A Fully‑Printed Wearable Bandage‑Based Electrochemical Sensor with pH Correction for Wound Infection Monitoring

Wearable sensing systems have been designed to monitor health conditions in real-time by detecting analytes in human biofluids.Wound diagnosis remains challenging,necessitating suitable materials for high-performance wearable sensors to offer prompt feedback.Existing devices have limitations in measuring pH and the concentration of pH-dependent electroactive species simultaneously,which is crucial for obtaining a comprehensive understanding of wound status and optimizing biosensors.Therefore,improving materials and analysis system accuracy is essential.This article introduces the first example of a flexible array capable of detecting pyocyanin,a bacterial virulence factor,while correcting dynamic pH fluctuations.We demonstrate that this combined sensor enhances accuracy by mitigating the impact of pH variability on pyocyanin sensor response.Customized screen-printable inks were developed to enhance analytical performance.The analytical performances of two sensitive sensor systems(i.e.,fully-printed porous graphene/multiwalled carbon nanotube(CNT)and polyaniline/CNT composites for pyocyanin and pH sensors)are evaluated.Partial least square regression is employed to analyze nonzero-order data arrays from square wave voltammetric and potentiometric measurements of pyocyanin and pH sensors to establish a predictive model for pyocyanin concentration in complex fluids.This sensitive and effective strategy shows potential for personalized applications due to its affordability,ease of use,and ability to adjust for dynamic pH changes.

Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive （Staphylococcus aureus） and gram-negative （Escherichia coli, Pseudomonas aeruginosa） bacteria. Particle size, morphology and chemical composition were determined using scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. Results indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus, but not against Escherichia coli and Pseudomonas aeruginosa. It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacterial cell wall. Furthermore, lanthanum oxide bulk particles were fotmd to enhance the pyocyanin pigment production in Pseudomonas aeruginosa.

Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

Objective:To abrogate pathogenic vibrios in aquaculture by testing the potential of Pseudomonas isolates from fresh water,brackish and marine environments as probiotics.Methods:Antagonistic activity of the compound against 7 Vibrio spp.was performed.Influence of salinity on the production of pyocyanin and the toxicity was done through the compound using brine shrimp lethality assay.Molecular characterization was performed to confirm that the isolates werePseudomonas aeruginosa.Results:Salinity was found to regulate the levels of pyocyanin production,with 5-10 g/L as the optimum.All Pseudomonas isolates grew at salinities ranging from 5 to 70 g/L.Isolates of marine origin produced detectable levels of pyocyanin up to 45 g/L salinity.Brackish and freshwater isolates ceased to produce pyocyanin at salinities above 30 g/L and 20 g/L,respectively.Culture supernatants of all 5 Pseudomonas isolates possessed the ability to restrict the growth of Vibrio spp.and maximum antagonistic effect on Vibrio harveyi was obtained when they were grown at salinities of 5 to 10 g/L.The marine isolate MCCB117,even when grown at a salinity of 45 g/L possessed the ability to inhibit Vibrio spp.Conclusions:Purification and structural elucidation of antagonistic compound were carried out.ideal for application in freshwater,MCCB102 and MCCB103 in brackish water and MCCB117 and The present investigation showed that Pseudomonas aeruginosa MCCB119 would be MCCB118 in marine aquaculture systems as putative probiotics in the management of vibrios.

Homogentisic acid γ-lactone suppresses the virulence factors of Pseudomonas aeruginosa by quenching its quorum sensing signal molecules

Bacterial quorum sensing（QS） molecules are involved in the coordination of certain behaviors such as biofilm formation, virulence and antibiotic resistance. QS molecules（autoinducers） and their corresponding receptors have been recognized as important therapeutic targets for drug-resistant infections and biofilm-associated infections（BAI）. This study assessed the multiple biological effects of homogentisic acid y-lactone（HgAL）, a furanone derivative. The anti-QS and anti-biofilm effects of HgAL against PAO1 strain were evaluated using CLSM, SEM, HPLC and other biochemical methods The results showed that HgAL could effectively inhibit the production of pyocyanin and extracellular matrix, as well as reduce the adherence ability and biofilm formation of Pseudomonas aeruginosa. Inhibition of virulence is attributed to the suppressive effect of HgAL on biosynthesis of 3-oxo-C12-HSLand C4-HSL（two kinds of QS signaling molecules in P. aeruginosa）. Our results support HgAL as a potential agent for prevention of BAI in the healthcare settings.

Characterization,application and statistical optimization approach for enhanced production of pyocyanin pigment by Pseudomonas aeruginosa DN9

The aim of this work was to study the pyocyanin pigment from Pseudomonas aeruginosa DN9.The work involves optimiza-tion of process parameters for enhanced production of pyocyanin pigment under submerged fermentation condition.During optimization process,maximum pyocyanin production(92.12μg/ml)was obtained with carbon source mannitole,nitrogen source peptone,inorganic salt NaCl and metal ion FeSO_(4).Plackett Burman design and Response Surface Methodology(RSM)showed peptone,NaCl and KH_(2)PO_(4)are significant variable in the production of pyocyanin pigment.The FTIR and GC-MS study was done to evaluate structural properties of pyocyanin pigment.The purified pigment was further analyzed as colouring agent and for inhibitory action against pathogenic microorganisms.Thus,present study showed Pseudomonas aeruginosa DN9 as promising culture for pigment production with potential biotechnological application.