PET Membrane Research Articles

Green superhydrophobic surface engineering of PET fabric for advanced water-solvent separation

This paper presents the preparation of the PET membrane for effective organic solvent separation achieved through an advanced superhydrophobic surface engineering of PET fabric utilizing biomimicry and a green chemistry approach. The superhydrophobicity of the PET surface was reached through a hierarchical nanocomposite coating that involved the integration of biomimetic polydopamine (PDA) coating, green-synthesized zinc oxide (ZnO) nanoparticles (NPs), and non-fluorinated quaternary ammonium cation silane (Si-QAC) coverage. The morphology and surface chemical composition of the resultant Si-QAC/ZnO/PDA@PET membrane were characterized by SEM, EDS, FT-IR, XRD, and AFM analysis. The surface topography and water contact angle were also correlated with surface roughness and its superhydrophobicity. The resulting Si-QAC/ZnO/PDA@PET membrane exhibited promising superhydrophobic properties, characterized by a water contact angle ranging from 150° to 160° and a roll-off angle between 5° and 2° as well as stability against severe conditions, including acidic and alkaline exposure, mechanical abrasion, and UV radiations. Moreover, the Si-QAC/ZnO/PDA@PET membrane exhibited bacterial repulsive properties against E. coli and Staphylococcus sp. The separation efficiency of various aliphatic and aromatic organic solvents (n-hexane, toluene, chloroform, and petroleum ether) from water higher than 90 % was also observed, making the membrane a potential candidate for different industrial applications, particularly for the separation of organic solvents from water.

Osmotic energy harvesting using acrylic acid hydrogel PET membrane

In this study, we investigated the osmotic energy harvesting using a cation-selective membrane. The cation-selective membrane was synthesized by the incorporation of acrylic acid hydrogel in a porous support membrane. FTIR analysis and SEM images confirmed the presence of the acrylic acid hydrogel rods inside the porous support material. The exposure of the acrylic acid hydrogel PET (AP) membrane to a concentration gradient culminated in the generation of electric power. The AP membrane was evaluated in regard to the following parameters: EDiff, Io, Pmax and t+. The maximum power obtained with the membrane was 1.10 μW at the 40-fold concentration gradient (test area∽ 100 mm2). Increasing the concentration gradient increased the power output. However, a decrease in power output was observed after a certain value of the concentration gradient. An enhancement in power output was noted as the fraction of acrylic acid within the membrane was augmented. Additionally, the cation transference number also increased owing to a high charge density and a reduction in the mesh size. The AP membrane was also investigated in acidic and basic media. The time-dependent study revealed the superior chemical stability of the AP membrane.

In situ noninvasive monitoring of cell secretions based on MOFs/AAO hybrid membrane induced asymmetric ion transport

Nanofluidic hybrid membranes display distinct ionic current rectification (ICR) properties and provide high surface area for immobilizing probes on the outer surface, exhibiting great potential in detection of biomolecules. Herein, we fabricated MOFs/AAO hybrid membrane with aptamers functionalized on the outer surface for in situ detection of living cells released secretions. TNF-α (a small molecular protein secreted by macrophages) was used as a model. After TNF-α was specifically captured by aptamers on the membrane surface, the asymmetry of surface charge on the hybrid membrane was amplified, the ICR was increased from 3.89 to 18.85. According to the ICR change, TNF-α was sensitively measured with a detection limit of ∼0.49 pM, which was significantly lower than other reported methods. When the hybrid membrane was clamped in the middle of self-made device, PET membrane incubated macrophages was rolled up and inserted into the chamber to mimic cellular microenvironment. Macrophages released TNF-α could be real time monitored with ionic current, macrophages and normal cells could be effectively distinguished according to the released TNF-α level. Thus, we proposed a nanofluidic platform for accurately measuring cell secretions in an engineered cellular microenvironment with a direct manner, without the need for labels or amplification steps.

