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This study aimed to investigate the antibiofilm activity of alpha-mangostin (AMG) loaded nanoparticles (nanoAMG) against Staphylococcus aureus, including the methicillin-resistant strain MRSA252. The results indicated that treatment with 24 μmol/L nanoAMG inhibited the formation of biofilm biomass by 53–62%, compared to 40–44% for free AMG (p 50%. In contrast, activity of nanoAMG was limited on preformed mature biofilms, which at a concentration of 48 µmol/L were reduced only by 27% and 22% for NCTC6571 and MRSA252, respectively. The effects of AMG or nanoAMG on the expression of biofilm-related genes showed some noticeable differences between the two strains. For instance, the expression level of ebpS was downregulated in MRSA252 and upregulated in NCTC6571 when those strains were treated with either AMG or nanoAMG. In contrast, the expression of fnbB was down regulated in NCTC6571, while it was up-regulated in the MRSA252. The expression of other biofilm-related genes (icaC, clfB and fnbA) was down regulated in both strains. In conclusion, our results suggest that AMG coated nanoparticles had enhanced biological activity as compared to free AMG, indicating that nanoAMG could be a new and promising inhibitor of biofilm formation to tackle S. aureus, including strains that are resistant to multiple antibiotics.

Rice is a staple crop for a large part of the world population including Vietnam. Although its export is ranged of second place over the world just after Thailand, rice production in Vietnam is challenging by various issues. The most significant is application of agrochemicals, which are not eco-friendly, leading to side effects on the ecosystem and human health. Endophytic bacteria (EB) possess different beneficial traits such as Plant Growth Promoting (PGP) and antagonistic activities against plant pathogens. In this study, a collection of 150 EB strains have been isolated from upland rice roots grown on the mountain-farm in the Tung village, Nam Co commune, Mu Cang Chai district, Yen Bai province, Vietnam. 119/150 isolates showed siderophoreproduction ability including 12 isolates showed the halo orange zone surrounding colonies of 1 – 10 mm in diameter (Dh), considering them as low level of siderophore production, 80 strains exhibited the moderate activity, Dh of 11 – 30 mm and 27 strains showed strong/high activity, Dh more than 30 mm. All 119 endophytic bacterial isolates were screened for antifungal activity against Fusariumoxysporum (Fo), and antibacterial activity against ​Xanthomonasoryzaepv.​oryzae (Xoo). Of them, thirty isolates showed either antifungal or antibacterial or both activities. Indeed, five isolates showed antifungal activity fifteen isolates exhibited the antibacterial activity. Especially, ten isolates named NC88, NC89, NC126, NC129, NC130, NC131, NC134, NC152, NC153, and NC156 showed antimicrobial activity against both tested pathogens. These results are the starting-up for further investigation in planta under conditions of net house and field trial in order to reveal the potential strains for the development of bioinoculants toward to control the diseases caused by Fo andXoo.

Alpha-mangostin (MGS) is a natural xanthone compound extracted from mangosteen pericarps. It has great potential as an excellent anticancer agent. However, the extremely low solubility of MGS in water seriously impedes its medical application. Previously, we found that cyclodextrin (CD)-based hyperbranched polymer nanoparticles (CDNPs) solubilize MGS by encapsulating it in the CD cavity and that their binding constants are 100 times higher than those of native CDs. Our findings suggested that CDNPs could be good carriers of MGS. Here, we prepared three types of CDNP from α-, β-, and ɣCDs and compared them in terms of MGS release and in vitro and in vivo anticancer efficacy. βCDNP/MGS demonstrated the greatest anticancer efficacy, while no efficacy was observed for the other CDNPs. MGS release from CDNPs/MGS can be explained by a model in which the slow and rapid modes are connected in series; before release, MGS must shift from the slow to the rapid mode. We assumed that the slow and rapid modes are related to the interior and surface CDs of CDNPs. βCDNP/MGS showed the slowest release in the slow mode. We assume that slow release in the slow mode is essential for MGS retention until the cancerous region is reached. We examined drug release behavior and anticancer efficacy of cyclodextrin-based nanoparticles (CDNPs) containing alpha-mangostin (MGS) in three different type of CDs (α-, β-, and γ-CD). βCDNP containing MGS demonstrated the best anticancer efficacy, while no efficacy was observed for the other CDNPs. Our findings suggested the anticancer efficacy might depend on the drug retention capability in which the interior and surface CDs in the CDNPs relate to the slow and rapid release modes, respectively. We assume the drug retention capability of slow release mode is important for performing the anticancer efficacy.

