RSC Advances

Cai, Lei; Zhang, Zhaohui; Xiao, Haimei; Chen, Shan; Fu, Jinli

doi: 10.1039/c9ra08726epmid: 35541579

An eco-friendly fluorescent molecularly imprinted polymer anchored on the surface of graphene quantum dots (GQDs@MIP) was developed with an efficient sol–gel polymerization for highly sensitive and selective determination of p-nitroaniline (p-NA). The GQDs@MIP was characterized in detail by Fourier-transform infrared, fluorescence spectrometer, scanning electron microscope, transmission electron microscope and ultraviolet spectrophotometer. The results showed that the imprinted layer was successfully grafted on the surface of the GQDs. The fluorescence of the GQDs@MIP is efficiently quenched when p-NA recombines with the imprinting sites based on the photo-induced electron transfer fluorescence quenching mechanism. A good linear relationship was obtained between the fluorescence quenching efficiency of the GQDs@MIP and the concentration of p-NA in the range of 0–15.0 μM with a correlation coefficient of 0.99. The practicability of the proposed method in real samples was successfully evaluated through monitoring p-NA in water and fish samples with satisfactory recovery. The developed method provides a feasible and eco-friendly strategy to fabricate MIPs anchored on GQDs with good fluorescence properties for sensitive detection of organic pollutants in complex samples.

Utami, Maisari; Trisunaryanti, Wega; Shida, Kenji; Tsushida, Masayuki; Kawakita, Hidetaka; Ohto, Keisuke; Wijaya, Karna; Tominaga, Masato

doi: 10.1039/c9ra08834bpmid: 35541575

A platinum-loaded sulphated nanozirconia (Pt/nano ZrO2–SO4) bifunctional metal–acid catalyst was synthesized using a hydrothermal process. The nano ZrO2–SO4 was initially prepared by dispersing the nano ZrO2 in H2SO4, followed by wet impregnation via heating in an aqueous PtCl4 solution. This material was subsequently calcined and reduced under hydrogen gas to produce the catalyst. The Pt/nano ZrO2–SO4 was found to be a highly active, selective and stable solid acid catalyst for the conversion of waste low density polyethylene (LDPE) to high value hydrocarbons. The catalytic activity and stability of this material were evaluated during the hydrocracking of waste LDPE while optimizing the reaction temperature, time and catalyst-to-feed ratio. The activity of catalyst prepared by hydrothermal was attributed to highly dispersion of Pt species interacting with the support and inhibition of the agglomeration process. The impregnation method of hydrothermal generated highly active and selective catalyst with Pt loads of 1 wt%. The hydrocracking of waste LDPE over Pt/nanoZrO2–SO4 at 250 °C for 60 min with a catalyst-to-feed proportion of 1 wt% gave the largest gasoline fraction.

Velezheva, V. S.; Babii, O. L.; Khodak, A. A.; Alekseeva, E. A.; Nelyubina, Yu V.; Godovikov, I. A.; Peregudov, A. S.; Majorov, K. B.; Nikonenko, B. V.

doi: 10.1039/c9ra07807jpmid: 35541627

Novel continuous-flow cascade reactions are developed for producing 1,4-diaryl-disubstituted dipolar γ-carbolines 2 that contain a carboxylate group and their two pentacyclic precursors 6, 7 from hemiindigos 1. The nucleophilic and pro-electrophilic chemistry described is new to the hemiindigos 1, and it led to the discovery of antimycobacterial scaffold characteristic of rimino-type pentacycles 6, 7 and potent drug clofazimine. The new scaffold like clofazimine appears to be useful in developing lead agents active against drug-resistant/dormant TB.

