Engineering bionanoreactor in bacteria for efficient hydrogen production.

Hydrogen production through water splitting is a vital strategy for renewable and sustainable clean energy. In this study, we developed an approach integrating nanomaterial engineering and synthetic biology to establish a bionanoreactor system for efficient hydrogen production. The periplasmic space (20 to 30 nm) of an electroactive bacterium, Shewanella oneidensis MR-1, was engineered to serve as a bionanoreactor to enhance the interaction between electrons and protons, catalyzed by hydrogenases for hydrogen generation. To optimize electron transfer, we used the microbially reduced graphene oxide (rGO) to coat the electrode, which improved the electron transfer from the electrode to the cells. Native MtrCAB protein complex on S. oneidensis and self-assembled iron sulfide (FeS) nanoparticles acted in tandem to facilitate electron transfer from an electrode to the periplasm. To enhance proton transport, S. oneidensis MR-1 was engineered to express Gloeobacter rhodopsin (GR) and the light-harvesting antenna canthaxanthin. This led to efficient proton pumping when exposed to light, resulting in a 35.6% increase in the rate of hydrogen production. The overexpression of native [FeFe]-hydrogenase further improved the hydrogen production rate by 56.8%. The bionanoreactor engineered in S. oneidensis MR-1 achieved a hydrogen yield of 80.4 µmol/mg protein/day with a Faraday efficiency of 80% at a potential of -0.75 V. This periplasmic bionanoreactor combines the strengths of both nanomaterial and biological components, providing an efficient approach for microbial electrosynthesis.

Graphene promotes the growth of Vigna angularis by regulating the nitrogen metabolism and photosynthesis.

Graphene has promising applications in agriculture and forestry. In the current study, six different concentrations of graphene (0mg/L, 0.01mg/L, 0.10mg/L, 1.00mg/L, 10.00mg/L, and 100.00mg/L) were used to investigate its effect on the growth and development of V. angularis plants in soil culture. The results showed that the group treated with 1.00mg/L graphene (G-1) had significantly increased plant height (19.86%), stem diameter (24.33%), and leaf area (13.69%), compared to the control group (CK). Moreover, all concentrations of graphene had positive effects on the total root length, total root surface area, and the number of root tips of V. angularis. Compared to the CK group, the G-1 group had significantly increased leaf water potential (37.89%), leaf conductivity (2.25%), and SOD, POD, and CAT activities (47.67%, 35.22%, and 199.3%, respectively). The G-1 group also showed improved leaf net photosynthetic rate, chlorophyll content, and soluble sugar content (51.28%, 24.25%, and 38.35%, respectively), compared to the CK group. Additionally, 1.00mg/L graphene led to a 23.88% increase in the podding rate and a 17.04% increase in the yield of V. angularis plants. The rhizosphere soil of V. angularis treated with 1.00mg/L graphene had a 25.14% increase in hydrolyzable nitrogen content and a 66.67% increase in available phosphorus content. RNA-seq data indicated that 1.00mg/L graphene induced the expression of photosynthesis and nitrogen transmembrane transport genes, including ATP synthase subunit b, photosystem I reaction center subunit XI, photosystem I reaction center subunit IV A, ferredoxin, and psbP-like protein 1, as well as genes for photosynthesis antenna proteins, glutamine synthetase, glutamate dehydrogenase 1, cyanate hydratase, protein fluG-like, and NRT1/PTR family, suggesting that graphene promoted the growth and development of V. angularis by enhancing the photosynthesis and nitrogen metabolism processes in V. angularis plants. Our results indicated that a suitable concentration of graphene could significantly promote the growth of V. angularis plants in soil.

Few-layered graphene increases the response of nociceptive neurons to irritant stimuli.

