Characterizing Glomerular Barrier Dysfunction with Patient-Derived Serum in Glomerulus-on-a-Chip Models: Unveiling New Insights into Glomerulonephritis.

Glomerulonephritis (GN) is characterized by podocyte injury or glomerular filtration dysfunction, which results in proteinuria and eventual loss of kidney function. Progress in studying the mechanism of GN, and developing an effective therapy, has been limited by the absence of suitable in vitro models that can closely recapitulate human physiological responses. We developed a microfluidic glomerulus-on-a-chip device that can recapitulate the physiological environment to construct a functional filtration barrier, with which we investigated biological changes in podocytes and dynamic alterations in the permeability of the glomerular filtration barrier (GFB) on a chip. We also evaluated the potential of GN-mimicking devices as a model for predicting responses to human GN. Glomerular endothelial cells and podocytes successfully formed intact monolayers on opposite sides of the membrane in our chip device. Permselectivity analysis confirmed that the chip was constituted by a functional GFB that could accurately perform differential clearance of albumin and dextran. Reduction in cell viability resulting from damage was observed in all serum-induced GN models. The expression of podocyte-specific marker WT1 was also decreased. Albumin permeability was increased in most models of serum-induced IgA nephropathy (IgAN) and membranous nephropathy (MN). However, sera from patients with minimal change disease (MCD) or lupus nephritis (LN) did not induce a loss of permeability. This glomerulus-on-a-chip system may provide a platform of glomerular cell culture for in vitro GFB in formation of a functional three-dimensional glomerular structure. Establishing a disease model of GN on a chip could accelerate our understanding of pathophysiological mechanisms of glomerulopathy.

Efficacy of Mesenchymal-Stromal-Cell-Derived Extracellular Vesicles in Ameliorating Cisplatin Nephrotoxicity, as Modeled Using Three-Dimensional, Gravity-Driven, Two-Layer Tubule-on-a-Chip (3D-MOTIVE Chip).

Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) are known to have a therapeutic effect on nephrotoxicity. As animal models require significant time and resources to evaluate drug effects, there is a need for a new experimental technique that can accurately predict drug effects in humans. We evaluated the therapeutic effect of MSC-derived EVs in cisplatin nephrotoxicity using a three-dimensional, gravity-driven, two-layer tubule-on-a-chip (3D-MOTIVE chip). In the 3D-MOTIVE chip, 10 µM cisplatin decreased the number of attached cells compared to the vehicle. Conversely, annexin V and reactive oxygen species (ROS) were increased. Cell viability was increased 2.8-fold and 2.5-fold after treatment with EVs at 4 and 8 µg/mL, respectively, compared to the cisplatin-induced nephrotoxicity group. Cell attachment was increased 2.25-fold by treatment with 4 µg/mL EVs and 2.02-fold by 8 µg/mL EVs. Annexin V and ROS levels were decreased compared to those in the cisplatin-induced nephrotoxicity group. There were no significant differences in annexin V and ROS levels according to EV concentration. In sum, we created a cisplatin-induced nephrotoxicity model on a 3D-MOTIVE chip and found that MSC-derived EVs could restore cell viability. Thus, MSC-derived EVs may have the potential to ameliorate cisplatin-induced nephrotoxicity.

Circular Radio-Frequency Electrode With MEMS Temperature Sensors for Laparoscopic Renal Sympathetic Denervation.

OBJECTIVE: Laparoscopic renal denervation (LRDN) ablates sympathetic nerves on the outer wall of a renal artery to treat autonomic nervous system disorders such as hypertension and arrhythmia. Here, we developed a new circular radio frequency (RF) electrode for LRDN using micro-electro-mechanical systems (MEMS) technology. METHODS: The electrode consists of a parallel bipolar MEMS electrode, two MEMS thermocouples, and a shape-memory alloy (SMA) substrate. The electrode is automatically wrapped and unwrapped under actuation controlled by the heat generated by RF energy on the electrode-tissue interface. The electrode was designed through a computational simulation analysis, and its actuation and temperature-sensing performance were tested in laboratory experiments and a porcine animal study. RESULTS: In an in-vivo study of porcine renal arteries, the electrode could automatically wrap and unwrap around an artery during LRDN. The bipolar MEMS electrode required 13 Vrms for heat generation up to 60°C, while the two MEMS thermocouples reliably measured the temperature without noise signals (a temperature coefficient of 38.3 or 38.5 µV/°C and an accuracy of ±0.44 or ±0.49°C). As revealed in a histological analysis using hematoxylin and eosin staining and Masson's trichrome staining, the renal artery was intact after LRDN. CONCLUSION: The circular RF electrode improves the safety of LRDN by reliably measuring the electrode temperature of the electrode during RDN and enhances the effectiveness of LRDN by reducing the complicated manipulations of the surgical instrument. SIGNIFICANCE: The developed circular RF electrode will pave the way for LRDN treatment of autonomic nervous system disorders.

