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Amphiphilic nanoparticles are highly biocompatible frameworks widely used for shuttling hydrophobic molecules across hydrophilic cellular environments. Their use can also span applications focused on achieving a selective binding against a target receptor. However, the molecular factors leading to an optimal binding often remain a critical step to assess. Here we have evaluated through advanced sampling free-energy simulations, combined with electronic circular dichroism spectra predictions, the binding of an amphiphilic polyethylene glycol (PEG)-based nanoparticle incorporating folate monomers with human folate receptor alpha. It turns out from the free-energy predictions that the optimal binding is achieved when the receptor target and the ligand-mimicking nanoparticle have a comparable size and the shortest spacer length of the folate monomer. Furthermore, we calculated the ECD spectrum of the folate monomer binding the target receptor, as well as that of the binding pocket of the receptor. Noteworthy, only when the optimal binding is achieved, the two ECD spectra closely match each other. Shape factors control the binding efficacy of nanoparticles with target receptors.

International audience; The π-rich rings of conjugated polymers and molecular rotors shape their typical properties, allowing a variety of chemical and photoresponsive phenomena. Herein, we present a computational method in the framework of classical simulations to estimate the free-energy gap between ground and excited states of oligofluorenes, which is a class of molecular rotors widely used in optoelectronic devices, because of the inner torsional rotation triggered by light irradiation. We devised multiple sets of free-energy simulations in combination with free-energy perturbation theory to predict the free-energy gap between the ground state and the first excited state. The computed excitation energies show good agreement with experiments. The approach presented herein allows one to achieve comprehensive sampling of the conformational landscape and accurate estimates of the excited state free-energy landscapes at the same time.

The temperature dependence of the UV absorption spectra of biphenyl in solution is herein reported. The UV spectral shapes vary with an increase in temperature, where a decrease in intensity (hypochromism) and blue shifts are observed. The predicted UV spectra in the Time Dependent-Density Functional Theory (TD-DFT) framework within the B97D3 functional indicate a lowering of the biphenyl conjugation band and a blue shift of the spectra upon increasing the biphenyl twist dihedral angle.