THE POSSIBILITY OF USING PERFLUOROCARBON COMPOUNDS FOR VIRUS-ASSOCIATED PNEUMONIA TREATMENT

The issues of practicality in using perfluorocarbon gas transport emulsions (or pure perfluorocarbons) in severe virus-associated pneumonia treatment were considered, including those caused by coronavirus infection. Perfluorocarbons are fully fluorinated carbon compounds, on the basis of which artificial blood substitutes have been developed — gas transport perfluorocarbon emulsions for medical purposes. Perfluorocarbon emulsions were widely used in the treatment of patients in critical conditions of various genesis at the end of the last–the beginning of this century, accompanied by hypoxia, disorders of rheological properties and microcirculation of blood, perfusion of organs and tissues, intoxication, and inflammation. Large-scale clinical trials have shown a domestic plasma substitute advantage based on perfluorocarbons (perfluoroan) over foreign analogues. It is quite obvious that the inclusion of perfluorocarbon emulsions in the treatment regimens of severe virus-associated pneumonia can significantly improve this category's treatment results after analyzing the accumulated experience. A potentially useful area of therapy for acute respiratory distress syndrome is partial fluid ventilation with the use of perfluorocarbons as respiratory fluids as shown in the result of many studies on animal models and existing clinical experience. There is no gas-liquid boundary in the alveoli, as a result of which, there is an improvement in gas exchange in the lungs and a decrease in pressure in the respiratory tract when using this technique, due to the unique physicochemical properties of liquid perfluorocarbons. A promising strategy for improving liquid ventilation effectiveness using perfluorocarbon compounds is a combination with other therapeutic methods, particularly with moderate hypothermia. Antibiotics, anesthetics, vasoactive substances, or exogenous surfactant can be delivered to the lungs during liquid ventilation with perfluorocarbons, including to the affected areas, which will enhance the drugs accumulation in the lung tissues and minimize their systemic effects. However, the indications and the optimal technique for conducting liquid ventilation of the lungs in patients with acute respiratory distress syndrome have not been determined currently. Further research is needed to clarify the indications, select devices, and determine the optimal dosage regimens for perfluorocarbons, as well as search for new technical solutions for this technique The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.

Clinical and histo-pathophysiological features of diffused alveolar lesions (pneumonia) caused by SARS-CoV-2 in patients who need of respiratory support

Acute respiratory distress syndrome (ARDS) and respiratory failure are the main problems in patients with COVID-19. The main reason is primarily a violation of lung perfusion. Anatomical prerequisites for the work of PЕЕР (non-cardiogenic pulmonary edema, atelectasis and, consequently, the possibility of recruitment) are absent. Non-invasive lung ventilation can eliminate hypoxemia and reduce inspiratory effort. Otherwise, the use of mechanical ventilation to prevent self-induced lung injury should be considered. These characteristics are associated with a marked violation of the mechanics of respiration, high blood pressure of arterial carbon dioxide. The leading characteristic of COVID-19 progression is the gradual transition from edema or atelectasis to less reversible structural changes in the lungs, namely fibrosis. The mechanics of respiration are disturbed, the pressure of carbon dioxide in the arterial blood increases, the ability of the respiratory muscles decreases and there is no reaction to PЕEP in the abdominal position. © 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International License, CC BY, which allows others to freely distribute the published article, with the obligatory reference to the authors of original works and original publication in this journal.

Evaluation of the relationship between surfactant protein D levels and COVID-19 clinical severity: a case-control study

Purpose: Serum surfactant protein D (SP-D) plays roles in the body such as protection against viral infection, bacterial and fungal clearance, clearance of apoptotic cells and suppression of inflammation. This study aims to examine the relationship between SP-D level and coronavirus disease (COVID-19) severity. Methods: 80 patients (30 with mild disease and 50 with severe/critical COVID-19), and 50 healthy volunteers were enrolled in the study. SP-D levels were analyzed by ELISA in serum samples. Results: The median of SP-D was found to be 2.47 (1.67-7.79) ng/ml in mild disease and 5.65 (3.09-16.55) ng/ ml in severe/critical disease groups, while 2.89 (10.8-6.24) ng/ml in the healthy controls. The differences in SP-D levels between the severe/critical disease group compared to both mild disease and control groups were found statistically significant (p=0.007 and 0.001, respectively). ROC analysis showed greater AUC for the serum SP-D levels of the severe/critical COVID-19 patients compared to mild COVID-19 disease patients (AUC=0,691, 95% CI=0.56-0,822;p=0.004). Furthermore, SP-D levels were 86% sensitive and 51.6% specific at 2.44 ng/ml level (p=0.004) to detect severe/critical patients. Conclusion: SP-D levels is useful for COVID-19 patients in the prediction of clinical severity and prognosis. SP-D is a valuable biomarker for predicting the clinical severity and prognosis. © 2023, Pamukkale University. All rights reserved.

