A decisive step toward the origin of life.

Several hypotheses exist regarding how life emerged from the abiotic world, the most popular of which is the 'RNA World' hypothesis. Recent advances describe nonenzymatic polymerization of mononucleotides in a phospholipid liquid crystalline matrix, suggesting that a 'Lipid World' might have preceded the RNA World.

Guanidinylated dendritic molecular transporters: prospective drug delivery systems and application in cell transfection.

In the present review the crucial role of the guanidinium functional group in facilitating the transport of dendritic polymers through liposomal and cell membranes is discussed, along with other structural features of guanidinylated dendritic polymers that fine-tune their transport properties, and even determine their subcellular destinations. In this context, an ideal dendritic molecular transporter would need to possess a dendritic scaffold of the appropriate size and degree of guanidinylation, flexibility of the guanidinium moiety, and should exhibit a proper balance between hydrophilic and hydrophobic moieties located on the dendritic surface. All of the above are illustrated through selected paradigms from the relevant literature, which give a valuable insight into forging successful dendritic delivery systems for both drugs and genes. The main challenge for the future focus of the field is identified as the determination of the key structural and functional characteristics that will enhance cell internalisation, and secure localisation in specific subcellular organelles.