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In this work, we fabricate an omniphobic microporous membrane for membrane distillation (MD) by modifying a hydrophilic glass fiber membrane with silica nanoparticles followed by surface fluorination and polymer coating. The modified glass fiber membrane exhibits an antiwetting property not only against water but also against low surface tension organic solvents that easily wet a hydrophobic polytetrafluoroethylene (PTFE) membrane that is commonly used in MD applications. By comparing the performance of the PTFE and omniphobic membranes in direct contact MD experiments in the presence of a surfactant (sodium dodecyl sulfate, SDS), we show that SDS wets the hydrophobic PTFE membrane but not the omniphobic membrane. Our results suggest that omniphobic membranes are critical for MD applications with feed waters containing surface active species, such as oil and gas produced water, to prevent membrane pore wetting. ■ INTRODUCTIONMembrane distillation (MD) is a thermal separation process using a microporous hydrophobic membrane. 1−3 MD can operate at relatively low temperatures and is thus able to tap into the vast amount of low-grade waste heat. 4−6 MD is also advantageous over pressure-driven membrane processes, such as reverse osmosis (RO) or nanofiltration, as its low operating pressure reduces the capital cost due to the absence of expensive components, such as high pressure pumps and vessels, as well as pressure exchangers. Recently, MD has been proposed as a low-temperature thermal separation component for hybrid membrane processes coupled with forward osmosis for simultaneous wastewater reuse and mineral recovery 7,8 and with pressure retarded osmosis for harvesting low-grade waste heat. 9 Although MD, as any thermal separation process, is inherently less energy efficient than RO, 10,11 there exist scenarios in which MD may be preferred. For example, if an abundant amount of waste heat or solar thermal energy is readily available, MD can be employed to utilize such low-grade heat to considerably reduce the energy cost and carbon footprint for desalination compared to RO powered by conventional energy sources. 12−14 MD can also be used to desalinate high salinity brines, such as shale gas wastewater, as the osmotic pressure of such brines is far beyond the allowable pressure in RO operations. 15 In addition, MD can be employed for small-scale desalination in remote regions for which RO is not an option due to its dependence on grid power and costly high-pressure components that are not readily adaptable for small-scale systems.In MD desalination, a hydrophobic membrane is employed to create a vapor gap that separates a salty feed solution and the desalted permeate solution. 16 It is critically important that the membrane pores are not wetted by the feed solution as liquid flooding of the pores destroys the vapor gap and undermines the function of the membrane as a selective barrier for salt passage. 1,17,18 Preventing pore wetting is particularly challenging in desalinating shale gas wastewater or ot...

We fabricated a thin-film composite (TFC) forward osmosis (FO) membrane with an ultrathin spray-coated carbon nanotube (CNT) interlayer. The impact of the CNT interlayer on the polyamide (PA) layer structural properties and transport behavior in FO were investigated. Results indicate that the CNT interlayer provides an interface which enables the formation of a highly permeable and selective PA layer with a large effective surface area for water transport, while inhibiting the formation of a flowerlike PA structure inside the substrate pores. The TFC-FO membrane with the CNT interlayer exhibited a much greater water flux than previously reported for FO membranes, while maintaining comparable salt rejection. Specifically, a membrane perm-selectivity or ratio of water (A) to salt permeability coefficients (B) (A/B value) of 39 bar −1 was achieved for the TFC-PA-CNT membrane. Implications of the results for the fabrication of highperformance TFC-FO membranes are further discussed.

Failure of clinical trials of nonviral vector-mediated gene therapy arises primarily from either an insufficient transgene expression level or immunostimulation concerns caused by the genetic information carrier (e.g., bacteria-generated, double-stranded DNA (dsDNA)). Neither of these issues could be addressed through engineering-sophisticated gene delivery vehicles. Therefore, we propose a systemic delivery of chemically modified messenger RNA (mRNA) as an alternative to plasmid DNA (pDNA) in cancer gene therapy. Modified mRNA evaded recognition by the innate immune system and was less immunostimulating than dsDNA or regular mRNA. Moreover, the cytoplasmic delivery of mRNA circumvented the nuclear envelope, which resulted in a higher gene expression level. When formulated in the nanoparticle formulation liposome-protamine-RNA (LPR), modified mRNA showed increased nuclease tolerance and was more effectively taken up by tumor cells after systemic administration. The use of LPR resulted in a substantial increase of the gene expression level compared with the equivalent pDNA in the human lung cancer NCI-H460 carcinoma. In a therapeutic model, when modified mRNA encoding herpes simplex virus 1-thymidine kinase (HSV1-tk) was systemically delivered to H460 xenograft-bearing nude mice, it was significantly more effective in suppressing tumor growth than pDNA.

Multifunctional membrane-core nanoparticles, composed of calcium phosphate cores, arginine-rich peptides, cationic and PEGylated lipid membranes, and galactose targeting ligands, have been developed as synthetic vectors for efficient nuclear delivery of plasmid DNA and subsequent gene expression in hepatocytes in vivo. Targeted particles exhibited rapid and extensive hepatic accumulation and were predominantly internalized by hepatocytes, while the inclusion of such peptides in LCP was sufficient to elicit high degrees of nuclear translocation of plasmid DNA. Monocyclic CR8C significantly enhanced in vivo gene expression over ten-fold more than linear CR8C, likely due to a release-favoring mechanism of the DNA/peptide complex. Though 100-fold lower in activity than that achieved via hydrodynamic injection, this formulation presents as a much less invasive alternative. To our knowledge, this is the most effective synthetic vector for liver gene transfer.