ECMO for the immunocompromised pediatric patient: Our experience

Objectives: To present a series of immunosuppressed patients (oncohematological disease, congenital immunosuppression, hematopoietic stem cell (HSCT), and solid organ transplant) assisted on ECMO. Method(s): Descriptive, retrospective study (2011-2020) of a cohort of 9 immunosuppressed patients, supported on ECMO. Medical records were reviewed and demographic, clinical, and analytical variables were collected. Result(s): In our series of 9 patients, 5 were male, the median age was 8 years [RIC 3-11 years]. Considering the underlying disease, 6 were oncologic, 1 liver transplant and 2 with congenital immunodeficiency after HSCT. 4 were under active chemotherapy (median 6 days after the last cycle [RIC 5-188]). 6 were admitted due to acute respiratory failure, 3 due to hemodynamic instability (3/9), (one septic shock). The median PEEP was 12 [RIC 9-15] and FiO2 100% (81-100%). 78% (6) required vasoactive drugs (median inotropic score 35 [RIC 0-75]. 40%. 5 had severe neutropenia and/or plateletopenia in the 24 hours prior to ECMO, and alterations in acid-base balance (median pH 7. 1 [RIC 6.9-7.15]. 5 were on multiorgan failure. TPrimary ECMO transport was performed in 4 patients (44%). Cannulation was peripheral in 80% (57% cervical, 43% femoral) and central in 20%;70% VA-ECMO. Median time of assistance was 15 days [RIC 3.5-31.5] in cardiac ECMO (4), and 29 days [RIC 13.5-42] and in pulmonary ECMO (n=5). The median total time of admission was 45 days [RIC 27-59]. 9 had an infection, 2 COVID after HSCT, and 8 bleeding complications, but only one required surgical revision. Renal replacement therapy was used in 5 (median 9 days [RIC 5-34.5]). Other therapies used were polymyxin hemadsorption(2), intratracheal surfactant(2), plasma exchange(1), infusion of mesenchymal cells(1) and specific memory T lymphocytes(2). 4 patients died, 5 survived decannulation, 2 died later, with an overall survival rate to hospital discharge of 33% (3/9). Conclusion(s): Despite having a worse prognosis, ECMO can increase survival in immunosuppressed patients, in situations that are challenging and require a multidisciplinary approach.

The Role of Pulmonary Surfactant Phospholipids in Fibrotic Lung Diseases.

Diffuse parenchymal lung diseases (DPLD) or Interstitial lung diseases (ILD) are a heterogeneous group of lung conditions with common characteristics that can progress to fibrosis. Within this group of pneumonias, idiopathic pulmonary fibrosis (IPF) is considered the most common. This disease has no known cause, is devastating and has no cure. Chronic lesion of alveolar type II (ATII) cells represents a key mechanism for the development of IPF. ATII cells are specialized in the biosynthesis and secretion of pulmonary surfactant (PS), a lipid-protein complex that reduces surface tension and minimizes breathing effort. Some differences in PS composition have been reported between patients with idiopathic pulmonary disease and healthy individuals, especially regarding some specific proteins in the PS; however, few reports have been conducted on the lipid components. This review focuses on the mechanisms by which phospholipids (PLs) could be involved in the development of the fibroproliferative response.

A new tractable method for generating human alveolar macrophage-like cells in vitro to study lung inflammatory processes and diseases.

