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The impact of zwitterionic graphene oxide (GO-Arg) nanostructures into polyethersulfone (PES) membranes was studied, aiming to perform mixed matrix membranes (MMMs) with combined antibacterial and antifouling properties. For this purpose, 0.25, 0.50, and 1.0 wt% of GO-Arg were incorporated through the phase inversion method. The chemical composition reveals that the electrostatic interactions of PES, polyvinylpyrrolidone, and GO-Arg occur by enhancing the C--H/N-H vibrations associated with the intrinsic MMMs and their combined antibacterial and antifouling performance. Well-defined finger-like morphology was observed, performing the pore distribution and the finger-cavity inclination induced by the electrostatic charge of GO-Arg. As a result, GO-Arg MMM's hydrophobic properties decreased from 77.8[degrees] to 52.3[degrees], inducing a partially hydrophilic surface and improved water flux. The isoelectric point of nanostructured membranes slightly changes by the charge modulation produced by zwitterionic GO-Arg. The antibacterial activity against Gram (--) Escherichia coli was improved, closing the complete bacterial inhibition after 24 h. As a result, antifouling performance was improved, avoiding bacterial adhesion into the membrane surface and the possibility of promoting biofilm formation. Our results demonstrate that zwitterionic nanomaterials in MMMs perform the multifunctional capacity of materials, emerging as an effective alternative with potential application in wastewater treatment. Highlights * The incorporation of zwitterionic GO-Arg improves the mechanical properties of MMMs. * GO-Arg-enhanced well-defined porous finger-like morphology in MMMs. * GO-Arg improves the antibacterial/antifouling performance of PES-based MMMs. KEYWORDS antibacterial, antifouling, graphene oxide, nanostructured membranes, polyethersulfone membranes, zwitterionic, 1 | INTRODUCTION The constant increase in population and the exponential development of the industrial sector worldwide have severely affected the aquifers, resulting in the spread of toxic agents, pollutants, [...]

Antilipopolysaecharide factors (ALF) are antimicrobial peptides in the humoral defense mechanism in shrimps, with broad activity against bacteria, viruses, and fungi. Several ALF and their isoforms have been reported in decapod crustaceans, showing structural and functional differences. This work describes the Litopenaeus vannamei antilipopolysaecharide factor 5. initially found in a hepatopancreatic transcriptomic database. The LvALF5 gDNA sequence is 1,619 bp, with a complete mRNA sequence of 934 bp. The ORF encodes a 124 amino acids sequence, including a 26 amino acids signal peptide and 98 amino acids mature peptide, highly similar to the Litopenaeus stylirostris ALF peptide sequence (96%). This peptide shows main differences in the LPS-binding domain, having only 2 positive amino acids conserved. The evolutionary analysis shows that LvALF5 is in cluster 2, which indicates that structurally it has characteristics of the other white shrimp isoforms. LrALF5 is highly expressed in healthy shrimp hemocytes, 20-fold more than in other tissues. It is up-regulated during bacterial and viral challenges. Inhibition experiments using a recombinant LrALF5 show a more efficient antibacterial activity against Vibrio parahaemolytieus than Staphylococcus aureus bacteria strains. KEY WORDS: Litopenaeus vannamei, antimicrobial peptides, gene expression, Vibrio parahaemolvticus, WSSV, antibacterial activity, INTRODUCTION The Pacific white shrimp Litopenaeus vannamei is one of the most important cultured species in the aquaculture industry. Despite being a very profitable commercial product reaching 5.8 million tonnes [...]

Polylactide (PLA)-based biodegradable three-layer packaging film was fabricated using PLA, PLA/cinnamon oil (CEO), and PLA/graphene nanoplatelets (GNP). The central layer allows control over the release of antimicrobes, and the outer layer adds mechanical strength to the films. A comparison has been made on barrier, thermal, rheological, microstructural, and microbiological properties between single-layer and multilayer films (MLF). The water vapor and oxygen barrier properties of MLF showed little reduction compared with those of neat PLA. The tensile stress of the neat PLA increased significantly from 23.31 to 35.91 MPa for the MLF. Thermal analysis data showed improvements in the thermal stability of the MLF film, with onset and peak temperatures of 331.5 and 357.1[degrees]C, respectively. The dispersion of GNP in the PLA matrix and in MLF was assessed by XRD analysis and rheological measurement. The AFM roughness parameters Sa and Sq of those films varied widely, with the highest (13.9 and 20.9 [micro]m) and the lowest (0.08 and 0.11 [micro]m) magnitudes recorded for PLA/GNP and PLA/CEO films, respectively. Antibacterial assays of the film confirmed a strong bactericidal effect against Listeria monocytogenes and Salmonella typhimurium, maintaining this activity for 21 days. Highlights * Polylactide/cinnamon oil/ graphene nanoplatelet multilayer films were coextruded. * X-ray diffraction and rheology confirm the dispersion of graphene into PLA. * Tensile stress and thermal stability improved in the multilayer films. * AFM roughness parameters varied significantly between single- and multilayer films. * Antibacterial assays confirmed the strong bactericidal effect of films against pathogens. KEYWORDS coextrusion, complex viscosity, glass transition temperature, oxygen permeability, surface topography, thyme essential oil, 1 | INTRODUCTION Packaging is an integral part of the food industry's mission to content, protect, and provide safe food to consumers. Fossil fuel-derived plastics are traditionally used for food [...]

