Enhanced Water Oxidation Catalytic Performance of Graphene Oxide by Gamma Ray Irradiation Post-Treatment

Herein, we report the influence of γ-ray irradiation process on the physicochemical properties of partially reduced graphene oxide (PRGO) thin films. It is found that γ-ray irradiation at 25KGy alters the surface, chemical environment, and wettability properties of PRGO via inducing edge sites and oxygen moieties, resulting in increased water oxidation performance

Dextran Sulfate Nanocarriers: Design, Strategies and Biomedical Applications

Dextran sulfate (DXS) is a hydrophilic, non-toxic, biodegradable, biocompatible and safe biopolymer. These biomedically relevant characteristics make DXS a promising building block in the development of nanocarrier systems for several biomedical applications, including imaging and drug delivery. DXS polyanion can bind with metal oxide nanomaterials, biological receptors and therapeutic drug molecules. By taking advantage of these intriguing properties, DXS is used to functionalize or construct nanocarriers for specific applications. In particular, the diagnostic or therapeutic active agent-loaded DXS nanoparticles are prepared by simple coating, formation of polyelectrolyte complexes with other positively charged polymers or through self-assembly of amphiphilic DXS derivatives. These nanoparticles show a potential to localize the active agents at the pathological site and minimize undesired side effects. As DXS can recognize and be taken up by macrophage surface receptors, it is also used as a targeting ligand for drug delivery. Besides as a nanocarrier scaffold material, DXS has intrinsic therapeutic potential. DXS binds to thrombin, acts as an anticoagulant and exhibits an inhibitory effect against coagulation, retrovirus, scrapie virus and human immunodeficiency virus (HIV). Herein, biomedical applications involving the use of DXS as nanocarriers for drugs, biomolecules, and imaging agents have been reviewed. A special focus has been made on strategies used for loading and delivering of drugs and biomolecules meant for treating several diseases, including cancer, inflammatory diseases and ocular disease

Recent Advances in Biomedical Applications of Polymeric Nanoplatform Assisted with Two-Photon Absorption Process

Polymers are well-recognized carriers useful for delivering therapeutic drug and imaging probes to the target specified in the defined pathophysiological site. The functional drug molecules and imaging agents were chemically attached or physically loaded in the carrier polymer matrix via cleavable spacers. Using appropriate targeting moieties, these polymeric carriers (PCs) loaded with functional molecules were designed to realize target-specific delivery at the cellular level. The biodistribution of these carriers can be tracked using imaging agents with suitable imaging techniques. The drug molecules can be released by cleaving the spacers either by endogenous stimuli (e.g., pH, redox species, glucose level and enzymes) at the targeted physiological site or exogenous stimuli (e.g., light, electrical pulses, ultrasound and magnetism). Recently, two-photon absorption (2PA)-mediated drug delivery and imaging has gained significant attention because TPA from near-infrared light (700–950 nm, NIR) renders light energy similar to the one-photon absorption from ultraviolet (UV) light. NIR has been considered biologically safe unlike UV, which is harmful to soft tissues, cells and blood vessels. In addition to the heat and reactive oxygen species generating capability of 2PA molecules, 2PA-functionalized PCs were also found to be useful for treating diseases such as cancer by photothermal and photodynamic therapies. Herein, insights attained towards the design, synthesis and biomedical applications of 2PA-activated PCs are reviewed. In particular, specific focus is provided to the imaging and drug delivery applications with a special emphasis on multi-responsive platforms

The effects of competing precursors and pre-oxidation on NNitrosodimethylamine formation from ranitidine upon chloramination

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Structural Activity and HAD Inhibition Efficiency of Pelargonidin and Its Glucoside—A Theoretical Approach

Anthocyanins are an important pharmaceutical ingredient possessing diet regulatory, antioxidant, anticancer, antidiabetic, anti-obesity, antimicrobial, and anti-inflammatory properties. Pelargonidin is an important anthocyanin-based orange-red flavonoid compound used in drugs for treating hypoglycemia, retinopathy, skeletal myopathy, etc. The main sources of pelargonidin are strawberries and food products with red pigmentation. There is a lack of evidence for supporting its use as an independent supplement. In the present study, pelargonidin and pelargonidin-3-O-glucoside are studied for their structural properties using quantum chemical calculations based on density functional theory. The results confirmed that the parent compound and its glycosylated derivative acted as good electron donors. Electrostatic potential, frontier molecular orbitals, and molecular descriptor analyses also substantiated their electron donating properties. Furthermore, based on the probability, a target prediction was performed for pelargonidin and pelargonidin-3-O-glucoside. Hydroxyacyl-coenzyme A dehydrogenase was chosen as an enzymatic target of interest, since the presence work focuses on glucuronidated compounds and their efficacy over diabetes. Possible interactions between these compounds and a target with nominable binding energies were also evaluated. Further, the structural stability of these two compounds were also analyzed using a molecular dynamics simulation

Facile synthesis of catechol functionalized aziridinofullerenes for visible light photocatalysis applications

Using nitrene chemistry, catechol functionalized aziridinofullerenes (CAC60) were synthesized by reacting N-(3-azidopropyl)-2-(3,4- dihydroxyphenyl)acetamide with C60. Synthesis of CAC60 was confirmed by Fourier-transform infrared, Raman and X-ray photoelectron spectroscopies, and Thermogravimetric analysis. The photocatalytic activity of CAC60 was evaluated by measuring photodegradation of a pharmaceutical compound, cimetidine. CAC60 exhibited the instantaneous adsorption of cimetidine, followed by effective photooxidation under visible as well as ultraviolet irradiations. From the comparison of photodegradation behaviors of unmodified control C60, amine functionalized aziridinofullerenes, and CAC60, we concluded that the aziridine and catechol moieties were responsible for the visible light activity and hydrophilicity of CAC 60, respectively.close0

