Vesicle formation from a synthetic adenosine based lipid

We report the synthesis of a novel purine based amphiphile; di-oleyladenosinephosphocholine (DOAPC). Light microscopy, TEM and QELS studies on DOAPC in aqueous media support the formation of lamellar systems. These investigations indicate that the presence of adenine does not prohibit the formation of lamellar organizations. Stable small unilamellar vesicles can be prepared by using extrusion techniques.     

Nucleotides and nucleolipids derivatives interaction effects during multi-lamellar vesicles formation

In this paper a micellar interface, constituted by the cationic surfactant CTAB, in presence of 1,2-epoxydodecane and nucleotides was used for catanionic multi-lamellar vesicles (MLVs) formation. The micellar solution of CTAB is able to disperse the 1,2 epoxydodecane in the micellar core promoting the reaction of this reagent with the nucleotide attracted by the positive surface charge of the micellar aggregates. The alkylation of AMP and UMP nucleotides leads to the synthesis of nucleolipids. The behaviour of the supramolecular structures formed depends on the starting reagents (AMP, UMP and AMP+UMP) and on the assembly capabilities of the products. In particular nucleotides and nucleotides derivatives interaction effects are evaluated during the multi-lamellar vesicles formation. NMR spectroscopy and UV-vis measurements performed on MLVs showed strong aryl interactions. Interestingly, NMR spectra revealed prevailing stacking interactions between complementary nucleolipids. The assembly of complementary nucleotides affects the course of the reaction during the MLVs formation. Moreover the MLVs supramolecular stability has been tested by means of turbidity and UV-vis measurements. In particular, an enhanced stability has been found in systems prepared with complementary nucleotides confirming that in these systems the self-assembly process is influenced by nucleolipids interactions. Furthermore by following the hypocromic effect during the micellar catalysis, we showed that even in the earlier stages of the reaction significant differences are detectable.     

Rational design,properties, and applications of biosurfactants: a short review of recent advances

Biosurfactants combine physicochemical properties with biological activities. Although biosurfactants are often expressed by microorganisms, an increasing amount is produced by chemical synthesis. As many exist in the form of homologous compounds, it is often difficult to purify biosurfactants. But this has not limited the efforts to develop their commercial applications. In this short review, we have featured the recent advances in three important types of biosurfactants, lipopeptides, nucleolipids, and glycolipids. We have focused on comparing some of the key properties and functionalities between modern synthetic versions and their corresponding natural counterparts. We end the review by outlining the needs for not only strengthening their basic structure–property relationships through further research but also developing better technologies, irrespective of direct chemical synthesis or biological synthesis of biosurfactants through constructions of genetically engineered strains, to help advance the commercial use of biosurfactants.     

O‐2′,3′‐Ketal‐Nucleolipids of the Cytostatic 5‐Fluorouridine: Synthesis,Lipophilicity, and Acidic Stability

The synthesis of a series of cyclic and acyclic O‐2′,3′‐ketal derivatives of the cancerostatic 5‐fluorouridine ( 2a ) is described. The novel compounds were characterized by ¹H‐ and ¹³C‐NMR, and UV spectroscopy, as well as by elemental analyses. The lipophilicity values (log P, retention times in RP‐18 HPLC) of the cyclic ketals were determined and related to the ring tensions as well as the acid stability of the spiro‐linked ketal rings.