Negative Surface Charge Research Articles

Rapid synthesis of Silver Nanoparticles by Rheum ribes L Fruit Peels Anticancer and Antimicrobial Effects with Biocompatible Structures

Silver nanoparticles (AgNPs) are useful substances with a wide range of uses. utilizing the extract taken from the peels of the Rheum ribes L.(Rr) fruit growing in the Erzurum region, silver nanoparticles were speedily created in this study utilizing a quick, easy, and environmentally friendly technique without harmful stages. In order to evaluate the attributes of the synthesized Rr-AgNPs, FE-SEM or TEM micrographs were utilized to characterize the morphology of the AgNPs. A UV-visible spectrophotometer was used to assess the highest absorbance bands of RR-AgNPs. These data were used to produce RR-AgNPs, which were characterized as having exclusively negative surface charges of -25 mV, a spherical shape, maximum absorbance at 428 nm wavelength, and 96 nm size distribution. The effectiveness of the produced AgNPs for usage in medical applications was assessed using the MTT technique with microdilution. Minimum Inhibition Concentrations of Rr-AgNPs on pathogen strains were found to range from 0.03-0.50 mg/L. Additionally, it was discovered that AgNPs effectively suppressed malignant cells in the investigation for the anticancer effects of AgNPs, with rates of 86.27%, 74.67%, and 73.49%. Healthy cells were not subjected to any inhibitory effects at the same concentrations that caused this result.

Woody biomass derived nano lignin-enabled membrane with high structural stability for efficient wastewater treatment

The application of renewable and functional group-enriched lignin has recently gained massive popularity in wastewater treatment applications. Herein, woody biomass-derived organosolv lignin nanoparticles (LNPs) with uniform colloidal spherical morphology and average particle size (⁓150 nm) were synthesized via a simple and facile anti-solvent nanoprecipitation technique and used for the fabrication of ultrafiltration nanocomposite membrane. Upon the addition of LNPs to polyether sulfone (PES) matrix, the LNPs-impregnated membrane exhibited a thinner surface layer that induced low resistance to water flow, high pore density (83.2 ± 0.9%) with uniformly distributed pores, wider and well-connected internal macrovoids with higher sub-layer porosity, and a higher negative surface charge (−29.8 mV). These structural features hence contributed to high stable permeation flux (92.3 L m−2 h−1) and higher removal efficiencies (> 95%) for treating cationic (methylene blue) and anionic (methylene orange) dyes over a wide range of environmentally relevant pH conditions. The electrostatic interactions between the charged membrane surface and dye species revealed the underlying mechanism for higher dye rejection through the PES-LNP membrane. Finally, the structural stability analysis confirmed the complete incorporation/immobilization of LNPs within the PES matrix, making it ready for real-world applications in wastewater treatment.

Activated Carbon-Incorporated Tragacanth Gum Hydrogel Biocomposite: A Promising Adsorbent for Crystal Violet Dye Removal from Aqueous Solutions.

Biomaterials-based adsorbents have emerged as a sustainable and promising solution for water purification, owing to their eco-friendly nature and remarkable adsorption capacities. In this study, a biocomposite hydrogel was prepared by the incorporation of activated carbon derived from pomegranate peels (PPAC) in tragacanth gum (TG). The hydrogel biocomposite (PPAC/TG) showed a porous structure, a negative surface charge at a pH of more than 4.9, and good stability in aqueous media. The adsorption properties of the PPAC/TG hydrogel biocomposite were assessed for the removal of crystal violet dye (CV) from aqueous solutions using a batch adsorption. The equilibrium adsorption data followed the Sips isotherm model, as supported by the calculated R2 (>0.99), r-χ2 (<64), and standard error values (<16). According to the Sips model, the maximum values of the adsorption capacity of PPAC/TG were 455.61, 470.86, and 477.37 mg/g at temperatures of 25, 30, and 35 °C, respectively. The adsorption kinetic of CV onto the PPAC/TG hydrogel biocomposite was well described by the pseudo-second-order model with R2 values more than 0.999 and r-χ2 values less than 12. Thermodynamic studies confirmed that the CV dye adsorption was spontaneous and endothermic. Furthermore, the prepared hydrogel exhibited excellent reusability, retaining its adsorption capacity even after being used more than five times. Overall, this study concludes that the prepared PPAC/TG exhibited a significant adsorption capacity for cationic dyes, indicating its potential as an effective and eco-friendly adsorbent for water treatment.

