed a spherical to ellipsoidal shape with a particle size of <200 nm. In vitro release study indicated that the release of both drugs was between 70-80% within 24 h. Ex vivo permeation studies confirmed the ability of LNs to cross the stratum corneum. Stability studies (Q1AR2) indicated that both were stable, safe, and non-irritating (OECD 404). Xylene-induced ear edema model of inflammation showed both molecules to possess equivalent abilities to treat inflammation. Conclusion: Curcumin, being yellow coloured, is unstable at physiological pH and plasma and possesses poor bioavailability, while THC is a colorless stable molecule, making it a molecule of choice to be developed as an effective topical product.

Fabricating materials with nacre-like structure have received considerable attention as it shows an excellent combination of mechanical strength and toughness. A considerable number of researchers have reported the preparation method of bionic structure, such as layer-by-layer assembly, vacuum filtration, coextrusion assembly, electrophoresis deposition, water-evaporation-induced assembly, 3D printing, and freeze casting. Compared with other techniques, freeze casting, known as ice templating, is an environmentally friendly, prolongable, and potential method, so it has been rapidly developing and widely researched in recent decades. In this review, the front six methods with their benefits and limitations are briefly introduced. Then, the freeze casting technique with the preparation process and modified technique is emphatically analyzed. Finally, the future tendencies of materials application and technique application are discussed. Freeze casting consists of suspension preparation, solidification, sublimation, and post-treatment processes. The mechanism and influence of parameters during suspension preparation and solidification processes are principally discussed. It must be pointed out that the performance and structure of samples are closely related to the model and external force. Besides, the adjustable process parameters of freezing casting are a strong guarantee of obtaining the target product. The purpose of this review is to promote freeze casting workers to understand the influence of parameters and enlighten them in new experimental designs.

Recently, renewable and non-conventional energy production methods have been getting widespread attention. Fast research progress in establishing green energy indicates the relevance of carbon-free power production. Chemical energy stored in hydrogen molecules is considered green energy to substitute conventional energy sources. It is possible to produce hydrogen without carbon emission by water electrolysis. The action of appropriate catalysts can increase the rate of water electrolysis. Among various non-harmful and cost-effective catalysts, MoS2 nanostructures emerge as electrocatalysts in water electrolysis. This paper reviews the electrocatalytic properties of nanostructures of MoS2 by analyzing different characterization techniques used in water electrolysis, such as linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy and chronopotentiometry. This article explores the relationship between electrocatalytic characteristics and the reaction mechanism. How the reaction kinetics of electrocatalyst varies with respect to the structural changes of MoS2 nanostructures, pH of surrounding medium and longevity of catalyst are analysed here. It is found that the 1T phase of MoS2 has faster catalytic activity than the 2H phase. Similarly, among the various shapes and sizes of MoS2nanostructures, quantum dot or monolayer structures of MoS2; and doped version of MoS2 have better catalytic activity. Acidic electrolyte shows better kinetics for releasing hydrogen than other pH conditions. Longevity, catalytic behaviour over a wide pH range, cost-effective synthesis methods and non-toxicity of MoS2catalysts suggest its future scope as a better catalyst for commercial purposes. Electrocatalytic activity, stability, future scope and challenges of various MoS2 nanostructures are reviewed here.