3D-3D topotactic transformation in aluminophosphate molecular sieves and its implication in new zeolite structure generation.

Zeolites have unique pore structures of molecular dimensions and tunable compositions, making them ideal for shape selective catalysis and separation. However, targeted synthesis of zeolites with new pore structures and compositions remains a key challenge. Here, we propose an approach based on a unique 3D-3D topotactic transformation, which takes advantage of weak bonding in zeolites. This is inspired by the structure transformation of PST-5, a new aluminophosphate molecular sieve, to PST-6 by calcination. The structure of nano-sized PST-5 crystals is determined by 3D electron diffraction. We find that the 3D-3D topotactic transformation involves two types of building units where penta- or hexa-coordinated Al is present. We apply this approach to several other zeolite systems and predict a series of new zeolite structures that would be synthetically feasible. This method provides a concept for the synthesis of targeted zeolites, especially those which may not be feasible by conventional methods.

Combined Alkali-Organoammonium Structure Direction of High-Charge-Density Heteroatom-Containing Aluminophosphate Molecular Sieves.

The charge density mismatch concept was applied to the synthesis of high-charge-density silicoaluminophosphate SAPO-69 (OFF) and SAPO-79 (ERI) and zincoaluminophosphate PST-16 (CGS), PST-17 (BPH), PST-19 (SBS), and ZnAPO-88 (MER) molecular sieves. Combined alkali-organoammonium structure direction in these systems is thus enabled. Structure direction is treated from the perspective of stabilizing an ionic framework, the relationships between reaction charge density (OH- /H3 PO4 ), alkali and organoammonium content, and ionicity of tetrahedral framework atoms in successful structure direction are presented.

Two Aluminophosphate Molecular Sieves Built from Pairs of Enantiomeric Structural Building Units.

Herein we report the synthesis and structures of two new small-pore aluminophosphate molecular sieves PST-13 and PST-14 with mutually connected 8-ring channels. The structure of PST-13, synthesized using diethylamine as an organic structure-directing agent, contains penta-coordinated framework Al atoms bridged by hydroxy groups and thus edge-sharing 3- and 5-rings. Upon calcination, PST-13 undergoes a transformation to PST-14 with loss of bridging hydroxy groups and occluded organic species. The structures of both materials consist "nonjointly" of pairs of previously undiscovered 1,5- and 1,6-open double 4-rings (d4rs) which are mirror images of each other. We also present a series of novel chemically feasible hypothetical structures built from 1-open d4r (sti) or 1,3-open d4r (nsc) units, as well as from these two enantiomeric structural building units.

Fully Copper-Exchanged High-Silica LTA Zeolites as Unrivaled Hydrothermally Stable NH3 -SCR Catalysts.

Diesel engine technology is still the most effective solution to meet tighter CO2 regulations in the mobility and transport sector. In implementation of fuel-efficient diesel engines, the poor thermal durability of lean nitrogen oxides (NOx ) aftertreatment systems remains as one major technical hurdle. Divalent copper ions when fully exchanged into high-silica LTA zeolites are demonstrated to exhibit excellent activity maintenance for NOx reduction with NH3 under vehicle simulated conditions even after hydrothermal aging at 900 °C, a critical temperature that the current commercial Cu-SSZ-13 catalyst cannot overcome owing to thermal deactivation. Detailed structural characterizations confirm the presence of Cu2+ ions only at the center of single 6-rings that act not only as a catalytically active center, but also as a dealumination suppressor. The overall results render the copper-exchanged LTA zeolite attractive as a viable substitute for Cu-SSZ-13.

Microelectrical Impedance Spectroscopy for the Differentiation between Normal and Cancerous Human Urothelial Cell Lines: Real-Time Electrical Impedance Measurement at an Optimal Frequency.

