scholarly journals Fabrication of a Robust In2O3 Nanolines FET Device as a Biosensor Platform

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 642
Author(s):  
Zetao Zhu ◽  
Takao Yasui ◽  
Quanli Liu ◽  
Kazuki Nagashima ◽  
Tsunaki Takahashi ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Physiological Solution ◽  
Semiconductor Materials ◽  
Surface Immobilization ◽  
Electrical Stability ◽  
Physiological Conditions ◽  
Debye Shielding ◽  
Conductive Channel ◽  
Phosphate Buffered Saline

Field-effect transistors (FETs) are attractive biosensor platforms for rapid and accurate detection of various analytes through surface immobilization of specific bio-receptors. Since it is difficult to maintain the electrical stability of semiconductors of sensing channel under physiological conditions for long periods, passivation by a stable metal oxide dielectric layer, such as Al2O3 or HfO2, is currently used as a common method to prevent damage. However, protecting the sensing channel by passivation has the disadvantage that the distance between the target and the conductive channel increases, and the sensing signal will be degraded by Debye shielding. Even though many efforts use semiconductor materials directly as channels for biosensors, the electrical stability of semiconductors in the physiological environments has rarely been studied. In this work, an In2O3 nanolines FET device with high robustness in artificial physiological solution of phosphate buffered saline (PBS) was fabricated and used as a platform for biosensors without employing passivation on the sensing channel. The FET device demonstrated reproducibility with an average threshold voltage (VTH) of 5.235 V and a standard deviation (SD) of 0.382 V. We tested the robustness of the In2O3 nanolines FET device in PBS solution and found that the device had a long-term electrical stability in PBS with more than 9 days’ exposure. Finally, we demonstrated its applicability as a biosensor platform by testing the biosensing performance towards miR-21 targets after immobilizing the phosphonic acid terminated DNA probes. Since the surface immobilization of multiple bioreceptors is feasible, we demonstrate that the robust In2O3 FET device can be an excellent biosensor platform for biosensors.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

Long-term electrical stability of next generation LV Trench IGBT at Hitachi ABB Power Grids

2021 ◽  
pp. 114300
Author(s):  
Nick Schneider ◽  
Elizabeth Buitrago ◽  
Wolfgang Vitale ◽  
Luca De-Michielis
Keyword(s):  
Power Grids ◽  
Next Generation ◽  
Electrical Stability

scholarly journals Material Characterization of PCL:PLLA Electrospun Fibers Following Six Months Degradation In Vitro

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 700 ◽  
Author(s):  
Alyah H. Shamsah ◽  
Sarah H. Cartmell ◽  
Stephen M. Richardson ◽  
Lucy A. Bosworth
Keyword(s):  
Tissue Regeneration ◽  
Annulus Fibrosus ◽  
Hydrolytic Degradation ◽  
Electrospun Nanofibers ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Fiber Morphology ◽  
Phosphate Buffered Saline

The annulus fibrosus—one of the two tissues comprising the intervertebral disc—is susceptible to injury and disease, leading to chronic pain and rupture. A synthetic, biodegradable material could provide a suitable scaffold that alleviates this pain and supports repair through tissue regeneration. The transfer of properties, particularly biomechanical, from scaffold to new tissue is essential and should occur at the same rate to prevent graft failure post-implantation. This study outlines the effect of hydrolytic degradation on the material properties of a novel blend of polycaprolactone and poly(lactic acid) electrospun nanofibers (50:50) over a six-month period following storage in phosphate buffered saline solution at 37 °C. As expected, the molecular weight distribution for this blend decreased over the 180-day period. This was in line with significant changes to fiber morphology, which appeared swollen and merged following observation using Scanning Electron Microscopy. Similarly, hydrolysis resulted in considerable remodeling of the scaffolds’ polymer chains as demonstrated by sharp increases in percentage crystallinity and tensile properties becoming stiffer, stronger and more brittle over time. These mechanical data remained within the range reported for human annulus fibrosus tissue and their long-term efficacy further supports this novel blend as a potential scaffold to support tissue regeneration.

scholarly journals Neuro-Transistor Based on UV-Treated Charge Trapping in MoTe2 for Artificial Synaptic Features

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2326
Author(s):  
Shania Rehman ◽  
Muhammad Farooq Khan ◽  
Mehr Khalid Rahmani ◽  
Honggyun Kim ◽  
Harshada Patil ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Charge Trapping ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Long Term Memory ◽  
Ambient Conditions ◽  
Time Constants ◽  
Brain Functions ◽  
Gate Pulse

The diversity of brain functions depend on the release of neurotransmitters in chemical synapses. The back gated three terminal field effect transistors (FETs) are auspicious candidates for the emulation of biological functions to recognize the proficient neuromorphic computing systems. In order to encourage the hysteresis loops, we treated the bottom side of MoTe2 flake with deep ultraviolet light in ambient conditions. Here, we modulate the short-term and long-term memory effects due to the trapping and de-trapping of electron events in few layers of a MoTe2 transistor. However, MoTe2 FETs are investigated to reveal the time constants of electron trapping/de-trapping while applying the gate-voltage pulses. Our devices exploit the hysteresis effect in the transfer curves of MoTe2 FETs to explore the excitatory/inhibitory post-synaptic currents (EPSC/IPSC), long-term potentiation (LTP), long-term depression (LTD), spike timing/amplitude-dependent plasticity (STDP/SADP), and paired pulse facilitation (PPF). Further, the time constants for potentiation and depression is found to be 0.6 and 0.9 s, respectively which seems plausible for biological synapses. In addition, the change of synaptic weight in MoTe2 conductance is found to be 41% at negative gate pulse and 38% for positive gate pulse, respectively. Our findings can provide an essential role in the advancement of smart neuromorphic electronics.