Alveolar macrophages (AMs) are unique lung resident cells that contact airborne pathogens and environmental particulates. The contribution of human AMs (HAMs) to pulmonary diseases remains poorly understood due to the difficulty in accessing them from human donors and their rapid phenotypic change during in vitro culture. Thus, there remains an unmet need for cost-effective methods for generating and/or differentiating primary cells into a HAM phenotype, particularly important for translational and clinical studies. We developed cell culture conditions that mimic the lung alveolar environment in humans using lung lipids, that is, Infasurf (calfactant, natural bovine surfactant) and lung-associated cytokines (granulocyte macrophage colony-stimulating factor, transforming growth factor-ß, and interleukin 10) that facilitate the conversion of blood-obtained monocytes to an AM-like (AML) phenotype and function in tissue culture. Similar to HAM, AML cells are particularly susceptible to both Mycobacterium tuberculosis and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. This study reveals the importance of alveolar space components in the development and maintenance of HAM phenotype and function and provides a readily accessible model to study HAM in infectious and inflammatory disease processes, as well as therapies and vaccines.IMPORTANCEMillions die annually from respiratory disorders. Lower respiratory track gas-exchanging alveoli maintain a precarious balance between fighting invaders and minimizing tissue damage. Key players herein are resident AMs. However, there are no easily accessible in vitro models of HAMs, presenting a huge scientific challenge. Here, we present a novel model for generating AML cells based on differentiating blood monocytes in a defined lung component cocktail. This model is non-invasive, significantly less costly than performing a bronchoalveolar lavage, yields more AML cells than HAMs per donor, and retains their phenotype in culture. We have applied this model to early studies of M. tuberculosis and SARS-CoV-2. This model will significantly advance respiratory biology research.

Autoimmune pulmonary alveolar proteinosis in an adolescent girl with rapidly progressive dyspnea

Autoimmune pulmonary alveolar proteinosis (PAP) is a rare disease, especially in pediatrics, but important to consider, as it may avoid unnecessary and/or invasive investigations and delayed diagnosis. This case report highlights an adolescent girl with rapid onset dyspnea but an unremarkable physical exam and initial testing. However, due to a high index of suspicion, a chest computed tomography (CT) scan was done, revealing a "crazy paving" pattern, which then prompted expedited assessment. This finding, however, is not as specific as often discussed and has a broad differential diagnosis, which will be reviewed in detail as part of this case. Furthermore, this report demonstrates a diagnostic approach for PAP that avoids lung biopsy, previously considered to be required for diagnosis of PAP, but is increasingly becoming unnecessary with more advanced blood tests and understanding of their sensitivity and specificity. Additionally, management strategies for PAP will be briefly discussed.Copyright © 2022 Canadian Thoracic Society.

Pulmonary surfactant and COVID-19: A new synthesis

Chapter 1: COVID-19 pathogenesis poses paradoxes difficult to explain with traditional physiology. For instance, since type II pneumocytes are considered the primary cellular target of SARS-CoV-2;as these produce pulmonary surfactant (PS), the possibility that insufficient PS plays a role in COVID-19 pathogenesis has been raised. However, the opposite of predicted high alveolar surface tension is found in many early COVID-19 patients: paradoxically normal lung volumes and high compliance occur, with profound hypoxemia. That 'COVID anomaly' was quickly rationalised by invoking traditional vascular mechanisms-mainly because of surprisingly preserved alveolar surface in early hypoxemic cases. However, that quick rejection of alveolar damage only occurred because the actual mechanism of gas exchange has long been presumed to be non-problematic, due to diffusion through the alveolar surface. On the contrary, we provide physical chemical evidence that gas exchange occurs by an process of expansion and contraction of the three-dimensional structures of PS and its associated proteins. This view explains anomalous observations from the level of cryo-TEM to whole individuals. It encompasses results from premature infants to the deepest diving seals. Once understood, the COVID anomaly dissolves and is straightforwardly explained as covert viral damage to the 3D structure of PS, with direct treatment implications. As a natural experiment, the SARS-CoV-2 virus itself has helped us to simplify and clarify not only the nature of dyspnea and its relationship to pulmonary compliance, but also the fine detail of the PS including such features as water channels which had heretofore been entirely unexpected.Copyright ©

Exogenous surfactant reduces inflammation and redox imbalance in rats under prone or supine mechanical ventilation.

