Modelling the effects of E/Z photoisomerization of a cyclocurcumin analogue on the properties of cellular lipid membranes

The use of photosensitive molecules capable of isomerizing under light stimuli, and thus induce perturbation in biological systems, is becoming increasingly popular for potential light-activated chemotherapeutic purposes. We recently show that a cyclocurcumin derivative (CCBu), may be suitable for light-activated chemotherapy and may constitute a valuable alternative to traditional photodynamic therapy, due to its oxygen-independent mechanism of action, which allows the treatment of hypoxic solid tumors. In particular, we have shown that the E/Z photoisomerization of CCBu correlates with strong perturbations of model lipid bilayers. In this work, we perform all-atom classical molecular dynamics for a more complex bilayer, whose composition is, thus, much closer to eukaryotic outer cell membranes. We have evidenced important differences in the interaction pathway between CCBu and the complex lipid bilayer as compared to previous models, concerning both the membrane penetration capacity and the isomerization-induced perturbations. While we confirm that structural perturbations of the lipid membrane are induced by isomerization, we also show how the use of a simplified membrane model can result in an oversimplification of the system and hinder key physical and biological phenomena. Although, CCBu may be considered as a suitable candidate for light-activated chemotherapy, we also underline how the inclusion of bulkier substituents, inducing larger perturbations upon photoisomerization, may enhance its efficiency

A Photochemical Overview of Molecular Solar Thermal Energy Storage

The design of molecular solar fuels is challenging because of the long list of requirements these molecules have to fulfil: storage density, solar harvesting capacity, robustness, and heat release ability. All of these features cause a paradoxical design due to the conflicting effects found when trying to improve any of these properties. In this contribution, we will review different types of compounds previously suggested for this application. Each of them present several advantages and disadvantages, and the scientific community is still struggling to find the ideal candidate suitable for practical applications. The most promising results have been found using norbornadiene-based systems, although the use of other alternatives like azobenzene or dihydroazulene cannot be discarded. In this review, we primarily focus on highlighting the optical and photochemical aspects of these three families, discussing the recently proposed systems and recent advances in the field