A new, low-cost, and direct green synthesis strategy was developed for the preparation of polymer composites composed of silver nanoparticles (AgNPs) decorated on a shape memory polymer blend using Rubus caesius L. leaves. X-ray powder diffraction, ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS) elemental composition were applied to characterize the crystal size, morphology, and elemental composition of Ag-NPs. UV-vis spectra detected the characteristic absorbance signal of AgNPs at about 430 nm, and the average crystal size of nanoparticles was calculated as about 12.60 nm. When nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy, characteristic polylactic acid, and poly ethylene glycol (PEG) signals were determined. From the thermogravimetric analysis curves, it was determined that the amount of residue of nanocomposites increased as the amount of AgNP increased. It was seen that AgNPs did not affect the [T.sub.g] temperature of the nanocomposite films, while it was also a proof that the polymer blend was immiscible. It was observed that the shape recovery properties of nanocomposite films were better with increasing AgNPs content. Finally, both green synthesized AgNPs and nanocomposites prepared with shape memory polymers showed very good antibacterial activity against Gram-positive and Gram- negative bacteria. Highlights * Green synthesis of silver nanoparticles (AgNPs) was carried out with Rubus caesius L. leaves. * The synthesized AgNPs were characterized by ultraviolet visible spectroscopy and x-ray powder diffraction. * Composite films were prepared with poly lactic acid/poly [epsilon]- caprolactone blend by solvent casting method. * The amount of residue of nanocomposites increased with increasing AgNPs percentage. * The nanocomposite film containing 10% AgNPs has good activity. KEYWORDS antibacterial, green synthesis silver nanoparticles, nanocomposite, poly [epsilon]-caprolactone, poly lactic acid, shape memory effect, 1 | INTRODUCTION Nanoscale materials ranging from 1 to 100 nm are thought to provide solutions to environmental and technological challenges in medicine and water treatment. (1,2) This increasing demand [...]

Background The increasing global concern regarding antibiotic resistance necessitates in-depth studies to comprehend the phenotypic and genotypic characteristics of resistant bacterial strains. This study aimed to investigate the prevalence, antibiotic resistance profiles, and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates in an Iranian referral pediatrics hospital. Methods: In this study, we examined CRKP isolates collected from hospitalized pediatric patients across various wards. The isolates underwent antimicrobial susceptibility testing, the polymerase chain reaction (PCR) analysis for carbapenemase genes (bla.sub.NDM, bla.sub.VIM and bla.sub.IMP), and genetic relatedness assessment using pulsed-field gel electrophoresis (PFGE). Results Among 166 K. pneumoniae isolates, 54 (32.5%) exhibited resistance to carbapenems. Notably, all these resistant isolates were resistant to imipenem, with 35 (65%) displaying resistance to both imipenem and meropenem. Of the 54 CRKP isolates, 24 (44%) were metallo-[beta]-lactamases (MBL)-producing. The prevalence of the bla.sub.NDM gene among CKCP and MBL-producing isolates was 20% (n = 11) and 44% (n = 24), respectively. The bla.sub.VIM and bla.sub.IMP genes were not detected in any of the isolates. Twenty-six CRKP isolates (48%) were recovered from ICUs. PFGE analysis of CRKP isolates revealed 20 clusters, with cluster S being the most prevalent, comprising 24% of the total (n = 13). Conclusion Our study reveals a concerning prevalence of carbapenem resistance in K. pneumoniae isolates. Specifically, the detection of the bla.sub.NDM gene in 20% of CRKP isolates, with a significant proportion (82%) observed in isolated CRKP from the ICUs and emergency departments, underscores the potential clonal expansion of these resistant strains within these critical hospital wards. Keywords: Klebsiella pneumoniae, Genotyping, Carbapenem resistance, bla.sub.NDM, Author(s): Babak Pourakbari[sup.1], Setareh Mamishi[sup.1,2], Shiva Poormohammadi[sup.1], Reihaneh Hosseinpour Sadeghi[sup.1] and Shima Mahmoudi[sup.3,4] Background Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant challenge in healthcare, presenting a substantial threat due to [...]