Fast Active Merging of Microdroplets in Microfluidic Chambers Driven by Photo-Isomerisation of Azobenzene Based Surfactants

• Published in: Biosensors (Basel) Vol. 9; no. 4; p. 129
• Main Authors: Hayat, Zain, Bchellaoui, Nizar, Deo, Claire, Métivier, Rémi, Bogliotti, Nicolas, Xie, Juan, Buckle, Malcolm, El Abed, Abdel I
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.11.2019; MDPI
• Subjects: Active control; Azo compounds; Azo Compounds - chemistry; Biosensing Techniques - instrumentation; Chambers; conformational states; Droplets; Electrochemical Techniques - instrumentation; Irradiation; Isomerization; Lasers; Light; Light irradiation; microdroplets; Microfluidic Analytical Techniques - instrumentation; Microfluidics; Molecular Structure; opto-mechanics; Particle Size; photo-isomerisation; Photochemical Processes; photokinetics; Pollutants; Polymers; Stereoisomerism; Surface activity; Surface Properties; Surface-Active Agents - chemistry; Surfactants; Temporal resolution; Ultraviolet lasers; United States > US; conformational states; microdroplets; opto-mechanics; photo-isomerisation; photokinetics
• ISSN: 2079-6374; 2079-6374
• DOI: 10.3390/bios9040129

In this work, we report on the development of a newly synthesized photoactive reversible azobenzene derived surfactant polymer, which enables active and fast control of the merging of microdroplets in microfluidic chambers, driven by a pulsed UV laser optical stimulus and the well known - photo-isomerisation of azobenzene groups. We show for the first time that merging of microdroplets can be achieved optically based on a photo-isomerization process with a high spatio-temporal resolution. Our results show that the physical process lying behind the merging of microdroplets is not driven by a change in surface activity of the droplet stabilizing surfactant under UV illumination (as originally expected), and they suggest an original mechanism for the merging of droplets based on the well-known opto-mechanical motion of azobenzene molecules triggered by light irradiation.