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Soil derived dissolved organic matter (DOM) is an important component of the carbon cycle and influences numerous biogeochemical processes, including the formation of mineral-organic associations. DOM ranges in size from small organic molecules to macromolecules and colloidal aggregates. In this study we have used small angle neutron (SANS) and X-ray (SAXS) scattering to characterize the colloidal DOM fraction from the organic layer of a boreal forest soil, and its interactions with hematite (α-Fe₂O₃) mineral nanoparticles. Comparison between SAXS and contrast variation SANS patterns revealed that the scattering form factor of the colloidal DOM aggregates was essentially independent of the scattering contrast, implying that the colloidal aggregates have an essentially homogeneous chemical composition, down to the nanometre length scale. Variation of the D₂O/H₂O ratio of the solvent yielded a SANS intensity minimum at ca. 40 ​vol % D₂O, which was consistent with colloids composed of mainly polysaccharides. At pH 5.5 the pure hematite nanoparticles were colloidally stable in water and characterized by a ζ-potential of +25 ​mV and a hydrodynamic radius of ca. 70 ​nm. In the presence of DOM, the hematite nanoparticles lost the colloidal stability and aggregated into larger clusters, displaying a negative ζ-potential of ca. −25 ​mV. The charge reversal suggested that negatively charged polyanions of DOM adsorbed onto the hematite particles, possibly leading to bridging flocculation. Our results suggested that mainly low molecular weight components induced hematite aggregation because no or very limited interactions between DOM colloids and hematite were detected.

Hypothesis

Supramolecular self-assembly derived from amphiphilic molecules is one of the prime interests with the motivation to develop new building blocks to create different task-specific self-assemblies. Considering the emergent applicability of these self-aggregates across the globe, it would be necessary to develop an alternate technique for the manufacture of self-aggregates employing novel building blocks.

Experiment

With this aim, we synthesized a palmitoyl moiety functionalized carbon quantum dot (FCQD). Interestingly, the synthesized FCQD was found to form a stable amphiphilic inclusion complex (βCD-FCQD) with the ‘host’ β-cyclodextrin (βCD). This amphiphilic βCD-FCQD complex was utilized as a building block to form a hierarchical vesicular self-aggregate (βCD-FCQD vesicle).

Findings

This βCD-FCQD vesicle was successfully employed to detect cholesterol. Moreover, cholesterol lowering hydrophilic drug rosuvastatin loaded βCD-FCQD vesicle was found to be potential in regulation of cholesterol. This work is anticipated to encourage the construction of drug loaded self-assembly based formulation to achieve a way out towards graded combined treatment for cholesterol related disorder like hypercholesterolemia.

Cellulose nanocrystals (CNC) have received much attention as a drug delivery vehicle, but their hydrophilic nature hinders hydrophobic drug loading. Ionotropic gelation using CNC and chitosan (CS) can enhance the loading/encapsulation capacity of hydrophobic compounds, improve colloidal stability, and strengthen mucoadhesion due to the cationic surface of CS. The colloidal behavior of CNC/CS nanocomposites loaded with emamectin benzoate (EMB) were elucidated by measuring the particle size, zeta potential, contact angle, and morphological structure using transmission electron microscopy. The mucoadhesive properties of the nanocomposites were evaluated by viscometric and titration method, followed by testing with zebrafish mucus. A facile and reproducible protocol to synthesize mucoadhesive CNC/CS nanocomposites that can encapsulate hydrophobic drugs is demonstrated. The optimal mass ratio for the synthesis was 1:10 (CS:CNC w/w), yielding the smallest average particle size (∼200 nm), highest zeta potentials (+40 mV), and highest drug encapsulation capacity (68.8 ± 8.7%). The steric stabilization effect of polyvinylpyrrolidone (PVP) and amphiphilic CNC stabilized the colloidal system. Importantly, the CS-coating technique enhanced the colloidal stability due to electrostatic intramolecular repulsion of the positive CS. CNC/CS nanocomposites exhibited enhanced mucoadhesive interaction with porcine mucin protein and live zebrafish mucus.

The extracellular space is nanostructured, populated by heterogeneous classes of nanoparticles, e.g., extracellular vesicles and lipoproteins, which “made by cells for cells'' mediate intercellular, inter-organ, cross-species, and cross-kingdom communication. However, while techniques to study ENP biology in-vitro and in-vivo are becoming available, knowledge of their colloidal and interfacial properties is poor, although much needed. This paper experimentally shows, for the first time, that the aggregation of citrate-capped gold nanoparticles (AuNPs) triggered by lipid vesicle membranes and the related characteristic redshift of the plasmonic signature also applies/extends to lipoproteins. Such interaction leads to the formation of AuNP-lipoprotein hybrid nanostructures and is sensitive to lipoprotein classes and AuNP/lipoprotein molar ratio, paving the way to further synthetic and analytical developments.

This study examines the preparation of PVDF hybrid membranes mixed with natural zeolite mordenite, which are functionalized with various organosilanes, i.e., 3-aminopropyl-triethoxysilane (APTES), 3-ethylenediaminopropyl-trimethoxysilane (EDAPTMS), and 3-mercapto-propyl-trimethoxysilane (MPTMS) compounds. The addition of mordenite-MPTMS increased the β fraction on the hybrid membrane surfaces and improved the membrane hydrophilicity. The shape of the macropores in PME tends to be round, with the largest size among other hybrid membrane macropores resulting in the highest porosity. The congo red dye is very well filtered by all PVDF and hybrid membranes, with a rejection value of around 99%. The increase in porosity was parallel to the water flux value in the hybrid membrane, which is PME produces the highest water flux value. The degree of membrane pores fouling during the filtration of the congo red dye was successfully reduced by the addition of organosilane-modified mordenite.

