Functional imaging with linear and
non-linear microscopy

Leonardo Sacconi

We, 16 Mar 2016, at 10:00. Aula Querzoli

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Advances in the technologies for labelling and imaging biological samples drive a constant progress in our capability of studying structures and their dynamics within cells and tissues. In the last decade, the development of numerous linear and non-linear optical microscopies has led to a new prospective both in basic research and in the potential development of very powerful non-invasive diagnostic tools [1].

However, the main shortcoming of available technologies is their incapability of imaging multiple fast phenomena while controlling the biological determinants involved with adequate spatio-temporal resolution. Overcoming these limitations would significantly improve both basic biological research and the development of more effective diagnostic and therapeutic approaches. Membrane potential changes and intracellular Ca2+ fluxes, the two most fundamental phenomena of excitable cells, can be addressed only separately using voltage sensitive dyes or calcium sensors.

In this lesson I will describe research activities devoted to develop novel optical approaches to simultaneously probe and control these crucial determinants of cellular function. Ultrafast deflectors are used to rapidly scan laser beams across the sample, performing multiplexed optical measurements of action potential and Ca2+ release from multiple sites within cells and tissues [2]. The same scanning modality are used to control local membrane electrical activity by activation of light-gated ion channels allowing a full optical control of excitable cells.

[1] W. R. Zipfel, et al. "Nonlinear magic: multiphoton microscopy in the biosciences", Nat. Biotechnol. (2003)

[2] Crocini et al. "Defects in T-tubular electrical activity underlie local alterations of calcium release in heart failure", Proc. Natl. Acad. Sci. USA (2014)