Background Neorautanenia mitis, Hydnora abyssinica, and Senna surattensis are medicinal plants with a variety of traditional uses. In this study, we sought to isolate the bioactive compounds responsible for some of these activities, and to uncover their other potential medicinal properties. Methods The DCM and ethanol extracts of the roots of N. mitis and H. abyssinica, and the leaves of S. surattensis were prepared and their phytochemical components were isolated and purified using chromatographic methods. These extracts and their pure phytochemical components were evaluated in in-vitro models for their inhibitory activities against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Mycobacterium tuberculosis, α-amylase (AA), and α-glucosidase (AG). Results Rautandiol B had significant inhibitory activities against two strains of Plasmodium falciparum showing a high safety ratio (SR) and IC50 values of 0.40 ± 0.07 μM (SR - 108) and 0.74 ± 0.29 μM (SR - 133) against TM4/8.2 and K1CB1, respectively. While (−)-2-isopentenyl-3-hydroxy-8-9-methylenedioxypterocarpan showed the highest inhibitory activity against T. brucei rhodesiense with an IC50 value of 4.87 ± 0.49 μM (SR > 5.83). All crude extracts showed inhibitory activities against AA and AG, with three of the most active phytochemical components; rautandiol A, catechin, and dolineon, having only modest activities against AG with IC50 values of 0.28 mM, 0.36 mM and 0.66 mM, respectively. Conclusion These studies have led to the identification of lead compounds with potential for future drug development, including Rautandiol B, as a potential lead compound against Plasmodium falciparum. The relatively higher inhibitory activities of the crude extracts against AG and AA over their isolated components could be due to the synergistic effects between their phytochemical components. These crude extracts could potentially serve as alternative inhibitors of AG and AA and as therapeutics for diabetes.

Background: A therapeutic approach to treat diabetes is to decrease postprandial hyperglycemia. α-Glucosidase inhibitors from plant sources offer an attractive strategy for the control of hyperglycemia. Smilax glabra Roxb is a medicinal plant found in Asia, including Vietnam, which is used in the treatment of chronic diseases. However, the antidiabetic activity and the identification of α-glucosidase inhibitors from this plant have not been intensively investigated. This research was carried out to determine the α-glucosidase inhibitory activity of the extracts and that of the major phytochemical components of Smilax glabra Roxb. This could lead to further studies on the role of these compounds in hyperglycemia control, as well as identify their potential future applications. Methods: Column chromatography combined with crystallization procedures were used to isolate active fractions and two major compounds. The chemical structures of these compounds were determined by analysis of their NMR spectroscopic data, as well as MS data and comparisons made with the literature data. The α-glucosidase inhibitory activity was determined spectrophotometrically using p-nitrophenyl α-D-glucopyranoside as a substrate. The in vitro cytotoxicity of the isolated compounds and fractions was determined using the MTT assay. Results: The two major compounds, astilbin and 5-O-caffeoylshikimic acid together with two very active fractions, F7 and F8, were isolated from the rhizome. The two major compounds had α- glucosidase inhibitory activities with IC50 values of ca. 125 µg/mL and 38 µg/mL, respectively which are about 4 and 13 folds higher activity than the reference compound acarbose (IC50 of ca. 525 µg/mL). Fractions F7 and F8 showed very promising inhibitory activities towards α-glucosidase with IC50 values of 5.5 and 5.8 µg/mL, respectively. Cytotoxicity data on mouse fibroblast NIH3T3 cells indicated that the active compounds and fractions were not toxic at concentrations that are greater than their respective IC50 values. The α-glucosidase inhibitory activity of 5-Ocaffeoylshikimic acid and that of the two active fractions are reported here for the first time. Conclusion: The two major isolated compounds and fractions, F7 and F8, significantly contribute to the α-glucosidase inhibitory activity of S. glabra Roxb extract. Further work is needed to clarify their modes of action and potential application.

