Papers by estefania ortega
Journal of Colloid and Interface Science, 2021
Ligand-targeted microbubbles are focusing interest for molecular imaging and delivery of chemothe... more Ligand-targeted microbubbles are focusing interest for molecular imaging and delivery of chemotherapeutics. Novel lipid-peptide conjugates (lipopeptides) that feature alternating serine-glycine (SG) n segments rather than the classical poly(oxyethylene) chains as linkers between the polar head of the lipid and a targeting ligand were recently proposed for liposome-mediated, selective delivery of anti-cancer drugs. Here, we report the synthesis of perfluoroalkylated lipopeptides (F-lipopeptides) bearing two hydrophobic chains (C n F2 n +1, n = 6, 7, 8, 1-3) grafted through a lysine moiety on a hydrophilic chain composed of a lysine-serine-serine (KSS) sequence followed by 5 SG sequences. These F-lipopeptides are precursors of targeting lipopeptide conjugates. A hydrocarbon counterpart with a C10H21 chain (4) was synthesized for comparison. The capacity for the F-lipopeptides to spontaneously adsorb at the air/water interface and to form monolayers in combination with dipalmitoylphosp...
ACS Applied Nano Materials, 2020
Introducing fluorocarbon vapor in the air above an aqueous dispersion of clusters of nanodiamonds... more Introducing fluorocarbon vapor in the air above an aqueous dispersion of clusters of nanodiamonds induces their disaggregation, a prerequisite for most of their biomedical uses. Furthermore, the fluorocarbon gas promotes the adsorption of nanodiamonds at the gas/water interface. As an example of the benefits that can be gained from our findings relative to the implementation of nanomaterials for practical uses, we investigated the role that a fluorocarbon gas may play in the generation of microbubbles, which are currently actively investigated in ultrasound-mediated diagnosis and therapy. Remarkably, the fluorocarbon gas enables the production of microbubbles shelled only with nanodiamonds, in the absence of any other surfactant, which could not be achieved without the fluorocarbon being present. This demonstrates that a supernatant gas can decisively affect the adsorption of nanoparticles from an aqueous phase to an air/water interface, likely through physical adsorption at the nanodiamond surface. The investigations involved solid-state NMR and FTIR, microbubble generation experiments with acoustic attenuation monitoring, and bubble profile analysis tensiometry on spontaneously adsorbed Gibbs films. Perspectives include control of aggregation of nanodiamonds and their retrieval from aqueous dispersions, and applications in multimodal diagnostic imaging, bioimaging and therapeutic cell tracking. It is proposed that the disaggregating potency of fluorocarbons can be applied to other nanomaterials, providing a simple and effective means of alleviating aggregation.
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Papers by estefania ortega