Modeling of velocity and shear stress profiles in the ecological channel with floating vegetation.

Floating vegetation occurs in various environments, such as artificial floating islands, wetlands, river courses, and lakes, which constitute an important part of the river landscape and ecological restoration. The vertical distribution of the streamwise velocity of the channel flow with floating vegetation is of the utmost importance, and therefore, it is the basis for research on bed erosion and pollutant transport. Laboratory experiments on an open-channel flow covered by floating vegetation with unanchored roots have shown a two-layer structure of the velocity profile and a rapid decrease in the Reynolds stress across the interface in the vegetation layer but gradual in the non-vegetation layer. The flow was divided into four subzones in a vertical direction according to the organized flow structure in the experiment as follows: (I) the uniform region deep within the non-vegetation layer, (II) the outer region in the non-vegetation layer, (III) the inner region in the vegetation layer, and (IV) the uniform region deep within the vegetation layer. An analytical model based on the momentum balance in each subzone was developed to predict the profiles of velocity and Reynolds stress. The predictions from analytical models agree well with those from laboratory studies of floating vegetation and lay the theoretical foundation for future studies on water eutrophication and the transport of pollutants, sediments, and algae.

Direct discrimination of cell surface glycosylation signatures using a single pH-responsive boronic acid-functionalized polymer.

Cell surface glycans serve fundamental roles in many biological processes, including cell-cell interaction, pathogen infection, and cancer metastasis. Cancer cell surface have alternative glycosylation to healthy cells, making these changes useful hallmarks of cancer. However, the diversity of glycan structures makes glycosylation profiling very challenging, with glycan 'fingerprints' providing an important tool for assessing cell state. In this work, we utilized the pH-responsive differential binding of boronic acid (BA) moieties with cell surface glycans to generate a high-content six-channel BA-based sensor array that uses a single polymer to distinguish mammalian cell types. This sensing platform provided efficient discrimination of cancer cells and readily discriminated between Chinese hamster ovary (CHO) glycomutants, providing evidence that discrimination is glycan-driven. The BA-functionalized polymer sensor array is readily scalable, providing access to new diagnostic and therapeutic strategies for cell surface glycosylation-associated diseases.

A Polymer-Based Multichannel Sensor for Rapid Cell-Based Screening of Antibiotic Mechanisms and Resistance Development.

Antibiotic resistance presents a critical threat to public health, necessitating the rapid development of novel antibiotics and an appropriate choice of therapeutics to combat refractory bacterial infections. Here, we report a high-throughput polymer-based sensor platform that rapidly (30 min) profiles mechanisms of antibiotic activity. The sensor array features three fluorophore-conjugated polymers that can detect subtle antibiotic-induced phenotypic changes on bacterial surfaces, generating distinct mechanism-based fluorescence patterns. Notably, discrimination of different generations of antibiotic resistance was achieved with high efficiency. This sensor platform combines trainability, simplicity, and rapid screening into a readily translatable platform.

An array-based nanosensor for detecting cellular responses in macrophages induced by femtomolar levels of pesticides.

Environmental agents can induce cellular responses at concentrations far below the limits of detection for current viability and biomarker-based cell sensing platforms. Hypothesis-free cell sensor platforms can be engineered to maximize sensitivity to phenotypic changes, providing a tool for lowering the threshold for detecting cellular changes. Pesticides are one of the most prevalent sources of chemical exposure due to their use in food and agriculture fields. We report here a FRET-based nanosensor array engineered to maximize responses to changes at cell surfaces after pesticide exposure. This sensor array robustly detected macrophage responses to femtomolar concentrations of common pesticides-orders of magnitude lower concentrations than traditional toxicological and biomarker-based strategies. Significantly, this platform was able to classify these responses by pesticide class, demonstrating the ability to distinguish between changes induced by these different agents. Taken together, hypothesis-free cell surface sensing is a promising tool for detecting the effects of ultra-trace environmental chemicals on human health, as well as detecting threshold responses for use in drug discovery and diagnostics.

Differentiation of Cancer Stem Cells through Nanoparticle Surface Engineering.

Cancer stem cells (CSCs) are a crucial therapeutic target because of their role in resistance to chemo- and radiation therapy, metastasis, and tumor recurrence. Differentiation therapy presents a potential strategy for "defanging" CSCs. To date, only a limited number of small-molecule and nanomaterial-based differentiating agents have been identified. We report here the integrated use of nanoparticle engineering and hypothesis-free sensing to identify nanoparticles capable of efficient differentiation of CSCs into non-CSC phenotypes. Using this strategy, we identified a nanoparticle that induces CSC differentiation by increasing intracellular reactive oxygen species levels. Importantly, this unreported phenotype is more susceptible to drug treatment than either CSCs or non-CSCs, demonstrating a potentially powerful strategy for anticancer therapeutics.

