Optical techniques used in medical diagnosis, surgery, and therapy require efficient and flexible delivery of light from light sources to target tissues. While this need is currently fulfilled by ...glass and plastic optical fibers, recent emergence of biointegrated approaches, such as optogenetics and implanted devices, calls for novel waveguides with certain biophysical and biocompatible properties and desirable shapes beyond what the conventional optical fibers can offer. To this end, exploratory efforts have begun to harness various transparent biomaterials to develop waveguides that can serve existing applications better and enable new applications in future photomedicine. Here, the recent progress in this new area of research for developing biomaterial‐based optical waveguides is reviewed. It begins with a survey of biological light‐guiding structures found in plants and animals, a source of inspiration for biomaterial photonics engineering. The review then describes natural and synthetic polymers and hydrogels that offer appropriate optical properties, biocompatibility, biodegradability, and mechanical flexibility have been exploited for light‐guiding applications. Finally, perspectives on biomedical applications that may benefit from the unique properties and functionalities of light‐guiding biomaterials are discussed briefly.
A review on light‐guiding biomaterials for biomedical applications is provided. Some new medical applications, including diagnostics, drug delivery, phototherapy, optogenetic, and wearable optical devices and sensors require novel optical waveguides with specific optical, mechanical, and biological properties. Various natural and synthetic materials are developed to meet such requirements.
A biocompatible step‐index optical fiber made of poly(ethylene glycol) and alginate hydrogels is demonstrated. The fabricated fiber exhibits excellent light‐guiding efficiency in biological tissues. ...Moreover, the core of hydrogel fibers can be easily doped with functional molecules and nanoparticles for localized light emission, sensing, and therapy.
Among available genome relatedness indices, average nucleotide identity (ANI) is one of the most robust measurements of genomic relatedness between strains, and has great potential in the taxonomy of ...bacteria and archaea as a substitute for the labour-intensive DNA–DNA hybridization (DDH) technique. An ANI threshold range (95–96 %) for species demarcation had previously been suggested based on comparative investigation between DDH and ANI values, albeit with rather limited datasets. Furthermore, its generality was not tested on all lineages of prokaryotes. Here, we investigated the overall distribution of ANI values generated by pairwise comparison of 6787 genomes of prokaryotes belonging to 22 phyla to see whether the suggested range can be applied to all species. There was an apparent distinction in the overall ANI distribution between intra- and interspecies relationships at around 95–96 % ANI. We went on to determine which level of 16S rRNA gene sequence similarity corresponds to the currently accepted ANI threshold for species demarcation using over one million comparisons. A twofold cross-validation statistical test revealed that 98.65 % 16S rRNA gene sequence similarity can be used as the threshold for differentiating two species, which is consistent with previous suggestions (98.2–99.0 %) derived from comparative studies between DDH and 16S rRNA gene sequence similarity. Our findings should be useful in accelerating the use of genomic sequence data in the taxonomy of bacteria and archaea.
Our study is aimed at synthesizing cobalt oxide (Co3O4) with graphite carbon nitride (g-C3N4) to form a Co3O4@g-C3N4 hybrid through a green mechanochemical one-pot synthetic approach for ...manufacturing efficient supercapacitor electrodes and photocatalysts. In the present study, the Co3O4@g-C3N4 hybrid revealed a significantly higher specific capacitance (Cs) (of ~ 457.2 Fg−1 at a current density of 1 Ag−1) than that of the pristine Co3O4, which proved its pseudocapacitive behavior, with a couple of redox peaks observed in three electrode measurements (obtained by using a 3.0-M KOH aqueous electrolyte). The optimized Co3O4@g-C3N4 hybrid was further embedded for a symmetric supercapacitor performance, delivering an excellent Cs of ~ 92 Fg−1 at a current density of 1 Ag−1; this was supplemented with a remarkable cycling stability (~ 92% over 5000 cycles). The Co3O4@g-C3N4 hybrid was further examined for photocatalysis activity using a rhodamine B (RhB) dye, and more than 95% RhB dye was degraded through the photocatalytic reduction process (after 60 min of UV irradiation). This Co3O4@g-C3N4 hybrid catalyst exhibited excellent reusability and stability and appears to be a highly efficient, cost-effective, eco-friendly, and reusable catalyst; the g-C3N4 present with the Co3O4 acted as a conductive nano-network, leading to a higher capacitive and photocatalytic performance.