Mechanical ventilation (MV) is a lifesaving therapy for patients with acute or chronic respiratory failure. Despite, it can also cause lung injury by inducing or worsening inflammatory responses and oxidative stress. Several clinical approaches have protective effects on the lungs, including the prone position and exogenous surfactant; however, few studies have evaluated the association between the two strategies, especially in individuals without previous lung injury. We tested the hypothesis that the effects of the homogenization in lung aeration caused by the prone position in association with the anti-inflammatory properties of exogenous surfactant pre-treatment could have a cumulative protective effect against ventilator-induced lung injury. Therefore, Wistar rats were divided into four experimental groups: Mechanical Ventilation in Supine Position (MVSP), Mechanical Ventilation in Prone position (MVPP), Mechanical Ventilation in Supine Position + surfactant (MVSPS), and Mechanical Ventilation in Prone Position + Surfactant (MVPPS). The intranasal instillation of a porcine surfactant (Curosurf®) was performed in the animals of MVSPS and MVPPS 1 h before the MV, all the rats were subjected to MV for 1 h. The prone position in association with surfactant decreased mRNA expression levels of pro-inflammatory cytokines in ventilated animals compared to the supine position; in addition, the NfκB was lower in MVPP, MVSPS and MVPPS when compared to MVSP. However, it had no effects on oxidative stress caused by MV. Pre-treatment with exogenous surfactant was more efficient in promoting lung protection than the prone position, as it also reduced oxidative damage in the lung parenchyma. Nevertheless, the surfactant did not cause additional improvements in most parameters that were also improved by the prone position. Our results indicate that the pre-treatment with exogenous surfactant, regardless of the position adopted in mechanical ventilation, preserves the original lung histoarchitecture, reduces redox imbalance, and reduces acute inflammatory responses caused by mechanical ventilation in healthy adult Wistar rats.

Enhanced performance of algal-bacterial aerobic granular sludge in comparison to bacterial aerobic granular sludge for treating surfactant-containing wastewater

Increasing amounts of surfactants are used and emitted into the environment due to the COVID-19 pandemic, posing potential threats to ecological health. Algal-bacterial aerobic granular sludge (A-BAGS), with the advantages of compact structure, high-efficient nutrient uptake, and high tolerance to harsh conditions, was attempted in this study to treat surfactant-containing wastewater at relatively high concentrations. The treatment performance was also compared to bacterial AGS (BAGS). Results showed that A-BAGS is preferable for treating wastewater containing a high SDS concentration (30 mg/L), achieving nutrient removal efficiency of 86.3 % for organic carbon, 60.5 % for total nitrogen, and 58.7 % for total phosphorus within a short duration, compared to 70.1 %, 52.8 % and 42.3 % in BAGS reactor. Besides, the removal rate of ammonia nitrogen by A-BAGS was much faster than that of BAGS. The above results confirmed that A-BAGS is a promising technology for treating surfactant-containing wastewater with high nutrient removal efficiency being maintained.Copyright © 2023 Elsevier Ltd

DEVELOPMENT OF FERRITIN ELECTROCHEMICAL IMUNOSENSOR BASED ON CPE MODIFICATION

Ferritin is a major intracellular iron storage protein present in all cells, tissues and tissue fluids of the organism. Low ferritin levels result in lower iron concentrations which is directly involved with anemia. Elevated levels of ferritin, or hyperferritinemia, indicate the presence of viruses and bacteria into the body. Clinical observations on COVID-19 patients have reported cases accompanied by elevated levels of ferritin in blood. The aim of this research was to develop a new voltametric immunosensor for determination of ferritin based on the principles of biological recognition, antibody-antigen reaction combined with nanotechnology and the advantages of electrochemical detection strategies. Carbon paste electrode (CPE) modified with grain natural material, characterized as titanium magnetite is used as substrate for immunosensor. The immobilization of ferritine antibody (FeAb) can be effectively improved by using a thin film of surfactant, trimethyl-tetradecylammonium chloride (TTDC), onto the CPE substrate. The modification procedure of the immunosensor is characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The effect of FeAb incubation time and the FeAb-ferritine reaction kinetic are explored to provide optimum analytical performance. The quantitative determination of ferritine is based on the change in DPV response before and after antibodyantigen reaction. All measurements are done in pH = 7 phosphate buffer saline (PBS) at room temperature. Calibration method was based on the reduction of the DPV peak (%) in relation to the ferritin concentration. The time required for the immobilization of FeAb was studied, which resulted in 60 minutes, as well as the equilibrium time of the FeAb-ferritin reaction, which resulted in 30 minutes. The linear range resulted within the interval 0.05-0.5 mg/L ferritin (R2 = 0.9947). The recovery of ferritin addition in real sample matrix resulted from 87% to 125%. The specificity of FeAbferritin reaction evaluated in terms of binding constant, resulted in the order of 10-9 L/mol indicating a specific antibody-antigen reaction. Based on the values of affinity constants calculated in each case the quantification of ferritin with the studied sensors is based on the specific antiferritin-ferritin bond. The use of surfactant layer (TTDC), improves the process of antiferritin immobilization, which affects the increase of sensitivity and improve the analytical performance of the imunosensor. © 2023, Consulting and Training Center - KEY. All rights reserved.

