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Acute liver failure (ALF) occurs due to severe liver damage that triggers rapid loss of normal liver function. Here, we investigate the usefulness of an injectable liver extracellular matrix (LECM)-rich hydrogel generated from an optimized decellularization protocol incorporated with silver nanoparticles (AgNPs) as a promising therapy for ALF. First, we optimized a non-destructive protocol for rat liver decellularization to obtain ECM-rich well-preserved scaffold. Then, LECM hydrogel generated from two commonly used decellularization protocols were compared by LECM hydrogel obtained from our optimized protocol. The ALF model was induced by an intraperitoneal (IP) thioacetamide (TAA) injection followed by the IP injection of LECM hydrogel, collagen-AgNP mixture, or LECM hydrogel-AgNP mixture. LECM-rich scaffold and hydrogel were successfully obtained using our optimized decellularization protocol. Use of the LECM hydrogel-AgNP mixture to treat TAA-induced ALF greatly improved liver injury and histological liver regeneration. Interleukin-6 and transforming growth factor-beta expressions were significantly reduced, while albumin, hepatocyte growth factor, and Ki67-positive cells were highly expressed. Moreover, aspartate transaminase and alanine transaminase plasma levels and liver homogenate nitric oxide level were significantly lowered. In conclusion, the LECM hydrogel-AgNP mixture has potential efficient therapeutic and regenerative effects on TAA-induced liver injury., (© 2020 Wiley Periodicals LLC.)

Liver fibrosis results from excessive accumulation of extracellular matrix (ECM) proteins that distort the hepatic architecture. Progression of liver fibrosis results in cirrhosis and liver failure, and often, liver transplantation is required. The decellularized liver tissue contains different components that mimic the natural hepatic environment. We hypothesized that a decellularized liver hydrogel can be used to replace the necrotic hepatocytes and damaged ECM. Therefore, our aim in this study is to develop a therapy for treating liver fibrosis. Mice livers were decellularized and processed to form a hepatic hydrogel. We evaluated the biocompatibility and bioactivity of the hydrogel. The ability of the hydrogel to enhance the migration of hepatocytes and endothelial cells was investigated. Human hepatic stellate cell line (LX-2) activated by transforming growth factor-β1 (TGF-β1) was used as in vitro model for fibrogenesis. Then, the hydrogel was injected into the liver parenchyma of mice after the induction of liver fibrosis using thioacetamide. The resulting hydrogel maintained a complex composition, which included glycosaminoglycans, collagen, elastin, and growth factors. Hepatocytes and endothelial cells were shown to migrate toward the hydrogel in vitro. Liver hydrogel improved TGF-β1-induced LX-2 cells activation via blocking the TGF-β1/Smad pathway. The matrix was delivered successfully in vivo and enhanced the reduction of fibrosis and recovery to a nearly normal structure. In conclusion, we have demonstrated that the liver hydrogel can be utilized as an injectable biomaterial for liver tissue engineering in order to reduce the degree of fibrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Poly(N-isopropylacrylamide)/Laponite (PNIPAM/Laponite) gradient nanocomposite hydrogel actuators are developed as temperature-controlled actuators with excellent performance using a facile electrophoresis method. The actuators exhibit a rapid (20 s response time) and reversible response, as well as large deformation (bending angle of 231°), which is due to the graded forces generated by the thermo-induced anisotropic shrinkage and extension of the gradient hydrogels. A good linear relationship is observed between the maximum bending angles and the corresponding temperatures for the actuators with fixed sizes. Moreover, the gradient hydrogel with high water content achieved larger actuation angles and shorter response time than the one with low water content, showing an interesting water-promoted effect. Meanwhile, different types of actuators are designed to suit for more specific scenarios, and may be used for various applications, such as biosensing, artificial organization, and transportation of targeted objects., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The tough polyacrylamide/Laponite/titania (TiO2) dual nanocomposite (NC) hydrogel was fabricated by in situ radical polymerization of acrylamide (AAm) in the dispersion of Laponite and TiO2. TiO2 nanoparticles were prepared by sol‐gel method and used as both the inorganic filler and multi‐functional crosslinking agent. The morphology of hydrogel was tuned as functions of the sodium hydroxide (NaOH) concentration and the ratio of Ti (mmol) to clay (g) (mmol Ti/g clay). SEM and HR‐TEM morphologies revealed that Laponite and TiO2 