Emulsions of microdroplets (suspensions of micrometer-sized droplets in an immiscible medium) are used in a wide range of applications especially in pharmaceutical and biosciences, beauty and food industries. Even though the conventional techniques (e.g. high speed blenders, colloid mills, high pressure homogenizers) can produce emulsions in high quantities and at high rates, these techniques cannot produce monodisperse emulsions. Using conventional techniques, it is difficult to control the size distribution of the resulting droplets, which may affect rate of the droplet degradation, the kinetics of encapsulant release, and decrease the stability of the emulsion. This is particularly problematic in the pharmaceutical industry, where irregular drug quantities encapsulated in polydisperse drug-loaded droplets and particles can cause an initial burst of drug release in vivo, which eventually can lead to undesirable cytotoxic effects.
Fig. 1. Microfluidic chip for monodisperse droplet production.
On the other hand, monodisperse emulsions can be produced, manipulated and analyzed using microfluidics. This technique is employed in chemistry, biology, genomics, proteomics, pharmaceuticals, bio-defense and other areas where small quantities of liquids are involved and rapid analysis is required. The biggest advantages of microfluidics are production of monodisperse droplets and the small quantities of material required, reducing costs of expensive reagents. This is achieved by producing emulsions in micrometer sized channels in a droplet-by-droplet manner at kHz rates (Fig. 1). However, to have very high uniformity of the droplets, flow of the liquids and droplets size has to be monitored and regulated very rapidly, according to changing conditions. This is possible only by fully automated droplet production system, which can monitor droplet size, adjust flow rates and pressures of the liquids to compensate for any changes in the droplet production system and to maintain very high droplet production uniformity for long periods of time at the same time producing high amounts of monodisperse emulsions.
In this project fully automated droplet production system, which can monitor droplet size, adjust flow rates and pressures of the liquids to compensate for any changes in the droplet production system to maintain very high droplet production uniformity for long periods of time was developed (Fig 2).
Fig. 2. The principal scheme of droplet production and monitoring system with the feedback to regulate droplet size.