Surfactant Protein B Reduces Respiratory Viral Infectivity in Human Lungs

Purpose of Study: COVID pneumonia caused by SARS-CoV-2 can result in a depletion of surfactant & lung injury, which resembles neonatal respiratory distress syndrome. Exogenous surfactant has shown promise as a therapeutic option in intubated hospitalized patients. Our preliminary data in human lung organoids (LOs) with a deficiency of surfactant protein B (SP-B) showed an increased viral load compared to normal LOs. Single cell RNA sequencing (scRNAseq) revealed that SP-B-deficient cells showed increased viral entry genes (ACE2 receptor) & dysregulated inflammatory markers emanating from the lung cells themselves. Our objective was to determine: (1) cell-specific transcriptional differences between normal & SP-B deficient human lung cells after infection with SARS-CoV-2 and (2) a therapeutic role of SP-B protein & surfactant in COVID-19 pneumonia. Methods Used: We used normal and SP-B mutant (homozygous, frameshift, loss of function mutation p.Pro133GlnfsTer95, previously known as 121ins2) human induced pluripotent stem cells (hiPSC) and differentiated them into 3D proximal lung organoids. The organoids were infected with the delta variant of SARS-CoV-2 for 24 hours at an MOI of 1. Infected and uninfected organoids were fixed in trizol in triplicate and underwent processing for bulk RNA sequencing. We tested for differentially expressed genes using the program DEseq. We also plated normal iPSC derived lung organoids as a monolayer and pre-treated them with 1mg/ml of Poractant alfa or 5 uM of recombinant SP-B protein. The delta strain of SARS-CoV-2 was added to the 96 wells at an MOI of 0.1 for one hour with shaking, then an overlay with DMEM/CMC/FBS was added and left on for 23 hours. The plate was fixed and stained for nucleocapsid (NC) protein. Summary of Results: Bioinformatic analysis of the bulk RNA sequencing data showed an increase in the multiple cytokines and chemokines in the SP-B mutant LOs compared to control. We also saw differential gene expression patterns in the SP-B mutant LOs including a reduction in SFTPC, FOXA2, and NKX2-1 and an increase in IL1A, VEGFA, PPARG and SMAD3. In the exogenous surfactant experiments, there was a decrease in total expression of viral NC in the Poractant alfa & rSP-B-treated cells compared to SARS-CoV-2 infection alone (p<0.001). Conclusion(s): Surfactant modulates the viral load of SARS-CoV-2 infection in the human lung. Deficiency in SP-B results in the dysregulation of the lung epithelial inflammatory signaling pathways resulting in worsening infections.

Role of GM-CSF in lung balance and disease.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor originally identified as a stimulus that induces the differentiation of bone marrow progenitor cells into granulocytes and macrophages. GM-CSF is now considered to be a multi-origin and pleiotropic cytokine. GM-CSF receptor signals activate JAK2 and induce nuclear signals through the JAK-STAT, MAPK, PI3K, and other pathways. In addition to promoting the metabolism of pulmonary surfactant and the maturation and differentiation of alveolar macrophages, GM-CSF plays a key role in interstitial lung disease, allergic lung disease, alcoholic lung disease, and pulmonary bacterial, fungal, and viral infections. This article reviews the latest knowledge on the relationship between GM-CSF and lung balance and lung disease, and indicates that there is much more to GM-CSF than its name suggests.

