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Bacterial outer membrane vesicle (OMV) is a kind of spherical lipid bilayer nanostructure naturally secreted by bacteria, which has diverse functions such as intracellular and extracellular communication, horizontal gene transfer, transfer of contents to host cells, and eliciting an immune response in host cells. In this review, several methods including ultracentrifugation and precipitation for isolating OMVs were summarized. The latest progresses of OMVs in biomedical fields, especially in vaccine development, cancer treatment, infection control, and bioimaging and detection were also summarized in this review. We highlighted the importance of genetic engineering for the safe and effective application and in facilitating the rapid development of OMVs. Finally, we discussed the bottleneck problems about OMVs in preparation and application at present and put forward our own suggestions about them. Some perspectives of OMVs in biomedical field were also provided.

Protein biomarkers in blood have been widely used in the early diagnosis of disease. However, simultaneous detection of many biomarkers in a single sample remains challenging. Herein, we show that the combination of a sandwich assay and DNA-assisted nanopore sensing could unambiguously identify and quantify several antigens in a mixture. We use five barcode DNAs to label different gold nanoparticles that can selectively bind specific antigens. After the completion of the sandwich assay, barcode DNAs are released and subject to nanopore translocation tests. The distinct current signatures generated by each barcode DNA allow simultaneous quantification of biomarkers at picomolar level in clinical samples. This approach would be very useful for accurate and multiplexed quantification of cancer-associated biomarkers within a very small sample volume, which is critical for non-invasive early diagnosis of cancer.

Mitochondria play critical roles in the regulation of the proliferation and apoptosis of cancerous cells. Nanosystems for targeted delivery of cargos to mitochondria for cancer treatment have attracted increasing attention...

Abstract. Reactive oxygen species (ROS) carried or induced by particulate matter (PM) are suspected of inducing oxidative stress in vivo, leading to adverse health impacts such as respiratory or cardiovascular diseases. The oxidative potential (OP) of PM, displaying the ability of PM to oxidize the lung environment, is gaining strong interest in examining health risks associated with PM exposure. In this study, OP was measured by two different acellular assays (dithiothreitol, DTT, and ascorbic acid, AA) on PM10 filter samples from 15 yearly time series of filters collected at 14 different locations in France between 2013 and 2018, including urban, traffic and Alpine valley site typologies. A detailed chemical speciation was also performed on the same samples, allowing the source apportionment of PM using positive matrix factorization (PMF) for each series, for a total number of more than 1700 samples. This study then provides a large-scale synthesis of the source apportionment of OP using coupled PMF and multiple linear regression (MLR) models. The primary road traffic, biomass burning, dust, MSA-rich, and primary biogenic sources had distinct positive redox activity towards the OPDTT assay, whereas biomass burning and road traffic sources only display significant activity for the OPAA assay. The daily median source contribution to the total OPDTT highlighted the dominant influence of the primary road traffic source. Both the biomass burning and the road traffic sources contributed evenly to the observed OPAA. Therefore, it appears clear that residential wood burning and road traffic are the two main target sources to be prioritized in order to decrease significantly the OP in western Europe and, if the OP is a good proxy of human health impact, to lower the health risks from PM exposure.

Astaxanthin-loaded liposomes were prepared by employing a thin-film ultrasound method with the utilization of soy phosphatidylcholine. The preparation conditions of astaxanthin-loaded liposomes were optimized through response surface methodology. Under the optimum preparation conditions, the observed experimental results showed the vesicle size of astaxanthin-LL was 80.62 ± 4.52 nm with the polydispersity index of 0.20 ± 0.03, while the zeta potential was −31.80 ± 1.85 mV with the highest encapsulation efficiency of 97.68 ± 0.34%. The successful encapsulation of astaxanthin in liposomes was demonstrated by Fourier-transform infrared spectroscopy. Retention rate of 82.29% was obtained after 15 days of storage at 4°C in the stability study, which confirmed that the liposome membrane could retain astaxanthin effectively, especially at low storage temperature. Encapsulation could enhance significantly the antioxidant activity of astaxanthin. Additionally, the antioxidant activity of astaxanthin after encapsulation in liposomes was correlated with the incorporation efficiency of astaxanthin.Preparación de liposomas llenos de astaxantina: caracterización, capacidad de almacenamiento y actividad antioxidante RESUMEN En este estudio se prepararon liposomas llenos de astaxantina empleando el método de ultrasonido de capa fina y utilizando fosfatidilcolina de soya. Las condiciones de preparación de los liposomas llenos de astaxantina fueron optimizadas mediante la metodología de superficies de respuesta. Bajo estas condiciones óptimas de preparación, los resultados experimentales observados mostraron que el tamaño vesicular de la astaxantina-LL fue 80,62 ± 4,52 nm, registrando un índice de polidispersidad de 0,20 ± 0,03; además, el potencial zeta fue −31,80 ± 1,85 mV, y la mayor eficiencia de encapsulación registró un valor de 97,68 ± 0,34%. La exitosa encapsulación de la astaxantina en los liposomas se comprobó empleando la espectroscopía infrarroja transformada de Fourier. En lo que se refiere al estudio de estabilidad, al transcurrir 15 días de almacenamiento a una temperatura de 4°C se obtuvo una tasa de retención de 82,29%, lo que confirma que la membrana del liposoma puede retener eficazmente a la astaxantina, sobre todo a bajas temperaturas de almacenamiento. Por lo que, la encapsulación podría mejorar significativamente la actividad antioxidante de la astaxantina. Asimismo, se constató que después de la encapsulación en los liposomas dicha actividad se correlaciona con la eficiencia de incorporación de astaxantina.

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