Tailoring thin film composite membranes for clean water production: A study on structural variations and predictive insights using machine learning

This study focuses on the fabrication of three thin film composite membranes by interfacial polymerization on polyacrylonitrile support. The objective is to explore the influence of different monomers on structural and functional features of resultant membranes for treating saline water and removing micropollutants. A new linear aliphatic amine 4A–2E was used as an aqueous monomer for the first time. Trimesoyl chloride, isophthaloyl chloride, and terephthaloyl chloride were used as organic phase crosslinkers. The resulting membranes exhibited distinctive structural features such as varied roughness and hydrophilicity, which correlated with their functional performance. The membrane roughness for 4A–2E-TPC@PAN/PET reached the highest value of Ra = 56 nm among the fabricated membranes. Moreover, permeate flux of 32, 56, and 49 L m−2 h−1 at 25 bar was measured for 4A–2E-TPC@PAN/PET, 4A–2E-IPC@PAN/PET, and 4A–2E-TMC@PAN/PET, respectively. Notably, 4A–2E-TPC@PAN/PET membrane exhibited 98% rejection of MgCl2 among the tested divalent salts. Furthermore, the membrane displayed high rejections of micropollutants, with 85% rejection for Amitriptyline. Upon chlorine exposure, the 4A–2E-TPC@PAN/PET membrane proved more resistant than both 4A–2E-IPC@PAN/PET and 4A–2E-TMC@PAN/PET membranes. Machine learning predictive insight was developed using Matérn Gaussian Process Regression model to simulate flux before and after chlorination of membranes. The results in both training and testing proved reliable predictive insight with 99% accuracy in terms of Nash Sutcliffe Efficiency. Hence, current work highlights the use of a linear amine 4A–2E and TPC crosslinker to fabricate a dense polyamide membrane and the application of ML algorithms to desalination data makes it possible to predict the membrane performance.

Fabrication of highly efficient nanofiltration membranes decorated with praseodymium based triamino-functionalized MCM-41 for desalination and micropollutants removal

The nanofiltration membranes with a stable decoration of inorganic fillers such as zeolites are desperately required for enhancing the desalination performance of the membranes and hence three nanofiltration membranes were fabricated by decorating the membranes with praseodymium-based triamino-functionalized MCM-41 (Pr-(NH)2NH2-MCM-41). The membranes were applied for the removal of emerging pharmaceutically active micropollutants from water. The Pr-(NH)2NH2-MCM-41 was synthesized by using an in-situ approach where praseodymium oxide was chemically decorated in the framework of MCM-41 followed by simultaneous amine functionalization using N1-(3-Trimethoxysilylpropyl)diethylenetriamine (TMSPTA). A thorough characterization of the synthesized Pr-(NH)2NH2-MCM-41 was carried out by using HR-TEM, SEM, WCA, XRD, FTIR, BET, elemental and mapping analysis. Three different concentrations of synthesized Pr-(NH)2NH2-MCM-41 were decorated in the membrane active layer through interfacial polymerization in the presence of an aqueous tetra-amine solution and using terephthaloyl chloride as an organic crosslinker. Subsequently, the fabricated membranes were used for desalinating saline feed containing divalent (CaCl2, MgCl2, Na2SO4, MgSO4) and monovalent (NaCl) ions. The rejection of salts by PA/0.05-Pr-MCM@PSU/PET membrane was found to be the highest among all the fabricated membranes which were found to be 98 %, 96 %, 95 %, 87 %, and 82 % for CaCl2, MgCl2, MgSO4, Na2SO4 and NaCl, respectively. The permeate flux was found to be dependent on the applied feed pressure which was found to be 56 L m-2 h-1 (LMH) at 25 bar for PA/0.050-Pr-MCM@PSU/PET membrane. The rejection performance of the membranes was also evaluated by using different well-known pharmaceuticals (Caffeine, Sulfamethoxazole, Amitriptyline, and Loperamide) as micropollutants in the feed. All the pharmaceutical drugs were found to be highly rejected > 96 % by PA/0.5-Pr-MCM-41@PSU/PET membrane followed by PA/0.025-Pr-MCM-41@PSU/PET membrane. Therefore, the current approach of synthesizing functionalized zeolites is quite effective and efficient for the stable decoration of inorganic fillers in the membrane active layer and should be extended to other zeolites such as zeolites with antimicrobial potential.

