Development of an implantable three-dimensional model of a functional pathogenic multispecies biofilm to study infected wounds

Abstract

Chronic wounds cannot heal due to impairment of regeneration, mainly caused by the persistent infection of multispecies biofilms. Still, the effects of biofilm wound infection and its interaction with the host are not fully described. We aimed to study functional biofilms in physiological conditions in vitro, and their potential effects in health and regeneration in vivo. Therefore, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis were seeded in collagen-based scaffolds for dermal regeneration. After 24 h, scaffolds had bacterial loads depending on the initial inoculum, containing viable biofilms with antibiotic tolerance. Afterwards, scaffolds were implanted onto full skin wounds in mice, together with daily supervision and antibiotic treatment. Although all mice survived their health was affected, displaying fever and weight loss. After ten days, histomorphology of scaffolds showed high heterogeneity in samples and within groups. Wounds were strongly, mildly, or not infected according to colony forming units, and P. aeruginosa had higher identification frequency. Biofilm infection induced leucocyte infiltration and elevated interferon-γ and interleukin-10 in scaffolds, increase of size and weight of spleen and high systemic pro-calcitonin concentrations. This functional and implantable 3D biofilm model allows to study host response during infection, providing a useful tool for infected wounds therapy development.

Development of a Hibernation‐Inspired Preservation Strategy to Enhance the Clinical Translation of Photosynthetic Biomaterials

“…However, the values obtained lay within the normal ranges of TNF plasma levels in C57BL/6 mice. [44,45] This agrees with previous studies showing that certain fresh microalga and cyanobacteria can be safely delivered or implanted into mice, [11,12,46] and even humans. [21] However, such a similar response for preserved photosynthetic biomaterials had never been described before.…”

“…These parameters were scored between 0 and 3 as previously described. [44] Euthanasia and Tissue Samples Collection: After 10 d of scaffold implantation, animals were euthanized by intraperitoneal overdose of ketamine/xylazine (30/300 mg kg −1 respectively). Blood was collected via cardiac puncture, allowed to clot at RT for 1 h, and further centrifuged at 1500 g for 10 min.…”

Non Clinical Model to Assess the Mechanism of Action of a Combined Hyaluronic Acid, Chondroitin Sulfate and Calcium Chloride: HA+CS+CaCl2 Solution on a 3D Human Reconstructed Bladder Epithelium

“…In vitro reconstructed human epithelia models are closer in term of morphology (multistratified epithelium), biochemical and physiological properties to in vivo human tissues and represent the most promising alternative to animals, ex vivo explants and submerged cell monolayers to access efficacy, mechanism of action and safety of topically applied products in different fields, including the medical device sector. [23][24][25][26][27][28][29][30] The experimental approach adopted in this pre-clinical project was based on the use of a 3D reconstructed model of bladder epithelium chosen for its biological relevance as biological barrier it reproduces the inner mucosa of the bladder, a transition epithelium that covers the first tract of the ureters and is impermeable to counteract urine re-absorption. The main goal was to demonstrate that the test item was able to create an additional mechanical-physical barrier against E. coli adhesion without a direct interaction with the bacterium itself in terms of antimicrobial activity.…”

Efficient Photothermal, Flexible Wood-Based Hydrogel for Infected Wound Recovery

“…The skin is the first line of defense of the body against infection; therefore, an environmentally friendly, high-quality medical hydrogel is an excellent choice for treating infected skin wounds in the modern era. , Cellulose hydrogels typically employ the polyhydroxy functional groups of cellulose while ignoring the advantages of the natural structure of the wood . By delignifying lignin and hemicellulose, the porous and anisotropic properties of the natural structure of wood can be preserved, and the stiffness of the wood can be reduced to significantly increase its flexibility, greatly broadening its range of applications .…”