RSC Advances

Zhong, Huage; Zhao, Chang; Chen, Jie; Chen, Miao; Luo, Tao; Tang, Weizhong; Liu, Junjie

doi: 10.1039/d0ra01192dpmid: 35514560

Sensitive and reliable detection of tumour markers is of great significance for early diagnosis and monitoring recurrence of cancers. Herein, a simple electrochemical immunosensor is developed with an integrated electrochemical probe on the sensing surface, which is able to sensitively and reagentlessly detect the breast cancer biomarker, human epidermal growth factor receptor 2 (ErbB2). Ferrocene (Fc) is chosen as the signal indicator and covalently grafted on cationic polyelectrolyte poly(ethylene imine) (Fc-PEI). The redox Fc-PEI could alternately assemble with carboxyl functionalized single-walled carbon nanotubes (SWNTs) on an indium tin oxide electrode through layer-by-layerelectrostatic assembly. After Anti-ErbB2 antibody is covalently immobilized onto the outermost SWNTs layer followed by blocking the electrode with bovine serum albumin, a sensing interface with recognitive probe and electrochemical probe is obtained. In the presence of ErbB2, the formed antigen–antibody complex makes a barrier to inhibit electro-transfer of inner Fc, leading to a decreased electrochemical response. Owing to the SWNTs-facilitated charge transfer and abundant surface-bound probes, the developed sensor demonstrates outstanding performance for reagentless detection of ErbB2 in terms of wide detection range (1.0–200.0 ng mL−1) and low detection limit (0.22 ng mL−1). The developed immunosensor also exhibits good selectivity, reproducibility and stability. Real analysis of ErbB2 in human serum samples is also demonstrated.

Liu, Qinglei; Yang, Lehao; Sun, Peng; Liu, Haigang; Zhao, Jiahua; Ma, Xiankun; Wang, Yongfei; Zhang, Zhiqiang

doi: 10.1039/d0ra02894kpmid: 35514595

Due to the potential application in the future energy conversion system, there is an increasing demand for efficient, stable and cheap platinum-free catalysts for hydrogen evolution. However, it is still a great challenge to develop electrocatalysts with high activity similar to platinum or even higher, especially those that can work under alkaline conditions. Ruthenium (Ru), as a cheap substitute for platinum, has been studied as a feasible substitute for (HER) catalyst for hydrogen evolution reaction. In this paper, we designed and developed a novel Ru catalyst (Ru@CNT) supported on nitrogen-doped carbon nanotubes. Electrochemical tests show that even under alkaline conditions (1 M KOH), Ru@CNT still shows excellent catalytic performance and good durability. It only needs 36.69 mV overpotential to reach a current density of 10 mA cm−2, and its Tafel slope is 28.82 mV dec−1. The catalytic performance of the catalyst is comparable to that of 20% Pt/C. The significant activity is mainly attributed to the chelation of highly dispersed ruthenium atoms on nitrogen-doped carbon nanotubes. Secondly, the one-dimensional pore structures supported by nitrogen heterocarbon nanotubes can provide more opportunities for active centers. Excellent HER performance makes Ru@CNT electrocatalyst have a broad application prospect in practical hydrogen production.

Hikima, Kazuhiro; Huy Phuc, Nguyen Huu; Tsukasaki, Hirofumi; Mori, Shigeo; Muto, Hiroyuki; Matsuda, Atsunori

doi: 10.1039/d0ra02545cpmid: 35514596

The performances of next generation all-solid-state batteries might be improved by using multi-valent cation doped Li6PS5Cl solid electrolytes. This study provided solid electrolytes at room temperature using planetary ball milling without heat treatment. Li6PS5Cl was doped with a variety of multivalent cations, where an electrolyte comprising 98% Li6PS5Cl with 2% YCl3 doping exhibited an ionic conductivity (13 mS cm−1) five times higher than pure Li6PS5Cl (2.6 mS cm−1) at 50 °C. However, this difference in ionic conductivity at room temperature was slight. No peak shifts were observed, including in the synchrotron XRD measurements, and the electron diffraction patterns of the nano-crystallites (ca. 10–30 nm) detected using TEM exhibited neither peak shifts nor new peaks. The doping element remained at the grain boundary, likely lowering the grain boundary resistance. These results are expected to offer insights for the development of other lithium-ion conductors for use in all-solid-state batteries.

