Biomimetic Planar Polymer Membranes Decorated with Enzymes as Functional Surfaces

Functional surfaces were generated by a combination of enzymes with polymer membranes composed of an amphiphilic, asymmetric block copolymer poly(ethyleneglycol)-block-poly(γ-methyl-ε-caprolactone)-block-poly[(2-dimethylamino)ethylmethacrylate]. First, polymer films formed at the air–water interface were transferred in different sequences onto silica solid support using the Langmuir–Blodgett technique, generating homogeneous monolayers and bilayers. A detailed characterization of these films provided insight into their properties (film thickness, wettability, topography, and roughness). On the basis of these findings, the most promising membranes were selected for enzyme attachment. Functional surfaces were then generated by the adsorption of two model enzymes that can convert phenol and its derivatives (laccase and tyrosinase), well known as high-risk pollutants of drinking and natural water. Both enzymes preserved their activity upon immobilization with respect to their substrates. Depending on the properties of the polymer films, different degrees of enzymatic activity were observed: bilayers provided the best conditions in terms of both overall stability and enzymatic activity. The interaction between amphiphilic triblock copolymer films and enzymes is exploited to engineer “active surfaces” with specific functionalities and high efficacy resulting from the intrinsic activity of the biomolecules that is preserved by an appropriate synthetic environment

Functional Surfaces: Bio-Hybrid Membranes for Biosensing

Combining natural enzymes with synthetic membranes on solid support enables creation of functional surfaces able to serve for efficient biosensing. Enzymes (laccase and tyrosinase) integrated on soft copolymer mono- and bilayer membranes preserve their activity and specifically detect the presence of phenols. The straightforward approach to create these bio-hybrid membranes allows changing the enzyme type and thus producing functional surfaces for sensitive detection of desired molecules

Comprehensive in vitro and in ovo assessment of cytotoxicity: Unraveling the impact of sodium fluoride, xylitol, and their synergistic associations in dental products

Over the past several decades, dental health products containing fluoride have been widely employed to mitigate tooth decay and promote oral hygiene. However, concerns regarding the potential toxicological repercussions of fluoride exposure have incited continuous scientific inquiry. The current study investigated the cytotoxicity of sodium fluoride (NaF) and xylitol (Xyl), both individually and in combination, utilizing human keratinocyte (HaCaT) and osteosarcoma (SAOS-2) cell lines. In HaCaT cells, NaF decreased proliferation in a concentration-dependent manner and induced apoptosis-related morphological changes at low concentrations, whereas Xyl exhibited dose-dependent cytotoxic effects. The combination of NaF and Xyl reduced cell viability, particularly at higher concentrations, accompanied by apoptosis-like morphological alterations. Sub-cytotoxic NaF concentrations (0.2%) significantly affected caspase activity and the expression of pro-apoptotic genes. Conversely, Xyl demonstrated no discernible effect on these biological parameters. In SAOS-2 cells, NaF increased proliferation at high concentrations, contrasting with Xyl's concentration-dependent cytotoxic effects. The combination of NaF and Xyl had a minimal impact on cell viability. Sub-cytotoxic NaF concentrations did not influence caspase activity or gene expression, while Xyl induced dose-dependent morphological alterations, increased caspase activity, and upregulated pro-apoptotic gene expression. In ovo experiments on the chorioallantoic membrane (CAM) revealed that only NaF induced irritant effects, suggesting potential vascular adverse outcomes. This study advocates for the combined use of NaF and Xyl, highlighting their cytotoxicity benefits in healthy cells while maintaining safety considerations for tumor cells

"Active surfaces" formed by immobilization of enzymes on solid-supported polymer membranes

In various domains ranging from catalysis to medical and environmental sciences, there is currently much focus on the design of surfaces that present active compounds at the interface with their environments. Here, we describe the design of "active surfaces" based on solid-supported monolayers of asymmetric triblock copolymers, which serve as templates for the attachment of enzymes. A group of poly(ethylene glycol)-block-poly(gamma-methyl-epsilon-caprolactone)-block-poly[(2-di methylamino) ethyl methacrylate] amphiphilic copolymers, with different hydrophilic and hydrophobic domains (PEG(45)-b-PMCLx-b-PDMAEMA(y)) was selected to generate solid-supported polymer membranes. The behavior of the copolymers in terms of their molecular arrangements at the air-water interface was established by a combination of Langmuir isotherms and Brewster angle microscopy. Uniform thin layers of copolymers were obtained by transferring films onto silica solid supports at optimal surface pressure. These solid-supported polymer membranes were characterized by assessing various properties, such as monolayer thickness, hydrophilic/hydrophobic balance, topography, and roughness. Laccase, used as an enzyme model, was successfully attached to copolymer membranes by stable interactions as followed by quartz crystal microbalance with dissipation measurements, and its activity was preserved, as indicated by activity assays. The interaction between the amphiphilic triblock copolymer films and immobilized enzymes represents a straightforward approach to engineer "active surfaces", with biomolecules playing the active role by their intrinsic bioactivity

The Impact of Antibiotic Use on Mortality in Patients Hospitalized in a COVID-19 Centre from Romania: A Retrospective Study

