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There is still an urgent need to develop hydrogels with intelligent antibacterial ability to achieve on-demand treatment of infected wounds and accelerate wound healing by improving the regeneration microenvironment. We proposed a strategy of hydrogel wound dressing with bacteria-responsive self-activating antibacterial property and multiple nanozyme activities to remodel the regeneration microenvironment in order to significantly promote infected wound healing. Specifically, pH-responsive H2O2 self-supplying composite nanozyme (MSCO) and pH/enzyme-sensitive bacteria-responsive triblock micelles encapsulated with lactate oxidase (PPEL) were prepared and encapsulated in hydrogels composed of L-arginine-modified chitosan (CA) and phenylboronic acid-modified oxidized dextran (ODP) to form a cascade bacteria-responsive self-activating antibacterial composite hydrogel platform. The hydrogels respond to multifactorial changes of the bacterial metabolic microenvironment to achieve on-demand antibacterial and biofilm eradication through transformation of bacterial metabolites, and chemodynamic therapy enhanced by nanozyme activity in conjunction with self-driven nitric oxide (NO) release. The composite hydrogel showed 'self-diagnostic' treatment for changes in the wound microenvironment. Through self-activating antibacterial therapy in the infection stage to self-adaptive oxidative stress relief and angiogenesis in the post-infection stage, it promotes wound closure, accelerates wound collagen deposition and angiogenesis, and completely improves the microenvironment of infected wound regeneration, which provides a new method for the design of intelligent wound dressings. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the activity of Hydnophytum formicarum Jack (Ant Plant) tuber extract against Staphylococcus aureus and Escherichia coli and the mode of action of the extract on bacterial responses. The antibacterial activity was determined using agar well diffusion method. Resazurin-based 96-well microdilution method was used to determine the Minimal Inhibitory Concentrations (MIC) of the extract. Mode of action on bacterial death and response patterns to the extract were assessed by flow cytometry using membrane integrity and granularity profiles. The results, based on serial dilution and zones of inhibition against the bacteria, showed that 2,000 µg/well was potent against S. aureus (16.33±1.53 mm) and E. coli (14.33±0.58 mm). For S. aureus, the MIC concentration was 8,000 µg/mL, while 4,000 µg/mL concentration exhibited activity against E. coli. Flow cytometric profiles confirmed loss of intracellular components, followed by death, for both bacteria. Bacterial responses to the extract had consistent dose- and time-dependent behavior. This is the first mode of action study on bacterial responses to H. formicarum tuber extract. The results suggest that the extract of H. formicarum tuber could serve as a source of an initial active ingredient for developing effective medicines to battle infections caused by pathogens. [ABSTRACT FROM AUTHOR]

The present study investigated the variation in surface free energy, adhesion strength, and bacterial attachment during early colonization. Two different sizes of micro dimple textured surface MDS 400 and MDS 200 on Ti6Al4V were fabricated using mechanical micro-milling and studied with an un-textured surface. One polar (water) and dispersive liquid (diiodomethane) were used to study the work of adhesion and surface free energy of both surfaces. The Neumann method and Owen & Wendt approach were used to calculate the SFE. EDS analysis was carried out to check the surface composition. E. coli bacterial strain was used to study the early colonization responses using FESEM and optical microscope. Results indicate that the formed textures are uniform with good quality and as per the design of experiment. Area surface roughness values of the textured surface have been increased from UTS. Besides, no tool wear debris has been found on textured surfaces. SFE and adhesion strength of water and diiodomethane increase due to surface texturing and initial colonization of bacteria on textured surfaces is in the form of E. coli cellular chains has been observed. The current study offers insights into the surface free energy, adhesion strength of water and diiodomethane, and bacterial attachment during the early stage of colonization. [ABSTRACT FROM AUTHOR]

Obesity and diabetes are established comorbidities for COVID-19. Adipose tissue demonstrates high expression of ACE2 which SARS- CoV-2 exploits to enter host cells. This makes adipose tissue a reservoir for SARS-CoV-2 viruses and thus increases the integral viral load. Acute viral infection results in ACE2 downregulation. This relative deficiency can lead to disturbances in other systems controlled by ACE2, including the renin-angiotensin system. This will be further increased in the case of pre-conditions with already compromised functioning of these systems, such as in patients with obesity and diabetes. Here, we propose that interactions of virally-induced ACE2 deficiency with obesity and/or diabetes leads to a synergistic further impairment of endothelial and gut barrier function. The appearance of bacteria and/or their products in the lungs of obese and diabetic patients promotes interactions between viral and bacterial pathogens, resulting in a more severe lung injury in COVID-19.