α-Mangostin (MGS), an anti-cancer compound, is a xanthone derivative and is extracted from the pericarps of mangosteen. MGS exhibits a variety of bioactivities, such as antioxidant, cytotoxic, anti-inflammatory, and antibacterial effects, as well as anticancer activity. However, MGS has not been approved for clinical use because of its poor bioavailability. There have been many efforts to solve this problem by use of drug carriers. Cyclodextrins (CDs) are well known as nontoxic and biodegradable drug carriers and can encapsulate MGS. In this study, we prepared CD-based nanoparticles (CDNPs) by a polyaddition reaction using epichlorohydrin and characterized them by dynamic light scattering and static light scattering coupled with fractionation. The encapsulation of MGS into CDNPs was examined, and we found that the loading ratio of MGS for CDNPs is much higher than that for CDs themselves. The cytotoxicity of the CDNP/MGS complex was examined, indicating the potential of CDNP as a carrier of MGS. In this study, we synthesized and characterized cyclodextrin-based nanoparticles (CDNPs) by polyaddition reactions using epichlorohydrin and three different type of CDs (α-, β-, and γ-CD). We found that cyclodextrin tended to cover surface of our nanoparticles; while epichlorohydrin network enlarged when weight ratio of epichlorohydrin/cyclodextrin increased. Our CDNPs demonstrated a very high loading ratio against α-mangostin (MGS), and getting close to 1:1 ratio.

Ethyl 2-((4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl)thio)acetate (3) which was synthesized starting from anthranilic acid (1) via 2-thioxo-3-phenylquinazolin-4(3H)-one (2) reacted with hydrazine hydrate to afford 2-((4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl)thio)acetohydrazide (4). Reaction of (4) with thiocarbonyl-bis-thioglycolic acid gave a new compound nameN-(4-oxo-2-thioxothiazolidin-3-yl)-2-((4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl)thio)acetamide (5). Knoevenagel condensation of (5) with appropriate aldehydes gave fourteen (Z)-N-(5-arylidene-4-oxo-2-thioxothiazolidin-3-yl)-2-((4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl)thio)acetamide compounds (6a–o) with moderate yield. The chemical structure of the compounds was elucidated on the basis of IR,1H-NMR,13C-NMR, and HR-MS spectral data. The 5-arylidene-2-thioxothiazolidinone compounds exhibited mild-to-moderate cytotoxic activity against both K562 (chronic myelogenous leukemia) cells and MCF7 (breast cancer) cells.

Clinacanthus nutans Lindau has been traditionally used for healing of bone fragility, but the mechanism of actions has not been clarified yet. In this study, the bone regeneration activity of lupeol derived from C. nutans was assessed using an in vitro model of osteoblast cells MC3T3-E1. The finding revealed that the compound was not significantly toxic to osteoblast cells at concentration of ≤40 μg/mL. Lupeol demonstrated the osteogenic activity through enhancement of alkaline phosphatase (ALP) of osteoblast cells up to 31.2%, 21%, and 12% at concentrations of 5, 10, and 20 µg/mL, respectively ( p p p

Silica/Polypyrrole nanocomposites (SiO2/PPy) incorporating oxalate as counter anion (SiO2/PPyOx) were chemically polymerized in the solution with the presence of pyrrole, silica, and sodium oxalate. Nanocomposites SiO2/PPyOx at different concentrations of oxalate anion were characterized with FTIR, XRD, EDX, TGA, and TEM. The corrosion protective properties for carbon steel of nanocomposites in epoxy coating were studied by electrochemical techniques including electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP). FTIR results of nanocomposites show a slightly red-shift in terms of wavelength compared with the case of PPy and SiO2 spectra. It may be due to a better conjugation and interactions between PPy and SiO2 in nanocomposite structure. TEM image indicated that nanocomposites have spherical morphologies with diameters between 100 and 150 nm. The EIS results showed that |Z| modulus values of epoxy coatings containing SiO2/PPyOx composites reached about 109.7 Ω.cm2, always higher than that of epoxy coating. These results are also confirmed by OCP results. It proves that the presence of oxalate anion can enhance the resistance against corrosion and it has been shown that the content of counter anion strongly affects the anticorrosion ability.