scholarly journals Fretting fatigue crack initiation and propagation in Ti6Al4V sheets under tribocorrosive conditions of artificial seawater and physiological solutions

2020 ◽  
Vol 234 (12) ◽  
pp. 1526-1534 ◽  
Author(s):  
Zeeshan Anjum ◽  
Masood Shah ◽  
Hassan Elahi ◽  
Mushtaq Khan ◽  
Mohammad Mujahid ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Testing Machine ◽  
Fatigue Crack Initiation ◽  
Physiological Solution ◽  
Fretting Corrosion ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Dry Conditions ◽  
Phosphate Buffered Saline

The interaction of mechanical components experiencing relative movements and cyclic loads in a corrosive environment is known as fretting corrosion or tribocorrosion. In the current work, the mechanism of crack initiation and propagation in dovetail slots of Ti6Al4V samples (in contact with carbide rods) under fretting corrosion conditions was investigated. A newly developed test rig installed on a universal testing machine was used to conduct tests at 20 Hz frequency under 5 and 7.5 kN fretting loads. Tests were conducted at room temperature in 3.5% NaCl and phosphate-buffered saline solutions. Crack propagation in all samples was examined by a metallurgical microscope, and the detailed analysis of fractured samples was carried out by a scanning electron microscope. In comparison to dry conditions, early crack initiation and faster crack propagation were observed in salt and physiological solution environments. Colored spots and large amounts of chlorine, sodium, and oxygen were found around cracks, and plastically deformed regions in the 3.5% NaCl environment provided the evidence of a corrosive attack. Large amounts of oxygen, phosphorous, chlorine, potassium, and sodium were detected in the phosphate-buffered saline environment.

scholarly journals Cancer Nano-Immunotherapy from the Injection to the Target: The Role of Protein Corona

2020 ◽  
Vol 21 (2) ◽  
pp. 519
Author(s):  
Idoia Mikelez-Alonso ◽  
Antonio Aires ◽  
Aitziber L. Cortajarena
Keyword(s):  
Protein Corona ◽  
Biological Properties ◽  
Immune Reactivity ◽  
Target Tissue ◽  
Physiological Conditions ◽  
Different Types ◽  
Cancer Remission ◽  
New Strategies

Immunotherapy has become a promising cancer therapy, improving the prognosis of patients with many different types of cancer and offering the possibility for long-term cancer remission. Nevertheless, some patients do not respond to these treatments and immunotherapy has shown some limitations, such as immune system resistance or limited bioavailability of the drug. Therefore, new strategies that include the use of nanoparticles (NPs) are emerging to enhance the efficacy of immunotherapies. NPs present very different pharmacokinetic and pharmacodynamic properties compared with free drugs and enable the use of lower doses of immune-stimulating molecules, minimizing their side effects. However, NPs face issues concerning stability in physiological conditions, protein corona (PC) formation, and accumulation in the target tissue. PC formation changes the physicochemical and biological properties of the NPs and in consequence their therapeutic effect. This review summarizes the recent advances in the study of the effects of PC formation in NP-based immunotherapy. PC formation has complex effects on immunotherapy since it can diminish (“immune blinding”) or enhance the immune response in an uncontrolled manner (“immune reactivity”). Here, future perspectives of the field including the latest advances towards the use of personalized protein corona in cancer immunotherapy are also discussed.

Genome flux in tomato cell clones cultured in vitro in different physiological equilibria. II. A RAPD analysis of variability

Genome ◽  
1996 ◽  
Vol 39 (5) ◽  
pp. 846-853 ◽  
Author(s):  
Patrizia Bogani ◽  
Alessandra Simoni ◽  
Pietro Lio' ◽  
Angela Scialpi ◽  
Marcello Buiatti
Keyword(s):  
Rapd Analysis ◽  
Cell Populations ◽  
Physiological Conditions ◽  
Active Defense ◽  
Cell Clones ◽  
Pattern Correlation ◽  
Key Words Tomato ◽  
High Competence

An analysis of the effect of changing physiological conditions on genome evolution in tomato cell populations has been carried out on long-term in vitro cultured clones grown on different auxin–cytokinin equilibria or selected for low–high competence for active defense against Fusarium oxysporum f.sp. lycopersici. RAPD analysis, confirmed through pattern rehybridization, was used as a random tool to measure the genetic variability. Through the use of a modified ANOVA, variation was shown to depend on both the initial genotype and the physiological conditions. Pattern correlation analysis through a mutual information algorithm suggested the fixation of RAPD patterns specific to physiological equilibria. The results are discussed in view of the possible relevance for evolution at hierarchical levels higher than cell populations. Key words : tomato clones, somaclonal variation, RAPD, coadaptation.

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