Demonstrating microdroplet coalescence for tailored and biodegradable microgel fabrication

Abstract

Coalescence of droplets is a microscopic phenomenon that is frequently occurring in Nature. Microfluidics can mimic those phenomena. In this field, the coalescence of microdroplets is widely in use for several processes such as synthesis of organic or inorganic nano- or micro-particles, mixing or design of biological or chemical components for medical applications. Here, a microfluidic design for passive coalescence of microdroplets has been analysed demonstrating a simplified mechanism for fusing the droplets (without synchronisation of the phase of the droplets). An intriguing application of this “lab-on-a-chip” has been the formation of high aspect ratio biodegradable microgels via stabilisation with crosslinker (aldehydes). Geometrical aspect ratio, absorption, and biodegradability can be tuned by controlling the mode of coalescence. Those protein microgels and their derivatives can be considered as “smart materials” and may be applied in the biological or medical field. Microgel biodegradability which indicates good biocompatibility for those materials has been also investigated displaying characteristic time ranging from 1 h to 5 h.