The unique properties of few-layered graphene (FLG) make it interesting for a variety of applications, including biomedical applications, such as tissue engineering and drug delivery. Although different studies focus on applications in the central nervous system, its interaction with the peripheral nervous system has been so far overlooked. Here, we investigated the effects of exposure to colloidal dispersions of FLG on the sensory neurons of the rat dorsal root ganglia (DRG). We found that the FLG flakes were actively internalized by sensory neurons, accumulated in large intracellular vesicles, and possibly degraded over time, without major toxicological concerns, as neuronal viability, morphology, protein content, and basic electrical properties of DRG neurons were preserved. Interestingly, in our electrophysiological investigation under noxious stimuli, we observed an increased functional response upon FLG treatment of the nociceptive subpopulation of DRG neurons in response to irritants specific for chemoreceptors TRPV1 and TRPA1. The observed effects of FLG on DRG neurons may open-up novel opportunities for applications of these materials in specific disease models.

Graphene oxide and bacteria interactions: what is known and what should we expect?

Graphene oxide (GO) and graphene-based materials (GBMs) have gained over the last two decades considerable attention due to their intrinsic physicochemical properties and their applications. Besides, a lot of concern regarding the potential toxicity of GBMs has emerged. One of the aspects of concern is the interactions between GBMs and different environmental compartments, especially indigenous microbial and, in particular, bacterial communities. Recent research showed that GO and GBMs impacted bacterial pure culture or bacterial communities; therefore, these interactions have to be further studied to better understand and assess the fate of these materials in the environment. Here, we present our opinion and hypotheses related to possible degradation mechanisms of GO that can be used by environmental bacteria. This work is the first attempt to deduce and summarize plausible degradation pathways of GO, from structurally similar recalcitrant and toxic compounds, such as polyaromatic hydrocarbons.

Graphene enhances artemisinin production in the traditional medicinal plant Artemisia annua via dynamic physiological processes and miRNA regulation.

We investigated the effects of graphene on the model herb Artemisia annua, which is renowned for producing artemisinin, a widely used pharmacological compound. Seedling growth and biomass were promoted when A. annua was cultivated with low concentrations of graphene, an effect which was attributed to a 1.4-fold increase in nitrogen uptake, a 15%-22% increase in chlorophyll fluorescence, and greater abundance of carbon cycling-related bacteria. Exposure to 10 or 20 mg/L graphene resulted in a âˆ¼60% increase in H2O2, and graphene could act as a catalyst accelerator, leading to a 9-fold increase in catalase (CAT) activity in vitro and thereby maintaining reactive oxygen species (ROS) homeostasis. Importantly, graphene exposure led to an 80% increase in the density of glandular secreting trichomes (GSTs), in which artemisinin is biosynthesized and stored. This contributed to a 5% increase in artemisinin content in mature leaves. Interestingly, expression of miR828 was reduced by both graphene and H2O2 treatments, resulting in induction of its target gene AaMYB17, a positive regulator of GST initiation. Subsequent molecular and genetic assays showed that graphene-induced H2O2 inhibits micro-RNA (miRNA) biogenesis through Dicers and regulates the miR828-AaMYB17 module, thus affecting GST density. Our results suggest that graphene may contribute to yield improvement in A. annua via dynamic physiological processes together with miRNA regulation, and it may thus represent a new cultivation strategy for increasing yield capacity through nanobiotechnology.

Exploring the environmental factor fulvic acid attenuates the ecotoxicity of graphene oxide under food delivery exposure.

There is limited understanding of nanoparticle potential ecotoxicity, particularly regarding the influence of environmental factors that can be transferred through the food chain. Here, we assessed the transfer behavior and the ecotoxicity of commercially manufactured graphene oxide nano-materials (GO, <100 nm) in a food chain perspective spanning from Escherichia coli (E. coli) to Caenorhabditis elegans (C. elegans) under simulated environmental conditions. Our findings revealed that E. coli preyed upon GO, subsequently transferring it to C. elegans, with a discernible distribution of GO observed in the digestive system and reproductive system. Accumulated GO generated serious ecological consequences for the higher level of the food chain (C. elegans). More importantly, GO and the resulting injurious effects of germ cells could be transferred to the next generation, indicating that GO exposure could cause genetic damage across generations. Previous research has demonstrated that GO can induce degradation of both the inner and outer cell membranes of E. coli, which is then transmitted to C. elegans through the food chain. Additionally, fulvic acid (FA) possesses various functional groups that enable interaction with nanomaterials. Our findings indicated that these interactions could mitigate ecotoxicity caused by GO exposure via food delivery, and this approach could be extended to modify GO in a way that significantly reduced its toxic effects without compromising performance. These results highlighted how environmental factors could attenuate ecological risks associated with nanomaterial transmission through the food chain.

