Unravelling the secret of seedbased gels in water: the nanoscale 3D network formation

Chia (Salvia hispanica) and basil (Ocimum basilicum) seeds have the intrinsic ability to form a hydrogel concomitant with moisture-retention, slow releasing capability and proposed health benefits such as curbing diabetes and obesity by delaying digestion process. However, the underlying mode of gelation at nanoscopic level is not clearly explained or explored. The present study elucidates and corroborates the hypothesis that the gelling behavior of such seeds is due to their nanoscale 3D-network formation. The preliminary study revealed the influence of several conditions like polarity, pH and hydrophilicity/ hydrophobicity on fiber extrusion from the seeds which leads to gelation. Optical microscopic analysis clearly demonstrated bundles of fibers emanating from the seed coat while in contact with water, and live growth of fibers to form 3D network. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies confirmed 3D network formation with fiber diameters ranging from 20 to 50 nm

Self-assembled hydrogel fibers for sensing the multi-compartment intracellular milieu

Targeted delivery of drugs and sensors into cells is an attractive technology with both medical and scientific applications. Existing delivery vehicles are generally limited by the complexity of their design, dependence on active transport, and inability to function within cellular compartments. Here, we developed self-assembled nanofibrous hydrogel fibers using a biologically inert, low-molecular-weight amphiphile. Self-assembled nanofibrous hydrogels offer unique physical/mechanical properties and can easily be loaded with a diverse range of payloads. Unlike commercially available E. coli membrane particles covalently bound to the pH reporting dye pHrodo, pHrodo encapsulated in self-assembled hydrogel-fibers internalizes into macrophages at both physiologic (37°C) and sub-physiologic (4°C) temperatures through an energy-independent, passive process. Unlike dye alone or pHrodo complexed to E. coli, pHrodo-SAFs report pH in both the cytoplasm and phagosomes, as well the nucleus. This new class of materials should be useful for next-generation sensing of the intracellular milieu

Plexin-B2 Negatively Regulates Macrophage Motility, Rac, and Cdc42 Activation

Plexins are cell surface receptors widely studied in the nervous system, where they mediate migration and morphogenesis though the Rho family of small GTPases. More recently, plexins have been implicated in immune processes including cell-cell interaction, immune activation, migration, and cytokine production. Plexin-B2 facilitates ligand induced cell guidance and migration in the nervous system, and induces cytoskeletal changes in overexpression assays through RhoGTPase. The function of Plexin-B2 in the immune system is unknown. This report shows that Plexin-B2 is highly expressed on cells of the innate immune system in the mouse, including macrophages, conventional dendritic cells, and plasmacytoid dendritic cells. However, Plexin-B2 does not appear to regulate the production of proinflammatory cytokines, phagocytosis of a variety of targets, or directional migration towards chemoattractants or extracellular matrix in mouse macrophages. Instead, Plxnb2−/− macrophages have greater cellular motility than wild type in the unstimulated state that is accompanied by more active, GTP-bound Rac and Cdc42. Additionally, Plxnb2−/− macrophages demonstrate faster in vitro wound closure activity. Studies have shown that a closely related family member, Plexin-B1, binds to active Rac and sequesters it from downstream signaling. The interaction of Plexin-B2 with Rac has only been previously confirmed in yeast and bacterial overexpression assays. The data presented here show that Plexin-B2 functions in mouse macrophages as a negative regulator of the GTPases Rac and Cdc42 and as a negative regulator of basal cell motility and wound healing

Gradient High Performance Liquid Chromatography Method Development and Validation for Simultaneous Determination of Phenylephrine and Ibuprofen in Tablet Dosage Form

Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid dosage form.Methods: HPLC determination was carried out on an Agilent XDB C-18 column (4.6 x 150mm, 5 μ particle size) with a gradient mobile phase composed of 0.1 % orthophosphoric acid and acetonitrile at a ratio of: 0.01/95/5, 2.5/95/5, 6/10/90, 8/10/90, 8.1/95/5 and 13/95/5 for time (min)/0.1 % orthophosphoric acid (%)/acetonitrile (%) at a flow rate of 1.0 mL/min. Column temperature was maintained at 30 °C and detection was carried out using a photodiode array (PDA) detector at 210 nm. Validation parameters, including system suitability, linearity, precision, accuracy, specificity, limit of detection (LOD), limit of quantification (LOQ), stability of sample and standard stock solutions as well as robustness were obtained as per International Conference on Harmonization (ICH) guidelines. The proposed method was applied to the determination of phenylephrine and ibuprofen in commercial tablets.Results: Retention time for phenylephrine and ibuprofen were 2.7 and 8.4 min, respectively while % recovery was 99.42 and 99.80 %, respectively. The relative standard deviation (% RSD) for assay of the tablets was < 2 %.Conclusion: The method is fast, accurate, precise and sensitive, and hence it can be employed for routine quality control of tablets containing both drugs in quality control (QC) laboratories and pharmaceutical industry.Keywords: Phenylephrine, Ibuprofen, Simultaneous determination, Validation, Gradient HPLC