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1.
ACS Appl Mater Interfaces ; 14(45): 50543-50556, 2022 Nov 16.
Article in English | MEDLINE | ID: mdl-36331290

ABSTRACT

The COVID-19 pandemic has revealed the importance of the detection of airborne pathogens. Here, we present composite air filters featuring a bioinspired liquid coating that facilitates the removal of captured aerosolized bacteria and viruses for further analysis. We tested three types of air filters: commercial polytetrafluoroethylene (PTFE), which is well known for creating stable liquid coatings, commercial high-efficiency particulate air (HEPA) filters, which are widely used, and in-house-manufactured cellulose nanofiber mats (CNFMs), which are made from sustainable materials. All filters were coated with omniphobic fluorinated liquid to maximize the release of pathogens. We found that coating both the PTFE and HEPA filters with liquid improved the rate at which Escherichia coli was recovered using a physical removal process compared to uncoated controls. Notably, the coated HEPA filters also increased the total number of recovered cells by 57%. Coating the CNFM filters did not improve either the rate of release or the total number of captured cells. The most promising materials, the liquid-coated HEPA, filters were then evaluated for their ability to facilitate the removal of pathogenic viruses via a chemical removal process. Recovery of infectious JC polyomavirus, a nonenveloped virus that attacks the central nervous system, was increased by 92% over uncoated controls; however, there was no significant difference in the total amount of genomic material recovered compared to that of controls. In contrast, significantly more genomic material was recovered for SARS-CoV-2, the airborne, enveloped virus, which causes COVID-19, from liquid-coated filters. Although the amount of infectious SARS-CoV-2 recovered was 58% higher, these results were not significantly different from uncoated filters due to high variability. These results suggest that the efficient recovery of airborne pathogens from liquid-coated filters could improve air sampling efforts, enhancing biosurveillance and global pathogen early warning.


Subject(s)
Air Filters , COVID-19 , Viruses , Humans , Pandemics , SARS-CoV-2 , COVID-19/prevention & control , Bacteria , Dust , Polytetrafluoroethylene
2.
ACS Appl Mater Interfaces ; 14(4): 6148-6156, 2022 Feb 02.
Article in English | MEDLINE | ID: mdl-35042335

ABSTRACT

Antifouling membranes that offer excellent operational lifetimes are critical technologies needed to meet the growing demand for clean water. In this study, we demonstrate antifouling membranes featuring an ultrathin oil layer that stayed immobilized on the surface and in the pore walls of poly(vinylidene fluoride) membranes for multiple cycles of operation at industrially relevant transmembrane pressures. An optimized quantity of a commercial Krytox oil with either a low (K103) or a high viscosity (K107) was infused onto the active surface and into the pores of membranes with a 0.45 µm pore size. The presence of the oil layer was qualitatively confirmed using crystal violet staining and variable pressure scanning electron microscopy. Using a dead-end stirred cell, a consistent pure water permeance value of 3000 L m-2 h-1 bar-1 was achieved for the K103 liquid-infused membranes for at least 10 operation cycles, which was expectedly lower than the permeance of bare control membranes (∼16 000 L m-2 h-1 bar-1), suggesting that a stable oil layer was formed on all membrane-active sites. To quantify if oil was lost during membrane operation, extensive thermogravimetric analysis was conducted on both the as-prepared and used membranes. When challenged with the microorganism, Escherichia coli K12, the liquid-infused membranes statistically reduced microbial attachment by ∼50% versus the control membranes. For the first time, we have demonstrated that by forming an immobilized, robust, and stable oil-coated membrane, we can generate high-performance membranes with stable permeance values that can be operated at relevant transmembrane pressures and provide long-lasting antifouling properties.