N,N,N-Trimethyl chitosan nanoparticles for controlled intranasal delivery of HBV surface antigen

Hepatitis B virus surface antigen (HBsAg) loaded N,N,N-trimethyl chitosan nanoparticles (N-TMC NPs) were formulated and studied for controlled intranasal delivery. The size and surface properties of the NPs can be tuned by modifying the concentration of N-TMC and found to be 66 +/- 13, 76 +/- 9 nm for 0.25 and 0.5 wt.% respectively. Loading of 380 and 760 ill of HBsAg yielded 143 +/- 33, 259 +/- 47 nm sized spherical N-TMC NPs with highest loading efficiency and capacity of 90-93%, and 96-97% respectively. In vitro drug release analysis ensured 93% cumulative release of HBsAg antigen over prolonged period (43 days). In vivo immunological study was performed using 6-8 weeks old female BALB mice and reveals adjuvants efficiency of NPs for antigen is highly stable and better than standard. Obtained results show that N-TMC NPs can be extensively used in controlled intra nasal delivery to treat various diseases including hepatitis B and allergic rhinitis.close

Titanium dioxide nanofibers integrated stainless steel filter for photocatalytic degradation of pharmaceutical compounds

A photocatalytically active stainless steel filter (P-SSF) was prepared by integrating electrospun TiO2 nanofibers on SSF surface through a hot-press process where a poly(vinylidene fluoride) (PVDF) nanofibers interlayer acted as a binder. By quantifying the photocatalytic oxidation of cimetidine under ultraviolet radiation and assessing the stability of TiO2 nanofibers integrated on the P-SSF against sonication, the optimum thickness of the TiO2 and PVDF layer was found to be 29 and 42??m, respectively. At 10L/m2h flux, 40-90% of cimetidine was oxidized when the thickness of TiO2 layer increased from 10 to 29??m; however, no further increase of cimetidine oxidation was observed as its thickness increased to 84??m, maybe due to limited light penetration. At flux conditions of 10, 20, and 50L/m2h, the oxidation efficiencies for cimetidine were found to be 89, 64, and 47%, respectively. This was attributed to reduced contact time of cimetidine within the TiO2 layer. Further, the degradation efficacy of cimetidine was stably maintained for 72h at a flux of 10L/m2h and a trans-filter pressure of 0.1-0.2kPa. Overall, our results showed that it can potentially be employed in the treatment of effluents containing organic micropollutants.close

Highly Durable Antimicrobial Tantalum Nitride/Copper Coatings on Stainless Steel Deposited by Pulsed Magnetron Sputtering

Highly durable and antimicrobial tantalum nitride/copper (TaN/Cu) nanocomposite coatings were deposited on D-9 stainless steel substrates by pulsed magnetron sputtering. The Cu content in the coating was varied in the range of 1.42–35.42 atomic % (at.%). The coatings were characterized by electron probe microanalyzer, X-ray diffraction, scanning electron microscope and atomic force microscope. The antibacterial properties of the TaN/Cu coatings against gram-negative Pseudomonas aeruginosa were evaluated using a cell culture test. The peak hardness and Young’s modulus of TaN/Cu with 10.46 at.% Cu were 24 and 295 GPa, respectively, which amounted to 15 and 41.67% higher than Cu-free TaN. Among all, TaN/Cu with 10.46 at.% exhibited the lowest friction coefficient. The TaN/Cu coatings exhibited significantly higher antibacterial activity than Cu-free TaN against Pseudomonas aeruginosa. On TaN, the bacterial count was about 4 × 106 CFU, whereas it was dropped to 1.2 × 102 CFU in case of TaN/Cu with 10.46 at.% Cu. The bacterial count was decreased from 9 to 6 when the Cu content increased from 25.54 to 30.04 at.%. Live bacterial cells were observed in the SEM images of TaN, and dead cells were found on TaN/Cu. Overall, TaN/Cu with 10.46 at.% Cu was found to be a potential coating composition in terms of higher antimicrobial activity and mechanical durability

Recent Advances in the Preparation and Performance of Porous Titanium-Based Anode Materials for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are among the most cost-effective and environmentally benign electrical energy storage devices required to match the needs of commercialized stationary and automotive applications. Because of its excellent chemical characteristics, infinite abundance, and low cost, the SIB is an excellent technology for grid energy storage compared with others. When used as anodes, titanium compounds based on the Ti4+/Ti3+ redox couple have a potential of typically 0.5–1.0 V, which is far from the potential of dangerous sodium plating (0.0–0.1 V). This ensures the operational safety of large-scale SIBs. Low lattice strain, usually associated with Ti-based materials, is also helpful for the longevity of the cycling of SIBs. Numerous Ti-based anode materials are being developed for use in SIBs. In particular, due to adequate electrode–electrolyte interaction and rapid charge transportation, hierarchical porous (HP) Ti-based anode materials were reported as having high specific capacity, current density, and cycling stability. HPTi-based anode materials for SIBs have the potential to be used in automobiles and portable, flexible, and wearable electronic devices. This review addresses recent developments in HPTiO2-based SIBs and their preparation, properties, performance, and challenges