Rational design of iron oxide binding peptide tags
We present an effective implicit surface model (EISM), which includes interaction models for electrostatic and van der Waals interactions, and entropic effects, to predict interactions between iron oxide nanoparticles (IONs) and peptides. Data from binding experiments of ION agglomerates to different peptides, immobilized on cellulose membranes, have been used to parameterize the model, including the surface accessible area force field contribution term. Prediction of peptide binding on IONs, made by EISM, were verified with peptide array experiments in an iterative optimization process. Negatively charged peptides were identified as best binders for IONs in Tris buffer. Furthermore, the incorporation of glycine leads to higher binding scores compared to the incorporation of cysteine in negatively charged peptides.
Anti-inflammatory effect of active nanofibrous polymeric membrane bearing nanocontainers of atorvastatin complexes
Polymeric membranes for local administration of non soluble anti-inflammatory statin can be used as potential wound patch in rheumatic joint or periodontal lesions. Electrospun polycaprolactone membranes were fitted with polysaccharide-atorvastatin nanoreservoirs by using complexes with poly-aminocyclodextrin. Polyamino-β-CD was chosen to achieve a double objective: to solubilize the poorly soluble hydrophobic atorvastatin through formation of inclusion complexes in the CD cavities and/or nanoplexes and to be suitable for the build-up of the nanoreservoirs, as it is a positively charged polyelectrolyte.
The complexes were characterized by methods such UV-Visible and X-ray photoelectron spectroscopy, molecular dynamics, scanning and transmission electron microscopy. The behavior of this complex system in solution demonstrated their formation through fluorescence and UV-vis spectroscopy, corroborated by MD simulations and MM-PBSA free energy calculations where all complexes are thermodynamically stable.
Ligand-lipid and ligand-core affinity control the interaction of gold nanoparticles with artificial lipid bilayers and cell membranes
Interactions between nanoparticles (NPs) and biomembranes depend on the physicochemical properties of the NPs, such as size and surface charge. Here we report on the size-dependent interaction of gold nanoparticles (AuNPs), stabilized with ligands differing in charge, i.e. sodium 3-(diphenylphosphino)benzene sulfonate (TPPMS) and sodium 3,3′,3″-triphenylphosphine sulfonate (TPPTS), respectively, with artificial membranes (black lipid membranes; BLMs) and HeLa cells. The TPPTS-stabilized AuNPs affect BLMs at lower size than TPPMS-stabilized ones. On HeLa cells we found decreasing cytotoxicity with increasing particle size, however, with an overall lower cytotoxicity for TPPTS-stabilized AuNPs. We attribute size-dependent BLM properties as well as reduced cytotoxicity of TPPTS-stabilized AuNPs to weaker shielding of the AuNP core when stabilized with TPPTS. We hypothesize that the partially unshielded hydrophobic gold core can embed into the hydrophobic membrane interior. Thereby we demonstrate that ligand-dependent cytotoxicity of NP can occur even when the NPs are not translocated through the membrane.