Chkirida, Soulaima; Zari, Nadia; Achour, Redouane; Qaiss, Abou el kacem; Bouhfid, Rachid

doi: 10.1039/d0ra02898cpmid: 35514547

The focal point of this work is the design and comparison of two types of iron doped TiO2 prepared by a simple sol–gel method and then encapsulated in an alginate matrix. The as-prepared recyclable bio-nanocomposite photocatalysts were made of different amounts of TiO2-Fe2O3 and TiO2-Fe3O4 (1%, 2.5%, 5%, and 10%) and were developed to improve the photocatalytic efficiency of TiO2 and simultaneously to achieve an expanded visible-light response range with high visible-light absorption potential in order to degrade organic pollutants from aqueous solutions, as a potential application. As it is essential to characterize a material to better understand it, accurate characterization of the resulting bio-nanocomposites was carried out using X-ray diffraction (XRD), scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and UV-diffuse reflectance spectroscopy (UV-DRS). In this study, the emphasis on blending the alginate and the iron doped-TiO2 photocatalyst nanoparticles results in a multicomponent particular shaped system that exhibits a porous structure, an exceptional surface area and a smaller band gap due to the presence of iron nanoparticles that could also maintain e−/hole separation for better photocatalytic activity under visible light.

Karaman, Maja; Vraneš, Milan; Tot, Aleksandar; Papović, Snežana; Miljaković, Dragana; Gadžurić, Slobodan; Ignjatov, Maja

doi: 10.1039/d0ra02475apmid: 35514570

The fungal genus Alternaria Nees 1816 includes the most prevalent pathogenic species that can cause crop diseases such as blight, black spot, and dark leaf spot. In accordance with the aim of developing modern sustainable approaches in agriculture for the replacement of synthetic and toxic substances with environmentally friendly alternatives, the objective of this study was to examine the in vitro antifungal activities of 18 newly synthesized ionic liquids (ILs) against three Alternaria strains: A. padwickii, A. dauci and A. linicola. The antifungal activities of the ILs were estimated via a microdilution method to establish minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values. The results confirmed that 17 of the 18 ILs showed strain specificity, including good antifungal activity toward Alternaria strains, with MIC and MFC values in the range of 0.04 to 0.43 mol dm−3. The strongest antifungal effects toward all analyzed Alternaria strains were displayed by the compounds with long alkyl chains: [omim][Cl] (MIC/MFC: 0.042 mol dm−3), [dmim][Cl] (MIC/MFC: 0.043 mol dm−3), [ddmim][Cl] (MIC/MFC: 0.053 mol dm−3), [ddTSC][Br] (MIC/MFC: 0.053 mol dm−3), and [Allyl-mim][Cl] (MIC/MFC: 0.054 mol dm−3). The introduction of oxygen as a hydroxyl group resulted in less-pronounced toxicity towards Alternaria compared to the introduction of an ether group, while the contribution of the hydroxyl group was shown to be a more determining factor than the prolongation of the side-chain, resulting in overall fungicidal activity decrease. Our results indicate the possibility that the most effective ILs ([Allyl-mim][Cl], [omim][Cl], [dmim][Cl], [ddmim][Cl], [bTSC][Br], [hTSC][Br], [oTSC][Br], [dTSC][Br], and [ddTSC][Br]) could be applied to the control of plant diseases caused by Alternaria species, based on their potential as an environmentally friendly crop protection approach. Since salts based on TSC cations are significantly cheaper to synthesize, stable under mild conditions, and environmentally friendly after degradation, thiosemicarbazidium-based ILs can be a suitable replacement for commercially available imidazolium ILs.

Ibrahem, Mohammed A.; Rasheed, Bassam G.; Mahdi, Rahman I.; Khazal, Taha M.; Omar, Maryam M.; O'Neill, Mary

doi: 10.1039/d0ra03858jpmid: 35514594

This work shows the enhancement of the visible photocatalytic activity of TiO2 NPs film using the localized surface plasmonic resonance of Au nanostructures. We adopted a simple yet effective surface treatment to tune the size distribution, and plasmonic resonance spectrum of Au nanostructured films on glass substrates, by hot plate annealing in air at low temperatures. A hybrid photocatalytic film of TiO2:Au is utilized to catalyse a selective photodegradation reaction of Methylene Blue in solution. Irradiation at the plasmonic resonance wavelength of the Au nanostructures provides more effective photodegradation compared to broadband artificial sunlight of significantly higher intensity. This improvement is attributed to the active contribution of the plasmonic hot electrons injected into the TiO2. The broadband source initiates competing photoreactions in the photocatalyst, so that carrier transfer from the catalyst surface to the solution is less efficient. The proposed hybrid photocatalyst can be integrated with a variety of device architectures and designs, which makes it highly attractive for low-cost photocatalysis applications.