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•One-pot mechanochemical green Co3O4@g-C3N4 hybrid material.•Material is explored as supercapacitor electrode as well as photocatalyst.•Co3O4@g-C3N4 hybrid exhibited higher specific capacitance than pristine Co3O4,•The Co3O4@g-C3N4 hybrid was examined for photocatalysis through Rhodamine B.•More than 90% RhB dye was degraded after subjected UV irradiations for the 50 min.
Metal organic frameworks (MOFs), which constitute a new class of porous organic–inorganic hybrid materials, have gained considerable attention in the fields of electrochemical energy storage and ...conversion devices owing to their open topological structures, large surface areas, tunable morphologies, and extreme redox activity. A synthesis protocol that comprises coprecipitation followed by controlled calcination processes to design a battery‐type electrode is used. This electrode consists of three‐dimensional (3D), ant cave‐like polyhedrons of nickel–cobalt alloy on graphitic carbon (GC; NiCo@GC) nanostructures; trimesic acid is used as a potential MOF‐linker. The developed NiCo@GC sample exhibits mesoporous characteristics with the maximum surface area of 94.08 m2 g−1 at 77 K. In addition, the redox activity at different sweep rates reveals the battery‐type charge storage behavior of the NiCo@GC electrode; its three‐electrode assembly provides 444 C g−1 specific capacity at 2 A g−1 with long‐term capacity retention. The constructed supercapattery (SC) devices (i.e., AC//NiCo@GC) achieved capacity, specific energy, and specific power are 74.3 mAh g−1, 39.5 Wh kg−1, and 665 W kg−1, respectively. Owing to its reasonable electrochemical characteristics, the prepared NiCo@GC material is a promising candidate for supercapattery electrodes for portable electronic devices.
Ultrahigh energy supercapatteries are assembled with elegant 3D ant cave‐like polyhedrons of NiCo@GC positive electrode and activated carbon negative electrode. The mesoporous nature and extremely high electrical conductivity of NiCo@GC result in prolonged cycling stability, high specific capacity and specific energy, and excellent capacity retention even at high current rates.
A Schiff base ligand (SBL), N
, N
-bis (anthracen-9-ylmethylene) pyridine-2, 3-diamine, was synthesized through the condensation of 2,6-diaminopyridine and anthracene-9-carbaldehyde using a 1:2 ...ratio.
H NMR spectra confirmed the observation of non-involvement aromatic carboxylic proton in SBL. A novel series of lanthanide (i.e., praseodymium (Pr), erbium (Er), and ytterbium (Yb))-based SBL metal complexes was successfully synthesized, and their functional groups were elaborately demonstrated using UV-visible, Fourier transform infrared (FT-IR), and fluorescence spectroscopy analyses. FT-IR spectral studies revealed that SBL behaved as a bidentate ligand and it was structured with metal ions by the two azomethine nitrogens. The synthesized SBL-based metal complexes were elaborately performed for cytotoxicity activity versus Vero, human breast cancer (MCF7), and cervical (HeLa) anticancer cell lines.
Abstract
The present study investigates the fabrication of hierarchical 3D nanostructures with multi-component metal oxides in the presence of highly-porous graphene and characterized for its ...applications in high-performance supercapacitors. A hierarchical flowers like 3D nanostructure of Co
3
O
4
@MnO
2
on nitrogen-doped graphene oxide (NGO) hybrid composite was synthesized by thermal reduction process at 650 °C in the presence of ammonia and urea. The synthesized Co
3
O
4
@MnO
2
/NGO hybrid composites were studied
via
Raman, XRD, X-ray XPS, FE-SEM, FE-SEM with EDX, FE-TEM and BET analyses. The electrochemical analysis of Co
3
O
4
@MnO
2
/NGO hybrid composite electrode was investigated using cyclic voltammetry, chronopotentiometry and electrochemical impedance measurements. The hybrid composite electrode showed significant specific capacitance results of up to 347 F/g at 0.5 A/g and a corresponding energy density of 34.83 Wh kg
−1
with better rate performance and excellent long-term cycling stability were achieved for 10,000 cycles. The obtained electrochemical results paved a way to utilize Co
3
O
4
@MnO
2
/NGO composite electrode as a promising electrode material in high performance supercapacitors.
