Modification of polyvinylidene fluoride membrane by silver nanoparticles-graphene oxide hybrid nanosheet for effective membrane biofouling mitigation

In this work, we designed and fabricated a multifunctional nanocomposite system that consists of chitosan, raspberry-like silver nanoparticles, and graphene oxide. The room temperature atmospheric pressure microplasma (RT-APM) process provides a rapid, facile, and environmentally-friendly method for introducing silver nanoparticles into the composite system. Our composite can achieve a pH controlled single and/or dual drug release. Under pH 7.4 for methyl blue loaded on chitosan, the drug release profile features a burst release during the first 10 h, followed by a more stabilized release of 70–80% after 40–50 h. For fluorescein sodium loaded on graphene oxide, the drug release only reached 45% towards the end of 240 h. When the composite acted as a dual drug release system, the interaction of fluorescein sodium and methyl blue slowed down the methyl blue release rate. Under pH 4, both single and dual drug systems showed a much higher release rate. In addition, our composite system demonstrated strong antibacterial abilities against E. coli and S. aureus, as well as an excellent photothermal conversion effect under irradiation of near infrared lasers. The photothermal conversion efficiency can be controlled by the laser power. These unique functionalities of our nanocomposite point to its potential application in multiple areas, such as multimodal therapeutics in healthcare, water treatment, and anti-microbials, among others.

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Biofilm inhibition and bactericidal activity of NiTi alloy coated with graphene oxide/silver nanoparticles via electrophoretic deposition

Scientific Reports ◽

10.1038/s41598-021-92340-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sirapat Pipattanachat ◽

Jiaqian Qin ◽

Dinesh Rokaya ◽

Panida Thanyasrisung ◽

Viritpon Srimaneepong

Keyword(s):

Surface Roughness ◽

Silver Nanoparticles ◽

Graphene Oxide ◽

Electrophoretic Deposition ◽

Biofilm Formation ◽

Niti Alloy ◽

Surface Characteristics ◽

Dependent Manner ◽

Biofilm Inhibition ◽

Coating Time

AbstractBiofilm formation on medical devices can induce complications. Graphene oxide/silver nanoparticles (GO/AgNPs) coated nickel-titanium (NiTi) alloy has been successfully produced. Therefore, the aim of this study was to determine the anti-bacterial and anti-biofilm effects of a GO/AgNPs coated NiTi alloy prepared by Electrophoretic deposition (EPD). GO/AgNPs were coated on NiTi alloy using various coating times. The surface characteristics of the coated NiTi alloy substrates were investigated and its anti-biofilm and anti-bacterial effect on Streptococcus mutans biofilm were determined by measuring the biofilm mass and the number of viable cells using a crystal violet assay and colony counting assay, respectively. The results showed that although the surface roughness increased in a coating time-dependent manner, there was no positive correlation between the surface roughness and the total biofilm mass. However, increased GO/AgNPs deposition produced by the increased coating time significantly reduced the number of viable bacteria in the biofilm (p < 0.05). Therefore, the GO/AgNPs on NiTi alloy have an antibacterial effect on the S. mutans biofilm. However, the increased surface roughness does not influence total biofilm mass formation (p = 0.993). Modifying the NiTi alloy surface using GO/AgNPs can be a promising coating to reduce the consequences of biofilm formation.

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Enhanced photo-driven ion pump through silver nanoparticles decorated graphene oxide membranes

Nano Research ◽

10.1007/s12274-021-3527-4 ◽

2021 ◽

Author(s):

Yaping Feng ◽

Haoyu Dai ◽

Yi Zhang ◽

Jianjun Chen ◽

Fengxiang Chen ◽

...

Keyword(s):

Silver Nanoparticles ◽

Graphene Oxide ◽

Ion Pump ◽

Oxide Membranes ◽

Graphene Oxide Membranes

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Generating Electricity from Natural Evaporation Using PVDF Thin Films Incorporating Nanocomposite Materials

Energies ◽

10.3390/en14030585 ◽

2021 ◽

Vol 14 (3) ◽

pp. 585

Author(s):

Ariel Ma ◽

Jian Yu ◽

William Uspal

Keyword(s):

Thin Films ◽

Graphene Oxide ◽

Polyvinylidene Fluoride ◽

Capillary Flow ◽

Short Circuit ◽

Current Source ◽

Nanocomposite Materials ◽

The Other ◽

Pvdf Film ◽

Ambient Conditions

Natural evaporation has recently come under consideration as a viable source of renewable energy. Demonstrations of the validity of the concept have been reported for devices incorporating carbon-based nanocomposite materials. In this study, we investigated the possibility of using polymer thin films to generate electricity from natural evaporation. We considered a polymeric system based on polyvinylidene fluoride (PVDF). Porous PVDF films were created by incorporating a variety of nanocomposite materials into the polymer structure through a simple mixing procedure. Three nanocomposite materials were considered: carbon nanotubes, graphene oxide, and silica. The evaporation-induced electricity generation was confirmed experimentally under various ambient conditions. Among the nanocomposite materials considered, mesoporous silica (SBA-15) was found to outperform the other two materials in terms of open-circuit voltage, and graphene oxide generated the highest short-circuit current. It was found that the nanocomposite material content in the PVDF film plays an important role: on the one hand, if particles are too few in number, the number of channels will be insufficient to support a strong capillary flow; on the other hand, an excessive number of particles will suppress the flow due to excessive water absorption underneath the surface. We show that the device can be modeled as a simple circuit powered by a current source with excellent agreement between the theoretical predictions and experimental data.

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Graphene oxide-based rechargeable respiratory masks

Oxford Open Materials Science ◽

10.1093/oxfmat/itab003 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Stelbin Peter Figerez ◽

Sudeshna Patra ◽

G Rajalakshmi ◽

Tharangattu N Narayanan

Keyword(s):

Graphene Oxide ◽

Polyvinylidene Fluoride ◽

Occupational Safety ◽

Low Cost ◽

Triboelectric Nanogenerator ◽

Layer System ◽

Retention Capacity ◽

Simple Modification ◽

Nonwoven Fabrics ◽

Mask Design

Abstract Respiratory masks having similar standards of ‘N95’, defined by the US National Institute for Occupational Safety and Health, will be highly sought after, post the current COVID-19 pandemic. Here, such a low-cost (∼$1/mask) mask design having electrostatic rechargeability and filtration efficiency of >95% with a quality factor of ∼20 kPa−1 is demonstrated. This filtration efficacy is for particles of size 300 nm. The tri-layer mask, named PPDFGO tri, contains nylon, modified polypropylene (PPY), and cotton nonwoven fabrics as three layers. The melt-spun PPY, available in a conventional N95 mask, modified with graphene oxide and polyvinylidene fluoride mixture containing paste using a simple solution casting method acts as active filtration layer. The efficacy of this tri-layer system toward triboelectric rechargeability using small mechanical agitations is demonstrated here. These triboelectric nanogenerator (TENG)-assisted membranes have high electrostatic charge retention capacity (∼1 nC/cm2 after 5 days in ambient condition) and high rechargeability even in very humid conditions (>80% RH). A simple but robust permeability measurement set up is also constructed to test these TENG-based membranes, where a flow rate of 30–35 L/min is maintained during the testing. Such a simple modification to the existing mask designs enabling their rechargeability via external mechanical disturbances, with enhanced usability for single use as well as for reuse with decontantamination, will be highly beneficial in the realm of indispensable personal protective equipment.

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