In vitro assessments of nanoplexes of polyethylenimine-coated graphene oxide-plasmid through various cancer cell lines and primary mesenchymal stem cells.

Efficient gene therapy relies on an efficient gene delivery system. Viral gene delivery approaches excel in transferring and expressing external genes; however, their immunogenicity and difficulty in large-scale production limit their clinical applications. In contrast, nanoparticle-based gene delivery systems have gained increasing attention due to less immunogenicity and more convenience for large-scale production. Nevertheless, their poor transfection efficiency compared to viral systems remains a significant obstacle. In the present study, we investigated the transfection efficiency of our PEI-coated graphene oxides in HEK293T, Calu-3, Calu-6 cell lines, and primary human bone marrow mesenchymal stem cell (MSC). The high surface ratio and good biocompatibility of graphene oxide make it an appealing tool for gene delivery systems. However, the low dispersity of graphene oxide in aqueous environments is the first barrier that needs to be conquered. For this, we enhanced the dispersity and stability of graphene oxide in water by sonicating it for at least 5 hours at a pH of 7. Then, graphene oxide was conjugated with branched PEI (25 kDa) to have a positive charge, enabling it to condense nucleic acids with a naturally negative potential. The physio-chemical characteristics of our synthesized nano-carriers (GO-PEI) were determined by DLS, FT-IR, and AFM. The utilized plasmid in polyplexes contained a GFP gene, allowing us to verify transfection efficiency through fluorescent microscopy and flow cytometry. While GO-PEI carriers were highly efficient in transfecting HEK293T cells, the transfection efficiency in MSCs and Calu-3 cells was notably low. We suppose that the main reason for the low transfection efficiency of GO-PEI in these cells is due to its higher toxicity. Despite this, considering the various advantages of graphene oxide in drug delivery as well as its optical and electrical applications in biomedicine, we propose to functionalize graphene oxide with more biocompatible materials to enhance its potential as a successful gene carrier in these cell types.

Electric Potential at the Interface of Membraneless Organelles Gauged by Graphene.

Eukaryotic cells contain membrane-bound and membrane-less organelles that are often in contact with each other. How the interface properties of membrane-less organelles regulate their interactions with membranes remains challenging to assess. Here, we employ graphene-based sensors to investigate the electrostatic properties of synapsin 1, a major synaptic phosphoprotein, either in a single phase or after undergoing phase separation to form synapsin condensates. Using these graphene-based sensors, we discover that synapsin condensates generate strong electrical responses that are otherwise absent when synapsin is present as a single phase. By introducing atomically thin dielectric barriers, we show that the electrical response originates in an electric double layer whose formation governs the interaction between synapsin condensates and graphene. Our data indicate that the interface properties of the same protein are substantially different when the protein is in a single phase versus within a biomolecular condensate, unraveling that condensates can harbor ion potential differences at their interface.

Global transcriptional analysis of Geobacter sulfurreducens gsu1771 mutant biofilm grown on two different support structures.

Electroactive biofilms formation by the metal-reducing bacterium Geobacter sulfurreducens is a step crucial for bioelectricity generation and bioremediation. The transcriptional regulator GSU1771 controls the expression of essential genes involved in electron transfer and biofilm formation in G. sulfurreducens, with GSU1771-deficient producing thicker and more electroactive biofilms. Here, RNA-seq analyses were conducted to compare the global gene expression patterns of wild-type and Δgsu1771 mutant biofilms grown on non-conductive (glass) and conductive (graphite electrode) materials. The Δgsu1771 biofilm grown on the glass surface exhibited 467 differentially expressed (DE) genes (167 upregulated and 300 downregulated) versus the wild-type biofilm. In contrast, the Δgsu1771 biofilm grown on the graphite electrode exhibited 119 DE genes (79 upregulated and 40 downregulated) versus the wild-type biofilm. Among these DE genes, 67 were also differentially expressed in the Δgsu1771 biofilm grown on glass (56 with the same regulation and 11 exhibiting counter-regulation). Among the upregulated genes in the Δgsu1771 biofilms, we identified potential target genes involved in exopolysaccharide synthesis (gsu1961-63, gsu1959, gsu1972-73, gsu1976-77). RT-qPCR analyses were then conducted to confirm the differential expression of a selection of genes of interest. DNA-protein binding assays demonstrated the direct binding of the GSU1771 regulator to the promoter region of pgcA, pulF, relA, and gsu3356. Furthermore, heme-staining and western blotting revealed an increase in c-type cytochromes including OmcS and OmcZ in Δgsu1771 biofilms. Collectively, our findings demonstrated that GSU1771 is a global regulator that controls extracellular electron transfer and exopolysaccharide synthesis in G. sulfurreducens, which is crucial for electroconductive biofilm development.

