Direct detection and measurement of wall shear stress using a filamentous bio-nanoparticle

The wall shear stress (WSS) that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology (e.g. angiogenesis) and affects the microvasculature's primary function of molecular transport. Points of fluctuating WSS show abnormalities in a number of diseases; however, there is no established technique for measuring WSS directly in physiological systems. All current methods rely on estimates obtained from measured velocity gradients in bulk flow data. In this work, we report a nanosensor that can directly measure WSS in microfluidic chambers with sub-micron spatial resolution by using a specific type of virus, the bacteriophage M13, which has been fluorescently labeled and anchored to a surface. It is demonstrated that the nanosensor can be calibrated and adapted for biological tissue, revealing WSS in micro-domains of cells that cannot be calculated accurately from bulk flow measurements. This method lends itself to a platform applicable to many applications in biology and microfluidics

Genomics-driven discovery of a biosynthetic gene cluster required for the synthesis of BII-Rafflesfungin from the fungus Phoma sp. F3723

10.1186/s12864-019-5762-6BMC Genomics20137

A dry film technology for the manufacturing of 3-D multi-layered microstructures and buried channels for lab-on-chip

The development of innovative and reliable techniques for devices miniaturization are enabling the massive growth of lab on chip (LOC) applications. In this article, we briefly review the technological options for LOC microfabrication, then we present the optimization of a process for the realization of tridimensional multi-layered structures and buried channels in a microfluidic network using a photo-patternable dry film, with a potential for LOC manufacturing. The tuning of all the fabrication parameters is widely discussed and micrographs and optical profiler images are reported to show fabrication results. The fabrication process is used for a Split-flow-thin (SPLITT) fractionation cell configuration. SPLITT is a particle fractionation technique based on the combined effect of two laminar streams (the sample containing the particles and a carrier) flowing inside a thin microchannel and the action of a vertical driving force for particle displacement. Since the SPLITT implemented in this work is electrically driven, patterned electrodes (thickness: 100 nm) are also integrated in the flow cell walls. The functionality of the cell was tested first verifying the presence of proper flow conditions for microfluidic SPLITT (absence of mixing between the streams) and then proving electrical fractionation with two different proteins (BSA and b-lactoglobulin) at different levels of ionic strength. The flow of the streams within the microfluidic channel was also simulated by a numerical 2-D model exactly reproducing the cell geometry, with a good accordance with experimental results