Weakly anionic lipids

Derivatized Species By exploring the specific reactivity of the primary amine group, derivative methods including with Fmoc chloride and 4-(dimethylamino)benzoic acid have been developed to enhance the analysis of PE species [44—46]. The enhancement of ionization efficiency in the negative-ion mode is achieved after derivatization through turning weakly anionic lipids (or weakly zwitterionic lipids) into anionic lipids (Chapters 2 and 3). 

A low-concentration of lithium chloride (e.g., 50 mM in aqueous phase) is preferable for lipid extraction for MDMS-SL since the lithium adduct of lipid species can yield unique and informative fragmentation patterns after CID (Part II). Moreover, the weakly acidic conditions resulted from a weak Lewis base of lithium ion and a strong Lewis acid of chloride could improve the extraction efficiency of anionic lipids to a certain degree and could lead to increased intrasource separation of molecular specie of anionic lipid classes from PE species in negative-ion ESI-MS (Chapter 3). Under such weakly acidic conditions, degradation of plasmalogen species does not occur. 

In conclusion, we have designed a synthetic vesicular DNA carrier that physically and functionally mimics an enveloped virus particle. To achieve an acceptable degree of encapsulation within the vesicle, we use a process that is essentially inverse to the preparation of cationic lipid-DNA complexes. A suitable DNA condensing agent is introduced that, at a certain critical concentration, conveys a weak net cationic charge to the condensed DNA that then interacts spontaneously with a liposome containing one or more anionic components. These DNA formulations behave distinctly different from classic cationic liposome DNA complexes in vitro in as much as they have been shown to be nontoxic, to display a traditional linear dose response, and to be serum-insensitive. 

---