Wireless Electrical Signals Induce Functional Neuronal Differentiation of BMSCs on 3D Graphene Framework Driven by Magnetic Field.

Bone marrow mesenchymal stem cells (BMSCs) are suggested as candidates for neurodegeneration therapy by autologous stem cells to overcome the lack of neural stem cells in adults. However, the differentiation of BMSCs into functional neurons is a major challenge for neurotherapy. Herein, a methodology has been proposed to induce functional neuronal differentiation of BMSCs on a conductive three-dimensional graphene framework (GFs) combined with a rotating magnetic field. A wireless electrical signal of about 10 µA can be generated on the surface of GFs by cutting the magnetic field lines based on the well-known electromagnetic induction effect, which has been proven to be suitable for inducing neuronal differentiation of BMSCs. The enhanced expressions of the specific genes/proteins and apparent Ca2+ intracellular flow indicate that BMSCs cultured on GFs with 15 min/day rotating magnetic field stimulation for 15 days can differentiate functional neurons without any neural inducing factor. The animal experiments confirm the neural differentiation of BMSCs on GFs after transplantation in vivo, accompanied by stimulation of an external rotating magnetic field. This study overcomes the lack of autologous neural stem cells for adult neurodegeneration patients and provides a facile and safe strategy to induce the neural differentiation of BMSCs, which has potential for clinical applications of neural tissue engineering.

Targeting SOD1 via RNAi with PEGylated graphene oxide nanoparticles in platinum-resistant ovarian cancer.

Acquired platinum resistance poses a significant therapeutic impediment to ovarian cancer patient care, accounting for more than 200,000 deaths annually worldwide. We previously identified that overexpression of the antioxidant superoxide dismutase 1 (SOD1) in ovarian cancer is associated with a platinum-resistant phenotype via conferring oxidative stress resistance against platinum compounds. We further demonstrated that enzymatic inhibition using small-molecule inhibitors or silencing of SOD1 via RNA interference (RNAi) increased cisplatin sensitivity and potency in vitro. We launched this study to explore the potential therapeutic applications of SOD1 silencing in vivo in order to reverse cisplatin resistance using a graphene-based siRNA delivery platform. PEGylated graphene oxide (GO) polyethyleneimine (GOPEI-mPEG) nanoparticle was complexed with SOD1 siRNA. GOPEI-mPEG-siSOD1 exhibited high biocompatibility, siRNA loading capacity, and serum stability, and showed potent downregulation of SOD1 mRNA and protein levels. We further observed that cisplatin and PEI elicited mitochondrial dysfunction and transcriptionally activated the mitochondrial unfolded protein response (UPRmt) used as a reporter for their respective cytotoxicities. SOD1 silencing was found to augment cisplatin-induced cytotoxicity resulting in considerable tumour growth inhibition in cisplatin-sensitive A2780 and cisplatin-resistant A2780DDP subcutaneous mouse xenografts. Our study highlights the potential therapeutic applicability of RNAi-mediated targeting of SOD1 as a chemosensitizer for platinum-resistant ovarian cancers.

Blocking tau transmission by biomimetic graphene nanoparticles.