Abstract: This study investigates the role that surface functionalisation of silicone elastomer (SE) by atmospheric pressure plasma induced graft immobilisation of poly(ethylene glycol) methyl ether methacrylate (PEGMA) plays in the attendant biological response. SE is used in modern ophthalmic medical devices and samples of the material were initially plasma treated using a dielectric barrier discharge reactor (DBD) to introduce reactive oxygen functionalities, prior to in situ grafting of two molecular weights of PEGMA (MW 1000Da: PEGMA1000, MW 2000Da: PEGMA2000). The variously processed surfaces were characterised by water contact angle analysis, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and atomic force microscopy. Lens epithelial cells were then cultured on the PEGMA grafted SE surfaces. It was found that cells on the pristine surface were not well spread and had shrunken morphology. On the DBD pre-treated surfaces, the cells were well spread. On the PEGMA1000 surface, the cells displayed evidence of shrinkage and were on the verge of detaching. Remarkably, on the PEGMA2000 surface, no cell adhesion was detection. Bacterial adhesion to the surfaces was studied using Staphylococcus aureus NTC8325. There was no difference in the number of bacteria adhering to any of the surfaces studied. [Copyright &y& Elsevier]

• External EMBR was set up with superhydrophobic/organophilic electrospun membrane. • External EMBR achieved the salt rejection, phenol permeation and biodegradation. • Phenol and ammonium were simultaneously removed in external EMBR for detoxication. • Microbial community, gene enumeration and EPS release varied with phenol conc. Phenol-laden saline wastewaters can adversely affect water, groundwater, soil, organisms and ecosystems. Given that frequently-used biodegradation process is generally inhibited by salinity, this work aims to solve the problem through a novel configuration of external extractive membrane bioreactor (EMBR) for the objective of simultaneous phenol permeation, salt rejection and biodegradation. Contact angles of 160.9 ± 2.2° (water) and 0.0° (phenol) were observed on the electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane, suggesting this superhydrophobic/superorganophilic membrane was suitable for separating phenol from water-soluble salt. Phenol ranging from 14.1 ± 2.7 to 290.7 ± 10.4 mg/L (stages 1 to 8) was continuously permeated and completely biodegraded in external EMBR under a hydraulic retention time (HRT) of 24 h, which corresponded with detoxification performance improving from 6.3% to 70.5%. After phenol exposure of 8 stages, Proteobacteria and Saccharibacteria became the main phyla for microorganisms. Enumeration of functional genes (phe , amoA , narG , nirS) confirmed that phenol was mainly consumed by denitrifiers and other heterotrophs as the sole carbon and energy source via oxidation and ring cleavage. As bacterial responses, these genes' proliferation was promoted under low phenol concentrations but inhibited under high phenol concentrations. Meanwhile, results of extracellular polymeric substances revealed that protein was the key substance in toxicity resistance, phenol adsorption and transfer. [ABSTRACT FROM AUTHOR]

Obesity and diabetes are established comorbidities for COVID-19. Adipose tissue demonstrates high expression of ACE2 which SARS- CoV-2 exploits to enter host cells. This makes adipose tissue a reservoir for SARS-CoV-2 viruses and thus increases the integral viral load. Acute viral infection results in ACE2 downregulation. This relative deficiency can lead to disturbances in other systems controlled by ACE2, including the renin-angiotensin system. This will be further increased in the case of pre-conditions with already compromised functioning of these systems, such as in patients with obesity and diabetes. Here, we propose that interactions of virally-induced ACE2 deficiency with obesity and/or diabetes leads to a synergistic further impairment of endothelial and gut barrier function. The appearance of bacteria and/or their products in the lungs of obese and diabetic patients promotes interactions between viral and bacterial pathogens, resulting in a more severe lung injury in COVID-19., Competing Interests: IK ILK is the managing partner of Wellcomet GmbH. Wellcomet GmbH provided support in the form of salaries for ILK, but did not have any additional role in decision to publish or preparation of the manuscript. The commercial affiliation of ILK with Wellcomet GmbH does not alter the adherence to all journal policies on sharing data and materials. MS, PS No competing interests declared, (© 2020, Kruglikov et al.)