Boric Acid-Functionalized Carbon Dots as a High-Performance Antibacterial Agent against Escherichia coli.

Bacterial infections and antibiotic abuse are a global threat to human health. In recent years, there has been a boom in research on antimicrobial agents with low toxicity and efficient nanomaterials. Boric acid-functionalized carbon dots (B-CDs) with negative surface charge were synthesized by the hydrothermal method. Covalent bonds were formed between the boric acid groups and the cis-diol groups of the polysaccharide in the bacterial cell wall, and numerous B-CDs were trapped on the bacterial surface. In the experiments of antibacterial activity, B-CDs presented strong bactericidal activity against Escherichia coli (E. coli) with a minimum bactericidal concentration of 12.5 μg/mL. The antibacterial mechanism suggested that B-CDs entered the cell interior by diffusion and posed significant damage to the double helix structure of E. coli DNA. Furthermore, B-CDs exhibited low toxicity. The results demonstrated that the novel antimicrobial B-CDs not only fought against E. coli infection and antibiotic misuse but also provided new ideas for safe and effective antimicrobial agents of carbon nanomaterials.

Separation and recovery of Nd(III) via adsorption on Three-Dimensional Wood-Based imprinted chitosan composite membranes

Neodymium is a crucial strategic resource, which requires enhanced adsorption and recovery methods. Various researchers have utilized chitosan as an adsorbent for neodymium element adsorption. However, the low surface negative charge of the chitosan adsorbent affects its adsorption efficiency, and its inadequate mechanical properties hinder reusability. To address these issues, this study developed two composite membranes: the 3D wood imprinted carboxylated chitosan composite membrane (3DW-ICNTs/COOH/CS) and the 3D wood carboxylated chitosan composite membrane (3DW-CNTs/COOH/CS) for the separation and recovery of rare earth Nd(III). Kinetic experimental results indicate that both composite membranes reached 80% of maximum adsorption capacity within 200 min, indicating the significant negative charge on the surface of the carboxylated carbon nanotube-modified chitosan material. Even after ten adsorption and desorption cycles, imprinted composite membranes maintained a removal rate of about 80%. The utilizing delignified wood as a support material preserved the mechanical properties of the composite membrane, thereby providing a favorable condition for its industrial application.

Microalgal harvesting for biofuels – Options and associated operational costs

Microalgae are a source of a range of natural products, including biofuels, but financial and technical limitations can make large-scale production challenging to commercialize. A significant limitation is the practical and economical bulk harvesting of microalgae from the cultivation medium. Based on chemical and energy demands, common harvesting processes can have high costs due to microalgae having a similar specific gravity as their medium, negative surface charges and significant variability between strains.Determining the cost-effectiveness of harvesting methods is complicated as many publications commonly quote harvesting as costing 20–30 % of the operational cost, regardless of the method of biomass production (e.g., open ponds, bioreactors, etc.) or the harvesting method selected. This non-specific statement does not reflect that specific harvesting methods will have different operational costs. This paper aims to provide a more accurate, method-specific cost analysis of the harvesting stage operating costs to help in the economic analysis of microalgae production systems.The four primary harvesting mechanisms currently used, centrifugation, flocculation, flotation, and filtration, are assessed for their energy and chemical consumption. Centrifugation, flocculation, flotation, and filtration had an average biomass recovery of 92 %, 95 %, 92 % and 91 % and an energy requirement range of 1–8 kWh m−3, 0.1–6.7 kWh m−3, 0.015–7.6 kWh m−3 and 0.1–5.9 kWh m−3, respectively. Furthermore, the operational costs, based on energy requirements and the use of flocculants, were 0.448–1.086 USD m−3, 0.014–16.65 USD m−3, 0.08–31.3 USD m−3 and 0.013–0.791 USD m−3, respectively. Finally, the biomass production costs were calculated as ranging between 0.02–0.177 USD kg−1, 0.006–35.05 USD kg−1, 0.169–26.95 USD kg−1 and 0.02–3.00 USD kg−1 for centrifugation, flocculation, flotation, and filtration microalgae harvesting technologies, respectively.

