Optimized antibody immobilization on natural silica-based nanostructures for the selective detection of E. coli.

This study reports for the first time the surface modification of fluorescent nanoparticles derived from geothermal silica precipitate with Escherichia coli (E. coli) antibody. The immobilization of biomolecules on the inorganic surface has been carried out using two different pathways, namely the silanization and hydrosilylation reactions. The former applied (3-aminopropyl)triethoxysilane (APTES) as the crosslinker, while the latter used N-hydroxysuccinimide coupled with N-ethyl-N'-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC/NHS). Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX), and fluorescence spectroscopy were used to confirm the chemical, physical, and optical properties of the surface-modified fluorescent silica nanoparticles (FSNPs). Based on the results of the FTIR, fluorescence spectroscopy and stability tests, the modified FSNPs with EDC/NHS with a ratio of 4 : 1 were proven to provide the optimum results for further conjugation with antibodies, affording the FSNP-Ab2 sample. The FSNP-Ab2 sample was further tested as a nanoplatform for the fluorescence-quenching detection of E. coli, which provided a linear range of 102 to 107 CFU mL-1 for E. coli with a limit of detection (LoD) of 1.6 × 102 CFU mL-1. The selectivity of the biosensor was observed to be excellent for E. coli compared to that for P. aeruginosa and S. typhimurium, with reductions in the maximum fluorescence intensity at 588 nm of 89.22%, 26.23%, and 54.06%, respectively. The inorganic nanostructure-biomolecule conjugation with optimized coupling agents showed promising analytical performance as a selective nanoplatform for detecting E. coli bacteria.

Reduced graphene oxide nanosheets decorated with core-shell of Fe3O4-Au nanoparticles for rapid SERS detection and hyperthermia treatment of bacteria.

In this study, the core-shell of Fe3O4-Au nanoparticles (NPs) were prepared by seeding AuNPs onto Fe3O4 NPs modified with poly-ethylenimine (PEI). Later, Fe3O4-Au NPs were attached to cationic poly(dimethyldiallylammonium chloride) (PDDA)-modified graphene oxide (GO) nanosheets through in situ self-assembly behaviors, termed as Fe3O4-Au@RGO nanocomposites, for surface-enhanced Raman scattering (SERS) detection and hyperthermia treatment of bacteria. The resulting Fe3O4-Au@RGO nanocomposites were evaluated systematically by transmission electron microscope, zeta potential, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometer. It revealed that the core-shell structured Fe3O4-Au NPs were dispersed homogeneously on the surface of the GO nanosheets. Furthermore, the rapid SERS detection for small biomolecules and bacteria was conducted by Raman spectroscopy. The results showed that the greatest SERS intensity was fne tuned at the weight ratio of Fe3O4-Au/RGO nanosheets was 20/1, displaying the optimal interparticle gap of AuNPs to induce the huge hot-spots effect. The magnetic inductive heating capability of Fe3O4-Au@RGO nanocomposites was produced under high frequency magnetic field exposure and can kill high than 90% of the bacteria at 10 min. Hence, the newly developed Fe3O4-Au@RGO nanocomposites were demonstrated to be viable for SERS detection of biomolecules and microbes and potential applications for magnetically capturing and hyperthermia treatment of bacteria.

Genetic association-based functional analysis detects HOGA1 as a potential gene involved in fat accumulation.

Although there are a number of discoveries from genome-wide association studies (GWAS) for obesity, it has not been successful in linking GWAS results to biology. We sought to discover causal genes for obesity by conducting functional studies on genes detected from genetic association analysis. Gene-based association analysis of 917 individual exome sequences showed that HOGA1 attains exome-wide significance (p-value < 2.7 × 10-6) for body mass index (BMI). The mRNA expression of HOGA1 is significantly increased in human adipose tissues from obese individuals in the Genotype-Tissue Expression (GTEx) dataset, which supports the genetic association of HOGA1 with BMI. Functional analyses employing cell- and animal model-based approaches were performed to gain insights into the functional relevance of Hoga1 in obesity. Adipogenesis was retarded when Hoga1 was knocked down by siRNA treatment in a mouse 3T3-L1 cell line and a similar inhibitory effect was confirmed in mice with down-regulated Hoga1. Hoga1 antisense oligonucleotide (ASO) treatment reduced body weight, blood lipid level, blood glucose, and adipocyte size in high-fat diet-induced mice. In addition, several lipogenic genes including Srebf1, Scd1, Lp1, and Acaca were down-regulated, while lipolytic genes Cpt1l, Ppara, and Ucp1 were up-regulated. Taken together, HOGA1 is a potential causal gene for obesity as it plays a role in excess body fat development.

