Advanced Imaging Techniques Reveal the Dual Function of a Thiophene Based Compound to Modulate Cell Behaviours

Living systems possess the unique capacity to produce complex structures starting from “molecular building blocks”. Exogenous compounds internalized into the cell may interact with metabolic machinery and produce hybrid structures with novel properties. We previously demonstrated the capability of cells and whole animals to produce fluorescent and conductive biofibers starting from a thiophene based compound, named DTTO [1, 2]. Here, by confocal microscopy and holotomography techniques we show the diverse function played by the compound when present as monomer or following in vivo self-assembling into microfibrils. In fact, following short pulses of photostimulation the cell death was induced by the monomer, while the microfibers strongly protected the cells from the death pathway. By merging data from non invasive label free holography and detection of reactive oxidative species (ROS) we could relate the cell death to the ROS production and study the dynamic of this process. Electrophysiological recordings and in vitro assays confirmed the different cell behaviour induced by the monomer and its self assembled form. This differences is likely due to a combination of a reduced surface area exposed by the fibers and a variation of the energy levels of the aggregated form, suggesting a DTTO dual role as photosensitizer and as novel building block for conductive materials.<br/><br/>1. M. Moros, F. Di Maria, P. Dardano, G. Tommasini, H. Castillo-Michel, A. Kovtun, M. Zangoli, M. Blasio, L. De Stefano, A. Tino, G. Barbarella and C. Tortiglione, <i>iScience</i>, 2020, <b>23</b>, 101022.<br/>2. I. Palamà, F. Di Maria, I. Viola, E. Fabiano, G. Gigli, C. Bettini and G. Barbarella, <i>J Am Chem Soc</i>, 2011, <b>133</b>, 17777-17785.