Biochar obtained from alkaline earth metal-treated mushroom residue: Thermal behavior and methyl orange adsorption capability

To achieve the resource utilization of edible fungi residue and obtain efficient adsorbents for treating dyeing wastewater, biochars were prepared from mushroom residue (MR) with the introduction of alkaline-earth metals (AEMs) and used for methyl orange (MO) wastewater treatment. The thermal behavior of the AEM-treated MR was analyzed using thermogravimetric analysis. The physicochemical properties of the biochars obtained from AEM-treated MR (MRCs) were characterized using Fourier transform infrared spectroscopy, laser particle size analyzer, N2 adsorption/desorption, and scanning electron microscopy. The adsorption performance of MRCs on MO was also investigated. The involvement of AEMs was found to obviously move the main pyrolysis zone of MR to a low temperature region and reduce the temperature corresponding to the maximum weight loss rate and activation energy, which is highly dependent on the concentration of AEMs, the anion and cationic species of the AEMs. Moreover, the addition of AEMs resulted in a decrease in oxygen-containing functional groups (-OH, CO, or C–O), a weakening of surface negative charges, an enhancement in aromatic functional groups, and an increase in specific surface area of the MRCs. The adsorption performance of MO on MRCs was significantly improved with the introduction of AEMs as well. Among them, MR pre-treated with 5 mmol/g MgCl2 (MR-MgCl2-5) shows the lowest temperature corresponding to the maximum weight loss rate and the lowest activation energy of 278.52 °C and 4.28 kJ/mol, respectively. The biochar prepared from MR-MgCl2-5 under 400 °C (MR-MgCl2-5-400C) has the weakest surface negative charge and the highest adsorption capacity for MO. The adsorption isotherms, adsorption kinetics, and thermodynamic analysis results showed that the adsorption of MO on MR-MgCl2-5-400C was a spontaneous, chemically dominant monolayer adsorption, with a theoretical maximum adsorption capacity of 81.30 mg/g. This study suggests that AEMs treatment, especially with 5 mmol/g MgCl2, can readily transform edible fungi residue into a low-cost, high-efficient dyeing wastewater adsorbent.

Enhanced dispersing properties of kaolin due to high-strength kneading process

In this study, the influence of high-strength kneading process on the dispersibility of kaolin was investigated. Various factors including crystallinity, shape and interaction energy of kaolin particles were investigated systematically based on XRD, SEM, FTIR, Zeta potential and DLVO analyses. The results showed that the high-strength kneading treatments increased the proportion of kaolinite (001) planes, reducing the friction between kaolin particles but increasing their crystallinity. In addition, this treatment promoted the tendency of kaolin to a pseudo-hexagonal shape. DLVO analyses further showed that the electrostatic repulsion energy between kaolin particles was proportional to the kneading time due to the increased specific surface area (e.g., increased from 14.63 to 18.24 m2·g−1) and negative charge value (e.g., decreased from −15 to −32 mV) of kaolin sample. This correspondingly led to a lower viscosity of kaolin pulp with better dispersing properties, e.g., the viscosity of kaolin samples decreased by 65.41% when kneading time was extended from 0 to 6 h. This study therefore provides a new strategy to reutilize kaolin sources with low dispersing properties and crystallinity after a high-strength kneading process.

Bacteriophage Engineering for Improved Copper Ion Binding.

In this study, fd viruses are genetically modified to display seven cropped versions (H, HG, HGF, HGFA, HGFAN, HGFANV and HGFANVA) of the previously identified Cu(II) specific peptide (HGFANVA). Atomic force microscopy (AFM) imaging reveals the typical filamentous structures of recombinant phages with thicknesses of ≈2-5nm in dry state. Scanning electron microscopy (SEM) imaging shows that HGFANVA viruses form larger elongated assemblies than H viruses that are deposited with a mineral layer after Cu(II) treatment. C and N peaks are detected for virus samples through Energy dispersive X-ray spectroscopy (EDX) analyses confirming the presence of phage organic material. Cu peak is only detected for engineered viruses after Cu(II) exposure. Enzyme-linked immunosorbent assay (ELISA) analyses show the selective Cu(II) binding of engineered phages. Agarose gel electrophoresis (AGE) and zeta potential analyses reveal negative surface charges of engineered viral constructs. Positively charged Cytopore beads are coated with bacteriophages and used for Cu(II) ion sorption studies. ICP-MS analyses clearly show the improved Cu(II) binding of engineered viruses with respect to wild-type fd phages. Such bottom-up constructed, genetically engineered virus-based biomaterials may be applied in bioremediation studies targeting metal species from environmental samples.