Magnetic Graphene-Based Nanosheets with Pluronic F127-Chitosan Biopolymers Encapsulated α-Mangosteen Drugs for Breast Cancer Cells Therapy.

In this study, multifunctional chitosan-pluronic F127 with magnetic reduced graphene oxide (MRGO) nanocomposites were developed through the immobilization of chitosan and an amphiphilic polymer (pluronic F127) onto the MRGO. Physicochemical characterizations and in-vitro cytotoxicity of nanocomposites were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, particle size analysis, vibrating sample magnetometer, Raman spectroscopy and resazurin-based in-vitro cytotoxicity assay. FESEM observation shows that the magnetic nanoparticles could tethered on the surface of MRGO, promoting the magnetic properties of the nanocomposites. FTIR identification analysis revealed that the chitosan/pluronic F127 were successfully immobilized on the surface of MRGO. Furthermore, α-mangosteen, as a model of natural drug compound, was successfully encapsulated onto the chitosan/pluronic F127@MRGO nanocomposites. According to in-vitro cytotoxicity assay, α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could significantly reduce the proliferation of human breast cancer (MFC-7) cells. Eventually, it would be anticipated that the novel α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could be promoted as a new potential material for magnetically targeting and killing cancer cells.

Physically crosslinked PVA/graphene-based materials/aloe vera hydrogel with antibacterial activity.

Burn is a major skin injury that occurs worldwide. For second-degree burns, special treatment should be given for creating a suitable wound healing environment. Hydrogel wound dressing as the primary care should possess extra properties that include antibacterial activity and cytocompatibility to enhance the treatment effectiveness. Additional therapy such as electrical stimulation can be applied as well promote wound healing. Herein, we used the tissue engineering concept to create a novel antibacterial and cytocompatible hydrogel made of polyvinyl alcohol (PVA), graphene-based material (GBM), and aloe vera extract (Av) through the freeze-thaw process. We prepared the PVA/GBM/Av hydrogel and examined its potential as a wound dressing. We found that it exhibited excellent hydrophilicity with a contact angle between 15 and 31 degrees and electrical conductivity within the range of 0.0102-0.0154 S m-1, which is comparable to that of the human skin tissue and possesses tensile strength up to 1.5 MPa with elongation of 405%. It also demonstrated good stability in phosphate buffer saline with a weight ratio of 73-80% after 14 days of immersion. We presented that the addition of graphene and graphene oxide (GO) inhibited the growth of Gram-positive Staphylococcus aureus ATCC 6538 with the lowest bacterial population observed in PVA/GO, which is 1.74 × 107 cfu mL-1 after 1 day incubation and 99.94% bacterial reduction. Furthermore, our PVA/GBM/Av showed no toxicity to 3T3 fibroblast cells after 48 h with viability up to 295% for PVA/GO/Av. In summary, our fabricated hydrogels have shown their potential as wound dressing with antibacterial and non-cytotoxic properties.

Microplastic contamination in the Skipjack Tuna (Euthynnus affinis) collected from Southern Coast of Java, Indonesia.

