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Alumni – Interdisciplinary Projects
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High-resolu­tion optoge­net­ics with organic light-emitting diodes (OLEDs)

Giuseppe Ciccone – Hector Fellow Karl Leo

Rodrigo Fernan­dez Lahore – Hector Fellow Peter Hegemann

In this project, the appli­ca­tion of organic light-emitting diodes (OLEDs) in optoge­net­ics will be inves­ti­gated. Several new techno­log­i­cal approaches will be addressed to achieve optoge­netic activa­tion and inhibi­tion of neurons with previ­ously impos­si­ble lateral resolu­tion. For this purpose, a new OLED technol­ogy is to be used, which can imitate electri­cally switch­able differ­ent colours. These OLEDs will be struc­tured into cell-sized pixels and protected against degra­da­tion by thin-film encap­su­la­tion. In combi­na­tion with a matrix drive with organic transis­tors, it is thus possi­ble to stimu­late local opto-genetic effects in an extremely flexi­ble way. The devel­oped OLEDs are to be tested on new channel rhodopsins, which repre­sent a fusion of two proteins with comple­men­tary ion conduc­tiv­ity. First tests will be performed on Chlamy­domonas algae and HEK cells and later neuronal networks will be inves­ti­gated in cell cultures and tissue sections. Here, the signal propa­ga­tion within a network will be inves­ti­gated, whereby individ­ual neurons will be specif­i­cally switched on and off.

The project will be carried out in close inter­dis­ci­pli­nary cooper­a­tion between the Hector Fellows Karl Leo, in the Depart­ment of Physics, and Peter Hegemann, in the Depart­ment of Biophysics. The two doctoral researchers involved are Giuseppe Ciccone (Technis­che Univer­sität Dresden) and Rodrigo Fernande Lahore (Humboldt Univer­sity of Berlin).

Giuseppe Ciccone

Doctoral student

Rodrigo Fernan­dez Lahore

Doctoral student
   

AC-driven OLEDs as optoge­netic tools

Giuseppe Ciccone, Technis­che Univer­sität Dresden

AC-gesteuerte OLEDs als optogenetische Werkzeuge

AC-driven OLEDs layout: simula­tion of the electro­mag­netic wave propa­gat­ing in the device and its spectral radiant intensity.

Photo­stim­u­la­tion of optoge­net­i­cally modified cells provides profound selec­tive stimu­la­tion of their electri­cal activ­ity and inter­de­pen­dence. While a plethora of devices have been proposed for optoge­net­ics, AC-driven organic light emitting diodes (OLEDs) are examined in this project as optoge­netic tools with the unprece­dented stabil­ity in biolog­i­cal environ­ment, high spatial resolu­tion, and their possi­bil­ity to induce both enhance­ment and inhibi­tion via on-demand color emission.

Activa­tion and inhibi­tion of neurons with previ­ously unattain­able spatial resolu­tion can be triggered with two differ­ent colors by using a new technol­ogy that exploits AC-driven OLEDs struc­tured into micro-pixels and protected against degra­da­tion with thin encap­su­la­tion. The archi­tec­ture of these devices will be tailored accord­ing to the absorp­tion spectra of excita­tory and inhibitory state of the art photo­sys­tems. Moreover, the devices will be tested on in vitro models to trigger their electri­cal responses. With a view on future in vivo tests, biodegrad­able substrates will be examined as devices supports for further implan­ta­tion in model animals.

   

Photoac­ti­va­tion of neurons using channelrhodopsins

Rodrigo Fernan­dez Lahore, Humboldt Univer­sity of Berlin

Photoaktivierung von Neuronen mittels Kanalrhodopsinen

a) Overview of the most impor­tant micro­bial rhodopsins.
b) Normal­ized photocur­rents of selected channel­rhodopsins at differ­ent activa­tion wavelengths in compar­i­son to red-shifted CsChrim­son.
c) Spectrum of a blue-light emitting OLED overlaid with the action spectra of GtACR2 and CsChrim­son.
Sources: a) and b) J. Vierock, PhD Thesis, Humboldt-Univer­sität Berlin, 2019
c) Courtesy of Caroline Murawski

Due to the speed of complex neuronal networks, their study requires tools which enable precise spatial and tempo­ral control of their processes. Using light-gated ion channels named channel­rhodopsins (ChRs) origi­nally found in unicel­lu­lar algae, it is possi­ble to switch neurons on and off with the use of e.g. lasers and LEDs in a field known as optogenetics.

This project is concerned with the testing of organic LEDs (OLEDs), which emit both blue and red light, for appli­ca­tions in optoge­net­ics. For this purpose, cells express­ing either fused or separated blue-shifted GtACR2 and red-shifted CsChrim­son are exposed to OLEDs (provided by cooper­a­tion partner HF Prof. Dr. Karl Leo). The separate activa­tion of the two channel rhodopsins with a single OLED on a single cell scale will be tested. First, exper­i­ments will be performed in animal cell culture (HEK293 and ND7/23 cells) and after advanced optimiza­tion the OLEDs will be tested for use in neurons.

   

Supported by

Prof. Dr.

Karl Leo

Physics

Hector Fellow since 2013Disziplinen Karl Leo

Prof. Dr.

Peter Hegemann

Biology, Chemistry & Medicine

Hector Fellow since 2015Disziplinen Peter Hegemann

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