Theory analysis of mass spectra of long-chain isocyanates.

Electron impact mass spectra of four long-chain isocyanates, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate and octadecyl isocyanate, were obtained with a GCT high-resolution time-of-flight mass spectrometer. The four isocyanates studied gave a common base peak of m/z 99, which suggested the formation of a stable six-membered ring structure to decentralize the positive charge. Quantum-mechanical energy calculation justified that the six-membered ring base peak had the lowest energy.

Structure-function relationship research of glycerol backbone-based cationic lipids for gene delivery.

Transfection activities of two series of synthetic glycerol backbone-based cationic lipids were studied as gene delivery carriers. The variable length of hydrocarbon chains, diverse quaternary ammonium heads, different linkage, as well as alternative anion combined with them allowed to find how these factors affect cationic lipids on their gene delivery performance. The structure-function relationship of the synthetic glycerol backbone-based cationic lipids was discussed, and the transfection efficiency of some of the cationic liposomes was superior or parallel to that of two commercial transfection agents.

Carbamate-linked cationic lipids for gene delivery.

Series of cationic lipids 1a-p, with variable length of hydrocarbon chains, alternative quaternary ammonium heads, carbamate linkages between hydrocarbon chains and quaternary ammonium heads, as well as different anion combined with them, were synthesized for liposome-mediated gene delivery. Two plasmid DNAs, pGL3-control and pGFP-N2, were transferred by cationic liposomes formed from the above cationic lipids into five mammalian cell lines, and the transfection efficiency of some of the cationic liposomes was superior or parallel to that of two commercial transfection agents, Lipofectamine2000 and Sofast.

Synthetic diether-linked cationic lipids for gene delivery.

Quaternary ammonium lipids 2a-p, with diether linkages between hydrocarbon chains and their ammonium headgroups, were synthesized as potential vectors for cationic liposome-mediated gene delivery. Varying the length of carbon chains and quaternary ammonium heads as well as different anionic complexes will enable the study of the structure-function relationships of these cationic lipids in terms of gene delivery properties.

Synthesis and characterization of a series of carbamate-linked cationic lipids for gene delivery.

A series of pH-sensitive lipids, la-h [(2,3-bis-alkylcarbamoyloxy-propyl)-trialkylammonium halide] and 2a-d (1-di-methylamino-2,3-bis-alkylcarbamoyloxy-propane), with carbamate linkages between the hydrocarbon chains and an ammonium or tertiary amine head, were synthesized for liposome-mediated gene delivery. The variable length of the carbon chains and the quaternary ammonium or neutral tertiary amine heads allowed us to identify the structure-function relationship showing how these factors would affect cationic lipids in gene delivery performance.

Synthesis of carbamate-linked lipids for gene delivery.

Series of lipids 1a-d and 2a,b, with carbamate linkages between hydrocarbon chains and ammonium or tertiary amine head, which were pH sensitive, were synthesized for liposome-mediated gene delivery. The variable length of carbon chains and quaternary ammonium or neutral tertiary amine heads allowed to find the structure-function relationship of how these factors affect cationic lipids on gene delivery performance.