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The COVID-19 pandemic has revealed weaknesses in healthcare systems and underscored the need for advanced antimicrobial materials. This study investigates the quaternization of agar, a seaweed-derived polysaccharide, and the development of electrospun membranes for air filtration in facemasks and biomedical applications. Using the betacoronavirus MHV-3 as a model, quaternized agar and membranes achieved a 90-99.99 % reduction in viral load, without associated cytotoxicity. The quaternization process reduced the viscosity of the solution from 1.19 ± 0.005 to 0.64 ± 0.005 Pa.s and consequently the electrospun fiber diameter ranged from 360 to 185 nm. Membranes synthesized based on polyvinyl alcohol and thermally cross-linked with citric acid exhibited lower water permeability. Avoiding organic solvents in the electrospinning technique ensured eco-friendly production. This approach offers a promising way to develop biocompatible and functional materials for healthcare and environmental applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Correct tip positioning is a critical aspect in central vascular access devices insertion. The verification of positioning at the cavo-atrial junction is usually performed by intracavitary electrocardiography. Recently, echocardiographic techniques were proposed, including the direct visualization of the catheter or the visualization of a saline/air bolus (i.e. "bubble test"). As for the latter, a push-to-bubbles delay time below 2 s was proposed to indicate a correct positioning of the catheter tip. The aim of this study was to measure the variations of the push-to-bubbles time at increasing distance from the cavo-atrial junction, to verify if a cut-off of 1-2 s correspond to a well-positioned catheter., Methods: We performed a prospective study including patients with clinical indication of positioning a peripherally inserted central catheter. The catheter tip was positioned at the cavo-atrial junction (P0) via intracavitary electrocardiography, and the push-to-bubbles delay time was measured. The catheter was then retracted 5 cm (P1) and 10 cm (P2), and the test was repeated at this positioning. Push-to-bubbles time measurements were performed off-line by analyzing an audio/video recording which included the echography screen and the voice signal of the operator., Results: Forty-nine patients were included. The average push-to-bubble time when the catheter tip was in the reference position was 0.41 ± 0.21 s. Retraction of the PICC catheter of 5 and 10 cm determined a significant increase of the push-to-bubbles time: mean time difference was +0.34 (95% IC 0.25-0.43, p  < 0.001) s between P0 and P1 (5 cm distance), and +0.77 (95% IC 0.62-0.92, p  < 0.001) s between P0 and P2 (10 cm distance). When the catheter was at the reference position (i.e. cavo-atrial junction) only 2.1% of bubbles delay times were above 1 s., Conclusion: The push-to-bubbles time is very low when the catheter tip is at the cavo-atrial junction. This delay increases progressively with increasing distance from the target. Push-to-bubbles delay time above 1 s might indicate a catheter not close to the cavo-atrial junction., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.