Multiplexed Covalent Patterns on Double‐Reactive Porous Coating

We have conceptualized and demonstrated an approach based on the combination of hydrophobicity, a substrate‐independent dip coating as porous material with double residual chemical reactivities for implementing multiplexed, miniaturized and unclonable bulk‐infused patterns of different fluorophores following distinct reaction pathways. The embedded hydrophobicity (∼102°) restricted the unwanted spreading of beaded aqueous ink on the coating. The constructions of micropatterns on porous dip‐coating via ink‐jet printing or microchannel cantilever spotting offered orthogonal read‐out and remained readable even after removal of the exterior of the coating

Structural insights and shedding light on preferential interactions of dietary flavonoids with G-quadruplex DNA structures: A new horizon

G-quadruplex, a structurally unique structure in nucleic acids present all throughout the human genome, has sparked great attention in therapeutic investigations. Targeting G-quadruplex structure is a new strategy for the drug development. Flavonoids are found in almost all dietary plant-based beverages and food products; therefore, they are ingested in significant proportions through the human diet. Although synthetically developed drug molecules are used vigorously but they have various adverse effects. While on the other hand, nature supplies chemically unique scaffolds in the form of distinct dietary flavonoids that are easily accessible, less poisonous, and have higher bioavailability. Because of their great pharmacological effectiveness and minimal cytotoxicity, such low molecular weight compounds are feasible alternatives to synthetic therapeutic medicines. Therefore, from a drug-development point of view, investigation on screening the binding capabilities of quadruplex-interactive small natural compounds like dietary flavonoids are expected to be highly effective, with a particular emphasis on the selectivity towards polymorphic G-quadruplex structures. In this respect, quadruplexes have scintillated research into their potential interaction with these dietary flavonoids. The purpose of this review is to offer an up-to-date close-up look at the research on their interaction with structurally varied dietary flavonoids with the goal of providing newer perspectives to construct novel therapeutic agents for next-generation disease managements

Hydropathy: the controlling factor behind the inhibition of Aβ fibrillation by graphene oxide

Protein and peptide aggregation/fibrillation is reported to be responsible for several neurological disorders. Fibrillation of the amyloid β-peptide fragment (25–35) which is a biologically active region of the full length peptide, has been observed to be significantly inhibited in presence of the two dimensional nanomaterial graphene oxide (GO). Fibrillation and inhibition of the Aβ_25–35 peptide by GO has been performed at 37 °C at physiological pH (pH 7.4). The inhibition process is monitored by ThioflavinT fluorescence (ThT), circular dichroism spectroscopy, matrix assisted laser desorption/ionization mass spectrometry, dynamic light scattering experiments etc. The soluble fraction of the protein is quantified by the BCA assay. Microscopic techniques are used to study the morphology of the fibrils formed. GO is observed to inhibit the fibrillation even at very low concentrations and is amplified with increase in concentration of GO. ThT kinetic data fitted well with a sigmoidal curve and shows that GO is able to lengthen the lag phase of the fibrillation process. It appears that surface adsorption of protein on the nanomaterial prevents the monomers to come together. It is speculated that the presence of both polar and non-polar moieties in GO interact strongly with the hydrophobic and hydrophilic residues of the Aβ_25–35 peptide monomer units, thus preventing further aggregation

Interfacial force-driven pattern formation during drying of Aβ (25–35) fibrils

Pattern formation during evaporation of biofluids finds significant applications in the biomedical field for disease identification. Aβ (25–35) is the smallest peptide in the amyloid peptide family that retains the toxicity of a full length peptide responsible for Alzheimer's disease and is chosen here as the model solute. Drying experiments on substrates of varying wettability exhibit unique drying patterns of Aβ (25–35) fibrils visualized through fluorescence microscopy and transmission electron microscopy. The unique pattern formations can be interpreted as manifestations of the changes in the self-pinning mechanism with changes in wettability, which in some cases resembles the well-known coffee ring effect. Additionally, the delicate balance between the drag and capillary forces has been perturbed by initiating controlled rates of evaporation and probing their effects on the fibril patterning

Description of a new species of genus Trachischium with a redescription of Trachischium fuscum (Serpentes: Colubridae: Natricinae)

Raha, Sujoy, Das, Sunandan, Bag, Probhat, Debnath, Sudipta, Pramanick, Kousik (2018): Description of a new species of genus Trachischium with a redescription of Trachischium fuscum (Serpentes: Colubridae: Natricinae). Zootaxa 4370 (5): 549-561, DOI: https://doi.org/10.11646/zootaxa.4370.5.

Probing the inhibitory potency of epigallocatechin gallate against human γB-crystallin aggregation: spectroscopic, microscopic and simulation studies

Aggregation of human ocular lens proteins, the crystallins is believed to be one of the key reasons for age-onset cataract. Previous studies have shown that human γD-crystallin forms amyloid like fibres under conditions of low pH and elevated temperature. In this article, we have investigated the aggregation propensity of human γB-crystallin in absence and presence of epigallocatechin gallate (EGCG), in vitro, when exposed to stressful conditions. We have used different spectroscopic and microscopic techniques to elucidate the inhibitory effect of EGCG towards aggregation. The experimental results have been substantiated by molecular dynamics simulation studies. We have shown that EGCG possesses inhibitory potency against the aggregation of human γB-crystallin at low pH and elevated temperature

Inhibition of Human Serum Albumin Fibrillation by Two-Dimensional Nanoparticles

The formation and deposition of amyloid fibrils have been linked to the pathogenesis of numerous debilitating neurodegenerative disorders. Serum albumins serve as good model proteins for understanding the molecular mechanisms of protein aggregation and fibril formation. Graphene-based nanotherapeutics appear to be promising candidates for designing inhibitors of protein fibrillation. The inhibitory effect of graphene oxide (GO) nanoparticles on the fibrillation of human serum albumin (HSA) in an in vitro mixed solvent system has been investigated. The methods used include ThT fluorescence, ANS binding, Trp fluorescence, circular dichroism, fluorescence microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. It was observed that GO inhibits HSA fibrillation and forms agglomerates with β-sheet rich prefibrillar species. Binding of GO prevents the formation of mature fibrils with characteristic cross-β sheet but does not promote refolding to the native state

Multispectroscopic Investigations of the Binding Interaction between Polyethylene Microplastics and Human Hemoglobin

In this investigation, different multispectroscopic analytical techniques have been used to explore the interaction between polyethylene microplastics (PE-MPs) and human hemoglobin (HHb), an oxygen carrier in the human blood circulatory system. Ultraviolet–visible absorption studies have demonstrated that HHb molecules may interact with PE-MPs, and thermal melting studies have indicated that PE-MPs have a stabilizing effect on HHb. Further circular dichroism and Fourier transform infrared spectroscopic studies have revealed the distinct changes in HHb’s secondary structures caused by the formation of the HHb–PE-MP binding complex. These findings imply that PE-MPs could enter the blood circulation system of humans and may be hazardous to humans. This work explains the potential binding interaction of microplastics at the molecular level and offers insight into the intermolecular interaction between PE-MPs and HHb