Increased Surface Hydrophilicity Research Articles

Drop Impact on Submillimeter-Structured Surfaces with Different Wetting Behaviors.

Droplet impact behaviors are crucial in controlling infectious diseases, inkjet printing, and anti-icing applications. The wettability and microstructure of the material surface are critical factors in this regard. Compared to microstructures, submillimeter structures are more damage-resistant, thereby ensuring droplet impact behaviors' stability. Herein, submillimeter-structured PDMS surfaces with varying wetting properties were prepared to investigate droplet impact behaviors. Experimental results indicate that submillimeter-structured surfaces are more prone to droplet splashing than flat surfaces, which can be suppressed by increasing surface hydrophilicity. An increase in the submillimeter pillar height and a decrease in spacing result in an increased critical Weber number. Additionally, the capillary forces of the superhydrophilic surface lead to droplet impact, accompanied by deposition. This study supports the long-term stable use of the droplet impact effect to achieve fluid separation.

The Cell Adhesion and Proliferation Enhancement Impact of Low-Temperature Atmospheric Pressure Plasma-Polymerized Heptylamine on the Surface of Ti6Al4V Alloy.

To chemically functionalize the Ti6Al4V alloy surface, a custom-made low-temperature atmospheric pressure plasma reactor device was used to polymerize heptylamine on it. The effect of different deposition times, an important process parameter, was also investigated. For each deposition time group, the surface morphology was observed via scanning electron microscopy (SEM). The surface chemical content was analyzed via X-ray photoelectron spectroscopy, and surface hydrophilicity was measured via water contact angle. The adhesion of bone marrow stromal cells (BMSCs) on the modified Ti6Al4V alloy surfaces was also observed via SEM. A quantitative evaluation of cell proliferation was performed via the Cell Counting Kit-8 assay. The results revealed that amino groups were introduced on the Ti6Al4V alloy surface via plasma-polymerized heptylamine (PPHA). The percentages of NH2/C for various deposition times (0 s, 30 s, 45 s, 60 s, 90 s, and 120 s) were 3.39%, 5.14%, 6.71%, 6.72%, 7.31%, and 7.65%. A 30 s, 45 s, and 60 s deposition time could significantly increase surface hydrophilicity with a mean water contact angle of 62.1 ± 1.6°, 65.7 ± 1.1°, and 88.2 ± 1.4°, respectively. Meanwhile, a 60 s, 90 s, and 120 s deposition time promoted BMSCs cell adhesion and proliferation. However, this promotion effect differed non-significantly among the three groups. In conclusion, the introduction of amino groups on the Ti6Al4V alloy surface exhibited surface modification and enhancement of cell adhesion and proliferation, which was partially associated with deposition time.

Sporopollenin exine capsules with polypeptide multilayer films promoting cell adhesion

Sporopollenin exine capsules (SECs), extracted from plant pollen, are emerging as attractive and natural microcapsules for a wide range of bio-composite applications due to their abundant availability, chemical and mechanical robustness, species-specific architectural features, striking structural uniformity, and large inner cavity. However, SECs have a predominantly hydrophobic interface hindering their application in biomaterials. Thus, developing robust surface functionalization strategies to increase their hydrophilicity would open the door to interfacing microcapsules with cells. Herein, we create SECs with increased surface hydrophilicity coated by polypeptide multilayer films using layer-by-layer (LbL) self-assembly technology. Furthermore, human bone marrow-derived stem cells adhere more to these LbL-treated SECs acting as seed cells for tissue engineering. In summary, our findings demonstrate that LbL modification of SECs improves their functional properties and has broad implications across bio-composite applications.

Removal of NOMs by Carbon Nanotubes/Polysulfone Nanocomposite Hollow Fiber Membranes for the Control of Disinfection Byproducts (DBPs)