Indonesia is the second-largest contributor of microplastics (MPs) pollution in the marine ecosystem. Most MPs pollution-related studies in Indonesia focus on seawater, sediment, with less information found on the commercially important fish species used for human consumption. Skipjack Tuna (Euthynnus affinis) is one of the major exporting fishery commodities from Indonesia. This exploratory study aimed to determine MPs presence in the digestive tract of Skipjack Tuna from the Southern Coast of Java, Indonesia. The fish samples were collected from five different fish traditional auction market along the Southern Coast of Java, Indonesia, namely Pangandaran, Pamayang Sari, Ciletuh, Santolo, and Palabuhan Ratu. The gastrointestinal tract of Skipjack tuna was pretreated using alkaline destruction and filtered. The presence of MPs in the treated samples was visually identified using an optical microscope, while Polybrominated diphenyl ethers (PBDEs) contaminants were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). A total of 19 suspected MPs particles were found in the form of filament (84%), angular (11%), and round (5%). This result would provide a better indication of the MPs contamination in marine life species in the Southern Coast of Java, Indonesia, as useful information for marine environmental monitoring program in the future.

Lemon Balm and Its Constituent, Rosmarinic Acid, Alleviate Liver Damage in an Animal Model of Nonalcoholic Steatohepatitis.

Nonalcoholic fatty liver disease (NAFLD) ranges in severity from hepatic steatosis to cirrhosis. Lemon balm and its major constituent, rosmarinic acid (RA), effectively improve the liver injury and obesity; however, their therapeutic effects on nonalcoholic steatohepatitis (NASH) are unknown. In this study, we investigated the effects of RA and a lemon balm extract (LBE) on NAFLD and liver fibrosis and elucidated their mechanisms. Palmitic acid (PA)-exposed HepG2 cells and db/db mice fed a methionine- and choline-deficient (MCD) diet were utilized to exhibit symptoms of human NASH. LBE and RA treatments alleviated the oxidative stress by increasing antioxidant enzymes and modulated lipid metabolism-related gene expression by the activation of adenosine monophosphate-activated protein kinase (AMPK) in vitro and in vivo. LBE and RA treatments inhibited the expression of genes involved in hepatic fibrosis and inflammation in vitro and in vivo. Together, LBE and RA could improve liver damage by non-alcoholic lipid accumulation and may be promising medications to treat NASH.

Chicoric acid attenuate a nonalcoholic steatohepatitis by inhibiting key regulators of lipid metabolism, fibrosis, oxidation, and inflammation in mice with methionine and choline deficiency.

SCOPE: Nonalcoholic fatty liver diseases (NAFLD) range histopathologically from hepatic steatosis to steatohepatitis. Chicoric acid has beneficial effects on obesity and liver injury, but its effects on nonalcoholic steatohepatitis (NASH) have not yet been determined. This study examined the effects of Crepidiastrum denticulatum extract (CDE) and its active compound chicoric acid in a mouse model of NASH and fibrosis. METHODS: CDE and chicoric acid were orally administrated to mice fed a methionine- and choline-deficient (MCD) diet. HepG2 and AML-12 cells in MCD medium were incubated with chicoric acid. MCD-fed mice developed the histopathological characteristics of human NASH, including altered regulation of lipid metabolism, inflammation, fibrosis, and oxidation-associated expression, along with augmented lipoperoxidation. Administration of CDE or chicoric acid to MCD-fed mice and HepG2 and AML-12 cells in MCD medium reduced oxidative stress by upregulating antioxidant enzymes and decreased inflammation by inhibiting proinflammatory cytokines and nuclear factor-κB activation. In addition, CDE or chicoric acid reduced fibrosis, apoptosis, and lipogenesis-related gene expression and increased AMP Kinase activation both in vivo and in vitro. CONCLUSIONS: CDE and chicoric acid may be effective in the treatment of NAFLD and NASH.

Stellera chamaejasme and its constituents induce cutaneous wound healing and anti-inflammatory activities.