The anti-inflammatory and antiviral properties of anionic pulmonary surfactant phospholipids.

The pulmonary surfactant system of the lung is a lipid and protein complex, which regulates the biophysical properties of the alveoli to prevent lung collapse and the innate immune system in the lung. Pulmonary surfactant is a lipoprotein complex consisting of 90% phospholipids and 10% protein, by weight. Two minor components of pulmonary surfactant phospholipids, phosphatidylglycerol (PG) and phosphatidylinositol (PI), exist at very high concentrations in the extracellular alveolar compartments. We have reported that one of the most dominant molecular species of PG, palmitoyl-oleoyl-phosphatidylglycerol (POPG) and PI inhibit inflammatory responses induced by multiple toll-like receptors (TLR2/1, TLR3, TLR4, and TLR2/6) by interacting with subsets of multiprotein receptor components. These lipids also exert potent antiviral effects against RSV and influenza A, in vitro, by inhibiting virus binding to host cells. POPG and PI inhibit these viral infections in vivo, in multiple animal models. Especially noteworthy, these lipids markedly attenuate SARS-CoV-2 infection including its variants. These lipids are natural compounds that already exist in the lung and, thus, are less likely to cause adverse immune responses by hosts. Collectively, these data demonstrate that POPG and PI have strong potential as novel therapeutics for applications as anti-inflammatory compounds and preventatives, as treatments for broad ranges of RNA respiratory viruses.

Biosurfactant: A Biodegradable Antimicrobial Substance

The coronavirus pandemic in 2020 increased the use of cleaning agents by residential individuals and businesses that maintained their operation even remotely. In formulating these products, one of the key ingredients is the surfactant molecule. Surfactants, in general, due to their characteristics, can act as antimicrobial agents. The presence of this active in cleaning products facilitates the process of removing dirt and reduces the occurrence of infections and health risks. However, most surfactants present in the consumer market, when used, require high consumption of water for removal and are also discharged into domestic sewage, without treatment, causing toxicity in different organisms due to their recalcitrance in the environment. Thus, the knowledge and use of biosurfactants, amphipathic molecules that can be obtained by plants and microbes, is important. Since, in addition to the same properties found in common surfactants, biosurfactants are highly biodegradable. This chapter discusses biosurfactants with a focus on their biodegradability, the different types of tests applied to assess this parameter and recent studies with importance in the applications of biosurfactants as antimicrobial agents. © 2022 Scrivener Publishing LLC.

Photodynamic inactivation of Rhizopus oryzae - in vitro study

During the COVID-19 pandemic, several complications arose in infected patients, one of them being mucormycosis, which is an extremely aggressive fungal disease with a high mortality rate, especially in patients with compromised immune systems. Most cases of mucormycosis are caused by the fungus Rhizopus oryzae, also known as black fungus, with 90% of cases affecting the rhinocerebral site. The treatment tools used are based on high doses of amphotericin B and posaconazole, associated with surgical resections when possible. However, even with aggressive antifungal treatment, the estimated attributable mortality rate is high [1]. In the absence of surgical debridement of the infected tissue, antifungal treatment alone is not curative. So there is a need for development of adjuvant treatments. Antimicrobial Photodynamic Therapy (aPDT) may constitute an auxiliary therapeutic option for mucormycosis [2]. Due to the lack of reports on the photodynamic inactivation of R. oryzae, we investigated different protocols Photodithazine (PDZ) as a photosensitizer. The response on the fungus growing rate under distinct treatment parameters as photosensitizer concentration, incubation time, and association with surfactant, will be presented for both white and black hyphal phases, and infective spore phase. Preliminary results show the potential use of photodynamic therapy for the inactivation and growth control of the R. oryzae.Copyright © 2023

