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A joint experimental and computational systematic exploration of the driving forces that govern (i) encapsulation of active ingredients (solvent, starting material dehydration, drug/material ratio, immersion time, and several consecutive impregnations) and (i) its kinetics of delivery (structure, polarity, ...) was performed using a series of porous biocompatible metal–organic frameworks (MOFs) that bear different topologies, connectivities, and chemical compositions. The liporeductor cosmetic caffeine was selected as the active molecule. Its encapsulation is a challenge for the cosmetic industry due to its high tendency to crystallize leading to poor loadings (<5 wt %) and uncontrolled releases with a subsequent low efficiency. It was evidenced that caffeine entrapping reaches exceptional payloads up to 50 wt %, while progressive release of this cosmetic agent upon immersion in the simulated physiological media (phosphate buffer solution pH = 7.4 or distilled water pH = 6.3, 37 °C) occurred mainly depending on the degree of MOF stability, caffeine mobility, and MOF–caffeine interactions. Thus, MIL-100 and UiO-66 appear as very promising carriers for topical administration of caffeine with both spectacular cosmetic payloads and progressive releases within 24 h.

Proteins persist longer in the fossil record than DNA, but the longevity, survival mechanisms and substrates remain contested. Here, we demonstrate the role of mineral binding in preserving the protein sequence in ostrich (Struthionidae) eggshell, including from the palaeontological sites of Laetoli (3.8 Ma) and Olduvai Gorge (1.3 Ma) in Tanzania. By tracking protein diagenesis back in time we find consistent patterns of preservation, demonstrating authenticity of the surviving sequences. Molecular dynamics simulations of struthiocalcin-1 and -2, the dominant proteins within the eggshell, reveal that distinct domains bind to the mineral surface. It is the domain with the strongest calculated binding energy to the calcite surface that is selectively preserved. Thermal age calculations demonstrate that the Laetoli and Olduvai peptides are 50 times older than any previously authenticated sequence (equivalent to ~16 Ma at a constant 10°C).DOI: http://dx.doi.org/10.7554/eLife.17092.001

Nanoscale mesoporous iron carboxylates metal-organic frameworks (nanoMOFs) have recently emerged as promising platforms for drug delivery, showing biodegradability, biocompatibility and important loading capability of challenging highly water-soluble drugs such as azidothymidine tryphosphate (AZT-TP). In this study, nanoMOFs made of iron trimesate (MIL-100) were able to act as efficient molecular sponges, quickly adsorbing up to 24 wt% AZT-TP with entrapment efficiencies close to 100%, without perturbation of the supramolecular crystalline organization. These data are in agreement with molecular modelling predictions, indicating maximal loadings of 33 wt% and preferential location of the drug in the large cages. Spectrophotometry, isothermal titration calorimetry, and solid state NMR investigations enable to gain insight on the mechanism of interaction of AZT and AZT-TP with the nanoMOFs, pointing out the crucial role of phosphates strongly coordinating with the unsaturated iron(III) sites. Finally, contrarily to the free AZT-TP, the loaded nanoparticles efficiently penetrate and release their cargo of active triphosphorylated AZT inside major HIV target cells, efficiently protecting against HIV infection.

We have identified and characterized three embryonic lethal mutations that alter or abolish expression of Drosophila Neuroglian and have used these mutations to analyze Neuroglian function during development. Neuroglian is a member of the immunoglobulin superfamily. It is expressed by a variety of cell types during embryonic development, including expression on motoneurons and the muscle cells that they innervate. Examination of the nervous systems of neuroglian mutant embryos reveals that motoneurons have altered pathfinding trajectories. Additionally, the sensory cell bodies of the peripheral nervous system display altered morphology and patterning. Using a temperature-sensitive mutation, the phenocritical period for Neuroglian function was determined to occur during late embryogenesis, an interval which coincides with the period during which neuromuscular connections and the peripheral nervous system pattern are established.

We have used nonlinear vibrational spectroscopy to determine the structure of l-phenylalanine adsorbed at the solution−polystyrene interface. Quantitative analysis of nonlinear susceptibility tensor elements was enabled by collecting spectra under various calibrated polarization schemes. We have proposed a technique for fitting the spectra that is well-suited to the challenging line shape resulting from coherent interferences between vibrational modes. Molecular-level vibrational hyperpolarizabilities have then been determined by electronic structure calculations with use of an effective solvent model. These hyperpolarizability values are used to predict spectral amplitudes for comparison with experimental results in order to determine the orientation distribution of the phenylalanine CH2 plane. We have found that the orientation of phenylalanine is relatively constrained at the polymer surface. Our data and analysis suggest amino acid aromatic rings may be inserted into polystyrene surface aromatic rings to achieve this quasi-immobilization.

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