It was hypothesized that activated carbons (ACs) prepared from hydrochar could be dispersed in solvents under certain conditions. The crude hydrochar formed by the hydrothermal carbonization (HTC) of glucose and was purified by dialysis. Dried dispersions of hydrochar were chemically activated with potassium bicarbonate (KHCO₃) at temperatures of 750–800 ​°C in N₂. The AC prepared from a freeze-dried dispersion of hydrochar could be dispersed in ethanol as 500 nm-sized colloids. It was noted that on regular drying of the hydrochar dispersions, macroscopically large, long, curved, and thin rods of hydrochar formed in the vials. The rods comprised colloidally-packed spherical particles. The rods may have formed from cracked and fractured colloidal coatings and detached from the wall of the vials. This conclusion was supported by analysing the structural features of the rods. The macroscopic shapes were retained on the chemical activation when the hydrochar precursor had been pyrolyzed in N₂ before activation. The ACs had specific surface areas of up to 1800 ​m²/g, and CO₂ uptake levels of up to 7.1 ​mmol/g at 0 ​°C and 101 ​kPa.

The lung is an attractive target for drug delivery because of the ease of non-invasive administration via inhalation, bypassing metabolism in the liver, direct delivery to the respiratory system for treatment of respiratory diseases, and a large surface area for drug absorption. Nanocarrier systems offer several benefits for pulmonary drug delivery, including uniform drug distribution among alveoli, improved drug solubility, sustained drug release, which reduces the dosing frequency and enhances patient compliance, and potential for cell drug internalization. Nanomedicine is also being utilized to combat emerging infectious illnesses like SARS-CoV, SARS-CoV-2, MERS-CoV, and influenza A/H1N1. This review gives a quick rundown of pulmonary diseases caused by infectious agents such as bacterial, viral, and biological roadblocks that prevent effective treatment of recalcitrant respiratory tract infections. We emphasized and summarized recent efforts to combat these infections using novel inhaled formulation-mediated pulmonary delivery strategies like nanocarriers such as liposomes, polymeric nanoparticles, and SLNs. In addition, we also reviewed the latest findings and advancements regarding the development of inhalable novel formulations that circumvent biological barriers and boost drug bioavailability.

Molecular docking (Mol.Doc) techniques were employed to ascertain the binding affinity and energetics of hydroxy derivatives of benzoic and cinnamic acids extract from Psidium guajava L. with Human Serum Albumin (HSA). Caffeic acid (CA), Ferullic acid (FA), Sinapic acid (SA), Syringic acid (SyA) and Vanillic acid (VA) are the derivatives phenolic acids (DPA) employed in docking studies which acts as the guest molecule. Docking of various feasible conformers of DPA with HSA (host) was explored and these conformers were categorized based on the docking score which is correlated to the binding energy (BE) and the stability depends upon the molecular interactions. Among the phenolic acids, SA-HSA complex was energetically more favorable and feasible based on BE and the order of binding stability upon complex formation of various DPA-HSA follows the order SA > FA = CA > VA > SyA, though SA and SyA are structurally similar to each other, likewise FA and VA exhibit a similar structure. The stability upon complex formation is correlated to the docking of the guest molecule in the binding domains of HSA and several molecular interactions. Hydrogen-bonding (HB) interaction governs the stability of host-guest complex is established. Interestingly, the presence of multiple hydrophobic interactions (pi-pi, pi-alkyl, pi-cation or anion, pi-sigma and pi-amide) competes over HB interaction in several conformers resulting in a decrease in BE. We report that SA acts as an excellent site selective and site-specific ligand that prefers to dock in Sudlow binding site II comprising of sub domains IIIA and IIIB respectively. However, all other phenolic acids do not behave neither as site selective nor site specific ligand such that they prefer to reside both in site II and site III (non-Sudlow binding site) of HSA. We authenticate that all the DPA as well as the amino acid moieties in HSA act as HB donor as well as acceptor sites apart from several hydrophobic interactions. We further establish that all the DPA has the least probable affinity to reside in binding site I (warfarin binding site), whereas sub domain IIIA of site II is the most preferred site which is energetically most favoured among all the sub domains.

The development of antibacterial photocatalytic nanomaterials is important. Here, we prepared Zn-porphyrin nanodisks by exfoliation of covalent organic frameworks (COFs). We exfoliated COFs with free-base porphyrins by simple simultaneous coordination of Zn²⁺ and 4-ethylphyridine. The synthesized Zn-porphyrin nanodisks exhibited higher photocatalytic singlet oxygen production by visible light irradiation, and showed substantial light-irradiated antimicrobial activity against Escherichia coli.

When a soft glassy colloidal suspension is displaced by a Newtonian fluid in a radial Hele-Shaw geometry, the pattern morphology that develops at the interface is determined by the complex rheology of the former. We had reported in an earlier work [Palak, V. R. S. Parmar, D. Saha and R. Bandyopadhyay, JCIS Open, 6 (2022) 100047] that a range of pattern morphologies characterised by distinctive structural features can be formed by controlling the elasticity of the displaced suspension, the flow rate of the displacing fluid and the interfacial tension of the fluid pair. Interestingly, all the different morphological features can be distinguished in terms of their areal ratios, defined as the ratio of the areas occupied by the fully-developed pattern and the smallest circle enclosing it. In a significant advance to this earlier work, we show here that a systematic study of spatio-temporal pattern growth can reveal important information about pattern selection mechanisms. We analyse the time-evolution of the patterns to reveal interesting correlations between their growth mechanisms and fully-developed morphologies. We believe that such systematic identification of the unique temporal features characterising pattern growth at the interface between an aging viscoelastic clay suspension and a Newtonian fluid can be useful in pre-empting and suppressing the onset and evolution of interfacial instabilities in the displacement of mud and cement slurries.