A cellulose-based membrane with temperature regulation and water transportation for thermal management applications

Thermal management materials are widely employed in the construction and textile industries due to their non-energy input and the ability to precisely adjust the temperature. However, the application of thermal management technique toward sustainable agriculture is still challenging due to the complex environment. Herein, a coupled insulation system with highly asymmetric thermal conductivity and unidirectional water penetration is developed by using the integration of thermal management and water diodes technologies. The hierarchical membrane shows asymmetric thermal conductivity of carbonized cellulose layer (CCL, 0.64 W m−1 K−1) and Al2O3/cellulose layer (ACL, 0.16 W m−1 K−1), and good moisture permeability owing to the anisotropic wettability of the material and hierarchical structure design. Thermal management performance revealed that compared with PET and cellulose membrane, the membrane temperature increased by 4.1 °C and 1.3 °C, respectively, resulting in a decrease in greenhouse heat dissipation. Besides, benefitting from the efficient photothermal conversion performance of carbonized cellulose, the outside can rapidly warm up to 42 °C under 120 W/m2 sun radiation, providing a suitable growth temperature for crops. Meanwhile, unidirectional water penetration achieved in the 60 s not only enables the membrane to maintain long-term and effective insulation, but also ensures the demand of crops for water during drought conditions. Furthermore, the anti-flaming property broadens the range of applications, reducing damage in an emergency such as a fire. The demonstrated membrane can potentially replace the commercial plastic-based greenhouse materials, and the gradient and bilayer design open a new avenue for sustainable thermal management application.

Breathable Films with Self-Cleaning and Antibacterial Surfaces Based on TiO2-Functionalized PET Membranes.

A promising approach that uses the sol-gel method to manufacture new breathable active films with self-cleaning and antibacterial surfaces is based on the PET membranes obtained via ion track technology with a pore density of 10-7 cm-2 and a pore diameter of about 500 ± 15 nm, coated with a layer of TiO2 anatase, with a thickness of up to 80 nm. The formation of the photocatalytically active TiO2 anatase phase was confirmed using Raman analysis. Coating the PET membrane with a layer of TiO2 increased the hydrophobicity of the system (CA increased from 64.2 to 92.4, and the antibacterial activity was evaluated using Escherichia coli and Staphylococcus aureus bacteria with the logarithmic reduction factors of 3.34 and 4.24, respectively).

Scalable Nanotrap Matrix Enhanced Electroporation for Intracellular Recording of Action Potential.

Electrophysiological recording, as a long-sought objective, plays a crucial role in fundamental biomedical research and practical clinical applications. The challenge in developing electrophysiological detection platforms is to combine simplicity, stability, and sensitivity in the same device. In this study, we develop a nanotrapped microelectrode based on a porous PET membrane, which is compatible with large-scale microtechnologies. The nanotraps can promote the protrusion of the local cell membrane in the hollow center and offer a unique nanoedge structure for tight sealing and effective electroporation. We demonstrate that scalable nanotraps can enhance cell-electrode coupling and perform high-quality intracellular recording. Further, the nanoedge-enhanced electroporation and minimally invasive nanotrapped recordings afford much longer intracellular access of over 100 min and permit consecutive electroporation events in a short period of time. This study suggests that the geometry-regulating strategy of the cell-electrode nanointerface could significantly improve the intracellular recording performance of a nanopatterned electrode.

