Language：English   Publisher：Biomedical Materials Bristol  

Bio-based hydrogels as three-dimensional (3D) constructs have attracted attention in advanced tissue engineering. Compared with conventional two-dimensional (2D) cell culture, cells grown in 3D scaffolds are expected to demonstrate the inherent behavior of living organisms of cellular spheroids. Herein, we constructed cell-laden nanofiber-based hydrogels in combination with 2,2,6,6-tetramethylpiperidine 1-oxyl-oxidized cellulose nanofiber (TOCNF) and chitosan nanofiber (CsNF) for bioadaptive liver tissue engineering. The carboxylates of TOCNF and amines of CsNF were directly crosslinked via EDC/NHS chemistry. The rheological properties of the solutions for the nanofibers and hydrogels revealed sufficient physical properties for the injection, printing, and plotting process, as well as significant encapsulation of living cells. As-designed hydrogels exhibited excellent viscoelastic properties with typical shear-thinning behavior, and had a storage modulus of 1234 Pa ± 68 Pa, suitable for cell culture. Non-cytotoxicity was confirmed using a live/dead assay with mouse-derived fibroblast NIH/3T3 cells. Human hepatocellular carcinoma HepG2 cells could be cultured on a gel surface (2D environment) and encapsulated in the gel structure (3D environment), which enabled 10 d growth with high gene expression level of albumin of HepG2 spheroids in the 3D gels. The biodegradable cell-laden hydrogels are expected to mimic the cellular microenvironment and provide potential for bioadaptive 3D cell cultures in biomedical applications.

DOI： 10.1088/1748-605X/acd49a

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PubMed

Language：English   Publisher：Small  

The intracellular uptake and interaction behavior of emulsion microparticles in liver cells critical to host defense and inflammation is significant to understanding their potential cytotoxicity and biomedical applications. In this study, the cell death responses of fibroblastic, hepatocyte, and Kupffer cells (KCs) induced by four types of emulsion particles that are stabilized by polysaccharide nanofibers (cellulose or chitin), an inorganic nanoparticle (β-tricalcium phosphate), or surfactants are compared. Pickering emulsion (PE) microparticles stabilized by polysaccharide nanofibers or inorganic nanoparticles have a droplet size of 1–3 µm, while the surfactant-stabilized emulsion has a diameter of ≈190 nm. Polysaccharide nanofiber-stabilized PEs (PPEs) markedly induce lactate dehydrogenase release in all cell types. Additionally, characteristic pyroptotic cell death, which is accompanied by cell swelling, membrane blebbing, and caspase-1 activation, occurs in hepatocytes and KCs. These PE microparticles are co-cultured with lipopolysaccharide-primed KCs associated with cytokine interleukin-1β release, and the PPEs demonstrate biological activity as a mediator of the inflammation response. Well-designed PPE microparticles induce pyroptosis of liver cells, which may provide new insight into regulating inflammation-related diseases for designing potent anticancer drugs and vaccine adjuvants.

DOI： 10.1002/smll.202207433

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Publisher：Bioresources  

Cellulose nanofiber (CNF) derived from woody bioresources is a fascinating natural nanomaterial. In this work, spherical microparticles were fabricated by using TEMPO-oxidized CNF (TOCNF) and cellulose diacetate (CDA) via Pickering emulsion templating. The CDA-dissolved organic solvents were emulsified stably with TOCNF, followed by removing the solvents to form microspheres with core-shell structures, where the CDA cores were covered with the TOCNF shells. The prepared spherical microparticles possessed an average diameter and sphericity index of 6.4 μm and 0.96, respectively. The zeta-potential value was approximately-48 mV, indicating the stable colloidal system in water. The CDA/TOCNF microparticles were stained with toluidine blue dye for negatively-charged TOCNF. Besides, furry nanofiber-like morphology was observed on the particle surface by scanning electron microscopy. Wood-derived CDA/TOCNF microspheres are a promising alternative to fossil resource-derived, non-biodegradable microbeads in cosmetic applications.

