Advances in three-dimensional rapid prototyping of microfluidic devices for biological applications

The capability of 3D printing technologies for direct production of complex 3D structures in a single step has recently attracted an ever increasing interest within the field of microfluidics. Recently, ultrafast lasers have also allowed developing new methods for production of internal microfluidic channels within the bulk of glass and polymer materials by direct internal 3D laser writing. This review critically summarizes the latest advances in the production of microfluidic 3D structures by using 3D printing technologies and direct internal 3D laser writing fabrication methods. Current applications of these rapid prototyped microfluidic platforms in biology will be also discussed. These include imaging of cells and living organisms, electrochemical detection of viruses and neurotransmitters, and studies in drug transport and induced-release of adenosine triphosphate from erythrocytes

Electric field driven addressing of ATPS droplets in microfluidic chips

Referujeme o možnosti ovlivňovat pohyb kapek (adresování kapek) pomocí stejnosměrného elektrického pole v systému dvoufázového vodného roztoku (ATPS). Byly zkoumány tři systémy ATPS typu polyetylenglykol/sůl, jmenovitě polyetylenglykol/fosfát, polyetylenglykol/síran a polyetylenglykol/uhličitan. Série pokusů s adresováním a slučováním kapek v mikrofluidním čipu ukázaly, že stejnosměrné elektrické pole může být užitečným nástrojem pro chytrou manipulaci kapek v systémech polyetylenglykol/sůl.The possibility of controlled droplet motion (droplet addressing) mediated by DC electric field in aqueous two-phase systems (ATPS) is here reported for the first time. Three ATPS of polyethylene glycol (PEG)/salt type, namely PEG/phosphate, EG/sulphate, and PEG/carbonate, were selected for this study. We observed fast motion of salty droplets dispersed in PEG continuous phase induced by electric field of relative low strength. Hence, three fluidic systems with separated electrode chambers for the evaluation of electrophoretic mobilities and for addressing experiments were fabricated. Electrophoretic mobilities of salty droplets always exceeded the value of 1 × 10−7 m2V−1s−1, which is about by one magnitude higher value than those typically measured in water–oil droplet systems. The electrophoretic mobilities in systems with free surface are the same or even smaller than in closed microfluidic structures, which is accounted mainly to the fact that a significant part of salty droplets is exposed to air and does not contribute to droplet forcing. Series of addressing and merging experiments in a microfluidic chip shows that DC electric field can be used as a powerful tool for smart manipulation of droplets in microfluidic systems with PEG/salt ATPS