Reduced graphene oxide (RGO) has proven to be effective in trace gas detection at room temperature ambient conditions. However, the slow response-recovery characteristic is a major hurdle for the RGO-based gas sensors. Herein, we report a gravure-printed chemoresistor-type NO2 sensor based on sulfonated RGO (S-RGO) decorated with Ag nanoparticles (Ag-S-RGO). Large amounts of silver nanoparticles with an average particle size of 10-20 nm were uniformly assembled on flat S-RGO surfaces. The printed Ag-S-RGO sensor possesses a high sensitivity and fast response-recovery characteristic over NO2 concentrations ranging from 0.5 to 50 ppm. Upon exposure to 50 ppm NO2 at room temperature, the Ag-S-RGO sensor shows a sensitivity of 74.6%, a response time of 12 s and a recovery time of 20 s. In addition, the Ag-S-RGO sensors exhibit satisfactory flexibility with an almost constant resistance after 1000 bending cycles. The printed and high-performance Ag-S-RGO sensors described here will be a good prospect in environmental monitoring of NO2.

Rosacea is a chronic inflammatory skin disease whose pathophysiological mechanism is still unclear. However, it is known that mast cell (MC) numbers is increased in the dermis of rosacea patients. MC proteases not only recruit other immune cells, which amplify the inflammatory response, but also cause vasodilation and angiogenesis. MCs are also one of the primary sources of cathelicidin LL-37 (Cath LL-37), an antimicrobial peptide that has been shown to be an enabler of rosacea pathogenesis. Here, we demonstrate that MCs are key mediators of cathelicidin initiated skin inflammation. Following Cath LL-37 injection into the dermis, MC deficient B6.Cg-KitW-sh/HNihrJaeBsmJ (KitW-sh) mice did not develop rosacea-like features. Conversely, chymase (p<0.001), tryptase and Mmp9 (p<0.01) mRNA levels were significantly higher in C57BL/6 Wild Type (WT) mice. Treating WT mice with a MC stabilizer significantly decreased the expressions of Mmp9 and Cxcl2 (p<0.01). Our data was confirmed on Erythematotelangiectatic rosacea subjects that showed a decrease in MMP activity (p<0.05), after eight weeks of topical cromolyn treatment. We conclude that MCs play a central role in the development of inflammation subsequent to Cath LL-37 activation and that down regulation of activated MCs may be a therapy for rosacea treatment.

Graphene-based materials have attracted increasing attention due to their atomically-thick two-dimensional structures, high conductivity, excellent mechanical properties, and large specific surface areas. The combination of biomolecules with graphene-based materials offers a promising method to fabricate novel graphene-biomolecule hybrid nanomaterials with unique functions in biology, medicine, nanotechnology, and materials science. In this review, we focus on a summarization of the recent studies in functionalizing graphene-based materials using different biomolecules, such as DNA, peptides, proteins, enzymes, carbohydrates, and viruses. The different interactions between graphene and biomolecules at the molecular level are demonstrated and discussed in detail. In addition, the potential applications of the created graphene-biomolecule nanohybrids in drug delivery, cancer treatment, tissue engineering, biosensors, bioimaging, energy materials, and other nanotechnological applications are presented. This review will be helpful to know the modification of graphene with biomolecules, understand the interactions between graphene and biomolecules at the molecular level, and design functional graphene-based nanomaterials with unique properties for various applications.

Background Mast cell (MC) progenitors leave the bone marrow, enter the circulation, and settle in the skin and other tissues. Their maturation in tissues is influenced by the surrounding microenvironment. Objective We tested the hypothesis that environmental factors play a role in MC maturation in the skin. Methods MCs were numerically, phenotypically, and functionally compared between germ-free (GF), SPF, and GF mice reconstituted with microbiota. Maturity of MCs was then correlated with skin levels of stem cell factor (SCF), a critical MC differentiation factor, and lipoteichoic acid (LTA), a TLR2 ligand. MCs were also evaluated in mice with keratinocyte-specific deletion of Scf. Results We found that GF mice express abnormally low amounts of stem cell factor (SCF), a critical MC differentiation factor, and contain MCs that are largely undifferentiated. Reconstituting the GF microbiota reverted this MC phenotype to normal, indicating that the phenotype is related to ongoing interactions of microbiota and skin. Consistent with the immaturity of GF MCs, degranulation-provoking compound 48/80 induced less edema in the skin of GF mice than in conventional mice. Our results show that the skin microbiome drives SCF production in keratinocytes, which triggers the differentiation of dermal MCs. Since the skin microbiome is a rich source of lipoteichoic acid (LTA), a TLR2 ligand, we mimicked the GF microbiome impact on MCs by applying LTA to the skin of GF mice. We also demonstrated that MC migration within the skin depends exclusively on keratinocyte-produced SCF. Conclusion This study has revealed a novel mechanism by which the skin microbiota signals the recruitment and maturation of MCs within the dermis via SCF production by LTA-stimulated keratinocytes.

