In this work, a mixture of a sodium salt of carboxymethylcellulose (CMCNa) and polyethylene glycol diacrylate (PEGDA700) was used for the preparation of a microporous structure by using the ...combination of two different procedures. First, physical foaming was induced using Pluronic as a blowing agent, followed by a chemical stabilization. This second step was carried out by means of an azobis(2-methylpropionamidine)dihydrochloride as the thermoinitiator (TI). This reaction was activated by heating the sample homogeneously using a microwave generator. Finally, the influence of different CMCNa and PEGDA700 ratios on the final properties of the foams was investigated. The viscosity, water absorption capacity, elastic modulus and porous structure were evaluated for each sample. In addition, preliminary biological characterization was carried out with the aim to prove the biocompatibility of the resulting material. The foam, including 20% of PEGDA700 in the mixture, demonstrated higher viscosity and stability before thermo-polymerization. In addition, increased water absorption capacity, mechanical resistance and a more uniform microporous structure were obtained for this sample. In particular, foam with 3% of CMCNa shows a hierarchical structure with open pores of different sizes. This morphology increased the properties of the foams. The full set of samples demonstrated an excellent biocompatibility profile with a good cell proliferation rate of more than 7 days.
Due to its intrinsic biocompatibility, degradability, and antibacterial properties, chitosan is widely explored for biomedical and pharmaceutical applications, especially for the development of ...tissue engineering scaffolds and controlled drug delivery systems. In this work, physically crosslinked chitosan-based particles with submicrometric size were synthesized by means of a modified coacervation process, starting from aqueous solutions differing for the chitosan molecular weight and concentration. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to analyse the particle morphology and the mean diameter yielded by the different synthesis parameters. Daily DLS measurements were also performed to monitor the expected swelling of the particles in a buffer solution, up to four days of storage. The experimental findings showed that submicrometric chitosan particles, with an average diameter in the range 150-400 nm, could be successfully produced, with both chitosan molecular weight and concentration affecting the particle size. Moreover, the smallest particles, among those synthesized, were found to be stable in water solutions up to three days. This seems to suggest the potential of the investigated particles for short-term biomedical applications, e.g., controlled drug delivery over time windows ranging from hours to days.
Current bone implants based on new biomaterials may cause a foreign body reaction (FBR) around the implant itself thus prolonging the healing time following bone fractures. In this paper, biomimetic ...chitosan-based scaffolds promoting bone tissue regeneration and controlling inflammatory response are proposed. First, the anti-inflammatory potential of scaffolds on hMSCs stimulated by lipopolysaccharide (LPS) was investigated by dosing the levels of some interleukins and oxidative stress metabolites (IL-1β, IL-10 and nitrites) involved in immune response. Then, to mimic the inflammation process at osteoporotic site, the effect of scaffolds was evaluated on in vitro co-culture model based on osteoblasts and macrophages stimulated by LPS. Results demonstrated that bioactivated scaffolds are able to i) inhibit synthesis of inflammatory mediators such as IL-1β; ii) reduce oxidative stress metabolites; and iii) promote anti-inflammatory markers generation (IL-10) in hMSCs. Finally, bioactivated scaffolds show an anti-inflammatory activity also on in vitro co-cultures, which better mimic in vivo damaged bone microenvironment.
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•Functionalization of chitosan-based scaffolds was obtained through organic and inorganic cues.•The effect of scaffolds to modulate inflammatory response was evaluated on in vitro model mimicking inflamed microenvironment.•Bioactivated scaffolds are able to prevent inflammation reaction and reduce oxidative stress on in vitro model of osteoporosis.
The rising prevalence of obesity and metabolic disorders worldwide highlights the urgent need to find new long-term and clinically meaningful weight-loss therapies. Here, we evaluate the therapeutic ...potential and the mechanism of action of a biomimetic cellulose-based oral superabsorbent hydrogel (OSH). Treatment with OSH exerts effects on intestinal tissue and gut microbiota composition, functioning like a protective dynamic exoskeleton. It protects from gut barrier permeability disruption and induces rapid and consistent changes in the gut microbiota composition, specifically fostering Akkermansia muciniphila expansion. The mechanobiological, physical, and chemical structures of the gel are required for A. muciniphila growth. OSH treatment induces weight loss and reduces fat accumulation, in both preventative and therapeutic settings. OSH usage also prevents liver steatosis, immune infiltration, and fibrosis, limiting the progression of non-alcoholic fatty liver disease. Our work shows the potential of using OSH as a non-systemic mechanobiological approach to treat metabolic syndrome and its comorbidities.