Nano Assessing Nano: Nanosensor-Enabled Detection of Cell Phenotypic Changes Identifies Nanoparticle Toxicological Effects at Ultra-Low Exposure Levels.

Industrial use of nanomaterials is rapidly increasing, making the effects of these materials on the environment and human health of critical concern. Standard nanotoxicity evaluation methods rely on detecting cell death or major dysfunction and will miss early signs of toxicity. In this work, the use of rapid and sensitive nanosensors that can efficiently detect subtle phenotypic changes on the cell surface following nanomaterial exposure is reported. Importantly, the method reveals significant phenotypic changes at dosages where other conventional methods show normal cellular activity. This approach holds promise in toxicological and pharmacological evaluations to ensure safer and better use of nanomaterials.

Rapid evaluation of gold nanoparticle-lipid membrane interactions using a lipid/polydiacetylene vesicle sensor.

Surface modification of gold nanoparticles (AuNPs) has significant and complicated effects on their interactions with cell membranes. In this study, we used a lipid/polyacetylene (PDA) vesicle sensor as the lipid membrane model to evaluate AuNP-lipid membrane interactions. Based on the colorimetric response (CR) of PDA vesicles before and after incubation with AuNPs, it was found that the interaction was highly dependent on the surface charge of AuNPs. As compared to the positively charged NPs, neutral and zwitterionic NPs adsorbed much less on the lipid membrane. Negatively charged NPs did not induce any noticeable color changes even at high concentrations. A class of cationic AuNPs with different degrees of surface hydrophobicity was further selected to investigate the role of hydrophobicity in interacting with lipid/PDA vesicles, and log(EC50) was employed as the evaluation index. According to the log(EC50)-NP concentration curve, the hydrophobicity of NPs enhanced the lipid membrane affinity, but electrostatic interactions weakened this effect. Finally, different concentrations of bovine serum albumin (BSA) were used to study the effect of the protein corona on NP-lipid membrane interactions. The formation of a NP-protein corona was found to mask the electrostatic interactions, leading to the decrease of the CR values of cationic NPs, and highly hydrophobic NPs were less affected by a low concentration of BSA due to the strong hydrophobic interactions. Although the effect of NP surface properties on their interactions with cells is far more complicated, our study provides a rapid and effective method for the evaluation of the interactions between surface modified AuNPs and lipid membranes.

High-content and high-throughput identification of macrophage polarization phenotypes.

Macrophages are plastic cells of the innate immune system that perform a wide range of immune- and homeostasis-related functions. Due to their plasticity, macrophages can polarize into a spectrum of activated phenotypes. Rapid identification of macrophage polarization states provides valuable information for drug discovery, toxicological screening, and immunotherapy evaluation. The complexity associated with macrophage activation limits the ability of current biomarker-based methods to rapidly identify unique activation states. In this study, we demonstrate the ability of a 2-element sensor array that provides an information-rich 5-channel output to successfully determine macrophage polarization phenotypes in a matter of minutes. The simple and robust sensor generates a high dimensional data array which enables accurate macrophage evaluations in standard cell lines and primary cells after cytokine treatment, as well as following exposure to a model disease environment.

Simple and robust polymer-based sensor for rapid cancer detection using serum.

We report a polymer-based sensor that rapidly detects cancer based on changes in serum protein levels. Using three ratiometric fluorescence outputs, this simple system identifies early stage and metastatic lung cancer with a high level of accuracy exceeding many biomarker-based assays, making it an attractive strategy for point-of-care testing.

Phytochemical-Based Nanocomposites for the Treatment of Bacterial Biofilms.

Biofilm infections are responsible for at least 65% of human bacterial infections. These biofilms are refractory to conventional antibiotics, leading to chronic infections and nonhealing wounds. Plant-derived antibiotics (phytochemicals) are promising alternative antimicrobial treatments featuring antimicrobial properties. However, their poor solubility in aqueous media limits their application in treating biofilm infections. Phytochemicals were incorporated into cross-linked polymer nanocomposite "sponges" for the treatment of bacterial biofilms. The results indicated encapsulating low log P phytochemicals effectively eliminated biofilms while demonstrating low cytotoxicity against mammalian fibroblast cells.

Rapid Identification of Biofilms Using a Robust Multichannel Polymer Sensor Array.

Infections caused by bacterial biofilms are challenging to diagnose because of the complexity of both the bacteria and the heterogeneous biofilm matrix. We report here a robust polymer-based sensor array that uses selective interactions between polymer sensor elements and the biofilm matrix to identify bacteria species. In this array, an appropriate choice of fluorophore enabled excimer formation and interpolymer FRET, generating six output channels from three polymers. Selective multivalent interactions of these polymers with the biofilm matrices caused differential changes in fluorescent patterns, providing a species-based signature of the biofilm. The real-world potential of the platform was further validated through identification of mixed-species bacterial biofilms and discrimination of biofilms in a mammalian cell-biofilm co-culture wound model.