Stellera chamaejasme L. (Thymelaeaceae) is a perennial herb that is widely used in traditional Chinese medicine to treat tumours, tuberculosis and psoriasis. S. chamaejasme extract (SCE) possesses anti-inflammatory, analgesic and wound healing activities; however, the effect of S. chamaejasme and its active compounds on cutaneous wound healing has not been investigated. We assessed full-thickness wounds of Sprague-Dawley (SD) rats and topically applied SCE for 2 weeks. In vitro studies were performed using HaCaT keratinocytes, Hs68 dermal fibroblasts and RAW 264.7 macrophages to determine cell viability (MTT assay), cell migration, collagen expression, nitric oxide (NO) production, prostaglandin E2 (PGE2) production, inflammatory cytokine expression and ß-catenin activation. In vivo, wound size was reduced and epithelisation was improved in SCE-treated SD rats. In vitro, SCE and its active compounds induced keratinocyte migration by regulating the ß-catenin, extracellular signal-regulated kinase and Akt signalling pathways. Furthermore, SCE and its active compounds increased mRNA expression of type I and III collagen in Hs68 fibroblasts. SCE and chamechromone inhibited NO and PGE2 release and mRNA expression of inflammatory mediators in RAW 264.7 macrophages. SCE enhances the motility of HaCaT keratinocytes and improves cutaneous wound healing in SD rats.

Effects of Hovenia dulcis Thunb. extract and methyl vanillate on atopic dermatitis-like skin lesions and TNF-α/IFN-γ-induced chemokines production in HaCaT cells.

OBJECTIVES: Here, we hypothesized that Hovenia dulcis branch extract (HDB) and its active constituents ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis (AD)-like skin lesions by modulating the T helper Th1/Th2 balance in NC/Nga mice and TNF-α- and IFN-γ-induced production of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in HaCaT cells. METHODS: HaCaT cells were stimulated by TNF-α/IFN-γ in the presence of HDB and its constituents. TARC and MDC were measured by ELISA and RT-PCR. For the in-vivo study, oral feeding of HDB was performed for 5 weeks with 2,4-dinitrochlorobenzene (DNCB) treatment every other day. The efficacy of HDB on parameters of DNCB-induced AD was evaluated morphologically, physiologically and immunologically. KEY FINDINGS: In-vitro studies showed that HDB and its constituents suppressed TNF-α/IFN-γ-induced production of TARC and MDC in HaCaT cells by inhibiting MAPK signalling. In-vivo studies showed that HDB regulated immunoglobulin (Ig) E and immunoglobulin G2a (IgG2a) levels in serum and the expression of mRNA for Th1- and Th2-related mediators in skin lesions. Histopathological analyses revealed reduced epidermal thickness and reduced infiltration of skin lesions by inflammatory cells. CONCLUSION: These results suggest that HDB inhibits AD-like skin diseases by regulating Th1 and Th2 responses in NC/Nga mice and in HaCaT cells.

Inhibitory effect of the branches of Hovenia dulcis Thunb. and its constituent pinosylvin on the activities of IgE-mediated mast cells and passive cutaneous anaphylaxis in mice.

Hovenia dulcis Thunb. (Rhamnaceae) is a hardy tree native to Europe, the Middle East, and North Africa, and it is also grown in parts of Asia and has been used in traditional medicine to treat liver toxicity, stomach disorders, and inflammation. This study investigated the anti-allergy potential of an extract of the branches of H. dulcis (HDB) using the antigen-stimulated mast cell-like cell line rat basophilic leukemia (RBL)-2H3 and a passive cutaneous anaphylaxis (PCA) mouse model. Degranulation assay, reverse transcription PCR, enzyme-lined immunosorbent assays, western blot analyses, and PCA were performed to measure allergic responses and proinflammatory mediators in antigen-stimulated rat basophilic leukemia (RBL)-2H3 mast cells and the PCA mouse model. In antigen-stimulated RBL-2H3 cells, HDB inhibited the secretion of ß-hexosaminidase (indicating the inhibition of degranulation) and histamine release; decreased expression and production of the inflammatory mediators, cyclooxygenase-2 and prostaglandin E2, and cytokines interleukin-4 and tumor necrosis factor-α; and suppressed activation of nuclear factor κB, a transcription factor involved in the response to cytokines. HDB attenuated phosphorylation of the mast cell downstream effectors Lyn, Syk, phospholipase Cγ, protein kinase Cµ, extracellular signal-regulated kinase and p38. In IgE-sensitized mice, HDB inhibited mast cell-dependent PCA. Furthermore, HDB contained pinosylvin and possessed significant anti-allergic activities. These results suggest that HDB would be of value in the prevention and treatment of allergic diseases.