Removal of Selected Organic Contaminants by Various (Nano) Adsorbent-Ultrafiltration Hybrid Systems

Organic contaminants, which result from overuse and discharge of dyes, pharmaceutically active compounds, personal care products, and endocrine-disrupting compounds, have been received attention as contemporary water issues. However, conventional water and/or wastewater treatment system cannot sufficiently control for these contaminants for their stability and complexity. In this study, combined novel adsorbent with ultrafiltration (UF) hybrid system (termed ‘adsorbent-UF’) was applied to removal selected organic contaminants. UF with upstream adsorption has positive effects on performance in terms of the removal of selected organic contaminants, separating used adsorbents and reducing foulants. Activated biochar, metal organic frameworks, and Ti3C2TX MXene were used as novel adsorbents for this study. For selected organic contaminants, retention and flux performance were investigated on adsorbent-UF. The adsorbent-UF system was also evaluated under various water quality such as pH, natural organic matter, and background ions for better understanding of behavior in real aquatic environments. Additionally, by comparing the performance of three adsorbent-UF and powdered activated carbon-UF system, feasibility of an adsorbent-UF was investigated as a suitable alternative technology. Consequently, property change of organic contaminants by various water quality are the key to better performance on adsorbent-UF. Also, based on these results, the adsorbent-UF can be a promising advanced water treatment technology and a realistic alternative to conventional systems

Sonodegradation of amitriptyline and ibuprofen in the presence of Ti3C2Tx MXene

This study, which investigated the sonodegradation of selected pharmaceutical active compounds (PhACs) (amitriptyline (AMT) and ibuprofen (IBP)) with MXene, was carried out in an aqueous solution. To investigate the practicality of the degradation process, the experiments were conducted in various water quality conditions, including pH, temperature, natural organic matter, and ionic strength. Based on the experimental results, the produced hydrogen peroxide, which could be a representative of the produced OH radicals, was a vital factor that affected the degradation performance of both PhACs. To confirm the importance of OH radicals, the effect of a OH radical promoter (H2O2) and scavenger (t-BuOH) was also studied. In addition, the synergism between ultrasonication (US) and MXene was evaluated with the rate constants of US only, MXene only, and a US/MXene combined system. Mineralization of the PhACs was also investigated, and removal of AMT was higher than that of IBP, which could be attributed to the physicochemical properties of the compounds and enhanced adsorption by the well-dispersed MXene. Overall, utilization of MXene by means of ultrasonication could enhance the removal performance of PhACs in water

Dual Function of Wnt Signaling during Neuronal Differentiation of Mouse Embryonic Stem Cells

Activation of Wnt signaling enhances self-renewal of mouse embryonic and neural stem/progenitor cells. In contrast, undifferentiated ES cells show a very low level of endogenous Wnt signaling, and ectopic activation of Wnt signaling has been shown to block neuronal differentiation. Therefore, it remains unclear whether or not endogenous Wnt/β-catenin signaling is necessary for self-renewal or neuronal differentiation of ES cells. To investigate this, we examined the expression profiles of Wnt signaling components. Expression levels of Wnts known to induce β-catenin were very low in undifferentiated ES cells. Stable ES cell lines which can monitor endogenous activity of Wnt/β-catenin signaling suggest that Wnt signaling was very low in undifferentiated ES cells, whereas it increased during embryonic body formation or neuronal differentiation. Interestingly, application of small molecules which can positively (BIO, GSK3β inhibitor) or negatively (IWR-1-endo, Axin stabilizer) control Wnt/β-catenin signaling suggests that activation of that signaling at different time periods had differential effects on neuronal differentiation of 46C ES cells. Further, ChIP analysis suggested that β-catenin/TCF1 complex directly regulated the expression of Sox1 during neuronal differentiation. Overall, our data suggest that Wnt/β-catenin signaling plays differential roles at different time points of neuronal differentiation

Nano-Interstice Driven Powerless Blood Plasma Extraction in a Membrane Filter Integrated Microfluidic Device

Blood plasma is a source of biomarkers in blood and a simple, fast, and easy extraction method is highly required for point-of-care testing (POCT) applications. This paper proposes a membrane filter integrated microfluidic device to extract blood plasma from whole blood, without any external instrumentation. A commercially available membrane filter was integrated with a newly designed dual-cover microfluidic device to avoid leakage of the extracted plasma and remaining blood cells. Nano-interstices installed on both sides of the microfluidic channels actively draw the extracted plasma from the membrane. The developed device successfully supplied 20 μL of extracted plasma with a high extraction yield (~45%) in 16 min

