RSC Advances

Chelaghmia, M. L.; Nacef, M.; Fisli, H.; Affoune, A. M.; Pontié, M.; Makhlouf, A.; Derabla, T.; Khelifi, O.; Aissat, F.

doi: 10.1039/d0ra07331hpmid: 35521251

Platinum (Pt) and platinum–nickel (Pt–Ni) electrocatalysts were prepared on activated graphite electrodes by an electrochemical deposition process. The electrocatalysts were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The electrocatalytic activity of the prepared electrocatalysts, their stability, and the effect of temperature toward ethanol and 2-propanol oxidation were evaluated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The results showed that the Pt–Ni/C exhibited higher catalytic activity, better stability and better tolerance to poisoning by ethanol and 2-propanol oxidation intermediate species compared to Pt/C, which was interpreted as synergistic and electronic effects between Pt and Ni. A study of the temperature dependence of ethanol and 2-propanol oxidation in the temperature range of 298–318 K, shows that the apparent activation energy for ethanol and 2-propanol oxidation on Pt–Ni/C was lower than on Pt/C. The results also revealed that the electro-oxidation of ethanol and 2-propanol on Pt/C were improved by raising the temperature and Ni modification.

Mullani, Sajid B.; Tawade, Anita K.; Tayade, Shivaji N.; Sharma, Kiran Kumar K.; Deshmukh, Shamkumar P.; Mullani, Navaj B.; Mali, Sawanta S.; Hong, Chang Kook; Swamy, B. E. Kumara; Delekar, Sagar D.

doi: 10.1039/d0ra06290apmid: 35521260

Nickel (Ni2+) ion doped zinc oxide-multi-wall carbon nanotubes (NZC) with different composition ratios of MWCNTs (from 0.01 to 0.1 wt%) are synthesized through an in situ sol–gel method. The synthesized NZC nanocomposites (NCs) are used as electrode materials with glassy carbon electrodes (GCEs) for electrochemical detection of uric acid (UA). The cyclic voltammogram of the representative NZC 0.1 modified GCE (NZC 0.1/GCE) revealed the highest electrochemical sensing activity towards the oxidation of UA at 0.37 V in 0.2 M phosphate buffer solution (PBS) having pH 7.4 ± 0.02. The limit of detection (LOD) and limit of quantification (LOQ) for the NZC 0.1/GCE are determined to be 5.72 nM and 19.00 nM (S/N = 3) respectively, which is the lowest compared to the literature values reported for enzymatic and non-enzymatic detection techniques. The synergistic effect of NZC 0.1 NCs is proposed as one of the factors for the enhanced electrochemical oxidation of UA complemented by the phase, lattice parameters, functional groups, morphology, elemental compositions, types of bonding and specific surface area with pore size ascertained using various techniques. The synthesized NZC 0.1 NCs are further proposed as selective electrode materials for the electrochemical detection of UA as authenticated further by performing interference tests with other metabolites such as ascorbic acid (AA), dopamine (DA) and d-glucose. The optimized electrochemical studies are further adopted for sensing of UA from human excretion samples using NZC 0.1 NCs.

Alshehri, Mansoor H.; Duraihem, Faisal Z.; Aba Oud, Mohammed A.

doi: 10.1039/d0ra06359bpmid: 35521264

In this study, we use classical applied mathematical modelling to employ the 6–12 Lennard-Jones potential function along with the continuous approximation to investigate the interaction energies between a double-stranded deoxyribonucleic acid (dsDNA) molecule and two-dimensional nanomaterials, namely graphene (GRA), hexagonal boron nitride (h-BN), molybdenum disulphide (MoS2), and tungsten disulphide (WS2). Assuming that the dsDNA molecule has a perpendicular distance Δ above the nano-sheet surface, we calculated the molecular interaction energy and determined the relation between the location of the minimum energy and Δ. We also investigated the interaction of a dsDNA molecule with the surface of each nano-sheet in the presence of a circular hole simulating a nanopore. The radius of the nanopore that results in the minimum energy was determined. Our results show that the adsorption energies of the dsDNA molecule with GRA, h-BN, MoS2, and WS2 nano-sheets corresponding to the perpendicular distance Δ = 20 Å are approximately 70, 82, 28, and 26 (kcal mol−1), respectively, and we observed that the dsDNA molecule moves through nanopores of radii greater than 12.2 Å.