3.
Cell Rep ; 13(11): 2425-2439, 2015 Dec 22.
Article in English | MEDLINE | ID: mdl-26673326

ABSTRACT

To identify therapeutic targets for glioblastoma (GBM), we performed genome-wide CRISPR-Cas9 knockout (KO) screens in patient-derived GBM stem-like cells (GSCs) and human neural stem/progenitors (NSCs), non-neoplastic stem cell controls, for genes required for their in vitro growth. Surprisingly, the vast majority GSC-lethal hits were found outside of molecular networks commonly altered in GBM and GSCs (e.g., oncogenic drivers). In vitro and in vivo validation of GSC-specific targets revealed several strong hits, including the wee1-like kinase, PKMYT1/Myt1. Mechanistic studies demonstrated that PKMYT1 acts redundantly with WEE1 to inhibit cyclin B-CDK1 activity via CDK1-Y15 phosphorylation and to promote timely completion of mitosis in NSCs. However, in GSCs, this redundancy is lost, most likely as a result of oncogenic signaling, causing GBM-specific lethality.


Subject(s)
CRISPR-Cas Systems/genetics , Cell Cycle Proteins/genetics , Genome, Human , Membrane Proteins/genetics , Neoplastic Stem Cells/metabolism , Nuclear Proteins/genetics , Protein Serine-Threonine Kinases/genetics , Protein-Tyrosine Kinases/genetics , CDC2 Protein Kinase/antagonists & inhibitors , CDC2 Protein Kinase/metabolism , Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/metabolism , Cell Survival/drug effects , Cyclin B/metabolism , ErbB Receptors/metabolism , Gene Library , Glioblastoma/metabolism , Glioblastoma/pathology , Humans , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/metabolism , Microscopy, Video , Mitosis , Neoplastic Stem Cells/cytology , Nuclear Proteins/antagonists & inhibitors , Nuclear Proteins/metabolism , Phosphorylation , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Protein-Tyrosine Kinases/antagonists & inhibitors , Protein-Tyrosine Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Pyrimidinones , RNA Interference , Time-Lapse Imaging , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
4.
Genes Dev ; 27(9): 1032-45, 2013 May 01.
Article in English | MEDLINE | ID: mdl-23651857

ABSTRACT

To identify key regulators of human brain tumor maintenance and initiation, we performed multiple genome-wide RNAi screens in patient-derived glioblastoma multiforme (GBM) stem cells (GSCs). These screens identified the plant homeodomain (PHD)-finger domain protein PHF5A as differentially required for GSC expansion, as compared with untransformed neural stem cells (NSCs) and fibroblasts. Given PHF5A's known involvement in facilitating interactions between the U2 snRNP complex and ATP-dependent helicases, we examined cancer-specific roles in RNA splicing. We found that in GSCs, but not untransformed controls, PHF5A facilitates recognition of exons with unusual C-rich 3' splice sites in thousands of essential genes. PHF5A knockdown in GSCs, but not untransformed NSCs, astrocytes, or fibroblasts, inhibited splicing of these genes, leading to cell cycle arrest and loss of viability. Notably, pharmacologic inhibition of U2 snRNP activity phenocopied PHF5A knockdown in GSCs and also in NSCs or fibroblasts overexpressing MYC. Furthermore, PHF5A inhibition compromised GSC tumor formation in vivo and inhibited growth of established GBM patient-derived xenograft tumors. Our results demonstrate a novel viability requirement for PHF5A to maintain proper exon recognition in brain tumor-initiating cells and may provide new inroads for novel anti-GBM therapeutic strategies.


Subject(s)
Brain Neoplasms/physiopathology , Carrier Proteins/genetics , Carrier Proteins/metabolism , Glioblastoma/physiopathology , RNA Interference , Animals , Brain Neoplasms/genetics , Cell Cycle Checkpoints , Cell Line , Cell Proliferation , Cell Survival/genetics , Gene Expression , Gene Expression Regulation, Neoplastic , Genome-Wide Association Study , Glioblastoma/genetics , Humans , Mice , Neoplastic Stem Cells/cytology , Neoplastic Stem Cells/metabolism , Protein Binding , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , RNA Splicing , RNA-Binding Proteins , Trans-Activators , Transplantation, Heterologous
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