Hydrophobic Patterning‐Based 3D Microfluidic Cell Culture Assay

Engineering physiologically relevant in vitro models of human organs remains a fundamental challenge. Despite significant strides made within the field, many promising organ-on-a-chip models fall short in recapitulating cellular interactions with neighboring cell types, surrounding extracellular matrix (ECM), and exposure to soluble cues due, in part, to the formation of artificial structures that obstruct >50% of the surface area of the ECM. Here, a 3D cell culture platform based upon hydrophobic patterning of hydrogels that is capable of precisely generating a 3D ECM within a microfluidic channel with an interaction area >95% is reported. In this study, for demonstrative purposes, type I collagen (COL1), Matrigel (MAT), COL1/MAT mixture, hyaluronic acid, and cell-laden MAT are formed in the device. Three potential applications are demonstrated, including creating a 3D endothelium model, studying the interstitial migration of cancer cells, and analyzing stem cell differentiation in a 3D environment. The hydrophobic patterned-based 3D cell culture device provides the ease-of-fabrication and flexibility necessary for broad potential applications in organ-on-a-chip platforms

Review of MXene-based nanocomposites for photocatalysis

Since multilayered MXenes (Ti3C2Tx, a new family of two-dimensional materials) were initially introduced by researchers at Drexel University in 2011, various MXene-based nanocomposites have received increased attention as photocatalysts owing to their exceptional properties (e.g., rich surface chemistry, adjustable bandgap structures, high electrical conductivity, hydrophilicity, thermal stability, and large specific surface area). Therefore, we present a comprehensive review of recent studies on fabrication methods for MXene-based photocatalysts and photocatalytic performance for contaminant degradation, CO2 reduction, H-2 evolution, and N-2 fixation with various MXene-based nanocomposites. In addition, this review briefly discusses the stability of MXene-based nanophotocatalysts, current limitations, and future research needs, along with the various corresponding challenges, in an effort to reveal the unique properties of MXene-based nanocomposites. (C) 2020 Elsevier Ltd. All rights reserved.N

Aqueous removal of inorganic and organic contaminants by graphene-based nanoadsorbents : a review

Various graphene-based nanoadsorbents, including graphenes, graphene oxides, reduced graphene oxides, and their nanocomposites, have been widely studied as potential adsorbents due to their unique physicochemical properties, such as structural variability, chemical strength, low density, and the possibility of large scale fabrication. Adsorption mechanisms are governed largely by the physicochemical properties of contaminants, the characteristics of nanoadsorbents, and background water quality conditions. This review summarizes recent comprehensive studies on the removal of various inorganic (mainly heavy metals) and organic contaminants by graphene-based nanoadsorbents, and also discusses valuable information for applications of these nanoadsorbents in water and wastewater treatment. In particular, the aqueous removal of various contaminants was reviewed to (i) summarize the general adsorption capacities of various graphene-based nanoadsorbents for the removal of different inorganic and organic contaminants, (ii) evaluate the effects of key water quality parameters such as pH, temperature, background major ions/ionic strength, and natural organic matter on adsorption, (iii) provide a comprehensive discussion of the mechanisms that influence adsorption on these nanoadsorbents, and (iv) discuss the potential regeneration and reusability of nanoadsorbents. In addition, current challenges and future research needs for the removal of contaminants by graphene-based nanoadsorbents in water treatment processes are discussed briefly.Accepted versio

Characterizing cellular mechanical phenotypes with mechano-node-pore sensing.

The mechanical properties of cells change with their differentiation, chronological age, and malignant progression. Consequently, these properties may be useful label-free biomarkers of various functional or clinically relevant cell states. Here, we demonstrate mechano-node-pore sensing (mechano-NPS), a multi-parametric single-cell-analysis method that utilizes a four-terminal measurement of the current across a microfluidic channel to quantify simultaneously cell diameter, resistance to compressive deformation, transverse deformation under constant strain, and recovery time after deformation. We define a new parameter, the whole-cell deformability index (wCDI), which provides a quantitative mechanical metric of the resistance to compressive deformation that can be used to discriminate among different cell types. The wCDI and the transverse deformation under constant strain show malignant MCF-7 and A549 cell lines are mechanically distinct from non-malignant, MCF-10A and BEAS-2B cell lines, and distinguishes between cells treated or untreated with cytoskeleton-perturbing small molecules. We categorize cell recovery time, ΔTr, as instantaneous (ΔTr ~ 0 ms), transient (ΔTr ≤ 40ms), or prolonged (ΔTr > 40ms), and show that the composition of recovery types, which is a consequence of changes in cytoskeletal organization, correlates with cellular transformation. Through the wCDI and cell-recovery time, mechano-NPS discriminates between sub-lineages of normal primary human mammary epithelial cells with accuracy comparable to flow cytometry, but without antibody labeling. Mechano-NPS identifies mechanical phenotypes that distinguishes lineage, chronological age, and stage of malignant progression in human epithelial cells