It has been well established that natural organic matters (NOMs) are precursors for the formation of disinfection by-products (DBPs) in drinking water supplies, thus the removal of NOMs is often used as an effective approach to limit DBPs production. In this study, we evaluated the application of oxidized multi-walled carbon nanotubes (OMWNTs)/polysulfone (PSU) nanocomposite hollow fiber membranes (HFM) for the removal of NOMs and its impact on the production of DBPs following water chlorination. Analysis of source water samples by fluorescence excitation/emission matrix (EEM) spectrometry indicated that the dominant dissolved organic matters were humic acid. Evaluation of the fabricated nanocomposite HFMs showed improved water fluxes (30~50%), better fouling resistance, and a comparable solute rejection rate when compared with the conventional PSU membranes. The flux increase was attributed to the increased surface hydrophilicity and porosity of the membrane after embedding the hydrophilic OMWNTs. The membrane filtration resulted in a reduction of UV254 by approximately 52%, 48%, and 38% for three water samples from Missouri River, Eagle Bluffs Conservation Area, and Columbia Water Treatment Plant, respectively. The corresponding reduction in trihalomethane formation potential (THMFP) reached 40%, 70%, and 27%, respectively. Overall, this study demonstrated that proper OMWNTs/PSU ultrafiltration membranes could remove a portion of NOMs from water at a relatively low cross-membrane pressure. It also illustrates the innovative concept that membrane design could be tailored for specific water quality conditions and regulatory requirements; in this particular case, to fabricate a membrane to reduce the THMFP to a level that meets the regulatory standards for trihalomethanes when the water was disinfected by chlorine.

Fabrication of EVOH/PANI Composite Nanofibrous Aerogels for the Removal of Dyes and Heavy Metal Ions.

Water pollution caused by the leakage and discharge of pollutants, such as dyes and heavy metal ions, can cause serious damage to the environment and human health. Therefore, it is important to design and develop adsorbent materials that are efficient and multifunctional for the removal of these pollutants. In this work, poly(vinyl alcohol-co-ethylene) (EVOH)/polyaniline (PANI) composite nanofibrous aerogels (NFAs) were fabricated via solution oxidation and blending. The aerogels were characterized by a scanning electron microscope, Fourier transform infrared spectrometry, a contact angle measuring instrument and a universal testing machine. The influences of the introduction of PANI nanorods on the structural properties of aerogels were investigated, and the adsorption performance of aerogels was also studied. The results showed that the introduction of PANI nanorods filled the fibrous network structure, reduced porosity, increased surface hydrophilicity and improved compressive strength. Furthermore, EVOH/PANI composite NFAs possess good adsorption performances for dyes and heavy metal ions: The adsorption capacities of methyl orange and chromium ions (VI) are 73.22 mg/g and 115.54 mg/g, respectively. Overall, the research suggests that EVOH/PANI NFAs have great potential as efficient and multifunctional adsorbent materials for the removal of pollutants from water.

Efficient fabrication of thermo-stable dissolving microneedle arrays for intradermal delivery of influenza whole inactivated virus vaccine.

Dissolving microneedle arrays (dMNAs) can be used to deliver vaccines via the intradermal route. Fabrication of dMNAs using centrifugation is the most common preparation method of dMNAs, but it results in a substantial loss of antigens. In order to solve the issue of antigen waste, we engineered an automatic dispensing system for dMNA preparation. Here, we report on the fabrication of influenza whole inactivated virus (WIV) vaccine-loaded dMNAs (WIV dMNAs) by using the automatic dispensing system. Prior to the dispensing process, polydimethylsiloxane (PDMS) moulds were treated with oxygen plasma to increase surface hydrophilicity. WIV dMNAs were prepared with 1% (w/v) trehalose and pullulan (50 : 50 weight ratio). During the dispensing process, reduced pressure was applied to the PDMS mould via a vacuum chamber to make microneedle cavities airless. After producing dMNAs, WIV was quantified and 1.9 μg of WIV was loaded per dMNA, of which 1.3 μg was in the microneedle tips. Compared to the centrifugation method, this automatic dispensing system resulted in a 95% reduction of antigen waste. A hemagglutination assay confirmed that WIV dMNA maintained the stability of the antigen for at least four weeks of storage, even at room temperature or at 37 °C. The WIV dMNAs displayed 100% penetration efficiency in human skin, and 83% of the microneedle volume was dissolved in the skin within 10 minutes. In a vaccination study, mice immunised with WIV dMNAs showed similar IgG levels to those that received WIV intramuscularly. In conclusion, using the automatic dispensing system for dMNA production strongly reduced antigen waste and yielded dMNAs with excellent physical, mechanical, and immunological properties.