In vitro Function Study of Different Negative Charge Pullulan Nanoparticles for Sentinel Lymph Node Angiography.

Many dyes or radioactive markers used for sentinel lymph node (SLN) have the shortcomings of false positive and radiation injury. Indocyanine green (ICG) seems to have a lower false positive rate and tissue damage, without a clear field of vision during the operation. For the shortcomings, we successfully synthesized three anionic pullulan materials, changed the degree of hydrophobic for size controlling (< 50nm) to prepare CHP nanoparticles (NPs) and changed the succinyl degree to prepare CHPC NPs with different negative surface potential. The size of those NPs were less than 50nm under (transmission electron microscope) TEM, with hydrodynamic size of 90.67 ± 2.2 nm of CHP, 105.8 ± 1.7 nm of CHPC1 and 115.9 ± 2.3 nm of CHPC2. Moreover, the Zeta potential of CHP, CHPC1 and CHPC2 were -1.9 ± 0.2 mV, -9.6 ± 0.3 mV and -19.4 ± 0.7 mV. The size of ICG-loading CHP, CHPC1 and CHPC2 NPs increased to 109.4 ± 2.7 nm, 113.8 ± 1.2 nm and 30.6 ± 3.5 nm, as the zeta potential decreased to -2.7 ± 0.4 mV, -12.5 ± 1.6 mV and -23.1 ± 1.2 mV. With the increasing degree of succinyl, the size increased and the zeta potential decreased. At the same time, the higher degree of succinyl drug-loading NPs have lower release and have increased the stability of ICG. We found that the blank-NPs had no significant toxicity to normal cells (HSF), as the ICG@CHP group had larger toxicity than the CHPCs and control. Moreover, the cellular uptake was decreased with the increased degree of succinyl. In this study, we successfully prepared CHPC2 carriers with the maximum negative surface charge, for follow-up research and providing new ideas for SLN.

Hybrid nanocarriers based on polyacrylic acid, polyvinyl pyrrolidone, and molybdenum disulfide for enhanced 5-fluorouracil delivery in lung cancer therapy

An innovative hydrogel nanocomposite, synthesized from a hybrid of PAA, PVP, and MoS2, represents a pioneering solution for pH-responsive drug delivery. This nanocomposite is specifically tailored for the controlled release of 5-Fluorouracil (5-FU), an anti-cancer agent. The infusion of MoS2 into the PAA-modified PVP hydrogel imparts a distinct feature, further enriched by the incorporation of Span 80 surfactant, culminating in the creation of stable niosomal microemulsions that enhance the retention of 5-FU. The incorporation of paraffin oil helps reduce the size of the microemulsions while maintaining their quasi-spherical shape. To characterize the microemulsions in this study, we employed FT-IR spectroscopy and X-ray diffraction (XRD) methods for our analysis. Additionally, Dynamic Light Scattering (DLS) analysis confirmed the presence of nanoparticles within the nanocarriers, with an average dimension of nearly 315 nm and a polydispersity index (PDI) of 0.27. These entities exhibit a spherical morphology, as revealed by SEM imaging. Zeta potential measurements highlight a negative surface charge of approximately –33.5 mV. Remarkably, we achieved significant drug loading and entrapment efficiencies, reaching 46 % and 87.25 %, respectively, surpassing those reported for other nanocarriers in previous studies. Cellular experiments conducted on A549 and L929 cell lines showcased the enhanced anticancer activity of 5-FU-loaded nanoparticles and assessed potential side effects.The results underscore the promising potential of the nanocarrier as a favorable strategy for delivering drugs in cancer treatment.

Graphene oxide quantum dots membrane: a hybrid filtration-advanced technology system to enhance process of wastewater reclamation

The inability of wastewater treatment plants to effectively remove emerging pollutants has necessitated the need to develop newer advanced technologies. An integrated approach of combining advanced oxidation processes (AOPs) and membrane technologies promises superior performances. In this study, graphene oxide quantum dots-based membranes (GQDs-Ms) were fabricated via the phase inversion method. The GQDs-Ms revealed high oxygen content and a negative surface charge. The incorporating graphene oxide quantum dots (GQDs) into the polymer matrix led to enhanced hydrophilicity, pore size, porosity, improved flux as well as superior inhibition of Escherichia coli cells. A multi-AOPs approach was used in this work, wherein AOPs were applied as both pre-treatment (using GQDs) and post-treatment (combining GQDs with peracetic acid) in the disinfection of wastewater. The evaluation of GQDs-Ms performance was carried out and compared with a commercial membrane (Film Tec™NF270). The obtained % removals with GQDs-Ms were 83.45%, 64.12%, 40.76% and 70.36% for turbidity, total dissolved solids, total organic carbon and electrical conductivity, respectively, which compared nearly with commercial membrane’s performance. Interestingly, the integrated hybrid system can further remove and inactivate microbes in wastewater. The developed hybrid filtration-advanced technology system can substantially improve conventional wastewater treatment plants for water reuse.