Mast cells (MCs) are well known effectors of allergic reactions and are considered sentinels in the skin and mucosa. In addition, through their production of cathelicidin, mast cells have the capacity to oppose invading pathogens. We therefore hypothesized that mast cells could act as sentinels in the skin against viral infections using antimicrobial peptides. Here, we demonstrate that mast cells react to Vaccinia virus (VV) and degranulate using a membrane-activated pathway that leads to antimicrobial peptide discharge and virus inactivation. This finding was supported using a mouse model of viral infection. Mast cell-deficient (Kitwsh−/−) mice were more susceptible to skin VV infection than the wild-type animals, while Kitwsh−/− mice reconstituted with mast cells in the skin showed a normal response to VV. Using mast cells derived from mice deficient in cathelicidin antimicrobial peptide, we showed that antimicrobial peptides are one important antiviral granule component in vivo skin infections. In conclusion, our paper demonstrates that: MC presence protects mice from VV skin infection. MC degranulation is required for protecting mice from VV. Neutralizing antibody to the L1 fusion entry protein of VV inhibits degranulation apparently by preventing S1PR2 activation by viral membrane lipids. Antimicrobial peptide release from mast cell granules is necessary to inactivate VV infectivity.

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Mast cells (MCs) are considered sentinels in the skin and mucosa. Their ability to release antimicrobial peptides, such as cathelicidin, protects against bacterial infections when the epithelial barrier is breached. We recently described that MCs defend against bacterial and viral infections through the release of cathelicidin during degranulation. In this study, we hypothesize that cathelicidin expression is induced in MCs by the activation of TLR2 from bacterial products (lipoteichoic acid) produced by commensal bacteria at the epithelial surface. Our research shows that signaling through TLR2 increases the production and expression of cathelicidin in mast cells, thereby enhancing their capacity to fight vaccinia virus. MCs deficient in cathelicidin were less efficient in killing vaccinia virus after lipoteichoic acid stimulation than wild-type cells. Moreover, the activation of TLR2 increases the MC recruitment at the skin barrier interface. Taken together, our findings reveal that the expression and control of antimicrobial peptides and TLR signaling on MCs are key in fighting viral infection. Our findings also provide new insights into the pathogenesis of skin infections and suggest potential roles for MCs and TLR2 ligands in antiviral therapy.

Vitis amurensis Rupr. is an exceptional wild-growing Vitis (grape) species that can safely survive a wide range of cold conditions, but the underlying cold-adaptive mechanism associated with gene regulation is poorly investigated. We have analyzed the physiochemical and transcriptomic changes caused by cold stress in a cold-tolerant accession, 'Heilongjiang seedling', of Chinese wild V. amurensis. We statistically determined that a total of 6,850 cold-regulated transcripts were involved in cold regulation, including 3,676 up-regulated and 3,174 down-regulated transcripts. A global survey of messenger RNA revealed that skipped exon is the most prevalent form of alternative spicing event. Importantly, we found that the total splicing events increased with the prolonged cold stress. We also identified thirty-eight major TF families that were involved in cold regulation, some of which were previously unknown. Moreover, a large number of candidate pathways for the metabolism or biosynthesis of secondary metabolites were found to be regulated by cold, which is of potential importance in coordinating cold tolerance with growth and development. Several heat shock proteins and heat shock factors were also detected to be intensively cold-regulated. Furthermore, we validated the expression profiles of 16 candidates using qRT-PCR to further confirm the accuracy of the RNA-seq data. Our results provide a genome-wide view of the dynamic changes in the transcriptome of V. amurensis, in which it is evident that various structural and regulatory genes are crucial for cold tolerance/adaptation. Moreover, our robust dataset advances our knowledge of the genes involved in the complex regulatory networks of cold stress and leads to a better understanding of cold tolerance mechanisms in this extremely cold-tolerant Vitis species.