Silver Nanoparticles Loaded on Polyethylene Terephthalate Films Grafted with Chitosan

Currently, polyethylene terephthalate (PET) is one of the most widely used polymeric materials in different sectors such as medicine, engineering, and food, among others, due to its benefits, including biocompatibility, mechanical resistance, and tolerance to chemicals and/or abrasion. However, despite all these excellent characteristics, it is not capable of preventing the proliferation of microorganisms on its surface. Therefore, providing this property to PET remains a difficult challenge. Fortunately, different strategies can be applied to remove microorganisms from the PET surface. In this work, the surface of the PET film was functionalized with amino groups and later with a dicarboxylic acid, allowing a grafting reaction with chitosan chains. Finally, the chitosan coating was loaded with silver nanoparticles with an average size of 130 ± 37 nm, presenting these materials with an average cell viability of 80%. The characterization of these new PET-based materials showed considerable changes in surface morphology as well as increased surface hydrophilicity without significantly affecting their mechanical properties. In general, the implemented method can open an alternative pathway to design new PET-based materials due to its good cell viability with possible bacteriostatic activity due to the biocidal properties of silver nanoparticles and chitosan.

Properties of Cold Sprayed Titanium and Titanium Alloy Coatings after Laser Surface Treatment.

Additive manufacturing (AM) has seen remarkable development in recent years due to relatively high efficiency of the process. Cold spraying (CS) is a particular method of AM, in which titanium and titanium alloy powders are used. CS is a very competitive technology enabling the deposition of coatings, repairing machine parts, and manufacturing new components. For specific applications, the surface of cold-sprayed materials may require further processing. This paper reports an attempt to employ laser surface treatment (LST) of cold-sprayed coatings on an aluminium alloy substrate. The influence of laser beam interaction time on the coatings' properties was analysed. The microstructure was investigated and observed employing scanning electron microscopy (SEM). To evaluate residual stress after CS and LST, the sin2ψ technique was used. Investigations were also performed on Vickers hardness, contact angle, and surface roughness. Significant changes in the surface morphology of the coatings and elevated residual stress levels dependent on the laser beam interaction time were observed. Increased Vickers hardness was recorded for titanium alloy Ti6Al4V. LST also led to increased surface hydrophilicity of the modified materials Ti and Ti6Al4V.

Development of Chitosan/Gelatin-Based Hydrogels Incorporated with Albumin Particles.

The research subject of this paper are natural polymer-based hydrogels modified with albumin particles. The proteins were obtained via the salt-induced precipitation method, and next characterized using dynamic light scattering (DLS), UV-Vis spectroscopy and FT-IR spectroscopy. The most favorable composition showing monodispersity and particles with a size lower than 40 nm was selected for modification of hydrogels. Such systems were obtained via the photopolymerization performed under the influence of UV radiation using diacrylate poly(ethylene glycol) as a crosslinking agent and 2-hydroxy-2-methylpropiophenone as a photoinitiator. Next, the hydrogels' swelling ability, mechanical properties, wettability and surface morphology were characterized. Moreover, FT-IR spectroscopy, incubation studies in simulated physiological liquids, pro-inflammatory activity analysis and MTT reduction assay with L929 murine fibroblasts were performed. The release profiles of proteins from hydrogels were also verified. Materials modified with proteins showed higher swelling ability, increased flexibility even by 50% and increased surface hydrophilicity. Hydrogels' contact angles were within the range 62-69° while the tensile strength of albumin-containing hydrogels was approx. 0.11 MPa. Furthermore, the possibility of the effective release of protein particles from hydrogels in acidic environment (approximately 70%) was determined. Incubation studies showed hydrogels' stability and lack of their degradation in tested media. The viability of fibroblasts was 89.54% for unmodified hydrogel, and approx. 92.73% for albumin-modified hydrogel, and such an increase indicated the positive impact of the albumin on murine fibroblast proliferation.