Tauopathies are a class of neurodegenerative diseases resulting in cognitive dysfunction, executive dysfunction, and motor disturbance. The primary pathological feature of tauopathies is the presence of neurofibrillary tangles in the brain composed of tau protein aggregates. Moreover, tau aggregates can spread from neuron to neuron and lead to the propagation of tau pathology. Although numerous small molecules are known to inhibit tau aggregation and block tau cell-to-cell transmission, it is still challenging to use them for therapeutic applications due to poor specificity and low blood-brain barrier (BBB) penetration. Graphene nanoparticles were previously demonstrated to penetrate the BBB and are amenable to functionalization for targeted delivery. Moreover, these nanoscale biomimetic particles can self-assemble or assemble with various biomolecules including proteins. In this paper, we show that graphene quantum dots (GQDs), as graphene nanoparticles, block the seeding activity of tau fibrils by inhibiting the fibrillization of monomeric tau and triggering the disaggregation of tau filaments. This behavior is attributed to electrostatic and π-π stacking interactions of GQDs with tau. Overall, our studies indicate that GQDs with biomimetic properties can efficiently inhibit and disassemble pathological tau aggregates, and thus block tau transmission, which supports their future developments as a potential treatment for tauopathies.

Investigation of thymine as a potential cancer biomarker employing tryptophan with nanomaterials as a biosensor.

Tryptophan and tryptophan-based nanomaterials sensors in a solution have been developed to directly evaluate thymine. The determination of thymine has been done via quenching of the fluorescence of tryptophan and tryptophan-based nanomaterials such as graphene (Gr), graphene oxide (GO), gold nanoparticles (AuNPs), gold-silver nanocomposite (Au-Ag NC) in a physiological buffer. As the concentration of thymine rises, the fluorescence of tryptophan and tryptophan/nanomaterials becomes less intense. Trp, Trp/Gr, and tryptophan/(Au-Ag) NC systems' quenching mechanisms were dynamic, but tryptophan /GO and tryptophan/AuNPs' quenching mechanisms were static. The linear dynamic range for the determination of thy by tryptophan and tryptophan /nanomaterials is 10 to 200 µM. The detection limits for tryptophan, tryptophan /Gr, tryptophan /GO, tryptophan /AuNPs, and tryptophan/Au-Ag NC were 3.21, 14.20, 6.35, 4.67and 7.79 Μm, respectively. Thermodynamic parameters for the interaction of the Probes with Thy include the enthalpy (H°) and entropy (S°) change values, were assessed, as well as the binding constant (Ka) of Thy with Trp and Trp-based nanomaterials. A recovery study was conducted utilizing a human serum sample after the addition of the required quantity of the investigational thymine.

Investigating the Theranostic Potential of Graphene Quantum Dots in Alzheimer's Disease.

Alzheimer's disease (AD) is one of the leading causes of death worldwide, with no definitive diagnosis or known cure. The aggregation of Tau protein into neurofibrillary tangles (NFTs), which contain straight filaments (SFs) and paired helical filaments (PHFs), is a major hallmark of AD. Graphene quantum dots (GQDs) are a type of nanomaterial that combat many of the small-molecule therapeutic challenges in AD and have shown promise in similar pathologies. In this study, two sizes of GQDs, GQD7 and GQD28, were docked to various forms of Tau monomers, SFs, and PHFs. From the favorable docked poses, we simulated each system for at least 300 ns and calculated the free energies of binding. We observed a clear preference for GQD28 in the PHF6 (306VQIVYK311) pathological hexapeptide region of monomeric Tau, while GQD7 targeted both the PHF6 and PHF6* (275VQIINK280) pathological hexapeptide regions. In SFs, GQD28 had a high affinity for a binding site that is available in AD but not in other common tauopathies, while GQD7 behaved promiscuously. In PHFs, GQD28 interacted strongly near the protofibril interface at the putative disaggregation site for epigallocatechin-3-gallate, and GQD7 largely interacted with PHF6. Our analyses revealed several key GQD binding sites that may be used for detecting, preventing, and disassembling the Tau aggregates in AD.

Graphene quantum dots enhance the osteogenic differentiation of PDLSCs in the inflammatory microenvironment.