The compound α-mangostin (AMG) extracted from Garcinia mangostana L. has potent anticancer properties but its clinical application is limited because of its poor solubility. In this study, AMG-loaded nanoparticles (NMG) were synthesized using a new formula and their apoptosis activity against human cervical carcinoma (HeLa) cells was investigated in comparison with organic solvent-soluble AMG in free form. The NMG was successfully synthesized with a particle size of 90% cell death (p

A rapid diagnosis of drug-resistant tuberculosis (TB) is critical for early initiation of effective therapy. Molecular testing with line probe assays (MTBDRplus and MTBDRsl) on culture isolates has been available for some time and significantly reduces the time to diagnosis of drug resistance. However, routine use of this test directly on sputum is less common. As part of enrollment screening procedures for tuberculosis clinical trials conducted in Hanoi, Vietnam, we evaluated the feasibility and performance of line probe assay (LPA) testing directly on sputum samples from 315 participants with no prior history of TB treatment. Test performance characteristics for the detection of rifampin (RIF) and isoniazid (INH) drug resistance as compared to culture-based drug susceptibility testing (DST) reference standard were calculated. LPA demonstrated high sensitivity and specificity for the diagnosis of drug resistance. Scaling up molecular testing on sputum as part of time-sensitive clinical trial screening procedures in high TB burden settings is feasible and will reduce both time to initiation of appropriate therapy and the risk of late exclusions due to microbiologic ineligibility.

ZnO nanoparticles are nontoxic inorganic oxides that have been extensively used as a supplement for zinc nutrients and antibacterial agents in the food industry, especially in edible coatings to protect food from deterioration by viruses, fungi, and bacteria. In this work, ZnO nanoparticles were fabricated by a hydrothermal method and characterized by scanning electron microscopy and X-ray diffraction. The prepared ZnO nanoparticles exhibited good antibacterial properties against several bacteria, including Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. The ZnO nanoparticles as an antibacterial agent were incorporated into a chitosan/gum arabic (CH/GA) edible coating, and the protective performance for the preservation of bananas was investigated. The obtained CH/GA/ZnO coating significantly improved the quality and shelf life of bananas at a temperature of 35 °C and relative humidity (RH) of 54 %. The banana surface treated with the CH/GA/ZnO coating was relatively smooth with a CH/GA/ZnO film thickness of approximately 50 μm. The utilization of the resultant coating enabled the maintenance of banana quality, including fruit firmness, weight loss, reducing sugar, and titratable acidity, for a remarkably longer period. The banana coated with the CH/GA/ZnO system was demonstrated to maintain freshness for more than 17 d in comparison with the less than 13 d for the control banana at 35 °C and 54 % RH.

Rhodomyrtone was isolated from the leaves of Rhodomyrtus tomentosa (Aiton) Hassk grown in Vietnam using chromatographic methods. Its chemical structure was confirmed by means of spectroscopic data analysis. The pH drop measurement, enzyme activity assays and fluorescence stain were used to examine rhodomyrtone anticaries activity. It was found that rhodomyrtone suppressed acid production by Streptococcus mutans, a major cariogenic agent in human by inhibiting enzyme activities responsible for acid production and tolerance, including membrane bound enzymes F-ATPase and phosphotransferase system (PTS), as well as glycolysis enzymes glyceraldehyphosphate dehydrogenase (GAPDH) and pyruvate kinase (PK) in cytoplasm with the IC50 values of 24 μM, 19 μM, 23 μM and 28 μM, respectively. Moreover, 50 μM rhodomyrtone reduced biofilm biomass formed by S. mutans up to 59% (p S. mutans.

This study was carried out to further examine the anti-biofilm activity of α-mangostin (αMG) isolated from Garcinia mangostana L. grown in Vietnam, against a strongly biofilm producing Streptococcus mutans, a major causative agent of dental caries. The obtained data indicated that topical applications (twice-daily, 60 s exposure each) of 150 μM αMG during biofilm formation on the surfaces of hydroxyapatite disks (sHA) by S. mutans UA159 resulted in 30.7% reduction in biofilm accumulation after 68 h of growth. The treatment did not affect the viability of S. mutans cells in the biofilms. The surface activities of two key enzymes responsible for biofilm formation, i.e. the glycosyltransferases GtfB and GtfC, were reduced by 20 and 35%, respectively (vs. vehicle control, P < 0.05). Interestingly, αMG specifically targeted S. mutans in mixed biofilms, resulting in the decrease of the S. mutans population and total biofilm biomass. αMG was also found to accumulate within the biofilm of S. mutans up to 4.5 μg/biofilm, equal to a concentration of >10 μM/biofilm. In conclusion, this study confirmed anti-biofilm activity of αMG against S. mutans. A brief exposure to αMG may suppress biofilm formation by targeting key enzymes imvolved in biofilm formation.