PURPOSE: To distinguish between normal (SV-HUC-1) and cancerous (TCCSUP) human urothelial cell lines using microelectrical impedance spectroscopy (µEIS). MATERIALS AND METHODS: Two types of µEIS devices were designed and used in combination to measure the impedance of SV-HUC-1 and TCCSUP cells flowing through the channels of the devices. The first device (µEIS-OF) was designed to determine the optimal frequency at which the impedance of two cell lines is most distinguishable. The µEIS-OF trapped the flowing cells and measured their impedance at a frequency ranging from 5 kHz to 1 MHz. The second device (µEIS-RT) was designed for real-time impedance measurement of the cells at the optimal frequency. The impedance was measured instantaneously as the cells passed the sensing electrodes of µEIS-RT. RESULTS: The optimal frequency, which maximized the average difference of the amplitude and phase angle between the two cell lines (p < 0.001), was determined to be 119 kHz. The real-time impedance of the cell lines was measured at 119 kHz; the two cell lines differed significantly in terms of amplitude and phase angle (p < 0.001). CONCLUSION: The µEIS-RT can discriminate SV-HUC-1 and TCCSUP cells by measuring the impedance at the optimal frequency determined by the µEIS-OF.

Targeted Synthesis of Two Super-Complex Zeolites with Embedded Isoreticular Structures.

A novel structural coding approach combining structure solution, prediction, and the targeted synthesis of new zeolites with expanding complexity and embedded isoreticular structures was recently proposed. Using this approach, the structures of two new zeolites in the RHO family, PST-20 and PST-25, were predicted and synthesized. Herein, by extending this approach, the next two higher generation members of this family, PST-26 and PST-28, have been predicted and synthesized. These two zeolites have much larger unit cell volumes (422,655 Å(3) and 614,912 Å(3), respectively) than those of the lower generations. Their crystallization was confirmed by a combination of both powder X-ray and electron diffraction techniques. Aluminate and water concentrations in the synthetic mixture were found to be the two most critical factors influencing the structural expansion of embedded isoreticular zeolites under the synthetic conditions studied herein.

Ex vivo characterization of age-associated impedance changes of single vascular endothelial cells using micro electrical impedance spectroscopy with a cell trap.

We aimed to characterize aging of single vascular endothelial cells, which are indicators of senescence, using micro electrical impedance spectroscopy (µEIS) for the first time. The proposed µEIS was equipped with two barriers under the membrane actuator near the sensing electrodes, increasing its cell-trapping capability and minimizing the interference between the target cell and subsequent cells. The cell-trapping capability in µEIS with barriers was considerably improved (90%) with a capture time of 5 s or less, compared to µEIS without barriers (30%). Cells were extracted from transgenic zebrafish to minimize an initial discrepancy originating from genetic differences. In order to estimate useful parameters, cytoplasm resistance and membrane capacitance were estimated by fitting an electrical equivalent circuit to the data of ex vivo sensor output. The estimated cytoplasm resistance and membrane capacitance in the younger vascular endothelial cells were 20.16 ± 0.79 kΩ and 17.46 ± 0.76 pF, respectively, whereas those in the older cells were 17.81 ± 0.98 kΩ and 20.08 ± 1.38 pF, respectively. Discrimination of each group with different aging showed statistical significance in terms of cytoplasm resistance (p < 0.001) and membrane capacitance (p < 0.001). Considering both of the sensor and cellular level, the optimal frequency was determined as 1 MHz at which the electrical impedance of each group was clearly discriminated (p < 0.001).

Evaluation of a Polymeric Flap Valve-Attached Ureteral Stent for Preventing Vesicoureteral Reflux in Elevated Intravesical Pressure Conditions: A Pilot Study Using a Porcine Model.

OBJECTIVE: To evaluate the effectiveness of a polymeric flap valve-attached ureteral stent for preventing vesicoureteral reflux (VUR) in an animal model. MATERIALS AND METHODS: One female Yorkshire pig was included in this study. A flap valve-attached and a conventional stent was inserted in the right and left ureters, respectively. The bladder was filled with contrast medium until the intravesical pressure reached 20 cm H2O. Subsequently, simulated voiding cystourethrography (VCUG) was performed 50 times by manually compressing the suprapubic area until the intravesical pressure reached 50 cm H2O. Intravenous pyelography (IVP) was performed thereafter to evaluate the urinary drainage. In addition, an in vitro durability test of the function of the flap valve was conducted under continuous hydrostatic pressure for 24 h. RESULTS: The volume of contrast medium needed to achieve an intravesical pressure of 20 cm H2O was 1740 mL. In the repeated simulated VCUG for the right ureter, VUR grades of 0 and I were recorded in 82.0 (n = 41) and 18.0% (n = 9) tests, respectively, whereas for the left ureter, grades of I, II, and III were recorded in 14.0 (n = 7), 82.0 (n = 41), and 4.0% (n = 2), respectively. Thus, a significantly lower VUR grade was recorded for the right ureter than for the left ureter (p < 0.001). In the bilateral VUR condition, the pressure for VUR occurrence was significantly greater in the right ureter than in the left ureter (p = 0.007). No urinary obstruction was caused by the flap valve-attached ureteral stent according to the IVP findings. The in vitro durability test demonstrated slightly enhanced antireflux function and slightly decreased intraluminal drainage at 12 h, and these findings sustained thereafter. CONCLUSION: A flap valve-attached ureteral stent effectively prevented VUR under conditions of elevated intravesical pressure without urinary obstruction.