DOI： 10.15376/biores.18.1.1482-1492

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Publisher：Advanced Functional Materials  

Highly porous three-dimensional (3D) scaffolds can mimic the lobular structure of a human liver where hepatocytes are organized. However, 3D scaffolds with uniformly porous and oriented structures are challenging to fabricate without cross-linking agents. Herein, this work presents a Pickering emulsion-induced interface approach to construct aligned porous scaffolds for 3D cell cultures through the combined use of surface-carboxylated cellulose nanofibers and chitosan nanofibers as stabilizers, and freezing/lyophilization to remove the oil phase. The obtained Pickering emulsions exhibit long-term stability and their droplet sizes are tunable from 2.7 to 10.2 µm. Assembly at the oil–water interface can be modulated by controlling the NaCl dosage and oil phase proportion, resulting in porous foams with tunable porosity and versatile architectures as an in vitro alternative to the native liver microenvironment. The foams are noncytotoxic, confirmed using mouse fibroblast NIH/3T3 cells, and the cells grow both on the surface and in the internal structure of the foam. Notably, the 3D porous scaffolds are favorable microenvironments for the formation of human liver carcinoma HepG2 spheroidal cells, which exhibit liver-like activity. This strategy based on Pickering emulsion templating provides a new avenue for constructing bioadaptive 3D scaffolds, specifically all-biomass porous foams, for tissue engineering.

DOI： 10.1002/adfm.202200249

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Publisher：Cellulose  

Abstract: The extracellular matrix (ECM) is critical to cell attachment, proliferation, and differentiation; therefore, development of bioadaptive ECM-mimetic cell culture scaffolds is an active area of research in tissue engineering. Collagen (rigid nanofiber morphology) and hyaluronan (carboxy groups displayed in a regular manner) are typical ECM components found in vivo. In this work, we used wood-derived crystalline cellulose nanofibers (CNFs) to provide bioadaptive microenvironments for cell culture. Catalytic oxidation of wood CNFs using 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) afforded crystalline nanofibrous scaffolds with various carboxy contents, ranging from 0.31 to 1.60 mmol g^–1, of the TEMPO-oxidized CNFs (TOCNFs). Mouse fibroblast cells were subjected to the hydrophilic TOCNF-coated substrates, which were transparent and exhibited a native cellulose I crystalline structure; good cell proliferation was observed for the TOCNFs with carboxy content of 0.8–1.0 mmol g^–1, although intact CNF was bioinert and an excess of carboxylates negatively impacted cell growth. Neither mercerized TOCNFs with a cellulose II structure nor carboxymethylated CNFs with irregular surface carboxy groups contributed to cell proliferation. Therefore, the rigid nanofiber morphology of xeno-free, crystalline TOCNFs with regular alignment of surface carboxy groups would hold the key to providing bioadaptive, ECM-mimetic cellular microenvironments. Graphic Abstract: [Figure not available: see fulltext.]

DOI： 10.1007/s10570-021-04154-5

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Language：English   Publisher：MDPI (Multidisciplinary Digital Publishing Institute)  

Extracellular matrix (ECM) as a structural and biochemical scaffold to surrounding cells plays significant roles in cell adhesion, migration, proliferation and differentiation. Herein, we show the novel combination of TEMPO-oxidized cellulose nanofiber (TOCNF) and surface-N-deacetylated chitin nanofiber (SDCtNF), respectively, having carboxylate and amine groups on each crystalline surface, for mouse fibroblast cell culture. The TOCNF/SDCtNF composite scaffolds demonstrated characteristic cellular behavior, strongly depending on the molar ratios of carboxylates and amines of polysaccharide NFs. Pure TOCNF substrate exhibited good cell attachment, although intact carboxylate-free CNF made no contribution to cell adhesion. By contrast, pure SDCtNF induced crucial cell aggregation to form spheroids; nevertheless, the combination of TOCNF and SDCtNF enhanced cell attachment and subsequent proliferation. Molecular blend of carboxymethylcellulose and acid-soluble chitosan made nearly no contribution to cell culture behavior. The wound healing assay revealed that the polysaccharide combination markedly promoted skin repair for wound healing. Both of TOCNF and SDCtNF possessed rigid nanofiber nanoarchitectures with native crystalline forms and regularly-repeated functional groups, of which such structural characteristics would provide a potential for developing cell culture scaffolds having ECM functions, possibly promoting good cellular adhesion, migration and growth in the designated cellular microenvironments.

DOI： 10.3390/nano12030402

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CiNii Research

Language：Japanese  

Language：Japanese  

Language：English