Bacterial infection has always been a great threat to public health, and new antimicrobials to combat it are urgently needed. Here, a series of quaternized β-chitin derivatives is prepared simply and homogeneously in an aqueous KOH/urea solution, which is a high-efficiency, energy-saving, and "green" route for the modification of chitin. The mild reaction conditions keep the acetamido groups of β-chitin intact and introduce quaternary ammonium groups on the primary hydroxyl at the C-6 position of the chitin backbone, allowing the quaternized β-chitin derivatives (QCs) to easily form micelles. These QCs are found to exhibit excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Rhizopus oryzae with minimum inhibitory concentrations (MICs) of 8, 12, 60, and 40 µg mL , respectively. As a specific highlight, their inherent outstanding biocompatibility and significant accelerating effects on the healing of uninfected, E. coli-infected, and S. aureus-infected wounds imply that these novel polysaccharide-based materials can be used as dressings for clinical skin regeneration, particularly for infected wounds.

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Bioimaging is a key technique for monitoring behavior and activity in vivo and plays an important role in the life science and medical fields. In the present work, for the first time, a new, safe cellulose based hybrid hydrogel was constructed from a cellulose solution containing rare-earth doped phosphor (PP) in an alkali/urea aqueous system using epichlorohydrin as a crosslinker. Its structure and properties were characterized by wide angle X-ray diffraction, FT-IR spectra, solid-state 13 C NMR, field emission scanning electron microscopy, UV-vis spectroscopy, fluorescence spectra, and compression tests. The results indicated that the PP particles were tightly embedded in the macroporous cellulose matrix, which not only supplied cavities for PP immobilization through relatively strong intermolecular hydrogen bonding interactions, but also supplied the pore wall as a shell to protect the structure and character of PP. Thus, the cellulose/PP hybrid (CPH) hydrogels emitted relatively strong green fluorescence under a UV lamp, as well as high brightness and long-lasting afterglow. This could avoid harmful radiation in the body and improve signal resolution with lower cell autofluorescence interference. Notably, CPH with strong afterglow could be detected both under the skin and in the stomach with and without excitation light, showing promising prospects as a candidate for bioimaging. Moreover, the hybrid hydrogels exhibited good compressive strength and processability.

In this work, chitin microspheres (NCM) having a nanofibrous architecture were constructed using a "bottom-up" fabrication pathway. The chitin chains rapidly self-assembled into nanofibers in NaOH/urea aqueous solution by a thermally induced method and subsequently formed weaved microspheres. The diameter of the chitin nanofibers and the size of the NCM were tunable by controlling the temperature and the processing parameters to be in the range from 26 to 55 nm and 3 to 130 μm, respectively. As a result of the nanofibrous surface and the inherent biocompatibility of chitin, cells could adhere to the chitin microspheres and showed a high attachment efficiency, indicating the great potential of the NCM for 3D cell microcarriers.

Conducting polymers have emerged as frontrunners to be alternatives for nerve regeneration, showing a possibility of the application of polyaniline (PANI) as the nerve guidance conduit. In the present work, the cellulose hydrogel was used as template to in situ synthesize PANI via the limited interfacial polymerization method, leading to one conductive side in the polymer. PANI sub-micrometer dendritic particles with mean diameter of ∼300 nm consisting of the PANI nanofibers and nanoparticles were uniformly assembled into the cellulose matrix. The hydrophobic PANI nanoparticles were immobilized in the hydrophilic cellulose via the phytic acid as "bridge" at presence of water through hydrogen bonding interaction. The PANI/cellulose composite hydrogels exhibited good mechanical properties and biocompatibility as well as excellent guiding capacity for the sciatic nerve regeneration of adult Sprague-Dawley rats without any extra treatment. On the basis of the fact that the pure cellulose hydrogel was an inert material for the neural repair, PANI played an indispensable role on the peripheral nerve regeneration. The hierarchical micro-nanostructure and electrical conductivity of PANI could remarkably induce the adhesion and guiding extension of neurons, showing its great potential in biomedical materials.

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BackgroundIn spite of progress in diagnostics and treatment of Hepatocellular Carcinoma (HCC), its prognosis remains poor, and improved treatment strategies for HCC require detailed understanding of the underlying mechanism. In this investigation we studied the role of Up-frameshift 1 (UPF1) in the tumorigenesis of HCC.MethodsWe determined the expression level of UPF1 in HCC tissues with quantitative real-time PCR and western blotting and then studied its clinical significance. Sodium bisulfite sequencing was used to investigate the regulation of UPF1. We explored the biological significance of UPF1 with gain-and-loss-of-function analyses both in vitro and in vivo. The relationship between UPF1 and SMAD7 was also investigated by western blotting and immunofluorescence.ResultsA great downregulation of UPF1 due to promoter hypermethylation was observed in tumor tissues compared to their adjacent normal tissues. Meanwhile, patients with low UPF1 expression have significantly poorer prognosis than those with high expression. Functionally, UPF1 regulated HCC tumorigenesis both in vitro and in vivo. Moreover, the decreased UPF1 level in HCC reduces NMD efficiency and leads to up-regulation of Smad7, then affects the TGF-β pathway.ConclusionOur findings revealed that UPF1 is a potential tumor suppressive gene and may be a potential therapeutic target for HCC.

For the first time, pure chitin fibers with relatively high strength, lustrous surface and circular cross section were spun directly from chitin solution dissolved in an NaOH-urea aqueous system with freezing. Subsequently, chitin nonwoven fabrics were constructed from the fresh wet fibers by hot pressing, and tested as wound dressings, showing excellent ability to accelerate healing, owing to the retainment of the intrinsic a-chitin structure.