Photo-initiated ring-opening polymerization of N- carboxyanhydrides and its potential application in photolithography
Stukenkemper , Timo (2017) Photo-initiated ring-opening polymerization of N- carboxyanhydrides and its potential application in photolithography. PhD thesis, Dublin City University.
Full text available as:
This thesis describes a novel synthesis of polypeptides via N5carboxyanhydride (NCA) ring5 opening polymerization (ROP). For the first time, NCA ROP photo5initiation by using a photoamine generator was demonstrated. The active initiator cyclohexylamine was produced in# situ by the UV5induced breakdown of the photoamine generator. Two NCA monomers, benzyl5L5glutamate (BLG) and TFA5L5lysine (TLL) were chosen to demonstrate the process. Optimizing the photo system by exchanging of the chromophoric group of the photoamine generator and the associated exchange of the light source towards a blacklight lamp showed similar polypeptide products as in conventional polymerization. Moreover, synthesis of a silane5based photoamine generator, bearing the same chromophoric protection group allowed photo5initiated grafting of polypeptide from solid surfaces such as silica nanoparticles and silicon wafers. Polypeptide grafted silica nanoparticles showed a significant increase of their hydrodynamic diameter, detected by Dynamic Light Scattering (DLS), and a significant weight loss, detected by Thermogravimetric Analysis (TGA). Silicon wafer surfaces grafted by polypeptides showed a significantly higher hydrophobicity. Ellipsometry results, together with elemental analysis with X5ray Photoelectron Spectroscopy (XPS) and Time5of5Flight Secondary Ion Mass Spectroscopy (Tof5SIMS) confirmed non5homogeneous polypeptide layers with a thickness of 3 nm. In addition, a novel drug delivery system was investigated by first synthesizing an amphiphilic block copolypeptide poly(benzyl5L5glutamate5b5L5arginine) (PBLG5b5PLR). This approach uses the PLR block as hydrophilic part, but also as Cell5Penetrating5Peptide for a potential selective drug delivery to diseased tissue. Two synthesis routes were investigated: (1) block copolymerization of BLG and the non5natural amino acid L5ornithine, which is modified after polymerization to the desired PLR block. The second synthesis route includes the ligation of the ROP5derived PBLG block with the Solid Phase Peptide Synthesis (SPPS)5derived PLR block. Both polymer materials were used for self5assembly studies.
Archive Staff Only: edit this record