The present invention relates to novel cationic lipids, 
transfection agents, microparticles, nanoparticles, and short interfering 
nucleic acid (siNA) molecules. The invention also features compositions, and methods of use for the study, diagnosis, and treatment of traits, diseases and conditions that respond to the modulation of 
gene expression and / or activity in a subject or 
organism. Specifically, the invention relates to novel cationic lipids, microparticles, nanoparticles and 
transfection agents that effectively transfect or deliver biologically active molecules, such as antibodies (e.g., 
monoclonal, chimeric, humanized etc.), 
cholesterol, hormones, antivirals, peptides, proteins, chemotherapeutics, small molecules, vitamins, co-factors, nucleosides, nucleotides, oligonucleotides, enzymatic nucleic acids, antisense nucleic acids, triplex forming oligonucleotides, 2,5-A chimeras, dsRNA, allozymes, aptamers, decoys and analogs thereof, and small 
nucleic acid molecules, such as short interfering 
nucleic acid (siNA), short interfering 
RNA (siRNA), double-stranded 
RNA (dsRNA), micro-
RNA (miRNA), and short hairpin RNA (shRNA) molecules, to relevant cells and / or tissues, such as in a subject or 
organism. Such novel cationic lipids, microparticles, nanoparticles and 
transfection agents are useful, for example, in providing compositions to prevent, inhibit, or treat diseases, conditions, or traits in a 
cell, subject or 
organism. The compositions described herein are generally referred to as formulated molecular compositions (FMC) or lipid nanoparticles (LNP).