Sharma, Jaswinder; Cullen, David A.; Polizos, Georgios; Nawaz, Kashif; Wang, Hsin; Muralidharan, Nitin; Smith, David Barton

doi: 10.1039/d0ra02888fpmid: 35514583

In the past decade, interest in hollow silica particles has grown tremendously because of their applications in diverse fields such as thermal insulation, drug delivery, battery cathodes, catalysis, and functional coatings. Herein, we demonstrate a strategy to synthesize hybrid hollow silica particles having shells made of either polymer-silica or carbon–silica. Hybrid shells were characterized using electron microscopy. The effect of hybrid shell type on particle properties such as thermal and moisture absorption was also investigated.

Knapczyk-Korczak, Joanna; Szewczyk, Piotr K.; Ura, Daniel P.; Berent, Katarzyna; Stachewicz, Urszula

doi: 10.1039/d0ra03939jpmid: 35514544

The water crisis is a big social problem and one of the solutions are the Fog Water Collectors (FWCs) that are placed in areas, where the use of conventional methods to collect water is impossible or inadequate. The most common fog collecting medium in FWC is Raschel mesh, which in our study is modified with electrospun polyamide 6 (PA6) nanofibers. The hydrophilic PA6 nanofibers were directly deposited on Raschel meshes to create the hierarchical structure that increases the effective surface area which enhances the ability to catch water droplets from fog. The meshes and the wetting behavior were investigated using a scanning electron microscope (SEM) and environmental SEM (ESEM). We performed the fog water collection experiments on various configurations of Raschel meshes with hydrophilic PA6 nanofibers. The addition of hydrophilic nanofibers allowed us to obtain 3 times higher water collection rate of collecting water from fog. Within this study, we show the innovative and straightforward way to modify the existing technology that improves water collection by changing the mechanisms of droplet formation on the mesh.

Ha, Yeonjeong; Kwon, Jung-Hwan

doi: 10.1039/d0ra03108apmid: 35514581

Polyhexamethylene guanidine (PHMG) is a cationic antimicrobial oligomer that has been used prevalently over the past few decades. However, due to the lack of inhalation toxicity assessment of PHMG, it has caused severe health damage, including fatal lung fibrosis, after being used as one of the major active ingredients of humidifier disinfectants in Korea. Because the first step of the entry of PHMG into airway is its association with cell membranes, the distribution of PHMG between lipid membranes and water is very important to know the depositional flux in the respiratory systems and related toxic mechanisms. We developed a quantitative method to determine the distribution constant (Klipw) of PHMG between solid supported lipid membranes and water and evaluated the effects of lipid membrane compositions on the Klipw of PHMG. PHMG accumulated into anionic lipid membranes rapidly compared to into cationic or zwitterionic lipid membranes, suggesting fast adsorption of PHMG onto anionic lipid head groups. Klipw values with anionic/zwitterionic lipid mixtures were higher than Klipw values with anionic lipids only, potentially due to the later phase separation after preferential interaction between PHMG and anionic lipids in lipid mixtures. In addition, Klipw values increased with increasing single acyl chain lipid content in unsaturated lipids and decreasing cholesterol content. These results imply that changes in lipid spontaneous curvature and lipid bilayer packing density also affect the membrane distribution of PHMG.

Terakado, Nobuaki; Yoshimine, Toshikazu; Kozawa, Ryusei; Takahashi, Yoshihiro; Fujiwara, Takumi

doi: 10.1039/d0ra03026kpmid: 35514571

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures. Therefore, heat dissipation in glass components often becomes a problem and its applications to the thermal management has been limited to use as a heat insulator. To break this mold and to apply it to fields, e.g., transparent sealing materials, for which low thermal conductive glasses and organic polymers have been conventionally used, we fabricated an MgO-dispersed glass-ceramics in our previous work. It comprises MgO crystal and glass matrix and their reflective indices are matched, leading to optical transparency and improvement in thermal conductivity. Here we investigate the atomic-scale structures in the MgO-dispersed glass-ceramics by nuclear magnetic resonance, etc. and attempt to further improve the thermal conductivity and the transparency. As a result, we show an MgO-dispersed glass-ceramic with a thermal conductivity of 3.3 W (m−1 K−1), corresponding to 300% of that of the glass matrix, high optical transparency, and glass transition. This report highlights that our strategies pave the way for development of novel transparent, functional glass-ceramics.