tended to form a uniform and regular microstructure like peasecod in poly(acrylamide) (PAAm) matrix due to the synergistic effect between electrostatic interaction and covalent interaction when the concentration of NaOH used in TiO2 hydrosol increased to 1 × 10−1 mol/L. This homogeneous microstructure enhanced mechanical properties of hydrogel. The compression strength, modulus and fracture energy reached 2,107 kPa, 247 kPa, and 1,837 J/m2, respectively. The gels exhibited excellent fatigue resistance and good UV protective performance. It might have potential application in optical materials, wound dressing materials and tissue engineering scaffolds. POLYM. COMPOS., 40:E466–E475, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT: A facile method was explored to synthesize thermosensitive poly[N‐isopropylacrylamide (NIPAM)‐co‐methacryloxyethyltrimethyl ammonium chloride (DMC)]/Na2WO4 cationic hydrogels via copolymerization of NIPAM and DMC in the presence of Na2WO4. Na2WO4 acted as both a physical crosslinking agent and a porogen precursor. The hydrogels were characterized by Fourier transform infrared spectroscopy, energy dispersive X‐ray, thermogravimetry, environmental scanning electron microscopy, and transmission electron microscopy. Effects of various salt solutions, pH solutions on swelling were investigated. Thermosensitivity of the hydrogels were also investigated in various polar solvents at different temperatures. The resultant hydrogel showed a fast swelling rate and good salt tolerance. The hydrogels reached the swelling equilibrium within 10 min. Moreover, the swelling ratio of the hydrogels increased with the increase of the polarity of the solvent. In the water, the swelling ratio decreased with the increasing of temperature, but remained at a high level even at 80 °C since the pore structure weaken the lower critical solution temperature effect of PNIPAM. The swelling ratio increased instead in low polar solvent, while it became negligible in nonpolar solvent with the increasing of temperature. The whole swelling kinetics was fit for Schott's pseudo‐second order model. The hydrogels have a great potential as catalysts and smart materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46375. [ABSTRACT FROM AUTHOR]

A new dual nanocomposite hydrogel with excellent mechanical properties have been developed by sol-gel reaction of vinyl triethoxysilane (VTES) and in situ radical polymerization of acrylamide (AM) and VTES in the dispersion of Bentonite (Bent). Unlike conventional cationic surfactant intercalators, VTES was used as both an intercalator and a crosslinker. Good intercalation and exfoliation were confirmed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The covalent interaction between Bent and silica by condensation of VTES was confirmed by Fourier transform infrared spectroscopy (FTIR) and 29 Si solid-state NMR. The compressive stress of the gel reached up to 4.65 MPa with ha huge fracture energy of 6285.59 J m − 2 (water content of 85 wt%). The gel showed a high cross-linking density of 77.17 mol m − 3 by dynamic viscoelastic measurement. The compressive stress increased to above 25 MPa when the water content decreased to 50 wt%. In the tough nanocomposite hydrogel, the nano-scaled SiO 2 was covalently bonded to intercalated or exfoliated Bent and polymer chains, and thus greatly improved the mechanical properties of the gel [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Dual NC hydrogel with homogeneous SiO 2 @TiO 2 core-shell nanoparticle was fabricated. • Interaction of SiO 2 @TiO 2 NPs and polymers enhanced fluorescent stability. • Fluorescence and toughness were adjusted by the shell thickness of SiO 2 @TiO 2 NPs. • Dual crosslinking and dual nanocomposite contributed to high mechanical property. Abstract A tough and fluorescent NC hydrogel was fabricated by introduction of SiO 2 @TiO 2 core-shell structure nanoparticles (NPs) into polyacrylamide (PAAm)/Laponite nanocomposite (NC) hydrogel. The photoluminescent and mechanical properties of the resultant PAAm/Laponite/SiO 2 @TiO 2 dual NC hydrogel were explored with respect to the shell thickness of SiO 2 @TiO 2. The dual NC hydrogel emitted stable and bright blue photoluminescence (PL), when radiated at 350 nm. The emission wavelength was slightly shifted from 423 to 428 nm with the increasing of the shell thickness due to the surface interaction of SiO 2 @TiO 2 NPs and polymers. Besides, the compressive strength and compressive fracture energy of the PAAm/Laponite/SiO 2 @TiO 2 dual NC hydrogels were 7535.8 kPa and 5740.3 J/m2 which increased by 19 and 21%, respectively, relative to the MLS@T 0 dual NC hydrogel. The tensile strength was 207.2 kPa at a strain of 730%. The dual crosslinking of SiO 2 @TiO 2 NPs and Laponite, as well as the dual nanocomposite structure were responsible for the enhanced mechanical properties. [ABSTRACT FROM AUTHOR]