China 
Africa 
Explore chapters and articles related to this topic
Droplet Microfluidics
Published in George K. Knopf, Amarjeet S. Bassi, Smart Biosensor Technology, 2018
Flow focusing was an improvement from the co-flowing geometry, in which the continuous and dispersed phases flow coaxially at the junction and the dispersed phase is confined by channel walls. In such a flow-focusing geometry, a droplet is formed mainly due to the forces of pressure drop across the interface and interfacial tension instead of Plateau-Rayleigh instability. Hence, flow-focusing geometry generates more monodispersed droplets compared to co-flowing. Although the flow-focusing device has more complex geometry than the T-junction, it offers more flexibility in controlling droplet sizes by adding a small orifice after the junction. Additionally, the continuous phase is injected on both sides of the dispersed phase, resulting in more symmetric shearing, hence improving stability and control during the droplet formation process [39]. These features make flow-focusing one of the most popular droplet generators in microfluidic devices. Physical parameters that affect droplet formation in flow-focusing devices are found to be similar to that in T-junctions [40].
Finite Element Method for Micro- and Nano-Systems for Biotechnology
Published in Sarhan M. Musa, Computational Finite Element Methods in Nanotechnology, 2013
Focusing cells or particles in a microfluidic channel is an essential step for all cell chips. Two types of flow focusing exist: the two-phase flow focusing that is used to encapsulate biological objects and cells [55,56] and the single-phase flow focusing that is used to concentrate or focus a “beam” of liquid inside a sheath flow [57,58]. The biologic targets transported by the flow are focused or confined in a fraction of the cross section of the channel. Depending on the device, the focusing can be made along a wall of the microchannel or in a pinched streamflow (Figure 13.26). In the first case, the flow rate ratio is () Q1Q=12w1w
Nanobubbles: State of the Art, Features, and the Future
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Monica Argenziano, Federica Bessone, Roberta Cavalli
Through use of a microfluidic device with flow-focusing technology, the production of droplets of perfluoropentane with a uniform size distribution is demonstrated. Flow focusing microfluidic designs allows for greater control over the size of bubbles produced and their polydispersity [42].
Recent advances in micro-sized oxygen carriers inspired by red blood cells
Published in Science and Technology of Advanced Materials, 2023
Qiming Zhang, Natsuko F. Inagaki, Taichi Ito
Flow focusing has typically been used in the settings of microfluidic or T-junction devices to produce microdroplets based on Plateau – Rayleigh instability, with the advantage of a highly uniform size [85]. The production of OMBs by flow- focusing techniques has also been applied as post-processing after a sonification preparation of microbubbles to control the size range of and shell thickness of the synthesized OMBs [86]. Elena et al. [87] showed success in generating mono-dispersed, non-coated, air-filled microbubbles by simple flow-focusing via a modified microfluidic device. However, the microbubbles were not stabilized by surfactants or phospholipids for practical uses as AOCs.