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•Oral superabsorbent hydrogel (OSH) improves metabolic parameters in mice•Two mechanisms are involved: protects intestinal barriers and shapes the gut microbiota•Chemical and physical properties of OSH foster Akkermansia muciniphila growth
In brief, Silvestri et al. evaluate the therapeutic effects of a superabsorbent hydrogel as a non-systemic mechanobiological approach to treat metabolic syndrome and its comorbidities. Results imply that this device improves intestinal barrier protection while inducing changes in gut microbiota composition, specifically fostering Akkermansia muciniphila expansion.
In the last decade, cellulose-based hydrogels have been receiving increasing attention for a number of applications because of their smart swelling behavior, biodegradability, and biocompatibility. ...Given the dramatic spreading of obesity and overweight in the industrialized countries and the lack of scientific consensus over currently available dietary supplements, it was recently proposed that such hydrogels might be used as orally administered bulking agents in hypocaloric diets, because the hydrogel swelling in the stomach may greatly reduce the space available for food intake, thus giving a sense of fullness. This study is focused on the synthesis of cellulose-based hydrogels, starting from pharmaceutical and food grade cellulose derivatives, and shows that such hydrogels possess good swelling properties in water solutions mimicking the environmental conditions of the stomach and the intestine, as well as a good biocompatibility. The crosslinking agent used was a "zero-length" crosslinker, that is, a water soluble carbodiimide, which is washed out from the gel after the synthesis and does not affect the gel compatibility, as shown by preliminary biocompatibility assays. The experimental results confirmed that cellulose-based hydrogels might be a scientifically valid dietary adjuvant in the treatment of obesity and overweight, and provide further scientific evidence for future experiments on humans.
In this work, tunable nonwoven mats based on poly(3-hydroxybutyrate) (PHB) and type I collagen (Coll) were successfully produced by electrospinning. The PHB/Coll weight ratio (fixed at 100/0, 70/30, ...and 50/50, resp.) was found to control the morphological, thermal, mechanical, and degradation properties of the mats. Increasing collagen amounts led to larger diameters of the fibers (in the approximate range 600–900 nm), while delaying their thermal decomposition (from 245°C to 262°C). Collagen also accelerated the hydrolytic degradation of the mats upon incubation in aqueous medium at 37°C for 23 days (with final weight losses of 1%, 15%, and 23% for 100/0, 70/30, and 50/50 samples, resp.), as a result of increased mat wettability and reduced PHB crystallinity. Interestingly, 70/30 meshes were the ones displaying the lowest stiffness (~116 MPa; p<0.05 versus 100/0 and 50/50 meshes), while 50/50 samples had an elastic modulus comparable to that of 100/0 ones (~250 MPa), likely due to enhanced physical crosslinking of the collagen chains, at least at high protein amounts. All substrates were also found to allow for good viability and proliferation of murine fibroblasts, up to 6 days of culture. Collectively, the results evidenced the potential of as-spun PHB/Coll meshes for tissue engineering applications.
Micropatterned collagen scaffold with axially oriented pores embedded with poly(lactide-co-glycolide) nanoparticles (PLGA NPs) was synthesized and characterized. Two different concentrations of PLGA ...nanoparticles have been tested and the experimental results indicate that the concentration affects the release kinetic, whereas the stiffness, the crosslink density, and the degradation rate of the collagen matrix are comparable to bare scaffold. Further, the proposed crosslinking procedure provides a resistance to thermal and enzymatic degradation, thereby promoting the persistence of scaffold for a period of time compatible with nerve regeneration.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this study we investigated the impact of three different sterilization methods, dry heat (DHS), ethylene oxide (EtO) and electron beam radiation (β), on the properties of cylindrical collagen ...scaffolds with longitudinally oriented pore channels, specifically designed for peripheral nerve regeneration. Scanning electron microscopy, mechanical testing, quantification of primary amines, differential scanning calorimetry and enzymatic degradation were performed to analyze possible structural and chemical changes induced by the sterilization. Moreover, in vitro proliferation and infiltration of the rat Schwann cell line RSC96 within the scaffolds was evaluated, up to 10days of culture. No major differences in morphology and compressive stiffness were observed among scaffolds sterilized by the different methods, as all samples showed approximately the same structure and stiffness as the unsterilized control. Proliferation, infiltration, distribution and morphology of RSC96 cells within the scaffolds were also comparable throughout the duration of the cell culture study, regardless of the sterilization treatment. However, we found a slight increase of chemical crosslinking upon sterilization (EtO<DHS<β), together with an enhanced resistance to denaturation of the EtO treated scaffolds and a significantly accelerated enzymatic degradation of the β sterilized scaffolds. The results demonstrated that β irradiation impaired the scaffold properties to a greater extent, whereas EtO exposure appeared as the most suitable method for the sterilization of the proposed scaffolds.
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•Production of longitudinally oriented collagen scaffolds for nerve regeneration•Control of pore structure and crosslinking•Impact of terminal sterilization on the scaffold properties•Proliferation and infiltration of Schwann cells within the sterilized scaffolds
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