Impact of Incorporating Free Calcium and Magnesium on the Heat Stability of a Dairy- and Soy-Protein-Containing Model Emulsion.

This study investigated the impact of calcium chloride (CaCl2) and magnesium chloride (MgCl2) at varying concentrations on a model milk formulation's physical and chemical properties after thermal treatment. The model milk was subjected to two-stage homogenization and pasteurization before being supplemented with different concentrations of CaCl2 or MgCl2. The findings revealed that elevating the concentration of either calcium or magnesium resulted in the milk emulsion having a higher viscosity and median particle size following heating. CaCl2 had a slightly stronger impact than MgCl2, particularly at higher concentrations. The milk samples also exhibited a reduction in the zeta potential as the ionic strength of the salt solution increased, with the CaCl2-fortified milk displaying a slightly lower negative surface charge than the MgCl2-fortified milk at the same dose. The model milk's viscosity was evaluated after adding various salt concentrations and a temperature ramp from 20 to 80 °C. Notably, the viscosity and particle size changes demonstrated a non-linear relationship with increasing mineral levels, where a significant increase was observed at or above 5.0 mM. An emulsion stability analysis also revealed that the de-stabilization pattern of the high salt concentration sample differed significantly from its low salt concentration counterparts. These findings could serve as a basis for the future development of fortified UHT milk with nutritionally beneficial calcium and magnesium in industrial applications.

The Dlt and LiaFSR systems derepress SpeB production independently in the Δpde2 mutant of Streptococcus pyogenes.

The second messenger molecule, c-di-AMP, plays a critical role in pathogenesis and virulence in S. pyogenes. We previously reported that deleting the c-di-AMP phosphodiesterase gene pde2 severely suppresses SpeB production at the transcriptional level. We performed transposon mutagenesis to gain insight into the mechanism of how Pde2 is involved in SpeB regulation. We identified one of the genes of the dlt operon, dltX, as a suppressor of the SpeB-null phenotype of the Δpde2 mutant. The dlt operon consists of five genes, dltX, dltA, dltB, dltC, and dltD in many Gram-positive bacteria, and its function is to incorporate D-alanine into lipoteichoic acids. DltX, a small membrane protein, is a newly identified member of the operon. The in-frame deletion of dltX or insertional inactivation of dltA in the Δpde2 mutant restored SpeB production, indicating that D-alanylation is crucial for the suppressor phenotype. These mutations did not affect the growth in lab media but showed increased negative cell surface charge and enhanced sensitivity to polymyxin B. Considering that dlt mutations change cell surface charge and sensitivity to cationic antimicrobial peptides, we examined the LiaFSR system that senses and responds to cell envelope stress. The ΔliaR mutation in the Δpde2 mutant also derepressed SpeB production, like the ΔdltX mutation. LiaFSR controls speB expression by regulating the expression of the transcriptional regulator SpxA2. However, the Dlt system did not regulate spxA2 expression. The SpeB phenotype of the Δpde2ΔdltX mutant in higher salt media differed from that of the Δpde2ΔliaR mutant, suggesting a unique pathway for the Dlt system in SpeB production, possibly related to ion transport or turgor pressure regulation.