Background The striped catfish, Pangasianodon hypophthalmus, is a freshwater and benthopelagic fish common in the Mekong River delta. Catfish constitute a valuable source of dietary protein. Therefore, they are cultured worldwide, and P. hypophthalmus is a food staple in the Mekong area. However, genetic information about the culture stock, is unavailable for breeding improvement, although genetics of the channel catfish, Ictalurus punctatus, has been reported. To acquire genome sequence data as a useful resource for marker-assisted breeding, we decoded a draft genome of P. hypophthalmus and performed comparative analyses. Results Using the Illumina platform, we obtained both nuclear and mitochondrial DNA sequences. Molecular phylogeny using the mitochondrial genome confirmed that P. hypophthalmus is a member of the family Pangasiidae and is nested within a clade including the families Cranoglanididae and Ictaluridae. The nuclear genome was estimated at approximately 700 Mb, assembled into 568 scaffolds with an N50 of 14.29 Mbp, and was estimated to contain ~ 28,600 protein-coding genes, comparable to those of channel catfish and zebrafish. Interestingly, zebrafish produce gadusol, but genes for biosynthesis of this sunscreen compound have been lost from catfish genomes. The differences in gene contents between these two catfishes were found in genes for vitamin D-binding protein and cytosolic phospholipase A2, which have lost only in channel catfish. The Hox cluster in catfish genomes comprised seven paralogous groups, similar to that of zebrafish, and comparative analysis clarified catfish lineage-specific losses of A5a, B10a, and A11a. Genes for insulin-like growth factor (IGF) signaling were conserved between the two catfish genomes. In addition to identification of MHC class I and sex determination-related gene loci, the hypothetical chromosomes by comparison with the channel catfish demonstrated the usefulness of the striped catfish genome as a marker resource. Conclusions We developed genomic resources for the striped catfish. Possible conservation of genes for development and marker candidates were confirmed by comparing the assembled genome to that of a model fish, Danio rerio, and to channel catfish. Since the catfish genomic constituent resembles that of zebrafish, it is likely that zebrafish data for gene functions is applicable to striped catfish as well. Electronic supplementary material The online version of this article (10.1186/s12864-018-5079-x) contains supplementary material, which is available to authorized users.

α-Mangostin (AMG) extracted from Garcinia mangostana L., has potent anti-cancer properties, however its clinical application is limited due to poor aqueous-solubility. Here, we successfully synthesised and characterised water-soluble ß-cyclodextrin-coated AMG 30-50 nm-size nanoparticles (NMG). Similar cytotoxic activities against LU-1 (human lung adenocarcinoma) and HL-60 (human promyelocytic leukemia) cancer cells of water-soluble NMG and organic-solvent soluble AMG were found with IC50 of 8.86 and 9.86 µg/mL, respectively. The data demonstrates that the nanoparticles improve bioavailability while maintain anti-cancer activity of AMG.

Summary Objective: Zinc is used in oral care products as an antiplaque/antigingivitis agent. Our objective was to assess the antimicrobial actions of zinc against oral anaerobes associated with gingivitis, specifically Fusobacterium nucleatum and Prevotella intermedia, with focus on catabolism and oxidative metabolism. Methods: The oral anaerobes were grown in complex medium in an anaerobic chamber, harvested by centrifugation and used directly for experiments with suspensions. Biofilm growth involved super-infection by F. nucleatum of an initial biofilm formed by Streptococcus sanguis. Results: Zn2+ inhibited catabolism of glutamate, glutamyl-glutamate, glucose and fructose by F. nucleatum cells in suspensions with ID50 values, respectively, of 0.05, 0.005, 0.01 and 0.01 mM. The ID50 value for inhibition of glutamate catabolism by biofilms was 0.10 mM. Inhibition of glutamate catabolism could be related to inhibition of substrate uptake and of 2-oxoglutarate reductase. Zn2+ also inhibited catabolism of aspartate or aspartyl-aspartate by P. intermedia with ID50 values of 0.07 and about 0.03 mM, respectively. Respiration of intact cells of F. nucleatum and NADH oxidase in cell extracts were sensitive to zinc with ID50 values, respectively, of about 1.0 and 1.4 mM. Zinc also inhibited production of hydrogen peroxide by F. nucleatum (ID50 = ca. 0.04 mM.) but at high concentrations acted to potentiate and enhance peroxide killing of the anaerobe. Conclusion: Zn2+ is a potent inhibitor of catabolism by F. nucleatum and P. intermedia, including catabolism of peptides, which can be degraded to yield inflammatory metabolic end products. Zn2+ also inhibits O2 metabolism of F. nucleatum by about 50% and hydrogen peroxide production nearly completely but also enhances killing by peroxide added to cells.

