Recent advances in graphene nanoribbons for biosensing and biomedicine

In recent years, a new type of quasi-one-dimensional graphene-based material, graphene nanoribbons (GNRs), has attracted increasing attention. The limited domain width and rich edge configurations of GNRs endow them with unique properties and wide applications in comparison to two-dimensional graphene. This review article mainly focuses on the electrical, chemical and other properties of GNRs, and further introduces the typical preparation methods of GNRs, including top-down and bottom-up strategies. Then, their biosensing and biomedical applications are highlighted in detail, such as biosensors, photothermal therapy, drug delivery, etc. Finally, the challenges and future prospects in the synthesis and application of functionalized GNRs are discussed. It is expected that GNRs will have significant practical use in biomedical applications in the future.

Inorganic-inorganic nanohybrids for drug delivery, imaging and photo-therapy: recent developments and future scope

Advanced nanotechnology has been emerging rapidly in terms of novel hybrid nanomaterials that have found various applications in day-to-day life for the betterment of the public. Specifically, gold, iron, silica, hydroxy apatite, and layered double hydroxide based nanohybrids have shown tremendous progress in biomedical applications, including bio-imaging, therapeutic delivery and photothermal/dynamic therapy. Moreover, recent progress in up-conversion nanohybrid materials is also notable because they have excellent NIR imaging capability along with therapeutic benefits which would be useful for treating deep-rooted tumor tissues. Our present review highlights recent developments in inorganic-inorganic nanohybrids, and their applications in bio-imaging, drug delivery, and photo-therapy. In addition, their future scope is also discussed in detail.

Sarcosine Prostate Cancer Biomarker Detection by Controlling Oxygen in NiOx Membrane on Vertical Silicon Nanowires in Electrolyte-Insulator-Nanowire Structure

Sarcosine prostate cancer biomarker with the low concentration of 1 pM has been detected by controlling oxygen from 1 to 15 sccm in a NiO_x membrane on chemically etched vertical Si nanowires (SiNWs) in an electrolyte-insulator-nanowire (EIN) structure. The vertical Si nanowires with approximately 17 μm length and polycrystalline NiO_x membrane are observed by both field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM) images, respectively. The optimized NiO_x membrane with oxygen content of 4 sccm on planar SiO_x/Si substrate shows good pH sensitivity of approximately 50 mV/pH, low hysteresis of 3.4 mV, and low drift rate of 2.4 mV/h as compared to other oxygen content membranes of 1, 10, and 15 sccm. Further, uric acid with the concentration of 0.1 μM is detected directly by using the optimized NiO_x membrane. In addition, repeatable H₂O₂ sensing with the low concentration of 10 pM as well as prostate cancer biomarker is detected, which is owing to the reduction-oxidation phenomena of the NiO_x membranes. The sensing mechanism is owing to the Ni²⁺/Ni³⁺ oxidation states of the NiO_x membrane, which is confirmed by X-ray photoelectron spectroscopy. The optimized NiO_x membrane on vertical Si nanowire in the EIN structure shows a good drift rate of 3.84 mV/h and sarcosine detection with improvement of approximately 1000 times as compared to the planar Si in an electrolyte-insulator-semiconductor (EIS) structure. This sensor paves a way to detect early-stage diagnosis of prostate cancer rapidly in the near future.

Cd(ii) coordination compounds as heterogeneous catalysts for microwave-assisted peroxidative oxidation of toluene and 1-phenylethanol

Cd(ii) compounds as catalysts towards microwave assisted peroxidative oxidation (with tert-butylhydroperoxide, TBHP) of toluene and 1-phenylethanol under heterogeneous conditions are explored.

Hierarchically Grown NiO-Decorated Polyaniline-Reduced Graphene Oxide Composite for Ultrafast Sunlight-Driven Photocatalysis

Polymers and transition-metal oxides have gained great interest as a photocatalyst in environmental remediation. They could be modified with each other in order to improve their activity. Here, a sunlight-responsive hierarchically structured ternary composite of nickel oxide, polyaniline, and reduced graphene oxide (NiO@PANI/RGO) has been synthesized and employed as a catalyst for dye [methylene blue (MB)] degradation. PANI/GO synthesized by interfacial polymerization acts as a matrix for the growth of NiO using a microemulsion solvothermal method, ensuing an in situ reduction of graphene oxide during the formation of a hierarchical NiO@PANI/RGO composite. Morphological studies of the as-synthesized NiO@PANI/RGO composite reveal fine NiO (10 nm) nanoparticles intercalated between the uniformly grown PANI spines (50-60 nm) over the RGO surface. The optical band gap of ∼1.9 eV calculated from the UV-vis spectrum illustrates the extended light absorption range for the NiO@PANI/RGO photocatalyst. The efficiency of 98% MB degradation within 11 min with the degradation rate constant 0.086 min-1 for NiO@PANI/RGO has surpassed any other report on metal oxide/graphene-based ternary composites. Overall, this work could pave the way for the fabrication of futuristic hierarchical structured ternary nanocomposites as an efficient photocatalyst and facilitate their application in the environmental protection issues.