ZnO nanoparticles dispersed in nitrogen-enriched carbon matrix for the efficient adsorption and photocatalytic degradation of aqueous methylene blue molecules

In the present study, ZnO nanoparticles dispersed in graphitic carbon nitride (g-C3N4) composite is synthesized via hydrothermal route at 150 °C. The synthesized material (ZnO/g-C3N4) is further heat-treated at an optimized temperature of 500 °C in an air-rich environment and the heat-treated material is denoted as the ZnO/g-C3N4-HT. Physicochemical properties of the as-synthesized material are evaluated by various analytical and spectroscopic techniques. The obtained results confirm good dispersion of the ZnO nanoparticles on the surface of the g-C3N4. The ZnO/g-C3N4-HT is further tested for its adsorption ability and photocatalytic activity towards aqueous methylene blue (abbreviated as MB). The data show that the ZnO/g-C3N4-HT possesses remarkably high MB adsorption capacity of 251.70 mg/g at the pH value of 7. The MB adsorption capacity obtained in the present study is superior to most of the carbon-based adsorbents. The kinetic curve is found to be in good agreement with pseudo-second-order kinetic model. The remarkably high MB adsorption capacity is ascribed to the combined effects of surface area, wettability characteristic, and the negative surface charge of the material. The photocatalytic MB-degradation study over the ZnO/g-C3N4-HT yields a maximum degradation efficiency of 90% with pseudo-first-order rate constant value of 0.0113 min−1. The high MB-degradation efficiency of the material is attributed to the modified band gap and morphological properties of the material. With adequate optimization, the ZnO/g-C3N4-HT may be useful in the removal of several other recalcitrant organic pollutants from water.

Encapsulation in oleyl-modified hyaluronic acid nanogels substantially improves the clinical potential of the antimicrobial peptides SAAP-148 and Ab-Cath

Antimicrobial peptides (AMPs) are promising alternatives to antibiotics for treatment of antimicrobial resistant (AMR) bacterial infections. However, their narrow therapeutic window due to in vivo toxicity and limited stability hampers their clinical use. Here, we evaluated encapsulation of two amphiphilic AMPs, SAAP-148 and snake cathelicidin Ab-Cath, into oleyl-modified hyaluronic acid (OL-HA) nanogels to improve their selectivity index. The AMP-loaded OL-HA nanogels ranged 181–206 nm in size with a PDI of 0.2, highly negative surface charge (−47 to −48 mV) and moderate encapsulation efficiency (53–63%). The AMP-loaded OL-HA nanogels displayed similar activity in vitro as AMP solutions against AMR Staphylococcus aureus and Acinetobacter baumannii, with a dose-dependent effect over time. Importantly, the AMP-loaded OL-HA nanogels showed decreased cytotoxicity towards human erythrocytes and primary skin fibroblast, thereby improving the selectivity index of SAAP-148 and Ab-Cath by 2- and 16.8-fold, respectively. Particularly, the selectivity of Ab-Cath-loaded OL-HA nanogels has great clinical potential, with an index that reached ≥ 300 for S. aureus and ≥ 3000 for A. baumannii. These findings indicate that OL-HA nanogels are a promising drug delivery system to reduce the cytotoxicity of AMPs without substantially affecting their antimicrobial activity, thereby increasing their selectivity index and potential as therapeutics to combat AMR bacterial infections.

A mucoadhesive nanolipo gel containing Aegle marmelos gum to enhance transdermal effectiveness of linezolid for vaginal infection: In vitro evaluation, in vitro-ex vivo correlation, pharmacokinetic studies

Effective treatment of vaginal infections with conventional antibiotics often faces challenges like unavoidable dose-related side effects with increased risk of bacterial resistance. The study aims to deliver linezolid through natural gum based mucoadhesive nano lipogel to improve therapeutic effectiveness against vaginal infections. The linezolid loaded nanoliposomes (LNLs) were developed by thin film hydration method and were characterized by FTIR, DSC, XRD, FESEM, particle size analysis, zeta potential, drug loading capacity, in vitro release study etc. Selected LNLs was loaded into suitable gel formulation containing Aegle marmelos gum (as the mucoadhesive agent) and evaluated for in vitro, in vivo potentiality. FTIR/DSC test confirmed absence of any major interaction between selected drug and excipients. XRD showed amorphization of the drug encapsulated in NLs. FESEM studies showed spherical LNLs having smooth surface. LNLs had nanosize (51.03 nm), negative surface charge (-25.7 mV), satisfied drug loading capacity (11.5 ± 0.7 %) with sustained drug release. The experimental LNLs loaded lipogel showed desired physico-chemical properties viz. viscosity (37000 cps), spreadability (6.5 gm.cmsec-1), mucoadhesion (21.9 gf) and 61.04 % release of drug across rabbit vaginal mucosal membrane. The nanolipo gel exhibited improved antimicrobial activity against E. coli and C. albicans with respect to the pure linezolid. A good correlation was observed in between in vitro drug release and ex vivo permeation. Improved pharmacokinetic parameters like AUC, AUMC, MRT, Vd was observed for experimental nanolipo gel Vs. marketed formulation. The experimental nanolipo gel could be explored further for futuristic clinical application.