Waste PET derived Janus fibrous membrane for efficient oil/water emulsions separation

Effective treatment of diversified and complicated oily wastewater is of great significance but remains challenging, Janus membrane with asymmetric wettabilities is an urgent need in the field of ideal oil-water separation. Herein, this work presents a facile and versatile method to fabricate polydopamine/polyethylene terephthalate/polyvinylidene fluoride (PDA/PET/PVDF) Janus membrane via sequential electrospinning technique and surface chemical modification. Specifically, the PDA/PET side of the resultant Janus membrane possesses superhydrophilic/underwater superoleophobic properties and the PVDF side of Janus membrane exhibited hydrophobic/superoleophilic surface. It is indicated that the resulting asymmetric wettability of Janus membrane is controlled only by reversal, and the membrane can work as water/oil-removing material for on-demand emulsion separation. In addition, the as-obtained Janus membrane preserved asymmetric wettability for highly efficient separation of various oil-in-water emulsions (separation efficiency of 99.7 % and separation flux of 1,770 L·m-2·h-1) and water-in-oil emulsions (separation efficiency of 99.5 % and separation flux of 19,200 L·m-2·h-1bar-1). Furthermore, the Janus PET membrane also showed excellent mechanical property and good antifouling activity against contaminants due to the hierarchical porous structure. The waste-derived PET Janus fibrous membranes with mild fabrication processes show prominent separation efficiency, excellent mechanical property and good antifouling activity, which is of great importance for providing a flexible strategy to fabricate Janus membranes by using waste plastic as raw materials, as well as demonstrating a solution for multifunctional oil/water separation and purification.

8. Controlling the rate of presentation of BMP-2 from a highly structured composite for interbody fusion

<h3>BACKGROUND CONTEXT</h3> Clinical outcomes for patients with intervertebral disc injury or disease could be enhanced by a new generation of regenerative matrices that create tissue environments to control angiogenesis, chondrogenesis and bone formation. Regenerative matrices are a new class of controlled release biomaterials that use surface chemistry, materials architecture, and drug delivery kinetics to create optimised conditions for cell interactions that result in high quality tissue formation. A novel biodegradable polymer matrix that releases bone morphogenetic protein 2 (BMP-2) over a period of one month with a low Cmax and sustained presentation of active protein is investigated in this study. <h3>PURPOSE</h3> BMP-2 release kinetics and protein activity from a new regenerative matrix was quantified to develop an implant with 1-month release of the drug within a macroporous matrix. A rabbit posterolateral (PLF) vertebral fusion model was performed to assess bone formation and fusion outcomes as a function of dose and source of BMP-2 (E coli and CHO cells). <h3>STUDY DESIGN/SETTING</h3> The study was designed to investigate the effect of various biomaterial design factors and manufacturing methods on the rate of release of BMP-2, the activity of BMP-2 and the extent of in vivo bone formation. <h3>PATIENT SAMPLE</h3> This study did not involve patients. <h3>OUTCOME MEASURES</h3> Outcome measures were the mechanical properties of the regenerative matrix, the architecture and porosity of the matrix, BMP-2 release kinetics, BMP-2 activity as a function of release time and bone formation. <h3>METHODS</h3> BMP-2 activity was tested using two in vitro cell-based assays. BMP-2 solutions and regenerative matrix extracts were tested for their ability to induce alkaline phosphatase (ALP) activity in W-20-17 stromal cells using a modified version of the ASTM standard protocol for in vitro biological activity of recombinant human BMP-2 (F2131-02). Cells were exposed to serial dilutions of BMP-2 for 24 h, assayed for ALP activity and EC50s calculated allowing the relative potency to NIBSC WHO BMP-2 standard to be calculated. BMP-2 release was assessed with an in vitro assay of ALP activity in the mouse muscle myoblast cell line C2C12. Formulations were suspended above a C2C12 monolayer in an insert with a porous (8 µm) PET membrane. Following 3-4 days of exposure, the inserts containing LDGraft were transferred to fresh cells for a further 3-4 days. Cells exposed to LDGraft in this manner were assayed for ALP activity (normalised to protein content) once the inserts had been transferred to fresh cells. Fusion rate and new bone formation were compared to INFUSE in a single-level lumbar (L4-L5) posterolateral (PLF) vertebral fusion model in the New Zealand White rabbit based on standard protocols (Boden et al, 1995, ASTM F3207). Pre-formed implants (3 cc) of INFUSE (rhBMP-2 and absorbable collagen sponge) were implanted on decorticated dorsal surfaces of the transverse processes of L4 and L5 adjacent to the laminae. Fusion was assessed by radiograph at 6 weeks and by manual palpation, radiography and microCT at 12 weeks. <h3>RESULTS</h3> BMP-2 activity was retained over one month of release with the addition of protectants in the formulation and precise control of manufacturing processes. The matrix had a porosity of >70% with a high proportion of macropores (>200 micron diameter). Low doses of E. coli-produced BMP-2 induced fusion in the PLF model. <h3>CONCLUSIONS</h3> A one-month releasing BMP-2 formulation is described. This new regenerative matrix had internal architecture designed to host angiogenesis. Manufacturing and design challenges can be overcome to retain high biologic activity throughout the release period. <h3>FDA DEVICE/DRUG STATUS</h3> BMP-2, not approved for this indication.

