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Dimitra Markovitsi


Dimitra Markovitsi (Δήμητρα Μαρκοβίτση in Greek) is a Greek-French chemist. She is currently Emeritus Research Director at the French National Centre for Scientific Research (CNRS), affiliated to the Institut de Chimie Physique - Université Paris-Saclay.

She has expertise in the field of photophysics and photochemistry with special focus in time-resolved optical spectroscopy (absorption, fluorescence). After initiating spectroscopic studies on liquid crystals, she turned her attention to DNA. Since 2000 she studies the primary processes triggered by absorption of UV radiation directly by single - and double-strands, as well as by guanine quadruplexes [ 2-6].

The two aspects of her work constitute presently the topic of a Marie Skłodowska Curie European training network “LightDyNAmics – DNA as a training platform for photodynamic processes in soft materials”.

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Personal life and education
Markovitsi, daughter of Tryfon and Eleftheria, was born at Athens on 1954. From 1958 to 1969 she lived at Krya Vryssi Giannitson (Κρύα Βρύση Γιαννιτσών). Then, she returned to Athens, where she graduated from the National Technical University, receiving a degree in chemical engineering in 1978.

Thanks to a grant of the French government, she moved to France, where she obtained a “Diplôme d’Etudes Approfondies” (equivalent to Master degree) from the Université Paris VII (1979) on “Energy and Pollution”. Subsequently, she went to Strasbourg, where she prepared a Thèse d’Etat (PhD equivalent to Habilitation) in Chemistry at the Louis Pasteur University, defended in 1983. On 1982, she obtained French Citizenship, while maintaining the Greek one. Since 1993, she is married to Gerard Balland, Administrateur de l’Insee, now retired.

Career
In 1981, while being at Strasbourg, Markovitsi joined the CNRS. She spent one year (1984) as visiting scientist at the Royal Institution of Great Britain, whose director was Lord G. Porter. Then, she moved to the Paris region and, from 1985 till 2021, she worked at CEA-Saclay Center, in joint research Laboratories of the CNRS and the French Alternative Energies and Atomic Energy Commission.

She initiated the creation of the Francis Perrin Laboratory (FPL) and was his head from 2001 to 2014. The FPL, composed of 30-40 research scientists, engineers and technicians, was conducting research in Physical Chemistry, with a special focus on the interaction of light with molecular systems and nanoparticles. Markovitsi served as President of the European Photochemistry Association (2007-2010) and since 2018 she is the Chair of the International Foundation for Photochemistry.

Scientific contributions
Markovitsi demonstrated the occurrence of excitation transport in columnar phases with particular focus on the dimensionality of the process [ 7-11]. She addressed the effect of orientational disorder on the electronic excited states, introducing modelling based on the exciton theory with data issued from quantum calculations [ 12-14]. In parallel, she organized a series of French and European conferences entitled “Lights on organized molecular systems”, where the emerging soft materials were discussed in view of their applications in field of optoelectronics.

Having gained experience in the way that the interchromophore coupling and structural disorder influence the electronic excited states of multichromophoric systems, she tackled those questions in the case of DNA. She published the first studies examining how conformational disorder may affect the excited states of double helices [ 15] and of guanine quadruplexes [ 16]. At the same time, she investigated the intrinsic DNA fluorescence [ 5, 17-20], exploring its behaviour from femtoseconds to nanoseconds. She demonstrated the occurrence of excitation transport and evidenced the collective nature of the Franck-Condon states [ 21-24]. She published the first spectroscopic study on DNA excited states located in the UVA range [ 25]; despite their very weak absorption, such excited states may contribute to the damage of the genetic code by solar light, whose intensity in the UVA is stronger compared to the UVB and UVC.

Markovitsi discovered an unexpected phenomenon: low-energy UV radiation is capable of ionizing DNA multimers (but not their monomeric constituents) generating electron holes on the nucleobases [ 4, 26, 27]. The latter radical species are precursors to oxidative damage and promising for photoconductivity-based nanodevices. She showed that photoionization of guanine quadruplexes may be tuned thanks to the structural diversity of these systems [ 28].

Markovitsi also studied reaction dynamics in DNA from the nanosecond to the millisecond time-scales. This work concerns, on the one hand, dimerization of nucleobases [ 29, 30] and, on the other, guanine radical deprotonation [ 6] and tautomerization [ 31, 32]. Her studies revealed the anisotropic nature of such reactions, strongly depending on the local DNA environment, rendering the classical models of chemical kinetics inappropriate for their description.

Details on the Markovitsi scientific activities can be found at: ORCID https://orcid.org/0000-0002-2726-305X

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