LASU quarantine dye: Antimicrobial Phthalocyanine Activated by Indoor Light

Novel safe and stable teracationic Zinc phthalocyanine is efficient against bacteria, fungi and viruses also under indoor light Recently a novel photosensitizer with outstanding properties, phthalocyanine LASU has being developed. The compound possesses unprecedented stability and antimicrobial activity. It can be activated by a weak indoor light of 270 lux and shows the activity against G+ and G- bacteria as well as fungi and viruses. Over 3 log inactivation of bacteria and fungi on the surface of a LASU-impregnated material can be achieved in 1/2-1 h of illumination with a regular indoor and/or natural light. A cotton filter impregnated with 0.1 g/m2 of LASU eradicates on its surface the coronavirus HCoV-229E by 3.5 log in 30 minutes under indoor/natural light of 500 lux. The molecule is photostable and remains active for weeks with no significant bleaching. Another remarkable property is its ability to bind to cellulose support. It readily attaches to a fiber substrate through electrostatic interactions, moreover, the size of LASU ring matches the pitch of cellulose polymer, making the conjugate unusually strong. Hence the compound does not leech to water and is stable against temperature and surfactants. The toxicology studies also reveals that substance is non-irritating for human skin, and is non-mutagenic, which makes it suitable for human-wearable items.Copyright © 2023

Chemico-Physical Properties of Some 1,1'-Bis-alkyl-2,2'-hexane-1,6-diyl-bispyridinium Chlorides Hydrogenated and Partially Fluorinated for Gene Delivery.

The development of very efficient and safe non-viral vectors, constituted mainly by cationic lipids bearing multiple charges, is a landmark for in vivo gene-based medicine. To understand the effect of the hydrophobic chain's length, we here report the synthesis, and the chemico-physical and biological characterization, of a new term of the homologous series of hydrogenated gemini bispyridinium surfactants, the 1,1'-bis-dodecyl-2,2'-hexane-1,6-diyl-bispyridinium chloride (GP12_6). Moreover, we have collected and compared the thermodynamic micellization parameters (cmc, changes in enthalpy, free energy, and entropy of micellization) obtained by isothermal titration calorimetry (ITC) experiments for hydrogenated surfactants GP12_6 and GP16_6, and for the partially fluorinated ones, FGPn (where n is the spacer length). The data obtained for GP12_6 by EMSA, MTT, transient transfection assays, and AFM imaging show that in this class of compounds, the gene delivery ability strictly depends on the spacer length but barely on the hydrophobic tail length. CD spectra have been shown to be a useful tool to verify the formation of lipoplexes due to the presence of a "tail" in the 288-320 nm region attributed to a chiroptical feature named ψ-phase. Ellipsometric measurements suggest that FGP6 and FGP8 (showing a very interesting gene delivery activity, when formulated with DOPE) act in a very similar way, and dissimilar from FGP4, exactly as in the case of transfection, and confirm the hypothesis suggested by previously obtained thermodynamic data about the requirement of a proper length of the spacer to allow the molecule to form a sort of molecular tong able to intercalate DNA.

Synergistic Enhancement of Filtering Efficiency and Antibacterial Performance of a Nanofiber Air Filter Decorated with Electropolarized Lithium-Doped ZnO Nanorods.

According to clinical case reports, bacterial co-infection with COVID-19 can significantly increase mortality, with Staphylococcus aureus (S. aureus) being one of the most common pathogens causing complications such as pneumonia. Thus, during the pandemic, research on imparting air filters with antibacterial properties was actively initiated, and several antibacterial agents were investigated. However, air filters with inorganic nanostructures on organic nanofibers (NFs) have not been investigated extensively. This study aimed to demonstrate the efficiency of electropolarized poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) NFs decorated with Li-doped ZnO nanorods (NRs) to improve the filtering ability and antibacterial activity of the ultrathin air filter. The surfactant was loaded onto the ZnO─known for its biocompatibility and low toxicity─nanoparticles (NPs) and transferred to the outer surface of the NFs, where Li-doped ZnO NRs were grown. The Li-doped ZnO NR-decorated NF effectively enhanced the physical filtration efficiency and antibacterial properties. Additionally, by exploiting the ferroelectric properties of Li-doped ZnO NRs and PVDF-TrFE NFs, the filter was electropolarized to increase its Coulombic interaction with PMs and S. aureus. As a result, the filter exhibited a 90% PM1.0 removal efficiency and a 99.5% sterilization rate against S. aureus. The method proposed in this study provides an effective route for simultaneously improving the air filter performance and antibacterial activity.