Background: Non-invasive microwave hyperthermia approaches suffer from several limitations, such as maximum energy localization in the target tissue, reduced unwanted hotspots, less penetration time at specific penetration depth, and maximum directivity of applicators. For conformal body structures, curved patch applicators avoid mismatch losses and provide circular polarization to achieve maximum power deposition at the target tissue. At microwave frequencies, graphene also exhibits good absorption properties and utilizing graphene strips on both sides of a curved patch offers potential benefits of enhancement of gain, directional radiation pattern, and suppressed sidelobes. Objective: Designing a flexible graphene sheet-loaded curved patch for a non-invasive microwave hyperthermia applicator resonating at 2.45 GHz is the prime objective of current work. The proposed work is based on utilizing the absorbing properties of graphene sheets with hybrid hexagonal boron nitride (hBN) under various bending conditions on both sides of a curved patch. Methods: Graphene-loaded curved design offers structural flexibility due to the presence of ripples on the surface and their alignment in armchair configuration (ARC) and zigzag configuration (ZGC). The bending flexibility along the two configurations alters the electronic properties and opens the band gap. Thus, the FEM model has been developed for coupling bio-electromagnetic problems of human body phantom with graphene-loaded curved patch applicator by bending it in two different configurations. Results: For both ARC and ZGC antenna design, parameters, such as return loss and realized gain, have been investigated. The proposed design achieved a maximum return loss value of -30 dB and gain of 7.1 dBi for ARC configuration since it provides the maximum difference in valance band and conduction band in band gap structure, while these values are relatively less in the case of ZGC. The implementation of the design on cylindrical body phantom is realized for ARC with a maximum Efield value of 80.2 V/m at a maximum penetration depth of 40 mm. Further simulations are performed for evaluation of penetration time and fractional tissue damage due to necrosis, and it has been observed that 10 W of input power is sufficient to achieve maximum temperature range and tissue necrosis in a duration of 15 minutes. Conclusion: The results show that a curved graphene patch applicator provides a potential solution for targeted heating in hyperthermia applications.

Introduction: The current research aims to formulate a controlled release formulation of Actarit utilizing cyclodextrin based nanosponges as a nanocarriers. β-Cyclodextrin built nanosponges were prepared by condensation reaction using diphenyl carbonate as crosslinking agent. Methods: A 3-level, 3-factor Box-Behnken design was used to optimize the reaction conditions. The particle size, zeta potential and solubilization efficiency of prepared nanosponges were determined. Actarit was loaded into nanosponges by freeze drying method. Actarit loaded nanosponges were further evaluated for particle size, zeta potential, surface morphology, FTIR, DSC, XRD and Dissolution characteristics. The cyclodextrin nanosponges prepared under optimum conditions exhibited a particle size range of 143.42 to 152.76 nm with low polydispersity indices. FTIR spectra confirmed the formation of carbonyl bond between the β-Cyclodextrin molecules. Results and Discussion: Actarit loaded nanosponges exhibited a particle size range of 157.13 to 168.34 nm with minimum polydispersity index. The zeta potential value was sufficiently high to maintain the stability of colloidal nanosponges. TEM image exposed the spherical structure of drug loaded nanosponges that could be retained and released gradually over time. The FTIR, DSC and XRPD studies inveterate the interaction between Actarit and nanosponges. The drug loaded nanosponges displayed a significant progress in dissolution of drug when compared to plain Actarit. The initial rapid release of Actarit from nanosponges formulations was observed. After 24 h of study, around 90 % of the drug released from nanoformulation and only around 20 % of the drug from free drug suspension. Conclusion: Cyclodextrin based nanosponges displayed superior complexing capability with increased solubility of poorly soluble Actarit.

Background: We reported for the first time the preparation of carbon nanodots/ cajuput oil (C-dots/CJO) composites for potential antibacterial applications. Methods: The C-dots were synthesized from CJO distillation wastes via the low carbonization method. Then, the C-dots were mixed with CJO to obtain C-dots/CJO composites. The characteristics of the C-dots were determined using UV-Vis, PL, TRPL, FTIR, and HRTEM, whereas the C-dots/CJO composites were characterized using UV-Vis and FTIR. Results: Antibacterial properties were investigated for samples of C-dots, CJO, and C-dots/CJO with no-light, white light, and UV/violet light treatments. The C-dots produced cyan luminescence with a decay lifetime of 6.54 ns. Based on the antibacterial tests, the C-dots/CJO composites have DIZ higher than the pure C-dots. Conclusion: The C-dots/CJO composites reached the highest DIZ of 3.6 nm under white light, which was attributed to the photodynamic effect and photodisinfection of the C-dots and CJO, respectively. Hence, the C-dots/CJO composites can be potential antibacterial agents against E. coli bacteria.