Synthesis, Modification and Characterization of Biocompatible Polymers and Nanoparticles

Abstract

Engineered nanoparticle systems based on biocompatible/biodegradable polymers is one of the most promising candidates in the pharmaceutical industry. Therefore, the synthesis of biocompatible and hydrolytically degradable amino-functional polylactide-based copolymers and their nanocarrier formation for drug delivery were studied. AB type poly(L-lactide)-b-poly(L-serine lactone) (PLLA-b-PLSL) copolymers were successfully synthesized via sequential ring-opening polymerization (ROP). Self-assembly of block copolymers in aqueous solutions resulted in formation of micelles which are biocompatible as cell experiments revealed. Further research focused on the formation of enzyme-degradable nanoparticles for cancer therapy. Polymerization of L-lactide by MMP-2 cleavable bifunctional peptide sequences was achieved to yield triblock copolymer nanoparticles via a nonaqueous emulsion. Incubation of the cargo-loaded particles into MMP-2 medium resulted by remarkable cargo release based on the regular peptide sequence. Bioimaging is another emerging topic in pharmaceutical field, thus, fluorescence-modified tools are required for tracking and investigating dynamic behavior of materials. Polypeptides with a fluorescence label was described based on ROP of amino acid NCAs. For tagging the polypeptide by precise number of fluorescent dyes, perylene imides modified with alkylamino group was selected. Further investigations were based on the generation of micelle forming fluorescent amphiphilic block copolymers: PDI-poly(L-lysine)-b-poly(L-leucine) and PDI-poly(L-lysine)-b-poly(L-phenylalanine) were prepared as non-toxic carriers with improved aggregation properties. Finally, the potential of the fluorescent micelles for bioimaging applications was successfully evaluated by CLSM. Finally, the focus is on understanding the hazardous effects of the artificial plastics, which is a critical issue as environmental pollution poses a great threat for all living beings, particularly for the water ecosystem. For such purposes, polycarbonate and polystyrene nanoparticles were prepared and investigated on Fathead Minnow immune system, as they are the most disposed of plastic wastes to nature. Both PS and PC nanoparticles led to higher response, demonstrating the stress on the immune system of the fish species. In conclusion, the established multifunctional polymeric nanoparticles are highly versatile and thus present new opportunities in use for targeted and selective recognition systems which is highly crucial for various applications in the future for the pharmaceutical industry.