Array-based "Chemical Nose" Sensing in Diagnostics and Drug Discovery.

Array-based sensor "chemical nose/tongue" platforms are inspired by the mammalian olfactory system. Multiple sensor elements in these devices selectively interact with target analytes, producing a distinct pattern of response and enabling analyte identification. This approach offers unique opportunities relative to "traditional" highly specific sensor elements such as antibodies. Array-based sensors excel at distinguishing small changes in complex mixtures, and this capability is being leveraged for chemical biology studies and clinical pathology, enabled by a diverse toolkit of new molecular, bioconjugate and nanomaterial technologies. Innovation in the design and analysis of arrays provides a robust set of tools for advancing biomedical goals, including precision medicine.

Dynamically crosslinked polymer nanocomposites to treat multidrug-resistant bacterial biofilms.

Multidrug-resistant biofilms are highly resistant to current antimicrobial therapies. We have developed an antimicrobial platform that integrates the bacteria-killing phytochemical carvacrol into dynamically crosslinked polymer nanocomposites (DCPNs). Taking advantage of a reversibly crosslinked Schiff-base scaffold throughout the engineered emulsions, DCPNs exhibited long-term shelf-life and good stability in serum, while readily disassembling in acidic microenvironments. Furthermore, we demonstrated that DCPNs efficiently penetrate the biofilm matrix, eradicating both Gram-negative/positive bacteria enclosed within. Moreover, DCPNs showed no observable toxicity to fibroblast mammalian cells with the same antimicrobial concentrations necessary to eradicate MDR biofilms. Given their potent antimicrobial and stimuli-responsive dissociation characteristics in a biofilm setting, DCPNs are a suitable therapeutic platform for combating MDR bacterial infections.

Rapid phenotyping of cancer stem cells using multichannel nanosensor arrays.

Cancer stem cells (CSCs) contribute to multidrug resistance, tumor recurrence and metastasis, making them prime therapeutic targets. Their ability to differentiate and lose stem cell properties makes them challenging to study. Currently, there is no simple assay that can quickly capture and trace the dynamic phenotypic changes on the CSC surface. Here, we report rapid discrimination of breast CSCs from non-CSCs using a nanoparticle-fluorescent-protein based sensor. This nanosensor was employed to discriminate CSCs from non-CSCs, as well as CSCs that had differentiated in vitro in two breast cancer models. Importantly, the sensor platform could also discriminate CSCs from the bulk population of cells in patient-derived xenografts of human breast cancer. Taken together, the results obtained demonstrate the feasibility of using the nanosensor to phenotype CSCs and monitor their fate. Furthermore, this approach provides a novel area for therapeutic interventions against these challenging targets.

The Human RNA Surveillance Factor UPF1 Modulates Gastric Cancer Progression by Targeting Long Non-Coding RNA MALAT1.

BACKGROUND/AIMS: The long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is overexpressed in numerous cancers. However, whether MALAT1 is regulated and the related mechanisms in gastric cancer remain unclear. METHODS: Immunohistochemistry and qRT-PCR analyses were used to detect the expression levels of UPF1 and MALAT1 in gastric cancer and adjacent normal tissues. MTT, cell cycle, apoptosis and transwell assays were performed to examine the effects of UPF1 on cell cycle progression, cell proliferation, apoptosis, migration and invasion. Additionally, sodium bisulfate sequencing was used to test the promoter hypermethylation on UPF1 in gastric tumor tissues. Finally, RNA immunoprecipitation and luciferase reporter analyses demonstrated that UPF1 directly bound with MALAT1. RESULTS: The expression of UPF1 was significantly downregulated in gastric cancer and negatively correlated with MALAT1 expression. Patients with lower expression of UPF1 had poorer prognosis than those with higher expression. Overexpression of UPF1 inhibited cell proliferation, cell cycle progression, cell migration and invasion, and promoted cell apoptosis in gastric cancer cells. Moreover, the UPF1-mediated inhibition of gastric cancer progression was reversed by overexpression of MALAT1. A profound downregulation of UPF1 in gastric tumor tissues was due to promoter hypermethylation. Overexpression of UPF1 increased nonsense-mediated mRNA decay (NMD) efficiency and thus led to downregulation of MALAT1. CONCLUSION: Our results demonstrate that UPF1 is a potential modulator of MALAT1 and that UPF1/MALAT1 pathway could be a therapeutic target for gastric cancer.