Enhancing the permeability, anti-biofouling performance and long-term stability of TFC nanofiltration membrane by imidazole-modified carboxylated graphene oxide/polyethersulfone substrate

In this study, we attempt to enhance the permeability, biofouling resistance, and long-term stability of thin-film composite (TFC) nanofiltration membrane by tailoring the substrate membrane. Firstly, an imidazole-modified carboxylated graphene oxide (Im-CGO) with improved antibacterial property was synthesized. Next, the imidazole-modified carboxylated graphene oxide/polyethersulfone (Im-CGO/PES) ultrafiltration membrane was fabricated, and the corresponding TFC nanofiltration membrane was obtained based on the Im-CGO/PES substrate by interfacial polymerization. The pore structures, surface hydrophilicity, and permeability of Im-CGO/PES substrate membrane are improved by the introduction of membrane modifier (Im-CGO). Significantly, the water permeability of Im-CGO/PES based TFC membrane is greatly enhanced. The pure water flux of NF-0.5 membrane is 69.8 L m-2 h-1 at 0.6 MPa, and which is 80.8% higher than that of NF-0 membrane. The corresponding anti-biofouling test results suggest that Im-CGO/PES based TFC membrane possesses good anti-biofouling performance owing to the great increased surface hydrophilicity and a large number of antibacterial imidazole groups in substrate membrane. Furthermore, the long-term stability of Im-CGO/PES based TFC membrane is also enhanced compared to the PES based TFC membrane, attributing to the covalent connection between polyamide layer and Im-CGO/PES substrate.

Fabrication of the polyethersulfone/functionalized mesoporous carbon nanocomposite nanofiltration membrane for dyes and heavy metal ions removal: Experimental and quantum mechanical simulation method

AbstractThe presence of industrial pollutants, especially salts, heavy metals ions, and dyes in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, a high‐performing nanofiltration (NF) membrane was prepared by blending the functionalized mesoporous carbon CMK‐5 (F‐CMK‐5) nanofiller. This membrane was synthesized by introducing the active groups of sulfonyl and amide to the surface of mesoporous carbon CMK‐5 through covalent functionalization. Characterizations were conducted to study the membranes' physical properties and separation performance in terms of antifouling properties and rejection of salts, heavy metal ions, and dyes. The interactions between the active sites of the nanocomposite membrane and the studied solutes, including dyes and heavy metal ions in aqueous solutions, were studied by the density functional based tight binding method and structural optimization was carried out. Insertion of the F‐CMK‐5 nanofiller was eventuated in a remarkable increase in surface hydrophilicity, pure water flux, and antifouling properties. For all membranes, the lowest and the highest salt rejection was obtained for NaCl and Na2SO4, respectively, exhibiting the characteristics of NF membranes. Moreover, M0.3 with 0.3 wt% nanofiller showed the highest rejection for heavy metal ions (Fe2+ = 99.9%, Zn2+ = 99.9%, Cu2+ = 99.7%, and Pb2+ = 99.2%) and dyes (RB5 = 99.21, DR16 = 98.87, and MB = 98.12%), as well as high separation performance for filtration of multipollutant solutions. The reusability and 144 h uninterrupted filtration experiments for M0.3 confirmed the stability of the membrane. The findings suggest that the PES/F‐CMK‐5 nanocomposite NF membrane is a promising candidate for water and wastewater treatment.

Antimicrobial Activity of a Titanium Dioxide Additivated Thermoset

The transmission of pathogens via surfaces poses a major health problem, particularly in hospital environments. Antimicrobial surfaces can interrupt the path of spread, while photocatalytically active titanium dioxide (TiO2) nanoparticles have emerged as an additive for creating antimicrobial materials. Irradiation of such particles with ultraviolet (UV) light leads to the formation of reactive oxygen species that can inactivate bacteria. The aim of this research was to incorporate TiO2 nanoparticles into a cellulose-reinforced melamine-formaldehyde resin (MF) to obtain a photocatalytic antimicrobial thermoset, to be used, for example, for device enclosures or tableware. To this end, composites of MF with 5, 10, 15, and 20 wt% TiO2 were produced by ultrasonication and hot pressing. The incorporation of TiO2 resulted in a small decrease in tensile strength and little to no decrease in Shore D hardness, but a statistically significant decrease in the water contact angle. After 48 h of UV irradiation, a statistically significant decrease in tensile strength for samples with 0 and 10 wt% TiO2 was measured but with no statistically significant differences in Shore D hardness, although a statistically significant increase in surface hydrophilicity was measured. Accelerated methylene blue (MB) degradation was measured during a further 2.5 h of UV irradiation and MB concentrations of 12% or less could be achieved. Samples containing 0, 10, and 20 wt% TiO2 were investigated for long-term UV stability and antimicrobial activity. Fourier-transform infrared spectroscopy revealed no changes in the chemical structure of the polymer, due to the incorporation of TiO2, but changes were detected after 500 h of irradiation, indicating material degradation. Specimens pre-irradiated with UV for 48 h showed a total reduction in Escherichia coli when exposed to UV irradiation.

