This work was initiated by Markus Blocher, who graduated in 2000. The general idea was to see whether and to what extent the hydrophobic matrix of the POPC liposomes were capable of directing the synthesis of ?-amino acids towards selective polypeptide chains. 
 

In fact, it has been shown that when POPC liposomes are present in a solution containing a library of dipeptides,  they are able of selectively binding the most hydrophobic peptide, such as  Trp2. Also it is possible to oligomerize Trp-Trp to rather long chains (up to a polymerisation degree of 24) with the help of a matrix bound hydrophobic condensing agent (Blocher et al,1999).  In water, instead, there is no selectivity and a large variety of structures will be obtained. This finding may be relevant for the research on the origin of life, as it may suggest a mechanism of selection of peptides, as well as a mechanism of their polymerisation to form longer chains. The liposome-aided peptide synthesis has been extended to ionic liposomes and ionic amino acids by Dr. Daojun Liu during his postdoctoral studies in the laboratory, obtaining a variety of peptide sequences containing both hydrophobic and hydrophilic residues-including histidine and other catalytically interesting ?-amino acids (Blocher et al,2000). 
In this regard, of particular interest appears the possibility of synthesizing in situ a peptide catalyst. The eventual internalisation of such a catalyst would provide in fact a first rudimental model for a prebiotic cell. The graduate student Kenichi Morigaki in his dissertation as well as Markus Blocher (Blocher et al,2000) have done work in this direction. 

A particularly important branching of this work was realised when Markus Blocher utilised a racemic mixture of D,L-Trp for the polycondensation with NCA-amino acids, both in the presence and absence of liposomes. It was discovered, by using high resolution mass spectroscopy combined with high performance liquid chromatography (HPLC-MS), that in this case the homochiral oligomers were over represented, for example the L-Trp10 (or D-Trp10) were at least an order of magnitude more represented that one would have expected on the basis of  a Bernoullian statistics (Hitz et al,2001). 
 

These studies were continued by Thomas Hitz, who carried out studies also in the absence of liposomes, as well as in the presence of quartz,  and could show that the tendency to homochirality is actually a spontaneous, natural process in the poly condensation of amino acids (Hitz et al,2001: also, paper submitted ). The studies of Thomas Hitz with quartz also showed that in the case of Ile the longer homochiral sequences are bound to the quartz surface much more tightly than the short heterochiral stereoisomers: this permits a simple physical separation by water washing, which may simulate rain in a prebiotic scenario. In this way, the problem of the origin of homochirality in Nature is potentially shifted from a problem of separation of enantiomeric amino acids to a problem of separation of enantiomeric homochiral macromolecules - which appears to be of easier resolution in force of the larger binding force of longer chains to mineral surfaces or clays. Such studies are in progress also in collaboration with Prof. Juan Perez-Mercader in Madrid.