Unit 1, Anglian Business Park, Orchard Road, Royston, Hertfordshire, SG8 5TW, UK T: +44 (0)1763 242491 F: +44 (0)1763 246125 E: sales@dolomite-microfluidics.com W: www.dolomite-microfluidics.com Dolomite Microfluidics North America Office Blacktrace Inc, 29 Albion Place Charlestown, MA 02129, USA C: 617 803 6655 T: 617 848 1121 F: 617 500 0136 E: salesus@dolomite-microfluidics.com Mitos P-Pump Droplet Monodispersity A comparison of the size consistency of droplets formed by the Mitos P-Pump and a market leading syringe pump application note page About Monodisperse Droplet Formation 2 Monodispersity Test Set-up 2 P-Pump Results 3 Syringe Pump Results 4 Conclusions 4 The Dolomite Centre Limited Page 1 of 6
About Monodisperse Droplet Formation The formation of droplets of oil-in-water or water-in-oil has a range of uses in science and industry. Monodispersity, or size consistency, is the key to making droplet microfluidics a powerful tool for conducting accurate and repeatable experiments. Droplet Application Example Emulsion production in food or cosmetics Droplets as mini chemical reactors Drug delivery Performing biochemical assays or screens Requirement for Monodispersity Consistent texture and performance of sample Known chemical make-up of droplets to achieve a reaction Controlled dispersion of active ingredients Ability to keep conditions inside droplet constant and measure the effect of a single parameter Monodispersity Test Set-up To enable a comparison to be made between the Mitos P-Pump pressure pump technology and syringe pump technology, droplets were generated using each pump type and the droplet size distribution measured. A high speed video was captured to provide a data sample and processed using image analysis software. The droplet liquid was water with 10% v/v blue dye and the carrier liquid was mineral oil with 1% v/v Span 80 (Span 80 is a surfactant used to increase droplet stability). 3200032 F100 flow resistor F100 tube A 3000155 Mitos chip holder H 3000024 Mitos edge connector 4-way (2x) 3000301 Mitos droplet junction chip hydrophobic 3200016 Mitos P-Pump 3200028 F1 flow resistor F1 3200016 Mitos P-Pump Experimental set-up for monodispersity test of droplets generated by the Mitos P-Pump 3000155 Mitos chip holder H 3000024 Mitos edge connector 4-way (2x) 3000301 Mitos droplet junction chip hydrophobic Market leading syringe pump with 100µl syringe (water) and 1000 µl syringe (oil) Experimental set-up for monodispersity test of droplets generated by the syringe pump Mitos P-Pump Droplet Monodispersity application note Page 2 of 6
Droplet Count The Dolomite Centre Ltd P-Pump Results Image of water-in-oil droplets formed with the Mitos P-Pump and Mitos Droplet Junction Chip - Hydrophobic 140 Frequency Cumulative % 120% 120 100% 100 80 60 40 80% 60% 40% 20 20% 0 98 99 100 101 102 103 104 Droplet diameter (μm) Histogram of water droplet size distribution with water flow rate of 1 µl/min and oil flow rate of 8.4 µl/min. Sample data obtained with Mitos P-Pump and Mitos Droplet Junction Chip Hydrophobic and processed using image analysis software 0% Measure of Distribution Value Mean Droplet Diameter 99.7 µm Standard Deviation 0.6 µm Minimum Droplet Diameter 98.5 µm Maximum Droplet Diameter 102.2 µm Coefficient of Variation 0.6 % Table showing variation in droplet size Mitos P-Pump Mitos P-Pump Droplet Monodispersity application note Page 3 of 6
Droplet Count The Dolomite Centre Ltd Syringe Pump Results Image of water-in-oil droplets formed with a market leading syringe pump and Mitos Droplet Junction Chip - Hydrophobic 60 50 40 30 20 10 Frequency Cumulative % 120.00% 100.00% 80.00% 60.00% 40.00% 20.00% 0 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100101102 Droplet diameter (μm) 0.00% Histogram of water droplet size distribution with water flow rate of 1 µl/min and oil flow rate of 10 µl/min. Sample data obtained with market leading syringe pump and Mitos Droplet Junction Chip Hydrophobic and processed using image analysis software Measure of Distribution Value Mean Droplet Diameter 93.4 µm Standard Deviation 5.1 µm Minimum Droplet Diameter 76.8 µm Maximum Droplet Diameter 101.2 µm Coefficient of Variation 5.5 % Table showing variation in droplet size market leading syringe pump Mitos P-Pump Droplet Monodispersity application note Page 4 of 6
Conclusions For generating highly monodispersed droplets, the Mitos P-Pump presents a better solution than a market leading syringe pump. In this test, the Mitos P-Pump provides a coefficient of variation in the droplet diameter of 0.6% compared with 5.5% for the syringe pump. This illustrates that there is clear difference in flow smoothness with these two pump technologies. The precise pressure-driven pumping mechanism of the Mitos P-Pump delivers liquid with a smooth and even flow, whereas even the best motor drives and mechanics of a syringe pump have slight nonlinearities, which cause unwanted pulsation. As a result, the Mitos P-Pump technology offers optimum flow smoothness for microfluidic applications. Mitos P-Pump Droplet Monodispersity application note Page 5 of 6
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