Dataset Information

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

ABSTRACT: 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 cis-trans 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.

SUBMITTER: Hayat Z

PROVIDER: S-EPMC6956313 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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

Hayat Zain Z Bchellaoui Nizar N Deo Claire C Métivier Rémi R Bogliotti Nicolas N Xie Juan J Buckle Malcolm M El Abed Abdel I AI

Biosensors 20191101 4

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 <i>cis</i>-<i>trans</i> 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-tempo ...[more]

PMID: 31683751

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Project description:BACKGROUND AND PURPOSE:The photo-isomerizable local anaesthetic, quaternary ammonium-azobenzene-quaternary ammonium (QAQ), provides rapid, optical control over pain signalling without involving genetic modification. In darkness or in green light, trans-QAQ blocks voltage-gated K+ and Na+ channels and silences action potentials in pain-sensing neurons. Upon photo-isomerization to cis with near UV light, QAQ blockade is rapidly relieved, restoring neuronal activity. However, the molecular mechanism of cis and trans QAQ blockade is not known. Moreover, the absorption spectrum of QAQ requires UV light for photo-control, precluding use deep inside neural tissue. EXPERIMENTAL APPROACH:Electrophysiology and molecular modelling were used to characterize the binding of cis and trans QAQ to voltage-gated K+ channels and to develop quaternary ammonium-ethylamine-azobenzene-quaternary ammonium (QENAQ), a red-shifted QAQ derivative controlled with visible light. KEY RESULTS:trans QAQ was sixfold more potent than cis QAQ, in blocking current through Shaker K+ channels. Both isomers were use-dependent, open channel blockers, binding from the cytoplasmic side, but only trans QAQ block was slightly voltage dependent. QENAQ also blocked native K+ and Na+ channels preferentially in the trans state. QENAQ was photo-isomerized to cis with blue light and spontaneously reverted to trans within seconds in darkness, enabling rapid photo-control of action potentials in sensory neurons. CONCLUSIONS AND IMPLICATIONS:Light-switchable local anaesthetics provide a means to non-invasively photo-control pain signalling with high selectivity and fast kinetics. Understanding the mode of action of QAQ and related compounds will help to design of drugs with improved photo-pharmacological properties. LINKED ARTICLES:This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.

Dataset Information

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

Publications

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

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