Mohanakrishna, Gunda; Al-Raoush, Riyadh I.; Abu-Reesh, Ibrahim M.; Pant, Deepak

doi: 10.1039/c9ra06957gpmid: 35541583

A pristine soil environment supports a healthy soil biodiversity, which is often polluted with recalcitrant compounds. The bioelectrochemical remediation of the contaminated soils using bioelectrochemical systems (BESs) is gaining significant attention with respect to the restoration of the soil ecosystem. In this direction, a microbial fuel cell (MFC, an application of BES), was employed for the treatment of total petroleum hydrocarbons (TPHs) in a soil microenvironment at three ranges of pollution (loading conditions – 320, 590 and 840 mg TPH per L). TPHs degraded effectively in the soil-electrode vicinity in the range of 158 mg TPHR per L (320 mg TPH per L) and 356 mg TPHR per L (840 mg TPH per L). The study also demosntrated a maximum bioelectrogenesis of 286.7 mW m−2 (448 mV at 100 Ω) at the highest TPH loading concentration studied (840 mg TPH per L). The conditions prevailing in the soil MFC also facilitated the removal of sulfates (114 mg SO42− per L; 62.64%) and the removal of total dissolved solids (910 mg TDS per L, 12.08%) at an 840 mg TPH per L loading condition. The pH of the outlet wastewater prevailing in the mild alkaline range of 7.6 and 8.4, along with improved sulfate and TPH removal in the respective conditions suggested suitable conditions for sulfate-reducing bacteria (SRB). This study also signified the sustainability of the process for the effective treatment of hydrocarbon contaminated soil that also generates green energy.

Lin, Min; Weng, Si-Ying; Chai, Ke-Fu; Mao, Zhu-Jun

doi: 10.1039/c9ra07071kpmid: 35541578

The lipid metabolism relationship between non-alcoholic fatty pancreas disease (NAFPD) and type 2 diabetes mellitus (T2DM) is poorly defined. We aim to identify novel T2DM-related lipid biomarkers in addition to previous studies and provide the evidence for elucidating the relationship between NAFPD and T2DM in a lipid perspective. In this study, multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL) was used to investigate the potential discriminating lipid profile of the fasting plasma of 105 Chinese individuals (39 NAFPD patients, 38 T2DM patients and 30 healthy controls). Then multivariate statistical analysis combined with pathway analysis was performed to identify the lipid biomarker and explore the potential relationship of these two important diseases. The results described a marked reduction of plasmalogen and a significant 4-hydroxynonenal increase in the two diagnostic group, which indicated increased oxidative stress and peroxisomal dysfunction in patients. 60 discriminating metabolites were identified by multivariate statistical analysis of the lipidomics data. In addition, ingenuity pathway analysis (IPA) and a metabolic network constructed by prediction of IPA indicated that lipid metabolism, molecular transport, carbohydrate metabolism and small molecule biochemistry were correlated with disease progression. Our results revealed that the profile of plasma lipid alteration characteristic of NAFPD was similar to that of T2DM, especially during the period prior to the onset of T2DM.

Qi, Shaolong; Zhu, Lubao; Wang, Xinyu; Du, Jianshi; Yang, Qingbiao; Li, Yaoxian

doi: 10.1039/c9ra08555fpmid: 35541628

Near-infrared (NIR) fluorescent probes are widely employed in biological detection because of their lower damage to biological samples, low background interference, and high signal-to-noise ratio. Herein, a highly water-soluble NIR probe (NIRHA) based on a hemicyanine skeleton and bearing an acrylate moiety was synthesized. The probe showed high selectivity toward cysteine (Cys) over homocysteine (Hcy) and glutathione (GSH). The probe also had low cytotoxicity and was successfully applied in HeLa cells and mouse experiments. Results of bioimaging experiments indicated that the probe was effective for visualizing endogenous Cys in vitro and in vivo.

Hu, Anran; Li, Min; Zhang, Liping; Wang, Chunxia; Fu, Shaohai

doi: 10.1039/c9ra08312jpmid: 35541573

Poor stability, the toxicity of the used colorants and complex structure are the main problems for the current spectral simulation materials for vegetation. In this paper, a lightweight (0.052 g cm−3) and environmentally friendly bionic porous spectrum simulation material (BPSSM) was developed to simulate the Vis-NIR spectra of natural leaves. The porous structure of BPSSM was used to simulate the mesophyll tissue, which endows the BPSSM with a near-infrared plateau. Moreover, the relationship between pore structure (size, open porosity and volume density) and near-infrared plateau in the spectrum was also studied. The chlorophyll of leaves was simulated by vat dyes or organic pigments, and the green apex and red edge characteristics in the visible region were further adjusted by the chlorophyllin sodium copper salt. The water absorption of BPSSM with 100–120% water contents are consistent with the natural leaves spectral curve channel. Finally, the spectral correlation coefficients (rm) between BPSSM and different natural leaves are up to 0.984, suggesting that the BPSSM is universally applicable for the simulation of different leaves. Interestingly, the average radiant temperature difference between BPSSM and natural leaves is 0.25 °C within 24 hours, indicating it has similar thermal infrared properties to natural leaves. Moreover, the BPSSM can be combined with textiles to obtain a composite fabric, and its breaking strength and photostability were explored.