NH2-CuO-MCM-41 covalently cross-linked multipurpose membrane for applications in water treatment: Removal of hazardous pollutants from water, water desalination and anti-biofouling performance

The current study was planned to fabricate a new set of membranes to target multiple application areas such as desalting, removal of micropollutants and antibiofouling performance. In-situ incorporated copper oxide to MCM-41 (CuO-MCM-41) was synthesized and amine (-NH2) functionalized by reacting with N1-(3-trimethoxy silylpropyl) diethylenetriamine (NTSDETA) yielding NH2–CuO-MCM-41. Different concentrations of NH2–CuO-MCM-41 were covalently cross-linked in polyamide active layer during interfacial polymerization (IP) between N, N′-bis(3-aminopropyl)ethylenediamine and terephthaloyl chloride (TPC) on polysulfone/poly ester terephthalate (PS/PET) support. The membranes were extensively characterized by Water Contact Angle (WCA), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red (FTIR) spectroscopy, Energy Dispersive X-ray (EDX) analysis, Elemental mapping and Powder X-ray Diffraction (PXRD). From among the different versions of X-CuO-MCM-41/PA@PS/PET membranes, the 0.05%-CuO-MCM-41/PA@PS/PET membrane showed best performance in terms of rejecting a variety of salts, micropollutants and antibiofouling. The 0.05%-CuO-MCM-41/PA@PS/PET showed >98% rejection of MgCl2 and 78% rejection of caffeine with a permeate flux of 16 LMH at 25 bar. The 0.1-NH2-CuO-MCM-41inhibited S. aureus growth by 51.7%. Hence, the current strategy of membrane fabrication proved to be highly efficient for multipurpose applications in water treatment.

Design and fabrication of polyamine nanofiltration membrane by constituting multifunctional aliphatic linear amine and trifunctional cyanuric chloride for selective organic solvent nanofiltration

BackgroundThin film composite nanofiltration (TFC-NF) membranes have been developed for organic solvent nanofiltration. Most of the polyamide TFC-NF membranes are vulnerable to nucleophilic hydrolysis. MethodsA multifucntional amine was crosslinked with a trifucntional non-aqueous monomer namely cyanuric chloride (CC) on surface of self-fabricated polysulfone/polyester terephthalate (PS/PET) membarne support leading to a new polyamine active layer containing TFC-NF membrane named as PA@PS/PET. The fabricated PA@PS/PET membrane was thoroughly characterized by several characterization techniques such as ATR-FTIR, XPS, FE-SEM, Water Contact Angle (WCA), and EDX analysis. Significant FindingsPA@PS/PET TFC-NF membrane showed remakable perfomance in terms of solvent flux for all tested solvents including water, methanol, ethanol and isopropanol. The highest flux was found to be 29.58 L m−2h−1 at 8 bar for methanol. The flux of solvents was found to be inversly related to the viscosity of the solvents. The PA@PS/PET membrane showed remarkably high rejection of solute (Congo Red) reaching to a value of ∼98%. Moreover, the PA@PS/PET membrane showed permanant flux of 8.45 L m−2 h−1 at 2 bar during solute separation (CR dye rejection) tests which hinted the stability of the membrane under the applied operating conditions.