BACKGROUND AND OBJECTIVE: Graphene quantum dots (GQDs), a type of carbon-based nanomaterial, have remarkable biological, physical, and chemical properties. This study investigated the biological mechanisms of the proliferation and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) induced by GQDs in an inflammatory microenvironment. MATERIALS AND METHODS: PDLSCs were cultured in osteogenic-induced medium with various concentrations of GQDs in standard medium or medium mimicking a proinflammatory environment. The effects of GQDs on the proliferation and osteogenic differentiation activity of PDLSCs were tested by CCK-8 assay, Alizarin Red S staining, and qRT‒PCR. In addition, Wnt/ß-catenin signalling pathway-related gene expression was measured by qRT‒PCR. RESULTS: Compared with the control group, the mRNA expression levels of ALP, RUNX2, and OCN and the number of mineralized nodules were all increased in PDLSCs after treatment with GQDs. Moreover, during the osteogenic differentiation of PDLSCs, the expression levels of LRP6 and ß-catenin, which are Wnt/ß-catenin signalling pathway-related genes, were upregulated. CONCLUSION: In the inflammatory microenvironment, GQDs might promote the osteogenic differentiation ability of PDLSCs by activating the Wnt/ß-catenin signalling pathway.

Defect-free graphene enhances enzyme delivery to fibroblasts derived from patients with lysosomal storage disorders.

Enzyme replacement therapy shows remarkable clinical improvement in treating lysosomal storage disorders. However, this therapeutic approach is hampered by limitations in the delivery of the enzyme to cells and tissues. Therefore, there is an urgent, unmet clinical need to develop new strategies to enhance the enzyme delivery to diseased cells. Graphene-based materials, due to their dimensionality and favourable pattern of interaction with cells, represent a promising platform for the loading and delivery of therapeutic cargo. Herein, the potential use of graphene-based materials, including defect-free graphene with positive or negative surface charge and graphene oxide with different lateral dimensions, was investigated for the delivery of lysosomal enzymes in fibroblasts derived from patients with Mucopolysaccharidosis VI and Pompe disease. We report excellent biocompatibility of all graphene-based materials up to a concentration of 100 µg mL-1 in the cell lines studied. In addition, a noticeable difference in the uptake profile of the materials was observed. Neither type of graphene oxide was taken up by the cells to a significant extent. In contrast, the two types of graphene were efficiently taken up, localizing in the lysosomes. Furthermore, we demonstrate that cationic graphene flakes can be used as carriers for arylsulfatase B enzyme, for the delivery of the lacking enzyme to the lysosomes of Mucopolysaccharidosis VI fibroblasts. Arylsulfatase B complexed with cationic graphene flakes not only retained the enzymatic activity, but also exerted biological effects almost twice as high as arylsulfatase B alone in the clearance of the substrate in Mucopolysaccharidosis VI fibroblasts. This study lays the groundwork for the potential use of graphene-based materials as carriers for enzyme replacement therapy in lysosomal storage disorders.

Interaction of Graphene Oxide Nanoparticles with Human Mesenchymal Stem Cells Visualized in the Cell-IQ System.

Graphene oxide is a promising nanomaterial with many potential applications. However, before it can be widely used in areas such as drug delivery and medical diagnostics, its influence on various cell populations in the human body must be studied to ensure its safety. We investigated the interaction of graphene oxide (GO) nanoparticles with human mesenchymal stem cells (hMSCs) in the Cell-IQ system, evaluating cell viability, mobility, and growth rate. GO nanoparticles of different sizes coated with linear or branched polyethylene glycol (P or bP, respectively) were used at concentrations of 5 and 25 µg/mL. Designations were the following: P-GOs (Ø 184 ± 73 nm), bP-GOs (Ø 287 ± 52 nm), P-GOb (Ø 569 ± 14 nm), and bP-GOb (Ø 1376 ± 48 nm). After incubating the cells with all types of nanoparticles for 24 h, the internalization of the nanoparticles by the cells was observed. We found that all GO nanoparticles used in this study exerted a cytotoxic effect on hMSCs when used at a high concentration (25 µg/mL), whereas at a low concentration (5 µg/mL) a cytotoxic effect was observed only for bP-GOb particles. We also found that P-GOs particles decreased cell mobility at a concentration of 25 µg/mL, whereas bP-GOb particles increased it. Larger particles (P-GOb and bP-GOb) increased the rate of movement of hMSCs regardless of concentration. There were no statistically significant differences in the growth rate of cells compared with the control group.