Background and Objectives: Considering the significant number of patients worldwide that received empirical antibiotic therapy for COVID-19 infection due to their critical condition and the lack of therapeutical guidelines, we wanted to find out the consequences of antibiotic use in our study population. Materials and Methods: We conducted a retrospective cohort study including symptomatic patients older than 18 years, hospitalized for SARS-CoV-2 between March and December 2020 in the Internal Medicine and Pneumology Departments of Colentina Clinical Hospital. The elected outcome was death, while independent variables were antibiotic therapy and literature-cited parameters associated with mortality in this disease. Results: Out of 198 included patients, 96 (48.48%) patients received antibiotic therapy during hospitalization. Female gender (OR = 2.61, p = 0.04), history of neoplasm (OR = 7.147, p = 0.01), heart failure (OR = 8.62, p = 0.002), and diabetes mellitus (OR = 3.05, p = 0.02) were significantly associated with death in multivariate analysis. Antibiotic treatment showed a higher probability of death both in bivariate (OR = 5.333, p p = 0.01). Conclusions: After adjusting for confounders, in-hospital antibiotic administration did not improve survival in COVID-19 patients

Synthesis and Anticancer Evaluation of New 1,3,4-Oxadiazole Derivatives

In order to develop novel chemotherapeutic agents with potent anticancer activities, a series of new 2,5-diaryl/heteroaryl-1,3,4-oxadiazoles were designed and synthesized. The structures of the new compounds were established using elemental analyses, IR and NMR spectral data. The compounds were evaluated for their anticancer potential on two standardized human cell lines, HT-29 (colon adenocarcinoma) and MDA-MB-231 (breast adenocarcinoma). Cytotoxicity was measured by MTS assay, while cell cycle arrest and apoptosis assays were conducted using a flow cytometer, the results showing that the cell line MDA-MB-231 is more sensitive to the compounds’ action. The results of the predictive studies using the PASS application and the structural similarity analysis indicated STAT3 and miR-21 as the most probable pharmacological targets for the new compounds. The promising effect of compound 3e, 2-[2-(phenylsulfanylmethyl)phenyl]-5-(4-pyridyl)-1,3,4-oxadiazole, especially on the MDA-MB-231 cell line motivates future studies to improve the anticancer profile and to reduce the toxicological risks. It is worth noting that 3e produced a low toxic effect in the D. magna 24 h assay and the predictive studies on rat acute toxicity suggest a low degree of toxic risks

“Active Surfaces” Formed by Immobilization of Enzymes on Solid-Supported Polymer Membranes

In various domains ranging from catalysis to medical and environmental sciences, there is currently much focus on the design of surfaces that present active compounds at the interface with their environments. Here, we describe the design of “active surfaces” based on solid-supported monolayers of asymmetric triblock copolymers, which serve as templates for the attachment of enzymes. A group of poly­(ethylene glycol)-<i>block</i>-poly­(γ-methyl-ε-caprolactone)-<i>block</i>-poly­[(2-dimethylamino) ethyl methacrylate] amphiphilic copolymers, with different hydrophilic and hydrophobic domains (PEG₄₅-<i>b</i>-PMCL_<i>x</i>-<i>b</i>-PDMAEMA_<i>y</i>) was selected to generate solid-supported polymer membranes. The behavior of the copolymers in terms of their molecular arrangements at the air–water interface was established by a combination of Langmuir isotherms and Brewster angle microscopy. Uniform thin layers of copolymers were obtained by transferring films onto silica solid supports at optimal surface pressure. These solid-supported polymer membranes were characterized by assessing various properties, such as monolayer thickness, hydrophilic/hydrophobic balance, topography, and roughness. Laccase, used as an enzyme model, was successfully attached to copolymer membranes by stable interactions as followed by quartz crystal microbalance with dissipation measurements, and its activity was preserved, as indicated by activity assays. The interaction between the amphiphilic triblock copolymer films and immobilized enzymes represents a straightforward approach to engineer “active surfaces”, with biomolecules playing the active role by their intrinsic bioactivity

The Importance of International Collaboration to Enhance Education for Environmental Citizenship

Environmental Education is essential to promote awareness and facilitate the development of environmental citizens. To contribute to the enhancement of environmental awareness, Iceland, Serbia, Bosnia and Herzegovina, and Romania have collaborated in joint educational projects which aim at building capacities on sustainable development, delivering environmental teaching lectures, and developing open educational resources. This article presents past and ongoing collaborations between the mentioned countries, assesses the status of environmental education, and highlights the benefits of international collaboration. For this purpose, information on environmental courses in representative universities from each country was collected, SWOT analyses were performed in each country, and a survey among potential students was carried out. The presented analysis reveals that international collaboration raises environmental awareness and increases the likelihood of becoming environmental citizens

Biomimetic Planar Polymer Membranes Decorated with Enzymes as Functional Surfaces

Functional surfaces were generated by a combination of enzymes with polymer membranes composed of an amphiphilic, asymmetric block copolymer poly­(ethyleneglycol)-<i>block</i>-poly­(γ-methyl-ε-caprolactone)-<i>block</i>-poly­[(2-dimethylamino)­ethylmethacrylate]. First, polymer films formed at the air–water interface were transferred in different sequences onto silica solid support using the Langmuir–Blodgett technique, generating homogeneous monolayers and bilayers. A detailed characterization of these films provided insight into their properties (film thickness, wettability, topography, and roughness). On the basis of these findings, the most promising membranes were selected for enzyme attachment. Functional surfaces were then generated by the adsorption of two model enzymes that can convert phenol and its derivatives (laccase and tyrosinase), well known as high-risk pollutants of drinking and natural water. Both enzymes preserved their activity upon immobilization with respect to their substrates. Depending on the properties of the polymer films, different degrees of enzymatic activity were observed: bilayers provided the best conditions in terms of both overall stability and enzymatic activity. The interaction between amphiphilic triblock copolymer films and enzymes is exploited to engineer “active surfaces” with specific functionalities and high efficacy resulting from the intrinsic activity of the biomolecules that is preserved by an appropriate synthetic environment