Bilberry Supplementation after Myocardial Infarction Decreases Microvesicles in Blood and Affects Endothelial Vesiculation

Scope: Diet rich in bilberries is considered cardioprotective, but the mechanisms of action are poorly understood. Cardiovascular disease is characterized by increased proatherogenic status and high levels of circulating microvesicles (MVs). In an open-label study patients with myocardial infarction receive an 8 week dietary supplementation with bilberry extract (BE). The effect of BE on patient MV levels and its influence on endothelial vesiculation in vitro is investigated. Methods and results: MVs are captured with acoustic trapping and platelet-derived MVs (PMVs), as well as endothelial-derived MVs (EMVs) are quantified with flow cytometry. The in vitro effect of BE on endothelial extracellular vesicle (EV) release is examined using endothelial cells and calcein staining. The mechanisms of BE influence on vesiculation pathways are studied by Western blot and qRT-PCR. Supplementation with BE decreased both PMVs and EMVs. Furthermore, BE reduced endothelial EV release, Akt phosphorylation, and vesiculation-related gene transcription. It also protects the cells from P2X7-induced EV release and increase in vesiculation-related gene expression. Conclusion: BE supplementation improves the MV profile in patient blood and reduces endothelial vesiculation through several molecular mechanisms related to the P2X7 receptor. The findings provide new insight into the cardioprotective effects of bilberries

Cell and Particle Trapping in Microfluidic Systems Using Ultrasonic Standing Waves

Analysis methods are currently being miniaturized in order to save time and money while achieving higher sensitivities. The ultimate goal is to create a lab-on-a-chip where all analysis steps and instruments can be automated and integrated into a single chip. In order to perform cellassays and microparticle based bioassays on chip, methods to manipulate particles and cells in microsystems are desired. This thesis describes the development of a non-contact method of manipulating cells and particles in lab-on-a-chip systems based on ultrasonic standing waves. A short review on microfluidics and acoustics is presented, followed by an overview of other techniques for trapping particles and cells in microsystems. Previous work done within the field of acoustic trapping in macro- and microsystems is reviewed before the development and fabrication of the acoustic trapping platform is presented. The trapping platform provides a noncontact way of immobilizing cells and particles in a continuously flowing microsystem. The possiblity to use an array of trapping sites and move particles between different trapping sites is demonstrated. A model bioassays is presented to show the potential of the dynamic arraying concept, where the combination of microfluidics and an array of non-contact trapping sites is used to create a flexible platform for particlebased assays. The platform is also shown to be a gentle way of immobilizing live cells as demonstrated by culturing yeast cells suspended in a standing wave. A viability assay on levitated neural stem cells is also performed to show handling of a more sensitive cell type. The technique is applied to the field of forensics in sample preparation for DNA-analysis in rape cases. The acoustic technique is shown to achieve comparable purities of the separated DNA fraction in a substantially shorter time as compared to the standard methods used today. The results show that the acoustic trapping platform is a flexible and gentle cell handling technique and has the potential to become an important tool for cell and particle handling in microfluidic systems. Finally, an all-glass wet-etched device for acoustic continuous flow separations was demonstrated. Previously reported devices have been manufactured in silicon and the possibility to use glass as base material will lower the chip costs, simplifies the fabrication process and decrease the fabrication time

Acoustofluidics 20: Applications in acoustic trapping.

This part of the Acoustofluidics tutorial series reviews applications in acoustic trapping of micron-sized particles and cells in microfluidic systems. Acoustic trapping enables non-invasive and non-contact immobilisation of cells and particles in microfluidic systems. Acoustic trapping has been used for reducing the time needed to create 3D cell clusters, enhance particle-based bioassays and facilitated interaction studies of both cells and particles. An area that is increasingly interesting is the use of acoustic trapping for enriching low concentration samples and the washing or fractioning of cell populations prior to sensitive detection methods (MALDI-MS, PCR etc.) The main focus of the review is systems where particles can be retained against a flow while applications in which particles are positioned in a stationary fluid will be addressed in part 21 of the Acoustofluidics tutorial series (M. Wiklund, S. Radel and J. J. Hawkes, Lab Chip, 2012, 12, )

Acoustic Trapping

Acoustic trapping has been shown to be a gentle way of performing non-contact immobilization of cells and particles in microfluidic systems. Acoustic trapping uses localized ultrasonic standing waves that are created in microfluidic channels, cavities or other small, confined spaces. The standing wave creates a pressure node that attracts and holds particles and cells. Commonly, structures in the range of a couple of hundred micrometers are used, corresponding to acoustic frequencies in the MHz- range

Microfluidic PMMA interfaces for rectangular glass capillaries

We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics

Influence of Nonuniform Channel Width Distribution in Porous Silicon High Aspect Ratio Parallel Channel Micro Reactors

The paper focuses on the fact that, since the flow rate in parallel channels relies strongly on the channel width, the combination may lead to inaccurate results if errors in the fabrication process lead to an uneven distribution of channel widths. Parallel channel enzyme reactors were designed with channel widths distributed normally with different degrees of standard deviation. The reactors were then evaluated with regard to dispersion and to catalytic effect of the immobilised enzyme. It was shown that for lower concentrations the catalytic efficiency decreased significantly even for small variations in the distribution of channel widths and reactors with poor homogeneity in channel widths also diluted the sample more than the others

Acoustofluidics 5: Building microfluidic acoustic resonators.

Acoustophoresis is getting more attention as an effective and gentle non-contact method of manipulating cells and particles in microfluidic systems. A key to a successful assembly of an acoustophoresis system is a proper design of the acoustic resonator where aspects of fabrication techniques, material choice, thickness matching of involved components, as well as strategies of actuation, all have to be considered. This tutorial covers some of the basics in designing and building microfluidic acoustic resonators and will hopefully be a comprehensive and advisory document to assist the interested reader in creating a successful acoustophoretic device