Rapid and ultrasensitive detection of endocrine disrupting chemicals using a nanosensor-enabled cell-based platform.

Endocrine disrupting chemicals (EDCs) interact with estrogen receptors (ERs), causing a broad range of adverse health effects. Current assays for EDC activity are slow and often lack sensitivity. We report here an ultra-sensitive nanosensor that can detect estrogenic cellular changes in ER(+) MCF-7 cells rapidly (minutes) at several orders of magnitude lower than the generally used assays. Notably, the sensor responses at these ultra-low EDC levels correlated with an increased synthesis phase (S-phase) cell population of EDC-treated cells. The nanosensor was also able to detect binary EDC mixture effects, with synergism observed for bisphenol A (BPA) - 17ß-estradiol (E2), and antagonism for dicyclohexylphthalate (DCHP) - E2 and benzo(a)pyrene (BaP) - E2.

Biochemical and biomechanical drivers of cancer cell metastasis, drug response and nanomedicine.

Metastasis, drug resistance and recurrence in cancer are regulated by the tumor microenvironment. This review describes recent advances in understanding how cancer cells respond to extracellular environmental cues via integrins, how to build engineered microenvironments to study these interactions in vitro and how nanomaterials can be used to detect and target tumor microenvironments.

Effects of Traditional Chinese Medicine herbs for tonifying Qi and kidney, and replenishing spleen on intermittent asthma in children aged 2 to 5 years old.

OBJECTIVE: To evaluate the efficacy and safety of Traditional Chinese Medicine (TCM) herbs for tonifying Qi and kidney, and replenishing spleen on intermittent asthma in children aged 2 and 5 years. METHODS: A randomized, single-blind, placebo controlled trial was conducted. Children with intermittent asthma were enrolled and their baseline conditions were measured using a questionnaire. A total of 60 participants, aged 2 to 5, were randomized into either the treatment group (n = 40) or the placebo group (n = 20). The treatment group was treated with granules of TCM herbs for tonifying Qi and kidney, and replenishing spleen, and the placebo group was given placebo granules for 3 months. The number of asthma attacks was counted and TCM syndrome scores were measured at 1, 2, 3, 6, 9, and 12 months. The airway resistance and levels of eosinophil cationic protein for the two groups were observed before and after 3 months. The results were statistically analyzed. RESULTS: Compared with the placebo group, the number of asthma attacks significantly decreased in the treatment group (P < 0.05). For the treatment group, the TCM syndrome scores decreased after 1 and 2 months; there was also a significant difference in scores between the two groups (P < 0.05). The difference remained after the medicine was stopped for 9 months (P < 0.05). After the 3-month treatment, compared with the placebo group, the airway resistance decreased in the treatment group (P < 0.05). No adverse events were reported in the treatment group. CONCLUSION: The TCM herbs for tonifying Qi and kidney, and replenishing spleen reduced the number of intermittent asthma attacks, decreased the TCM syndrome scores, and reduced the airway resistance in the children aged 2 to 5.

Thr136Ile polymorphism of human vesicular monoamine transporter-1 (SLC18A1 gene) influences its transport activity in vitro.

OBJECTIVES: Although single nucleotide polymorphisms of the human vesicular monoamine transporter 1 (hVMAT1) gene SLC18A1 have been associated with neuropsychiatric disorders, there is limited information on the function of naturally occurring hVMAT1 variant proteins. This study evaluated transport activity of full length hVMAT1 isoform-a (NP_003044.1) with a threonine (Thr) or isoleucine (Ile) at amino acid 136 and hVMAT1 isoform-b (NP_00135796.1) with a 136-Thr and deletion of 32 amino acids in the central region of the protein. Genetic studies have previously linked the 136-Thr to bipolar disorder. METHODS: Expression vectors with hVMAT1 DNA coding for isoform variants were transfected into COS-1 cells. Expression of immunoreactive proteins was assessed by Western blotting, and function was assayed by ATP-dependent transport of radiolabeled serotonin and concentration-dependent inhibition by reserpine. RESULTS: Immunoreactive isoform-a proteins were observed as a major doublet (68-71 Kd) and a minor 39 Kd protein. The major isoform-b protein was 47 Kd with minor 57 and 115 Kd proteins. Isoform-b had no detectable transport activity, despite a large amount of immunoreactive protein. Transport activity of isoform-a with 136-Thr was 20-50% lower than with 136-Ile in time course studies (2.5-5 min) and in additional 5 min assays repeated with 5-6 transfections per variant. Kinetic analyses indicated a lower transport Vmax of isoform-a with 136-Thr but no significant differences in the transport Km or reserpine IC50. CONCLUSIONS: Deletion of amino acids 307-338 in hVMAT1 isoform-b abolishes transport activity, and a 136-Thr partially reduces activity of isoform-a.