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Microbial biofilm formation on medical devices paves the way for device-associated infections. Staphylococcus epidermidis is one of the most common strains involved in such infections as it is able to colonize numerous devices, such as intravenous catheters, prosthetic joints, and heart valves. We previously reported the antibiofilm activity against S. epidermidis of pentadecanoic acid (PDA) deposited by drop-casting on the silicon-based polymer poly(dimethyl)siloxane (PDMS). This material exerted an antibiofilm activity by releasing PDA; however, a toxic effect on bacterial cells was observed, which could potentially favor the emergence of resistant strains. To develop a PDA-functionalized material for medical use and overcome the problem of toxicity, we produced PDA-doped PDMS by either spray-coating or PDA incorporation during PDMS polymerization. Furthermore, we created a strategy to assess the kinetics of PDA release using ADIFAB, a very sensitive free fatty acids fluorescent probe. Spray-coating resulted in the most promising strategy as the concentration of released PDA was in the range 0.8–1.5 μM over 21 days, ensuring long-term effectiveness of the antibiofilm molecule. Moreover, the new coated material resulted biocompatible when tested on immortalized human keratinocytes. Our results indicate that PDA spray-coated PDMS is a promising material for the production of medical devices endowed with antibiofilm activity. [ABSTRACT FROM AUTHOR]

The clinical utility of hemoglobin-based oxygen carriers (HBOC) is limited by adverse heme oxidative chemistry. A variety of tyrosine residues were inserted on the surface of the γ subunit of recombinant fetal hemoglobin to create novel electron transport pathways. This enhanced the ability of the physiological antioxidant ascorbate to reduce ferryl heme and decrease lipid peroxidation. The γL96Y mutation presented the best profile of oxidative protection unaccompanied by loss of protein stability and function. N-terminal deletions were constructed to facilitate the production of recombinant hemoglobin by fermentation and phenylalanine insertions in the heme pocket to decrease the rate of NO dioxygenation. The resultant mutant (αV1del. αL29F, γG1del. γV67F, γL96Y) significantly decreased NO scavenging and lipid peroxidation in vitro. Unlike native hemoglobin or a recombinant control (αV1del, γG1del), this mutation showed no increase in blood pressure immediately following infusion in a rat model of reperfusion injury, suggesting that it was also able to prevent NO scavenging in vivo. Infusion of the mutant also resulted in no meaningful adverse physiological effects apart from diuresis, and no increase in oxidative stress, as measured by urinary isoprostane levels. Following PEGylation via the Euro-PEG-Hb method to increase vascular retention, this novel protein construct was compared with saline in a severe rat reperfusion injury model (45% blood volume removal for 90 minutes followed by reinfusion to twice the volume of shed blood). Blood pressure and survival were followed for 4 h post-reperfusion. While there was no difference in blood pressure, the PEGylated Hb mutant significantly increased survival., (© 2024. The Author(s).)

Over the last decades, various tissue-clearing techniques have broken the ground for the optical imaging of whole organs and whole-organisms, providing complete representative data sets of three-dimensional biological structures. Along with advancements in this field, the development of fluorescent markers for staining vessels and capillaries has offered insights into the complexity of vascular networks and their impact on disease progression. Here we describe the use of a modified water-soluble chitosan linked to cyanine dyes in combination with ethyl cinnamate-based optical tissue clearing for the 3D visualization of tissue vasculature in depth. The water-soluble fluorescent Chitosans have proven to be an optimal candidate for labeling both vessels and capillaries ex vivo thanks to their increased water solubility, high photostability, and optical properties in the near-infrared window. In addition, the nontoxicity of these markers broadens their applicability to in vitro and in vivo biological applications. Despite the availability of other fluorescent molecules for vascular staining, the present study, for the first time, demonstrates the potential of fluorescent chitosans to depict vessels at the capillary level and opens avenues for advancing the diagnostic field by reducing the complexity and costs of the currently available procedures., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Co-published by Nanjing University and American Chemical Society.)