Producing ultrapure wood cellulose nanofibrils and evaluating the cytotoxicity using human skin cells

Abstract

 Cellulose nanofibril dispersion (50 µg/ml) did not affect the cytotoxicity or metabolic activity of Normal Human Dermal Fibroblasts and Human Epidermal Keratinocytes  Aerogels made of cellulose nanofibrils induced a reduction of metabolic activity by the fibroblasts and keratinocytes, but no significant cell death  Cytokine profiling measuring 27 cytokines 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%) 3 AbstractWood cellulose nanofibrils 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 (CNF), 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±1.3 nm).Assessment of cytotoxicity and metabolic activity on Normal Human Dermal Fibroblasts and Human Epidermal Keratinocytes was done. CNF-dispersion of 50 g/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.

Evaluating the genotoxicity of cellulose nanofibrils in a co-culture of human lung epithelial cells and monocyte-derived macrophages

“…Nevertheless, it provides information that may be used for comparison purposes, namely with samples under similar conditions. Although the CNF was not tested for LPS contamination, previous studies by Nordli et al (2016) showed that the TEMPO-mediated oxidation performed in alkaline conditions strongly reduces the LPS content in the sample, becoming easier to wash out from the fibres after the oxidation process. Because washing was performed exhaustively in this CNF production it is unlikely that LPS still persists in the sample.…”

“…These nanocellulose types are generally considered as nontoxic, although nanocrystalline cellulose could induce low cytotoxicity and immunotoxicity in vitro and in vivo (Clift et al 2011;Yanamala et al 2014). Regarding CNF, the few published studies mainly indicate no relevant cytotoxic, genotoxic or immunotoxic effects (Alexandrescu et al 2013;;Nordli et al 2016;Pitkanen et al 2014;Vartiainen et al 2011). Nevertheless, a recent study by Catalán et al (2017) showed that C57Bl/6 mice exposure by pharyngeal aspiration to CNF produced through TEMPO oxidation led to an acute lung inflammatory response and induced DNA damage in lung cells.…”

Hemocompatibility of Ca2+‐Crosslinked Nanocellulose Hydrogels: Toward Efficient Management of Hemostasis

“…The possibility to create NFC‐based dressings for wound healing applications has been introduced and examined in a series of studies by ourselves and others, with promising results. However, to date, no work has addressed neither the hemocompatibility aspect of NFC‐based materials, nor the possibility of modifying these materials to obtain dressings that aid the first phase of wound healing—hemostasis.…”

Wide range humidity sensors printed on biocomposite films of cellulose nanofibril and poly(ethylene glycol)

“…All samples of CNF-based RH sensors showed an expected response to RH changes, that is, decrease of impedance with increase of RH. 16,56 The response of the biocomposite sample with PEG, that is, FS_T3.8_P40, was fast and stable at each level in the tested range. Based on this, we focused our efforts on the comparison between the samples without and with PEG where the sensor characteristic behavior differences were obvious.…”

“…The pulp fibers were washed three times with 0.1 M NaOH and autoclaved as described by Nordli et al 56 2,2,6,6-Tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation (3.8 and 6.0 mmol hypochlorite) was applied as pretreatment. An ULTRA-TURRAX was used for homogenizing the pulp fibers at a concentration of 2 wt %.…”