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In the textile industry, a high-efficiency dye removal and low-retention of salt is demanded for recycling wastewater. In this study, polyvinylidene fluoride (PVDF) ultrafiltration membrane was transformed to a negatively charged loose nanofiltration (NF) membrane through UV-grafting of acrylic acid. At the optimal exposure of PVDF membrane in UV light for 5 min, the membrane had a high dye recovery above 99% (Congo red and Eriochrome® Black T) and a low sodium chloride (NaCl) rejection of less than 15% along with pure water flux of 26 L∙m−2∙h−1∙bar−1. Its antifouling and oleophobicity surface properties were verified using fluorescent- bovine serum albumin (BSA) and underwater mineral oil contact angle, respectively. According to the fluorescent microscopic images, the modified membrane had ten times lower adhesion of protein on the surface than the unmodified membrane. The underwater oil contact angle was raised from 110° to 155°. Moreover, the salt rejection followed this sequence: Na2SO4 > MgSO4 > NaCl > MgCl2, which agreed with the typical negatively charged NF membrane. In addition, the physicochemical characterization of membranes was further investigated to understand and link to the membrane performance, such as surface functional group, surface elements analysis, surface roughness/morphology, and surface hydrophilicity. 

The effector response of immune cells dictated by an array of secreted proteins is a highly dynamic process, requiring sequential measurement of all relevant proteins from single cells. Herein, a microchip‐based, 10‐plexed, sequential secretion assay on the same single cells and at the scale of ≈5000 single cells measured simultaneously over 4 time points are shown. It is applied to investigating the time course of single human macrophage response to toll‐like receptor 4 (TLR4) ligand lipopolysaccharide (LPS) and reveals four distinct activation modes for different proteins in single cells. Protein secretion dynamics classifies the cells into two major activation states dependent on the basal state of each cell. Single‐cell RNA sequencing performed on the same samples at the matched time points further demonstrates the existence of two major activation states at the transcriptional level, which are enriched for translation versus inflammatory programs, respectively. These results show a cell‐intrinsic heterogeneous response in a phenotypically homogeneous cell population. This work demonstrates the longitudinal tracking of protein secretion signature in thousands of single cells at multiple time points, providing dynamic information to better understand how individual immune cells react to pathogenic challenges over time and how they together constitute a population response.

 

Controlled delivery of cytokines and growth factors has been an area of intense research interest for molecular and cellular bioengineering, immunotherapy, and regenerative medicine. This study shows that primary human lung fibroblasts chemically induced to senescence (cell cycle arrest) can act as a living source to transiently produce factors essential for promoting vasculogenesis or angiogenesis, such as vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and interleukin 8 (IL‐8). Coculture of senescent fibroblasts with human umbilical vein endothelial cells in a fibrin gel demonstrate accelerated formation and maturation of microvessel networks in as early as three days. Unlike the usage of nonsenescent fibroblasts as the angiogenesis‐promoting cells, this approach eliminates drawbacks related to the overproliferation of fibroblasts and the subsequent disruption of tissue architecture, integrity, or function. Coculture of mouse pancreatic islets with senescent fibroblasts and endothelial cells in a gel matrix maintains the viability and function of islets ex vivo for up to five days. Applying senescent fibroblasts to wound repair in vivo leads to increased blood flow in a diabetic mouse model. Together, this work points to a new direction for modeling the delivery of cytokines and growth factors that promote microvascular tissue engineering and tissue repairs.

 

The perivascular niche (PVN) plays an essential role in brain tumor stem‐like cell (BTSC) fate control, tumor invasion, and therapeutic resistance. Here, a microvasculature‐on‐a‐chip system as a PVN model is used to evaluate the ex vivo dynamics of BTSCs from ten glioblastoma patients. BTSCs are found to preferentially localize in the perivascular zone, where they exhibit either the lowest motility, as in quiescent cells, or the highest motility, as in the invasive phenotype, with migration over long distance. These results indicate that PVN is a niche for BTSCs, while the microvascular tracks may serve as a path for tumor cell migration. The degree of colocalization between tumor cells and microvessels varies significantly across patients. To validate these results, single‐cell transcriptome sequencing (10 patients and 21 750 single cells in total) is performed to identify tumor cell subtypes. The colocalization coefficient is found to positively correlate with proneural (stem‐like) or mesenchymal (invasive) but not classical (proliferative) tumor cells. Furthermore, a gene signature profile including PDGFRA correlates strongly with the “homing” of tumor cells to the PVN. These findings demonstrate that the model can recapitulate in vivo tumor cell dynamics and heterogeneity, representing a new route to study patient‐specific tumor cell functions.