Enriched Graphene Oxide-Polypropylene Suture Threads Buttons Modulate the Inflammatory Pathway Induced by Escherichia coli Lipopolysaccharide.

Graphene oxide (GO), derived from graphene, has remarkable chemical-physical properties such as stability, strength, and thermal or electric conductivity and additionally shows antibacterial and anti-inflammatory properties. The present study aimed to evaluate the anti-inflammatory effects of polypropylene suture threads buttons (PPSTBs), enriched with two different concentrations of GO, in the modulation of the inflammatory pathway TLR4/MyD 88/NFκB p65/NLRP3 induced by the Escherichia coli (E. coli) lipopolysaccharide (LPS-E). The gene and the protein expression of inflammatory markers were evaluated in an in vitro model of primary human gingival fibroblasts (hGFs) by real-time PCR, western blotting, and immunofluorescence analysis. Both GO concentrations used in the polypropylene suture threads buttons-GO constructs (PPSTBs-GO) decreased the expression of inflammatory markers in hGFs treated with LPS-E. The hGFs morphology and adhesion on the PPSTBs-GO constructs were also visualized by inverted light microscopy, scanning electron microscopy (SEM), and real-time PCR. Together, these results suggest that enriched PPSTBs-GO modulates the inflammatory process through TLR4/MyD 88/NFκB p65/NLRP3 pathway.

Discrimination of the H1N1 and H5N2 Variants of Influenza A Virus Using an Isomeric Sialic Acid-Conjugated Graphene Field-Effect Transistor.

There has been a continuous effort to fabricate a fast, sensitive, and inexpensive system for influenza virus detection to meet the demand for effective screening in point-of-care testing. Herein, we report a sialic acid (SA)-conjugated graphene field-effect transistor (SA-GFET) sensor designed using α2,3-linked sialic acid (3'-SA) and α2,6-linked sialic acid (6'-SA) for the detection and discrimination of the hemagglutinin (HA) protein of the H5N2 and H1N1 viruses. 3'-SA and 6'-SA specific for H5 and H1 influenza were used in the SA-GFET to capture the HA protein of the influenza virus. The net charge of the captured viral sample led to a change in the electrical current of the SA-GFET platform, which could be correlated to the concentration of the viral sample. This SA-GFET platform exhibited a highly sensitive response in the range of 101-106 pfu mL-1, with a limit of detection (LOD) of 101 pfu mL-1 in buffer solution and a response time of approximately 10 s. The selectivity of the SA-GFET platform for the H1N1 and H5N2 influenza viruses was verified by testing analogous respiratory viruses, i.e., influenza B and the spike protein of SARS-CoV-2 and MERS-CoV, on the SA-GFET. Overall, the results demonstrate that the developed dual-channel SA-GFET platform can potentially serve as a highly efficient and sensitive sensing platform for the rapid detection of infectious diseases.

Nitrobenzene reduction promoted by the integration of carbon nanotubes and Geobacter sulfurreducens.

Electron shuttles (ES) can mediate long-distance electron transfer between extracellular respiratory bacteria (ERB) and the surroundings. However, the effects of graphite structure in ES on the extracellular electron transfer (EET) process remain ambiguous. This work investigated the function of graphite structure in the process of nitrobenzene (NB) degradation by Geobacter sulfurreducens PCA, in which highly aromatic carbon nanotubes (CNTs) was studied as a typical ES. The results showed that the addition of 1.5 g L-1 of CNTs improved the NB biodegradation up to 81.2%, plus 18.8% NB loss due to the adsorption property of CNTs, achieving complete removal of 200 µM NB within 9 h. The amendment of CNTs greatly increased the EET rate, indicating that graphite structure exhibited excellent electron shuttle performance. Furthermore, Raman spectrum proved that CNTs obtained better graphite structure after 90 h of cultivation with strain PCA, resulting in higher electrochemical performance. Also, CNTs was perceived as the "Contaminant Reservoir", which alleviated the toxic effect of NB and shortened the distance of EET process. Overall, this work focused on the effects of material graphite structure on the EET process, which enriched the understanding of the interaction between CNTs and ERB, and these results might promote their application in the in-situ bioremediation of nitroaromatic-polluted environment.