Imitating the microenvironment of native biofilms using nanofibrous scaffolds to emulate chronic wound infections

Abstract

Three-dimensional scaffolds of electrospun fibers are widely investigated for in vitro human tissue engineering, whereas until now, their application for the cultivation of bacterial biofilms has been neglected. On the...

The interplay of Pseudomonas aeruginosa and Staphylococcus aureus in dual-species biofilms impacts development, antibiotic resistance and virulence of biofilms in in vitro wound infection models

“…In this study, bacterial biofilms were cultivated within a three-dimensional electrospun nanofibrous scaffold as substrate. This model system was previously developed by our group and allows to resemble a microenvironment comparable to that of in vivo wound infections in combination with ex vivo human skin [ 33 ]. For illustration, S1 Fig shows a representative micrograph of the nanofibrous scaffold, acquired with scanning electron microscopy (SEM).…”

“…Independent of the bacterial composition of the biofilm, the Raman spectrum of the fiber network was characterized by Raman signals of cellulose acetate and gelatin ( S3 Fig ) [ 33 – 36 ]. Raman scans acquired from P .…”

“…aeruginosa and S . aureus , as well as dual-species biofilms of both pathogens over 72 h. To allow the prolonged co-cultivation of both strains, we employed a model system, which was previously developed by our group and closely simulates the microenvironment of wound infections [ 33 ]. Particularly, the influence of bacterial composition on structural biofilm development including the morphology and spatial organization as well as antibiotic tolerance and virulence in the context of persistent wound infections were evaluated.…”

Thermo/Pressure-Sensitive Self-Fixation Surgical Meshes: The Role of Adhesive Hydrogels in Interface Attachment

“…Raman spectroscopy has demonstrated to be a powerful technique to discriminate absorption bonds when working with systems that absorbs a large amount of water, as is the case of hydrogels and fibrous matrices. , The Raman spectra recorded (Figure C) show the chemical stability of the PP surface, as well as the appearance of some other peaks attributed to the hydrogel copolymer chains. More in particular, the ratio between the peaks centered at 807 and 841 cm –1 , which are attributed to the CH 2 group of the crystalline and amorphous regions of the PP substrate, respectively, decreases with the addition of AAm units, indicating a reduction in the crystallinity of the sample .…”

Facile In Situ Assembly of Nanofibers within Three-Dimensional Porous Matrices with Arbitrary Characteristics for Creating Biomimetic Architectures

“…Different methods such as 3D printing, freeze-drying, and self-assembly have been developed to produce biomaterials. − 3D printing is a tailorable and user-friendly technology for producing 3D architectures, but the printing resolution is significantly limited to the microscale. , Freeze-drying is another simple and effective method for the fabrication of 3D architectures, and the resulting materials generally present nonfibrous structures. , Self-assembly can be used to fabricate amyloid-like fibrils. , However, it is very difficult to obtain the desired dimensions and structures of nanofibers and nanofibrous materials with natural polymers by this method because the fabrication process is influenced by multiple factors such as molecular sequence and size, pH, temperature, and solvents. ,− Currently, ECM-mimicking biomaterials based on nanofibers (diameter of <1 μm) and microfibers (diameter of ≥1 μm) have been developed for biomedical applications. ,− However, the fabrication of nanofibers relies mostly on electrospinning technology. − A 3D nano/microfibrous composite matrix can be fabricated by combining electrospinning with a microfiber-producing technique such as melt deposition or 3D printing. ,− Unfortunately, these approaches present several challenges. First, the electrospinning of nanofibers requires a high concentration and suitable viscosity of the polymer (e.g., protein or polysaccharide) solution. − For example, to electrospin silk fibroin nanofibers, the concentration of silk fibroin in an aqueous solution has to be around 20% (w/v) or even higher. , Although some solvents such as hexafluoroisopropanol or trifluoroacetic acid can be used instead to decrease the concentration of natural polymers in the electrospinning processing, they are very toxic and environmentally unfriendly. − Second, many pure natural proteins and polysaccharides such as alginate could not be electrospun into nanofibers due to the high viscosity and gelation-sensitive characteristics of their solutions even at a low concentration. , Third, the pores of electrospun nanofibrous networks are very small due to the layer-by-layer deposition of electrospun nanofibers, which significantly limits the infiltration of cells .…”