Nickel‐iron layered double hydroxides (Ni‐Fe LDHs) consist of stacked Fe3+‐doped positively charged Ni‐hydroxide layers containing charge‐balancing anions and water molecules between the layers. ...Although Ni‐Fe LDHs are highly active in the oxygen evolution reaction (OER) under alkaline conditions, their poor operational stability remains an issue. Herein, based on density functional theory calculations, it is proposed that the inclusion of a higher Fe content (>40%) than the theoretical Fe3+ limit (≈25%) permitted by Ni‐Fe LDHs can lead to improved structural stability. An Fe‐rich Ni‐Fe LDH electrode is therefore prepared via a growth strategy based on the controlled oxygen corrosion of an Fe substrate, by enabling the incorporation of additional Fe2+ into the Ni2+‐Fe3+ LDH structure. Indeed, microstructural and elemental analysis confirm the presence of additional Fe2+. This Fe‐rich Ni‐Fe LDH electrode not only offers a low OER overpotential (≈270 mV at 200 mA cm−2) but also exhibits an excellent operational stability under dynamic operating environments without any significant performance degradation or metal ion dissolution. Finally, the practical feasibility of the Fe‐rich Ni‐Fe LDH electrode is demonstrated in a single‐cell (34.56 cm2) operation. These findings are expected to aid in the development of reliable OER electrodes for use in commercial water electrolyzers.
For green hydrogen production, the development of highly active and durable electrode materials that function the under intermittent power supply of renewable energies is necessary. Rational design of a stable iron‐rich nickel‐iron layered double hydroxide (Fe‐rich Ni‐Fe LDH) under dynamic operating conditions for alkaline oxygen evolution reaction is proposed, and its practical feasibility for industrially relevant application for water electroyzers is demonstrated.
Summary
Polymer electrolyte membrane water electrolysis (PEMWE) is the most promising and environmentally friendly method for highly pure hydrogen production when integrated into renewable energy ...sources. Presently, water electrolysis has merely 4% contribution to global hydrogen production owing to its economic challenges. To reduce the capital and operational cost of PEM water electrolysis, the porous transport layer (PTL) has been investigated intensively in the recent past. A PTL, sandwiched between a catalyst layer and a flow field, is responsible to transport water and oxygen on the anode side as well as hydrogen on the cathode side. In addition to the role of multiphase fluid transportation, PTL also acts as a current collector. A comprehensive insight into PTL materials, structural properties, and their function is strongly required for researchers to enhance performance and reduce the cost of PEMWE system. In this review, we widely discussed the findings on PTL's structural properties, surface modifications, and their impact on enhancing electrochemical performance and durability. In particular, the effect of pore size, porosity, pore gradient, thickness, and pretreatment on ohmic, mass transport, activation overpotential, and PTL modeling has been intensively analyzed. This review will unequivocally increase the previous understanding and open up an avenue for the development of state‐of‐the‐art PTL, thereafter advancing the commercialization of PEMWE.
Porous transport layer (PTL), where both the reactants/products of the electrochemical reaction and electrical transporting happens, plays an important function in a polymer electrolyte membrane water electrolysis (PEMWE) system. In this review, we widely discussed the findings on PTL's structural properties, surface modifications, and their impact on enhancing electrochemical performance and durability. This review will unequivocally increase the previous understanding and open up an avenue for the development of state‐of‐the‐art PTL, thereafter advancing the commercialization of PEMWE.
Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide‐co‐poly(ethylene glycol) diacrylate) cores functionalized with ...phenylboronic acid. The complexation of the phenylboronic acid and cis‐diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range.
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