Tian, Hua; Dai, Yongcheng; Fu, Wenzhe; Liu, Haifang; Li, Mengting; Lv, Meiyuan; Yin, Xueqiong

doi: 10.1039/d0ra06097fpmid: 35521248

In this work, a multifunctional ratiometric fluorescence (FL) nanohybrid (CSCDs@DC) was synthesized from chitosan based carbon dots (CSCDs) and dansyl chloride (DC) at room temperature. The CSCDs@DC revealed strong FL intensity, great stability and excellent anti-photobleaching properties. Herein, CSCDs@DC was responsive to pH value in the range of 1.5–4.0 and exhibited color-switchable FL properties between acidic and alkaline environments. In addition, CSCDs@DC showed good selectivity and sensitivity towards Fe3+ ions. A good linear relationship for the Fe3+ ion detection was obtained in the range from 0 μM to 100 μM, with a detection limit of 1.23 μM. What's more, CSCDs@DC can be used as a fluorescent ink. It expressed superior optical properties after 3 months of storage or continuous exposure to UV light for 24 h. This study suggested that CSCDs@DC had potential in the detection of pH and metal ions, as well as showing promising application in the anti-counterfeiting field.

Batista, André M.; de Queiroz, Thiago B.; Antunes, Renato A.; Lanfredi, Alexandre J. C.; Benvenho, Adriano R. V.; Bonvent, Jean J.; Martinho, Herculano

doi: 10.1039/d0ra05830kpmid: 35521283

Confined and interstitial water has a key role in several chemical, physical and biological processes. It is remarkable that many aspects of water behavior in this regime (e.g., chemical reactivity) remain obscure and unaddressed. In particular for gold surfaces, results from simulations indicated that the first wetting layer would present hydrophilic behavior in contrast to the overall hydrophobic character of the bulk water on this surface. In the present work we investigate the properties of confined water on Au 〈111〉 nanochannels. Our findings, based on a large set of morphological, structural and spectroscopic experimental data and ab initio computer simulations, strongly support the hypothesis of hydrophilicity of the first wetting layer of the Au 〈111〉 surface. A unique oxidation process was also observed in the nanochannels driven by confined water. Our findings indicated that the oxidation product is Au(OH)3. Therefore, the Au surface reactivity against confined water needs to be considered for nanoscopic applications such as, e.g., catalysis in fine chemicals, pharmaceuticals, and the food industry green processes.

Li, Yi; Zhang, Xiao-Ling; Yuan, Xue; Hou, Jiang-Chun; Sang, Peng; Yang, Li-Quan

doi: 10.1039/d0ra90094jpmid: 35532481

Correction for ‘Probing intrinsic dynamics and conformational transition of HIV gp120 by molecular dynamics simulation’ by Yi Li et al., RSC Adv., 2020, 10, 30499–30507, DOI: 10.1039/d0ra06416e.

Sun, Xianfu; Pradeepkumar, Periyakaruppan; Rajendran, Naresh Kumar; Shakila, Harshavardhan; Houreld, Nicolette Nadene; Al Farraj, Dunia A.; Elnahas, Yousif M.; Elumalai, Nandhakumar; Rajan, Mariappan

doi: 10.1039/d0ra03790gpmid: 35521273

Solid–liquid nanocarriers (SLNs) are at the front of the rapidly emerging field of medicinal applications with a potential role in the delivery of bioactive agents. Here, we report a new SLN of natural deep eutectic solvent (NADES) and biotin-conjugated lysine–polyethylene glycol copolymer. The SLN system was analyzed for its functional groups, thermal stability, crystalline nature, particle size, and surface morphology through the instrumental analysis of FT-IR, TGA, XRD, DLS, SEM, and TEM. Encapsulation of PTX (paclitaxel) and 7-HC (7-hydroxycoumarin) with the SLN was carried out by dialysis, and UV-visible spectra evidenced the drug loading capacity and higher encapsulation efficiency obtained. The enhanced anticancer potential of PTX- and 7-HC-loaded SLN was assessed in vitro, and the system reduces the cell viability of MDA-MB-231 cells. The PTX- and 7-HC-loaded SLN system was investigated in a breast cancer-induced rat model via in vivo studies. It shows decreased lysosomal enzymes and increased levels of caspase to cure breast tumors. It very well may be reasoned that the designed PTX- and 7-HC-loaded SLN system has strong anticancer properties and exhibits potential for delivery of drug molecules in cancer treatment.