Nanofiltration Membranes Modified with a Clustered Multiquaternary Ammonium-Based Ionic Liquid for Improved Magnesium/Lithium Separation.

Lithium separation is of great significance to overcome the lithium supply shortage resulting from a heightened demand in the energy sector. The low selectivity of polymer nanofiltration membranes for lithium extraction from concentrated Mg/Li mixtures caused by miniaturized pore structures and weak and unstable positive surface charges limits their practical implementation. To address the surface charge strength and stability, a novel ionic liquid monomer, N1-(6-aminohexyl)-N1,N1,N6,N6,N6-pentamethylhexane-1,6-diaminium bromide (denoted as DABIL), is first synthesized and covalently anchored on a pristine polyamide thin-film composite (TFC) membrane via a secondary amidation reaction for improved selective lithium separation from Mg/Li mixtures. DABIL modification of the polyamide network contributes to increased surface hydrophilicity, an enlarged membrane pore structure, and reinforced Donnan exclusion effects. Molecular dynamics simulation confirmed that the difference of the interaction energies between water and the multication groups dominates the surface properties. The DABIL membrane exhibits sixfold enhancement of water permeability compared to the unmodified membrane and outperforms the recently reported state-of-the-art positively charged membranes. It presents an improved Li+/Mg2+ selectivity of 26.49, suggesting the membranes' potential for lithium recovery. Moreover, the membrane shows efficient antibacterial activity for mitigating biofilm formation. We establish that functionalization of TFC membranes with ionic liquids containing multication side chains could be a promising approach to achieve improved and sustainable permselectivity for the recovery of critical metal resources.

Molecular dynamics simulation of bubble nucleation in hydrophilic nanochannels by surface heating

ABSTRACT Bubble nucleation in liquid confined in nanochannel is studied using molecular dynamics simulations and compared against nucleation in the liquid over smooth surfaces (i.e. without confinement). Nucleation in liquid argon is achieved by heating part of a platinum surface to high temperatures using a surface-to-liquid heating algorithm implemented in LAMMPS. The surface hydrophilicity of nanochannels is increased to understand its effect on nucleation behaviour. Liquid structuring is found to play a significant role in altering thermodynamic properties of density and pressure in the nanochannels, which in turn changes the enthalpy of vaporisation. Increased surface hydrophilicity in nanochannels results in the delay of bubble formation as more energy is required for nucleation. Thus, delayed bubble nucleation in hydrophilic nanochannels can dissipate higher heat fluxes and can potentially be used for the thermal management of hot spots in power electronics.

Boosting visible-light-driven water splitting over LaTaON2via Al doping

LaTaON2 is an attractive visible-light-active photocatalyst for water splitting due to its broad visible light absorption as far as 650 nm and proper band edge positions. Notwithstanding these promising properties, LaTaON2 generally exhibits poor photocatalytic activity because of its high defect concentration that severely hinders charge separation. Here, LaTaON2 has been modified by doping Al into the Ta sublattice, i.e., LaTa1−xAlxO1−yN2−y (0 ≤ x ≤ 0.20). Al doping not only inhibits the defect concentration and increases surface hydrophilicity but also maintains the desired visible light absorption of LaTaON2. These important modifications substantially ameliorate the charge separation conditions within LaTaON2 and are responsible for a much enhanced photocatalytic performance for water redox reactions under visible light illumination. Under optimal conditions, the Al-doped LaTaON2 delivers an apparent quantum efficiency of 1.17% at 420 ± 20 nm for water oxidation into O2, outperforming most LaTaON2-based photocatalysts. These findings highlight Al as a useful dopant to open up the photocatalytic potential of metal oxynitrides whose activity is often undermined by a high defect concentration.