Low frequency sound absorption of adjustable membrane-type acoustic metamaterials

The membrane-type acoustic metamaterials with negative pressure cavity are designed to achieve near perfect sound absorption and sound absorption adjustment of low frequency spectrum line control. The soft membrane is replaced by PET membrane as the substrate to enhance tolerance. The membrane material has achieved strong geometric nonlinearity by the static negative pressure of the back cavity. The change in geometric stiffness caused by geometric nonlinearity is used to adjust structural sound absorption peak for low frequency spectrum line. The combined method of finite element and modal superposition is used to predict the sound absorption of membrane-type acoustic metamaterials. The experimental results agree well with the one from the analysis method. The advantages of this structure are that the location of the sound absorption peak can be adjusted. And a near perfect sound absorption can be achieved without damping adjustment. This structure has positive significance for low frequencies spectrum line noise control.

Fabrication of CuO nanoparticles immobilized nanofiltration composite membrane for dye/salt fractionation: Performance and antibiofouling

The separation of dye/salt mixtures is a challenging task in treating high salinity textile industrial wastewater. Therefore, there is a need to develop highly permeable and antibiofouling membranes for efficient disposal of textile industrial effluents. Membrane-based separation is evolving as an alternative purification technology to the conventional energy intensive separation and purification processes. In the current work, a new loose nanofiltration membrane was fabricated through two rounds of interfacial polymerization on ultrafiltration polysulfone support by constructing copper oxide (CuO) nanoparticles (NPs) containing semi-Interpenetrating Network (semi-IPN) polyamide as an active layer. The newly constructed thin film nanocomposite loose nanofiltration membrane namely CuO/PA@PS/PET was thoroughly characterized by ATR-FTIR, FESEM, AFM, Zeta-potential, Water Contact Angle (WCA), EDX, elemental mapping and XRD. FTIR and FESEM analysis of the membrane showed the contribution of hydrophilic CuO NPs in the crosslinking event of the fabrication of semi-IPN active layer. The WCA was decreased from 78° in case of PS/PET to 62° CuO/PA@PS/PET. The CuO/PA@PS/PET showed exceptional performance in terms of flux of DI water reaching to > 140 L/m2h−1 at 16 bars and > 99% rejection of Methylene Blue (MB) while allowing CaCl2, MgCl2 and NaCl to permeate through it. The incorporation of CuO NPs not only enhanced the water flux and rejection but it also developed antibiofouling features of the membrane as the CuO/PA@PS/PET showed bacteriostasis of E. coli and S. aureus upto 95.19% and 82.23%, respectively. Hence, the newly fabricated CuO/PA@PS/PET membrane can be an excellent choice for fractionating dye/salt mixtures with remarkable antibiofouling.

A 3D bio-printed spheroids based perfusion in vitro liver on chip for drug toxicity assays

Liver is the foremost organ of human being for drug metabolism, and it played a significant role in toxicity evaluation of drugs. Establishing a liver model in vitro can accelerate the process of the drug screening and new drug research and development. We provide a 3D printing based hepatic sinusoid-on-a-chip microdevice that reconstitutes organ-level liver functions to create a drug screening model of toxicity evaluation on chip. The microfluidic device, which recapitulates the hepatic sinusoid microenvironment, consists of PET polyporous membranes which mimic the perisinusoidal space, and experience fluid flow to mimic the hepatic arterial capillaries. The PET membrane was used to separate the hepatocyte and endotheliocyte. The endotheliocyte was cultured on the downside of the membrane and the hepatocyte were 3D seeded on the membrane via the 3D printer. This device was used to reproduce the in vitro liver model for drug toxicity assays. The expression of several biomarkers of liver was compared with the monoculture and 2D cultured conditions, and the results reveal that this organ-on-a-chip microdevice mimics the drug hepatoxicity that has not been possible by 2D cell-based and animal models, providing a useful platform for screening the drugs and developing an effective therapy in hepatopathy.

