Herstellung, Charakterisierung und Anwendung von kurzkettigen Chitosanen
The target of this study was the production, characterization and application of low-molecular-weight chitosans with a different degree of polymerisation. Low-molecular-weight chitosans with low polydispersity and monomodal molecular weight distribution were produced with an optimized acid hydrolysis. The influence of temperature, duration of hydrolysis and various acid concentrations were examined utilizing a central composite design. For the determination of the molecular weight high resolution spectra were shown with the aid of MALDI-TOF MS. In the linear modus, chitosans with a molecular weight higher than 11 kDa were presented in an overall view. The results were compared with these obtained from the investigations by GFC/MALLS. The degree of deacetylation for high- and low-molecular-weight chitosans were examined with a particle charge detector. The results of this very simple method were in agreement with these obtained from H-NMR and C-NMR. With the aid of sodium sulphate and sodium tripolyphosphate, micro- and nanoparticles were produced with various low-molecular weight chitosans. After loading the particles with plasmid-DNA, their absorption and transfection was examined in vitro. The success of the transfection increased with decreasing molecular weight of the used chitosan for both micro- and nanoparticles.