Over 60% of the original oil in a place (OOIP) is retained in a reservoir after conventional methods have been exploited. Application of enhanced oil recovery (EOR) technology gives an additional chance to get out possibly about 20% more oil from the reservoir. The use of water-soluble polymers improves the water–oil mobility ratio, therefore, the displacement efficiency increased, and leads to enhanced oil recovery. High-molecular-weight polyacrylamide group is widely and successfully used in EOR. But no commercial polymer composition can be used in conditions of high temperature and hardness brine offshore reservoirs yet. To avoid the time consumption and high expense for selection and synthesis of the appropriate-structural polymer for EOR application, we attempt to find additives to enhance the thermal stability of polymer solutions. In this paper, we report the results of improved viscosity stability of diluted polymer/seawater solutions aged at reservoir conditions for 31days by adding graphite-oxide particles (GOs). In the presence of 300 ppm of GOs, the viscosity stability of 1700 ppm acrylamide-based polymer in sea water solution increases from 92 °C to 135 °C. FESEM pictures show good distribution of GOs in polymer network, which is a result of integration of functional groups in GOs surfaces and hydrophilic polymer chains.

Magnetic Cr3+xFe3+2 − xFe2+O4 (0 x 0.1) porous nanoparticles were prepared by the aqueous co-precipitation method. The resulting magnetic nanoparticles were characterized by using an x-ray diffraction (XRD), field enhanced scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sampling magnetometer (VSM). The nitrogen gas adsorption/desorption isotherm showed a microporous structure of the obtained magnetic materials. A rod and round shape of Fe3O4 was observed as using polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) surfactant, respectively. The Fe3O4 nanoparticles exhibited superparamagnetic properties with easy separation and re-dispersion in solution by using an external magnet. More remarkably, the saturation magnetization (Ms) was enhanced up to 1.2 times for doping Cr3+ into the Fe3O4 lattice. The effect of surfactants and Cr3+ doping concentrations on size and the magnetic properties of Fe3O4 nanoparticles are studied.

We report the synthesis of magnetic iron oxide nanoparticles encapsulated in maleic acid-2-acrylamido-2-methyl-1-propanesulfonate based polymer. This composite nanoparticle is specified for the high-pressure/high-temperature (HPHT) oilfield scale inhibition application. The process includes a facile-ultrasound-supported addition reaction to obtain iron oxide nanoparticles with surface coated by oleic acid. Then via inverse microemulsion polymerization with selected monomers, the specifically designed copolymers have been formatted in nanoscale. The structure and morphology of obtained materials were characterized by transmission electron microscopy (TEM), x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and the thermal stability. The effectiveness of synthesized compounds as a carbonate scale inhibitor was investigated by testing method NACE standard TM 03-074-95 at aging temperature of 70, 90 and 120 °C. The magnetic nanocomposite particles can be easily collected and detected demonstrating their superior monitoring ability, which is absent in the case of conventional copolymer-based scale inhibitor.

SiO2 nanoparticles (NPs) were synthesized by the sol‐gel method in an ultrasound reactor and monodispersed NPs with an average particle size of 10‐12nm were obtained. The synergy occurring in blending NPs and anionic surfactant solutions was identified by ultra-low interfacial tension (IFT) reduction measured by a spinning drop tensiometer (Temco500). The oil displacement efficiency of the synergistic blends and surfactant solutions at Dragon South-East (DSE) reservoir temperature was evaluated using contact angle measurement (Dataphysics OCA 20). It was found that SiO2/surfactant synergistic blends displace oil as well as their original surfactant solutions at the same 1000ppm total concentration. Abundant slag appearing in the SiO2/surfactant medium during oil displacement could be attributed to an adsorption of surfactants onto the NPs. The results indicate that at a concentration of 1000ppm in total, the original surfactant SS16-47A and its blend with SiO2 NPs in the ratio of 8 : 2 exhibited an IFT reduction as high as fourfold of the IFT recorded for the DSE oil‐brine interface and very high speed of oil displacement. Therefore, it could potentially be applicable to enhanced oil recovery (EOR) in high-temperature reservoirs with high hardness-injection-brine, like the one at DSE. This opens up a new direction for developing effective EOR compositions, which require less surfactant and are environmentally safer.