Design and fabrication of fouling resistant cross-linked polyamide thin film composite nanofiltration membrane consisting of an aliphatic triamine and terephthaloyl chloride for water desalting applications

Although a lot of polyamide thin film composite nanofiltration (TFC-NF) membranes have been developed but organic and biofouling are affecting the performance and lifespan of such membranes. Hence, the development of new and efficient polyamide membrane with a great potential against fouling is desperately needed. A new polyamide TFC-NF membrane was fabricated by reacting a linear aliphatic diethylene triamine (DETA) and linear cross-linker terephthaloyl chloride (TPC) through interfacial polymerization on ultrafiltration porous support. The resulting membrane namely Polyamide@PSf/PET was further treated with 15% hydrofluoric acid (HF) for 1 week. Membranes were extensively characterized by XPS, AFM, Zeta-potential, FESEM, FTIR, EDX, Elemental mapping and Contact angle. The HF treated Polyamide@PSf/PET showed superior performance in terms of pure water flux and rejection of tested salts and flux recovery. The highest observed water flux was 48 LMH at 24 bars while the rejection of MgSO4 reached to > 95%. HF treated Polyamide@PSf/PET membrane showed greater flux recovery of 86.4% compared to Polyamide@PSf/PET which showed a flux recovery of 84.5%. The HF treated membrane showed lower tendency towards biofouling. The bacteriostatic studies revealed that the HF treated Polyamide@PSf/PET membrane inhibited S. aureus growth by 70.7%.

Facile fabrication of graphitic carbon nitride nanosheets and its integrated polyamide hyper-cross-linked TFC nanofiltration membrane with intrinsic molecular porosity for salts and organic pollutant rejection from water

A new intrinsically and molecularly porous highly dense hyper-cross-linked polyamide thin film composite nanofiltration membrane was fabricated by incorporating graphitic carbon nitride (g-C3N4) nanosheets in the polyamide (PA) active layer through interfacial polymerization on the surface of ultrafiltration PSf/PET support (fabricated by phase inversion). The g-C3N4 nanosheets were fabricated through thermal pyrolysis and homogenously dispersed in an aqueous solution of a linear aliphatic tetra-amine prior to interfacial polymerization with non-aqueous solution of terephthaloyl chloride (TPC) and the fabricated membrane was named as g-C3N4/PA@PSf/PET membrane. The g-C3N4 nanosheets and g-C3N4/PA@PSf/PET membrane were thoroughly characterized by TEM, FE-SEM, FT-IR, Water contact angle (WCA), elemental mapping and EDX analysis. FE-SEM of the g-C3N4/PA@PSf/PET membrane showed uniform and equal distribution of g-C3N4 nanosheets in the polyamide active layer. In the crossflow nanofiltration performance test, the membrane showed a water flux of 55.71 L m−2h−1 and % rejection of >85% of MgSO4 while the % rejection of Eriochrome Black T reached to >99.5% leading to clean and potable water as a permeate. The % rejection of membrane followed the following trend of % rejection as MgSO4 > MgCl2 > Na2SO4 > CaCl2 > NaCl. This study shows that the incorporation of g-C3N4 nanosheets is an excellent option for enhancing the nanofiltration performance of the membranes.

An Ammonia-Induced Calcium Phosphate Nanostructure: A Potential Assay for Studying Osteoporosis and Bone Metastasis.