Air plasma assisted spray coating of Pebax-1657 thin-film composite membranes for post-combustion CO2 capture

With recent focus on achieving carbon neutrality to tackle global warming, there is an increasing need for advanced carbon capture technology to reduce carbon emission to the atmosphere. Membrane separation is one of such technologies that can remove carbon dioxide (CO2) in an energy-efficient and cost-effective way. In particular, the well-studied thin-film composite (TFC) membranes based on commercial polyethylene oxide (PEO)-containing materials have demonstrated strong promise for large-scale industrial post-combustion CO2 capture. However, to realize high-performance PEO-based TFC membranes, a key challenge lies in maximizing the reduction in the thickness of the selective layer without compromising membrane integrity, which to date has achieved little progress probably due to the failure in addressing the poor selective/gutter layer interfacial compatibility issue. Here, we adopted a facile spray coating method to design a TFC membrane comprising an ultrathin Pebax-1657 selective layer, a polydimethylsiloxane (PDMS) gutter layer, and a porous polysulfone (PSF) substrate. To increase surface hydrophilicity and wettability for enhancing interfacial compatibility between the selective and gutter layers, the surface of the PDMS gutter layer was activated for a few seconds by air plasma prior to Pebax-1657 spray coating. Coupled with well-controlled spray coating manipulation, a defect-free Pebax-1657 selective layer with an ultrathin thickness as low as 30 nm could be formed. Correspondingly, the optimized TFC membrane exhibited a highest CO2 permeance at 2022 GPU with a CO2/N2 selectivity of close to 30.0, far surpassing the threshold for commercially viable post-combustion CO2 capture (CO2 permeance ≥1000 GPU and CO2/N2 selectivity ≥20). More importantly, the use of spray coating endows the TFC design with great scalability potential, rendering our membranes, which are made solely from commercially available materials, highly relevant for industrial CO2 separation.

In situ assembled zeolite imidazolate framework nanocrystals hybrid thin film nanocomposite membranes for brackish water desalination

Metal organic frameworks (MOFs) can provide additional angstrom-scale channels for unimpeded transport of water, thus various attempts are increasingly being made to effectively embed them into polyamide (PA) nanofilms. Conferring the inherent advantages of MOFs nanofillers to the thin-film nanocomposite membranes (TFN) remains challenging. Here, a novel coordination-driven in-situ self-assembly strategy is proposed for fabricating ZIF-8 nanocrystals hybrid TFN membrane with enhanced remarkably desalination performance. In this way, ZIF-8 nanocrystals are evenly in-situ grown onto the porous ultrafiltration substrate induced by poly(sodium 4-styrenesulfonate) (PSS)-metal ions complex interlayer, then are wrapped in-situ into PA active layer without agglomeration and defects via interfacial polymerization (IP) process. Benefiting from the homogeneous incorporation of ZIF-8 nanofillers, the optimal TFN-ZIF-8 membrane evinces a water flux of nearly four times that of the traditional TFC membrane, while remaining an improved NaCl rejection (∼99.03%). Moreover, the in-situ assembled ZIF-8 nanocrystals layer can tune surface morphology to evolve from typical leaf-like structures to smooth nodular features. Consequently, the significantly decreased surface roughness and increased surface hydrophilicity endow the TFN-ZIF-8 membrane with superior antifouling performance. In addition, it is universal for other MOFs nanofillers (ZIF-67 and HKUST-1) to fabricate the highly-permeable hybrid TFN membranes. Therefore, this work promotes the advancement of competent TFN membranes to overcome the current bottleneck for brackish water desalination.

Molecular basis for the performance and mechanisms of methylated decolorized bovine hemoglobin flocculants

A slaughterhouse by-product, bovine blood hemoglobin (Hb), has been reported as an adequate flocculant. However, the dark brown/red color originated from the heme prosthetic group of Hb severely limited its widespread adoption. To improve its flocculation efficiency and expand its applications, we removed the heme group by acidified acetone, carboxymethyl cellulose, and hydrogen peroxide oxidation. These heme-depleted Hbs (apo-Hbs) were further modified by methylation, yielding apo-MeHbs with considerably increased size (Rh ∼ 70–186 nm) and elevated isoelectric point (pI ∼ 10.0) compared to Hb and apo-Hbs (Rh ∼ 50–130 nm and pI ∼ 7.0). The apo-MeHbs exhibited significantly improved flocculation performance, evidenced by reduced optimal doses (∼15 mg/g kaolin) and broadened pH adaptability (pH 4.5–8.5). We demonstrated that charge neutralization was the dominating cause of their exceptional flocculation performance, and soluble aggregates contributed to bridging suspended particles. We further investigated the molecular transformations in Hb caused by these chemical modifications to understand the mechanism and establish a structural indicator for the flocculation improvement. Combined with the increased surface hydrophilicity, the decreased α-helix and simultaneously increased β-sheet and unstructured elements along with the disrupted tertiary contacts greatly facilitated the highly efficient flocculation process observed with the modified Hb.