Anti-Reflux Ureteral Stent with Polymeric Flap Valve Using Three-Dimensional Printing: An In Vitro Study.

PURPOSE: This article aims to describe the design of an anti-reflux ureteral stent with a polymeric flap valve and the fabrication methods using three-dimensional (3D) printing. The stent effectively prevents backward flow with a negligible reduction in forward flow. Fabrication of miniaturized valves was easy with high precision and rapid prototyping. MATERIALS AND METHODS: The proposed stent comprised a 7F Double-J (DJ) stent and a polymeric flap valve. The valve was made of Tango Plus FLX980 and was fabricated using a 3D printer. Two types of stent were prepared for in vitro tests: DJ stents with (1) an uncoated valve (UCV) stent and (2) a parylene C coated valve (PCV) stent for enhanced biocompatibility. The flow characteristics of each stent were evaluated considering flow direction, parylene coating, and stent side holes, and were compared to the intact DJ stent. RESULTS: The forward flow rate for the distal portion of the UCV and PCV stents was 9.8 mL/min and 7.8 mL/min at applied pressure of 15 cm H2O (normal anterograde pressure in patients with stents), respectively. Backward flow rate for the distal portion of the UCV and PCV stents was decreased by 28 times and 8 times at applied pressure of 50 cm H2O (maximum bladder pressure), respectively, compared with the distal portion of the intact DJ stent. Forward flow rates of whole stents were 22.2 mL/min (UCV stent) and 20.0 mL/min (PCV stent) at applied pressure of 15 cm H2O, and backward flow rates of whole UCV and PCV stents were decreased by 8.3 times and 4.0 times at applied pressure of 50 cm H2O, respectively, compared with the intact DJ stent. CONCLUSIONS: The anti-reflux ureteral stent was successfully designed and fabricated using a 3D printer. In vitro studies showed that the stent effectively prevented backward flow while minimizing reduction in forward flow.

Elastomeric angled microflaps with reversible adhesion for transfer-printing semiconductor membranes onto dry surfaces.

Recent research for unconventional types of electronics has revealed that it is necessary to transfer-print high-performance microelectronic devices onto diverse surfaces, including flexible or stretchable surfaces, to relieve mechanical constraints associated with conventional rigid electronics. Picking up and placing ultrathin microdevices without damage are critical procedures for the successful manufacture of various types of unconventional electronics. This paper introduces elastomeric angled microflaps that have reversible adhesion; i.e., they generate higher adhesion for picking up and low adhesion for printing because of their structural shapes and viscoelastic material properties. The microstructured stamp, fabricated in relatively simple ways, enables simultaneous transfer-printing of multiple silicon membranes that have irregular shapes in sizes ranging from micrometer to millimeter scales. Mechanical characterizations by experiment reveal optimal parameters for picking up and placing ultrathin membranes on a programmable custom-built microstage. Further refinement of the structures and materials should be useful for many applications requiring the microassembly of multiple semiconductor membranes in diverse shapes and sizes on dry surfaces without the aid of liquid adhesives.

An aluminophosphate molecular sieve with 36 crystallographically distinct tetrahedral sites.

The structure of the new medium-pore aluminophosphate molecular sieve PST-6 is determined by the combined use of rotation electron diffraction tomography, synchrotron X-ray powder diffraction, and computer modeling. PST-6 was prepared by calcination of another new aluminophosphate material with an unknown structure synthesized using diethylamine as a structure-directing agent, which is thought to contain bridging hydroxy groups. PST-6 has 36 crystallographically distinct tetrahedral sites in the asymmetric unit and is thus crystallographically the most complex zeolitic structure ever solved.

Anisotropic adhesion of micropillars with spatula pads.

Natural gecko adhesive structures consisting of angled setae, branched into thin spatulas, have remarkable properties including easily attachable and releasable anisotropic adhesion. The geometrically asymmetric structures lead to anisotropic adhesive properties. Inspired by the gecko, we fabricated an array of micropillars with asymmetric spatula pads from elastomeric materials. This paper describes the anisotropic properties of the micropillars with spatula pads as established by experimental measurements and observation together with finite element analysis. The results indicate that the structural difference of the spatula pad at one edge of the micropillar provides the anisotropic adhesive properties.