Anthracene-Based Down-Converting Copolymers for Non-Invasive Optogenetic Techniques

The down-conversion of high energy light with a fluorescent material may provide sufficient emission intensity to invoke a measurable neurological response in optogentically-active neurons. This work describes the use of anthracene-containing copolymers for use as a fixed emission material in optogenetic electrophysiology to demonstrate the feasibility of this technique. An anthracene-modified methacrylate was synthesized and copolymerized with methyl methacrylate to produce glassy copolymers with physical properties like those of poly(methyl methacrylate) (PMMA). The fluorescence in both solution and solid states are like those of pure anthracene and overlap fully with the absorption spectrum of channelrhodpsin-2. Scintillation is observed but is weak compared to fluorescence. The copolymers were found to be non-toxic to neuronal cultures. Whole cell patching measured the voltage changes of neurons under UV-irradiation in the absence and presence of a copolymer film. Increased frequencies and amplitudes of electrical events were observed in the presence of the polymers.