Polydopamine-coated graphene oxide nanosheets embedded in sulfonated poly(ether sulfone) hybrid UF membranes with superior antifouling properties for water treatment

• Fouling-resistant UF membranes developed by blending PDA-coated GO with SPES. • Agglomeration of the nanofillers was avoided even at 10 wt% loading. • Hybrid membranes showed superior permeability, HA rejection and fouling resistance. • Pristine and 10 wt% PDGO loaded membranes yielded R ir of 32% and 6.9%, respectively. A novel high-performance hybrid ultrafiltration (UF) membrane was fabricated by blending polydopamine-coated graphene oxide (PDGO) nanosheets with sulfonated poly(ether sulfone) (SPES) via phase inversion method and tested for the removal of natural organic matter (humic acid; HA) from aqueous solution. The PDGO nanosheets were synthesized via self-polymerization of dopamine with GO nanosheets in alkaline tris-buffer solution at room temperature for 24 h and were fully characterized. Hybrid SPES membranes were prepared by incorporating 1–10 wt% of PDGO, which were further characterized by Raman spectroscopy, surface zeta potential, and field emission scanning electron microscopy to confirm membrane stability without any defects even by adding up to 10 wt%, of PDGO nanosheets. The membranes demonstrated a significant increase in hydrophilicity, water flux, and retention rate for HA (R HA ). For instance, water permeability with 5 wt% PDGO (M5) (680.7 L m −2 h −1 bar −1 ) was ca. 1.8-folds that of the pristine SPES membrane (380.8 L m −2 h −1 bar −1 ), while maintaining an HA rejection (R HA ) of 91.7% for a 50 ppm HA feed solution. This was accompanied by a distinct increase in surface hydrophilicity of M5, which showed a water contact angle of 27.8°, well below that of pristine SPES membrane (59.1°). The hybrid UF membranes also demonstrated a significant reduction in HA adhesion onto the membrane surface along with a superior antifouling performance for the membrane containing 10 wt% PDGO, giving irreversible fouling ratio (R ir ) of only 6.9% compared to 32.7% for the pristine membrane.

Hydrophilic implants generated using a low-cost dielectric barrier discharge plasma device at the time of placement exhibit increased osseointegration in an animal pre-clinical study: An effect that is sex-dependent

ObjectivesIncreased wettability of titanium and titanium alloy surfaces due to processing and storage methods increases osteoprogenitor cell differentiation and osseointegration compared to microroughness alone. Implants that are exposed to air have a hydrophobic surface due to adsorption of atmospheric hydrocarbons, which can limit overall implant success. Dielectric barrier discharge plasma (DBD) is one method to increase surface hydrophilicity. Although current DBD methods yield a hydrophilic surface, adsorbed hydrocarbons rapidly restore hydrophobicity. We demonstrated that application of DBD to implants previously packaged in a vacuum, generates a hydrophilic surface that supports osteoblastic differentiation in vitro and this can be done immediately prior to use. In the present study, we tested the hypothesis that DBD treatment to alter surface wettability at the time of implant placement will improve osseointegration in vivo. Materials and methodsTwenty male and sixteen female rabbits were used in a preclinical trans-axial femur model of osseointegration. Control and DBD treatment implants were inserted randomized per hind limb in each rabbit (1 implant/hind-limb). At 6 weeks post-surgery, bone-to-implant contact, adjacent bone volume, and torque to failure were assessed by micro-CT, calcified histology, and mechanical testing. ResultsDBD plasma treatment of vacuum-sealed implants increased surface wettability and did not change surface chemistry or roughness. Peak torque and torsional energy, and bone-to-implant contact increased with DBD treatment in males. In contrast, female rabbits showed increased osseointegration equal to DBD treated male implants regardless of DBD plasma treatment. ConclusionDBD treatment is an effective method to enhance osseointegration by increasing surface wettability; however, this response is sex dependent. In healthy female patients, DBD treatment may not be necessary but in older patients or patients with compromised bone, this treatment could be an effective measure to ensure implant success.