•Ultrapure wood cellulose nanofibrils (CNF) have been produced with a final endotoxin level of 45 endotoxin units/g cellulose.•CNF dispersion (50μg/ml) did not affect the cytotoxicity or metabolic ...activity of fibroblasts and keratinocytes.•Aerogels made of CNF induced a reduction of metabolic activity by the fibroblasts and keratinocytes, but no significant cell death.•Cytokine profiling revealed that the keratinocytes and fibroblasts did not induce cytokines upon direct exposure to the CNF materials.•Due to the nano dimension of the CNFs, the aerogels had a high moisture-holding capacity (∼7500%).
Wood cellulose nanofibrils (CNF) have been suggested as a potential wound healing material, but its utilization is limited by FDA requirements regarding endotoxin levels. In this study a method using sodium hydroxide followed by TEMPO mediated oxidation was developed to produce ultrapure cellulose nanofibrils, with an endotoxin level of 45 endotoxin units/g (EU/g) cellulose. Scanning transmission electron microscopy (S(T)EM) revealed a highly nanofibrillated structure (lateral width of 3.7±1.3nm).
Assessment of cytotoxicity and metabolic activity on Normal Human Dermal Fibroblasts and Human Epidermal Keratinocytes was done. CNF-dispersion of 50μg/ml did not affect the cells. CNF-aerogels induced a reduction of metabolic activity by the fibroblasts and keratinocytes, but no significant cell death. Cytokine profiling revealed no induction of the 27 cytokines tested upon exposure to CNF. The moisture-holding capacity of aerogels was relatively high (∼7500%), compared to a commercially available wound dressing (∼2500%), indicating that the CNF material is promising as dressing material for management of wounds with a moderate to high amount of exudate.
•Nanocellulose shows potential in wound dressing applications.•Nanocellulose and PEG form translucent and ductile films.•Nanocellulose-PEG biocomposites are not cytotoxic against human skin ...cells.•Ductile and translucent nanocellulose-PEG films are appropriate for modification by printing techniques.
There is potential that nanocellulose structures can act as a substrate for biomedical applications in which printing can expand its use as a functionalized biomaterial. Nanocellulose has a variety of advantages, which make the material suitable for use in biomedical devices that include wound dressings. The material does not promote bacterial growth, allows for production of translucent films and provides a moist wound-healing environment. However it is intrinsically brittle so research is needed to develop its flexibility and strength through the addition of plasticisers. In this work, we explore the effect of Polyethylene Glycol (PEG 400) as a plasticizer on nanocellulose film formation and performance. The nanocellulose used was prepared with TEMPO mediated oxidation. We also demonstrated different methods such as laser profilometry and atomic force microscopy to observe the topography and morphology of the films. FTIR, UV–vis spectroscopy was used to look at the characteristics of the nanocellulose films. In addition, the mechanical strength of the films with and without plasticizers was assessed. This led to the formulation of films that included PEG400 at 10–40% by weight. These demonstrated properties that are suitable for wound dressings. Additionally, the PEG modification yielded films that showed a surface morphology adequate for surface modification by printing. Importantly, a cytotoxicity test was performed using Human Dermal Fibroblasts and Human Epidermal Keratinocytes. The results showed no effect on the metabolic activity when fibroblasts were incubated in the presence of films containing 10 and 25% PEG. A reduction was measured in the presence of PEG at 40%. However, no significant cell death was detected in any of the cell-types. Hence, the nanocellulose-PEG films are not considered to be cytotoxic against human skin cells at the concentrations applied in this study.
The development and persistence of antibody secreting cells (ASC) after antigenic challenge remain inadequately understood in teleosts. In this study, intraperitoneal (ip) injection of Atlantic ...salmon (Salmo salar) with salmonid alphavirus (WtSAV3) increased the total ASC response, peaking 3–6 weeks post injection (wpi) locally in the peritoneal cavity (PerC) and in systemic lymphoid tissues, while at 13 wpi the response was only elevated in PerC. At the same time point a specific ASC response was induced by WtSAV3 in PerC and systemic tissues, with the highest frequency in PerC, suggesting a local role. Inactivated SAV (InSAV1) induced comparatively lower ASC responses in all sites, and specific serum antibodies were only induced by WtSAV3 and not by InSAV1. An InSAV1 boost did not increase these responses. Expression of immune marker genes implies a role for PerC adipose tissue in the PerC immune response. Overall, the study suggests the Atlantic salmon PerC as a secondary immune site and an ASC survival niche.
•Infection with salmonid alphavirus induced a specific IgM secreting cell response.•The local B cell response in the peritoneal cavity was pronounced and long lasting.•Gene expression suggests peritoneal adipose tissue is involved in the B cell response.•The B cell response to inactivated virus was modest or absent, also after a boost.
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