Uranium(VI) interactions with Pseudomonas sp. PS-0-L, V4-5-SB and T5-6-I

Pseudomonas sp. are indigenous inhabitants of ombrotrophic bogs which can survive in acidic, nutrient-poor environments with wide temperature fluctuations. Their interactions with contaminant radionuclides can influence radionuclide biogeochemistry in boreal environment. Here, uranium (U(VI)) bioassociation by Pseudomonas sp. PS-0-L, V4-5-SB and T5-6-I isolated from a boreal bog was studied by a combination of batch contact experiments, spectroscopy and microscopy. All strains removed U from the solution and the U bioassociation efficiency was affected by the nutrient source, incubation temperature, time and pH. Highest U bioassociation occurred in the strains PS-0-L (0.199 mg U/gBDW) and V4-5-SB (0.223 mg U/gBDW). Based on in-situ attenuated total reflection Fourier transformation infrared spectroscopy (ATR FT-IR) analyses, the most likely functional groups responsible for U binding were the cell surface carboxyl groups. In addition, transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM/EDX) showed dense intra-cellular round- and needle-like U accumulations in the cytoplasm and near to the inner cell membrane. The presence of U with phosphorus was indicated in elemental mapping. Modelled data showed ≡ SOOHx−1 and ≡ SOCO2Hx−1 as the dominant surface sites, contributing to the negative cell surface charge. The U removal efficiency depended on the U(VI) speciation under different pH conditions. At pH 5, the main species reacting with bacterial cell surfaces was UO22+, while at pH 9 UO2(OH)2 and UO2(OH)3- dominated the reactions. Further, U bioassociation increased with increasing aqueous U(VI) concentrations. Our data suggests U bioassociation on 1) outer cell membrane/cell wall associated carboxyl groups (e.g., proteins), and 2) intracellular phosphate groups (e.g., phospholipids).

Antioxidant properties of ferulic acid-based lipophenols in oil-in-water (O/W) emulsions

Butyl ferulate (BF) and octyl ferulate (OF) were investigated to enhance oxidative stability of 1.0% vegetable oil-in-water (O/W) emulsions at pH 3.5 and 7.0 at different concentrations (5, 10, 15, 20, and 25 mg/L of emulsion). Particle size distribution, droplet surface charge, hydroperoxides (PV), hexanal and nonanal were monitored for 14 days at 35 °C. Higher concentrations of BF and OF generated smaller particles at pH 7.0 but not at pH 3.5. Control showed the highest negative surface charge (−58.38 ± 0.31 mV, pH 7.0) compared to BF and OF (−46.71 ± 0.06 mV at levels >0.10 mg/L). Both alkyl ferulates counteracted lipid oxidation, especially at pH 3.5, where PV decreased up to 96% compared to the control and delayed hexanal and nonanal formation. A low content of lipophenols allowed to achieve a tremendous shelf-life extension, demonstrating that BF and OF could be of great interest for food application.

Functional surfaces for exosomes capturing and exosomal microRNAs analysis

Exosomes are small extracellular vesicles well-studied both as cell signaling elements and as source of highly informative biomarkers, in particular microRNAs. Standard techniques for exosome isolation are in general scarcely efficient and give low purity vesicles. New techniques combining microfluidics with suitable functionalized surfaces could overcome these disadvantages. Here, different functional surfaces aimed at exosomes capture are developed thank to the functionalization of silicon oxide substrates. Charged surfaces, both positive and negative, neutral and immunoaffinity surfaces are characterized and tested in functional assays with both exosome mimicking vesicles and exosomes purified from cell supernatants. The different surfaces showed promising properties, in particular the negatively-charged surface could capture more than 4 × 108 exosomes per square centimeter. The captured exosomes could be recovered and their biomarker cargo analyzed. Exosomal microRNAs were successfully analyzed with RT-PCR, confirming the good performances of the negatively-charged surface. The best-performing functionalization could be easily moved to microdevice surfaces for developing modular microfluidic systems for on-chip isolation of exosomes, to be integrated in simple and fast biosensors aimed at biomarker analysis both in clinical settings and in research.