Yanyan, Sun; Guangxin, Wang; Guoqing, Sun; Yaming, Wang; Wuhui, Li; Osaka, Akiyoshi

doi: 10.1039/d0ra07636hpmid: 35521267

Conversion of calcium carbonate (calcite; CC) to hydroxyapatite (HAp) was examined when the CC particles of sub μm size were soaked at 37 °C for up to 10 d in 0.15 M K2HPO4 (20 ml), whose pH was set to 3–12. Here, the solution contained amino acids, such as glutamine (Glu), arginine (Arg), and glycine (Gly), and their content varied from 0–1.0 g per ml of solution. From the X-ray diffraction (XRD) intensity of the 104 and 211 diffractions of calcite and apatite, respectively, it was seen that the presence of the amino acids promoted the conversion. This was supported by the thermogravimetry (TG) results. The highest promotion was observed at 0.5 g addition of amino acids to the phosphate solution, while Glu showed the highest promotion among the amino acids and Gly the lowest. A scanning electron microscopy study indicated that petal-like HAp nano-crystallites covered the entire surface of the CC particles when they were soaked in the phosphate solution with 0.1 g or more of amino acid for 10 d. The XRD intensity ratio 104(CC)/211(HAp) indicated greater CC to HAp conversion in the solutions at pH 3 and 6 than in the more alkaline solutions. This was attributed to the dissolution of CC in the acidic solutions, which was confirmed by bubbling in these solutions.

Liao, Shengfu; Liu, Jianguo; Yan, Long; Liu, Qiying; Chen, Guanghui; Ma, Longlong

doi: 10.1039/d0ra06414apmid: 35521235

Anthraquinones are recognized as high efficiency photocatalysts which can perform various redox reactions in aqueous or organic phases. We have experimentally proven that 2-BrAQ can undergo hydrogen transfer with an alpha-aromatic alcohol under light conditions, thereby efficiently oxidizing the aromatic alcohol to the corresponding product. The yield of 1-phenethanol to acetophenone can reach more than 96%. In subsequent catalyst screening experiments, it was found that the electronegativity of the substituent at the 2 position of the anthraquinone ring and the acidity of the solvent affect the photocatalytic activity of anthraquinones. After using various aromatic alcohol substrates, 2-BrAQ showed good conversion and selectivity for most aromatic alcohols, but showed C–C bond cleavage and low selectivity with non-α-position aromatic alcohols. In order to explore the mechanism of the redox reaction of 2-BrAQ in acetonitrile solution, the corresponding free radical reaction pathway was proposed and verified by density functional theory (DFT). Focusing on calculations for 2-BrAQ during the reaction and the first-step hydrogen transfer reaction between the 2-BrAQ triplet molecule and the 1-phenylethanol molecule, we recognized the changes that occurred during the reaction and thus have a deeper understanding of the redox reaction of anthraquinone compounds in organic systems.

Bryant, Saffron J.; da Silva, Marcelo A.; Hossain, Kazi M. Zakir; Calabrese, Vincenzo; Scott, Janet L.; Edler, Karen J.

doi: 10.1039/d0ra07575bpmid: 35521254

Deep eutectic solvent (menthol : dodecanoic acid) in water (30 : 70) emulsions stabilised with partially oxidised cellulose nanoparticles remained stable for 200 days at room temperature. Deep eutectic-based emulsions offer potential for non-aqueous reaction systems, chemical extraction, and controlled release. Pickering emulsions using polysaccharides are less toxic and more stable than surfactant-stabilised emulsions.