Osteoclastic resorption of bones plays a central role in both osteoporosis and bone metastasis. A reliable in vitro assay that simulates osteoclastic resorption in vivo would significantly speed up the process of developing effective therapeutic solutions for those diseases. Here, we reported the development of a novel and robust nanostructured calcium phosphate coating with unique functions on the track-etched porous membrane by using an ammonia-induced mineralization (AiM) technique. The calcium phosphate coating uniformly covers one side of the PET membrane, enabling testing for osteoclastic resorption. The track-etched pores in the PET membrane allow calcium phosphate mineral pins to grow inside, which, on the one hand, enhances coating integration with a membrane substrate and, on the other hand, provides diffusion channels for delivering drugs from the lower chamber of a double-chamber cell culture system. The applications of the processed calcium phosphate coating were first demonstrated as a drug screening device by using alendronate, a widely used drug for osteoporosis. It was confirmed that the delivery of alendronate significantly decreased both the number of monocyte-differentiated osteoclasts and coating resorption. To demonstrate the application in studying bone metastasis, we delivered a PC3 prostate cancer-conditioned medium and confirmed that both the differentiation of monocytes into osteoclasts and the osteoclastic resorption of the calcium phosphate coating were significantly enhanced. This novel assay thus provides a new platform for studying osteoclastic activities and assessing drug efficacy in vitro.

Evaluating determinants of receipt of molecular imaging in biochemical recurrent prostate cancer.

BackgroundMolecular imaging with novel radiotracers is changing the treatment landscape in prostate cancer (PCa). Currently, standard of care includes either conventional and molecular imaging at time of biochemical recurrence (BCR). This study evaluated the determinants of and cost associated with utilization of molecular imaging for BCR PCa.MethodsThis is a retrospective observational cohort study among men with BCR PCa from June 2018 to May 2019. Multivariate logistic regression models were employed to analyze the primary outcome: receipt of molecular imaging (e.g. Fluciclovine PET and Prostate Specific Membrane Antigen PET) as part of diagnostic work‐up for BCR PCa. Multivariate linear regression models were used to analyze the secondary outcome: overall healthcare cost within a 1‐year time frame.ResultsThe study sample included 234 patients; 79.1% White, 2.1% Black, 8.5% Asian/Pacific Islander, and 10.3% Other. The majority were 55 years or older (97.9%) and publicly insured (74.8%). Analysis indicated a one‐unit reduction in PSA is associated with 1.3 times higher likelihood of receiving molecular imaging (p < 0.01). Analysis found that privately insured patients were associated with approximately $500,000 more in hospital reimbursement (p < 0.01) as compared to the publicly insured. Additionally, a one‐unit increase in PSA is associated with $6254 increase in hospital reimbursement or an increase in total payments by 2.1% (p < 0.05).ConclusionsHigher PSA was associated with lower likelihood for molecular imaging and higher cost in a one‐year time frame. Higher cost was also associated with private insurance, but there was no clear relationship between insurance type and imaging type.

Membrane-integrated glass chip for two-directional observation of epithelial cells

The investigation of the basic properties of epithelial cells, such as the observation of the morphology and evaluation of the barrier function, is important for pharmacotherapeutic applications. These investigations are traditionally achieved by culturing epithelial cells on Transwell filters. However, the cross section of the cell layer cannot be directly observed with this method, and the permeability measurement requires many steps. Herein, we developed a glass microfluidic chip sandwiching a porous PET membrane between two glass capillaries and present a model with two advantages over conventional models: 1) direct top-view and cross-sectional observation of the cell layer and 2) facile assessment of the epithelial permeability without laborious manual sampling. We designed and fabricated a glass microfluidic chip and evaluated its characteristics. We then cultured the epithelial cells in the chip to demonstrate the observation of the cell layer in both the x–y and x–z planes under a microscope. Furthermore, we measured the permeation of the fluorescence probe through a human trophoblast cell layer cultured on the chip without manual sampling. We believe that our chip would be a powerful tool for analysis of the epithelial cells with high usability.