Wu, Zehao; Zhang, Xuewei; Das, Atanu; Liu, Jinglan; Zou, Zhenxing; Zhang, Zilong; Xia, Yang; Zhao, Pei; Wang, Hongtao

doi: 10.1039/c9ra09268dpmid: 35541595

Transfer acts as a crucial bridge between the chemical vapor deposition (CVD) synthesis of large-scale graphene and its applications, but the quality evolution of a graphene film during transfer remains unclear. Here we use scanning Raman spectroscopy to monitor as-grown graphene during each step of wet transfer including floating on etchant solution, loaded onto a target substrate, and with additional annealing. Results show that the etchant solution results in strong compressive strain and p-type doping to floating graphene, but both are significantly reduced after the sample is loaded and rinsed especially for the doping. An annealing treatment increases the compressive strain in graphene but hardly its doping level. Moreover, when a poly(methyl methacrylate) (PMMA) layer is used to assist the transfer, it does not only increase the p-type doping of floating graphene but also lowers the crystalline quality of annealed graphene. Therefore, to obtain graphene with better quality, besides the attempts of improving CVD synthesis for its larger domain sizes, universal and easy-to-use polymer-free transfer techniques must be developed as well.

Prislan, Iztok; Sajko, Sara; Ulrih, Nataša Poklar; Fürst, Luka

doi: 10.1039/c9ra09800cpmid: 35541576

Measuring and quantifying thermodynamic parameters that determine both the stability of and interactions between biological macromolecules are an essential and necessary complement to structural studies. Although basic thermodynamic parameters for an observed process can be readily obtained, the data interpretation is often slow and analysis quality can be extremely variable. We have started to develop a web application that will help users to perform thermodynamic characterizations of oligonucleotide unfolding. The application can perform global fitting of calorimetric and spectroscopic data, and uses a three-state equilibrium model to obtain thermodynamic parameters for each transition step – namely, the Gibbs energy, the enthalpy, and the heat capacity. In addition, the application can define the number of K+ ions and the number of water molecules being released or taken up during unfolding. To test our application, we used UV spectroscopy, circular dichroism, and differential scanning calorimetry to monitor folding and unfolding of a model 22-nucleotide-long sequence of a human 3′-telomeric overhang, known as Tel22. The obtained data were uploaded to the web application and the global fit revealed that unfolding of Tel22 involves at least one intermediate state, and that K+ ions are released during the unfolding, whereas water molecules are taken up.

Arumugham, Thanigaivelan; Kaleekkal, Noel Jacob; Rana, Dipak; Sathiyanarayanan, Kulathu Iyer

doi: 10.1039/c9ra08945dpmid: 35541587

In this research work, novel perfluorooctanoic acid-modified melamine (PFOM) was synthesized as a hydrophobic filler using a facile one-pot synthesis. PFOM incorporating polyvinylidene fluoride (PVDF) solution was cast on a cellulose sheet to prepare a dual-layered membrane employing the phase-inversion technique for direct contact membrane distillation (DCMD) application. The influence of PFOM to tailor the dual-layered membrane performance was then investigated. The long perfluoro chain in PFOM hydrophobic fillers increased the surface roughness of the membranes due to its random overlapping with PVDF backbone, and these membranes exhibited a higher water contact angle value. The increase in pore size and membrane porosity did not significantly influence the liquid entry pressure of water (LEPw). The microporous membranes displayed good mechanical strength for use in the test setup. Pure water permeation was the highest (6.9 kg m−2 h−1) for membrane (M1) with 1 wt% of PFOM when tested with a simulated sea-water solution (3.5% w/v NaCl) in the direct contact distillation mode. These membranes also achieved the theoretical salt-rejection of 99.9%, thus confirming the potential of these membranes to be investigated for large scale membrane distillation (MD) applications like desalination of seawater.